Study on mechanism of macro failure and micro fracture of local nearly horizontal stratum in super-large section and deep buried tunnel

Li, Shu-cai,Wang, Jian-hua,Chen, Wei-zhong,Li, Li-ping,Zhang, Qian-qing,He, Peng Techno-Press 2016 Geomechanics & engineering Vol.11 No.2

The stability of surrounding rock will be poor when the tunnel is excavated through nearly horizontal stratum. In this paper, the instability mechanism of local nearly horizontal stratum in super-large section and deep buried tunnel is revealed by the analysis of the macro failure and micro fracture. A structural model is proposed to explain the mechanics of surrounding rock collapse under the action of stress redistribution and shed light on the macroscopic analytical approach of the stability of surrounding rock. Then, some highly effective formulas applied in the tunnel engineering are developed according to the theory of mixed-mode micro fracture. And well-documented field case is made to demonstrate the effectiveness and accuracy of the proposed analytical methods of mixed-mode fracture. Meanwhile, in order to make the more accurate judgment about yield failure of rock mass, a series of comprehensive failure criteria are formed. In addition, the relationship between the nonlinear failure criterion and $K_I$ and $K_{II}$ of micro fracture is established to make the surrounding rock failure criterion more comprehensive and accurate. Further, the influence of the parameters related to the tension-shear mixed-mode fracture and compression-shear mixed-mode fracture on the propagation of rock crack is analyzed. Results show that ${\sigma}_3$ changes linearly with the change of ${\sigma}_1$. And the change rate is related to ${\beta}$, angle between the cracks and ${\sigma}_1$. The proposed simple analytical approach is economical and efficient, and suitable for the analysis of local nearly horizontal stratum in super-large section and deep buried tunnel.

A Wide Dynamic Range NUC Algorithm for IRCS Systems

Li-Hua Cai,Feng-Yun He,Song-Tao Chang,Zhou Li 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.73 No.12

Uniformity is a key feature of state-of-the-art infrared focal planed array (IRFPA) and infrared imaging system. Unlike traditional infrared telescope facility, a ground-based infrared radiant char- acteristics measurement system with an IRFPA not only provides a series of high signal-to-noise ratio (SNR) infrared image but also ensures the validity of radiant measurement data. Normally, a long integration time tends to produce a high SNR infrared image for infrared radiant charac- teristics radiometry system. In view of the variability of and uncertainty in the measured target's energy, the operation of switching the integration time and attenuators usually guarantees the gual- ity of the infrared radiation measurement data obtainted during the infrared radiant characteristics radiometry process. Non-uniformity correction (NUC) coecients in a given integration time are often applied to a specified integration time. If the integration time is switched, the SNR for the infrared imaging will degenerate rapidly. Considering the effect of the SNR for the infrared image and the infrared radiant characteristics radiometry above, we propose a-wide-dynamic-range NUC algorithm. In addition, this essasy derives and establishes the mathematical modal of the algorithm in detail. Then, we conduct verification experiments by using a ground-based MWIR(Mid-wave Infared) radiant characteristics radiometry system with an 400 mm aperture. The experimental results obtained using the proposed algorithm and the traditional algorithm for different integration time are compared. The statistical data shows that the average non-uniformity for the proposed algorithm decreased from 0.77% to 0.21% at 2.5 ms and from 1.33% to 0.26% at 5.5 ms. The testing results demonstrate that the usage of suggested algorithm can improve infrared imaging quality and radiation measurement accuracy.

A Study on Cutting and Tribology Performances of TiN and TiAlN Coated Tools

Hua-Ying Li,Hui-Bo He,Wen-Qiang Han,Jun Yang,Tao Gu,Yuan-ming Li,류성기 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.

TiN and TiAlN coatings were deposited on the surface of AISI 5140 steel and cemented carbide YT15 by magnetron sputteringtechnique (MSP). The reciprocating sliding tests of TiN and TiAIN coatings on the surface of AISI 5140 steel were performed toinvestigate the friction coefficients of coatings affected by various normal loads with friction pair of 304 stainless steel balls. Drymachining tests on AISI 5140 hardened steel were carried out with the TiN and TiAlN coated tools on a CA6140A lathe. The effectsof cutting speed on cutting forces and surface roughness of TiN and TiAlN coated tools were obtained and analyzed to assess thecutting performance of coated tools. The microcosmic micrographs of wear areas of coated tools were observed and investigated byscanning electron microscope and energy dispersive spectrum. The results show that the friction coefficients of TiN coatings are lowerthan that of TiAlN coatings. The cutting force of TiAlN coated tool decreases and flank wear resistance enhances in comparison withTiN coated tool. The wear form and mechanisms of TiN coated tool are mainly crater wear on the rake face and adhesive wear andabrasive wear on the flank face. The wear form and mechanisms of TiAlN coated tool are mainly adhesive wear, the breakage ofcutting edge and the damage of tip, accompanied with diffusion and oxidation wear.

A Study on Cutting and Tribology Performances of TiN and TiAlN Coated Tools

Li, Hua-Ying,He, Hui-Bo,Han, Wen-Qiang,Yang, Jun,Gu, Tao,Li, Yuan-ming,Lyu, Sung-Ki Korean Society for Precision Engineering 2015 International Journal of Precision Engineering and Vol.16 No.4

TiN and TiAlN coatings were deposited on the surface of AISI 5140 steel and cemented carbide YT15 by magnetron sputtering technique (MSP). The reciprocating sliding tests of TiN and TiAIN coatings on the surface of AISI 5140 steel were performed to investigate the friction coefficients of coatings affected by various normal loads with friction pair of 304 stainless steel balls. Dry machining tests on AISI 5140 hardened steel were carried out with the TiN and TiAlN coated tools on a CA6140A lathe. The effects of cutting speed on cutting forces and surface roughness of TiN and TiAlN coated tools were obtained and analyzed to assess the cutting performance of coated tools. The microcosmic micrographs of wear areas of coated tools were observed and investigated by scanning electron microscope and energy dispersive spectrum. The results show that the friction coefficients of TiN coatings are lower than that of TiAlN coatings. The cutting force of TiAlN coated tool decreases and flank wear resistance enhances in comparison with TiN coated tool. The wear form and mechanisms of TiN coated tool are mainly crater wear on the rake face and adhesive wear and abrasive wear on the flank face. The wear form and mechanisms of TiAlN coated tool are mainly adhesive wear, the breakage of cutting edge and the damage of tip, accompanied with diffusion and oxidation wear.

AT1 Receptor Modulator Attenuates the Hypercholesterolemia-Induced Impairment of the Myocardial Ischemic Post-Conditioning Benefits

Yun-Wei Li,Yan-Ming Li,Yan Hon,Qi-Lin Wan,Rui-Li He,Zhi-Zhong Wang,Cui-Hua Zhao 대한심장학회 2017 Korean Circulation Journal Vol.47 No.2

Background and Objectives: Ischemic post-conditioning (PostC) has been demonstrated as a novel strategy to harness nature’s protection against myocardial ischemia-reperfusion (I/R). Hypercholesterolemia (HC) has been reported to block the effect of PostC on the heart. Angiotensin II type-1 (AT1) modulators have shown benefits in myocardial ischemia. The present study investigates the effect of a novel inhibitor of AT1, azilsartan in PostC of the heart of normocholesterolemic (NC) and HC rats. Materials and Methods: HC was induced by the administration of high-fat diet to the animals for eight weeks. Isolated Langendorff’s perfused NC and HC rat hearts were exposed to global ischemia for 30 min and reperfusion for 120 min. I/R-injury had been assessed by cardiac hemodynamic parameters, myocardial infarct size, release of tumor necrosis factor-alpha troponin I, lactate dehydrogenase, creatine kinase, nitrite in coronary effluent, thiobarbituric acid reactive species, a reduced form of glutathione, superoxide anion, and left ventricle collagen content in normal and HC rat hearts. Results: Azilsartan post-treatment and six episodes of PostC (10 sec each) afforded cardioprotection against I/R-injury in normal rat hearts. PostC protection against I/R-injury was abolished in HC rat hearts. Azilsartan prevented the HC-mediated impairment of the beneficial effects of PostC in I/R-induced myocardial injury, which was inhibited by L-N5-(1-Iminoethyl)ornithinehydrochloride, a potent inhibitor of endothelial nitric oxide synthase (eNOS). Conclusion: Azilsartan treatment has attenuated the HC-induced impairment of beneficial effects of PostC in I/R-injury of rat hearts, by specifically modulating eNOS. Azilsartan may be explored further in I/R-myocardial injury, both in NC and HC conditions, with or without PostC.

Roles of Immunohistochemical Staining in Diagnosing Pulmonary Squamous Cell Carcinoma

Yan, Yue,Zhang, Ya-Xiong,Fang, Wen-Feng,Kang, Shi-Yang,Zhan, Jian-Hua,Chen, Nan,Hong, Shao-Dong,Liang, Wen-Hua,Tang, Yan-Na,He, Da-Cheng,Wu, Xuan,Zhang, Li Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.2

Background: Differentiating morphologic features based on hematoxylin-eosin (HE) staining is the most common method to classify pathological subtypes of non-small-cell lung cancer (NSCLC). However, its accuracy and inter-observer reproducibility in pathological diagnosis of poorly differentiated NSCLC remained to be improved. Materials and Methods: We attempted to explore the role of immunohistochemistry (IHC) staining in diagnosing pulmonary squamous cell carcinoma (SQCC) with poorly differentiated features by HE staining or with elevated serum adenocarcinoma-specific tumor markers (AD-TMs). We also compared the difference of epidermal growth factor receptor (EGFR) mutation rate between patients with confirmed SQCC and those with revised pathological subtype. Logistic regression analyses were used to test the association between different factors and diagnostic accuracy. Results: A total of 132 patients who met the eligible criteria and had adequate specimens for IHC confirmation were included. Pathological revised cases in poor differentiated subgroup, biopsy samples and high-level AD-TMs cases were more than those with high/moderate differentiation, surgical specimens and normal-level AD-TMs. Moreover, biopsy sample was a significant factor decreasing diagnostic accuracy of pathological subtype (OR, 4.037; 95% CI 1.446-11.267, p=0.008). Additionally, EGFR mutation rate was higher in patients with pathological diagnostic changes than those with confirmed SQCC (16.7% vs 4.4%, p=0.157). Conclusions: Diagnosis based on HE staining only might cause pathological misinterpretation in NSCLC patients with poor differentiation or high-level AD-TMs, especially those with biopsy samples. HE staining and IHC should be combined as pathological diagnostic standard. The occurrence of EGFR mutations in pulmonary SQCC might be overestimated.

Synergistic Effect of Bone Marrow-Derived Mesenchymal Stem Cells and Platelet-Rich Plasma in Streptozotocin-Induced Diabetic Rats

( Zhen Zhen Lian ),( Xiao Jing Yin ),( Hua Li ),( Li Li Jia ),( Xiu Zhen He ),( Yong Bo Yan ),( Nai Hua Liu ),( Ka Yiu Wan ),( Xiao Kun Li ),( Shao Qiang Lin ) 대한피부과학회 2014 Annals of Dermatology Vol.26 No.1

Background: Diabetic wounds are a major clinical challenge, because minor skin wounds can lead to chronic, unhealed ulcers and ultimately result in infection, gangrene, or even amputation. Studies on bone marrow derived mesenchymal stem cells (BMSCs) and a series of growth factors have revealed their many benefits for wound healing and regeneration. Platelet-rich plasma (PRP) may improve the environment for BMSC development and differentiation. However, whether combined use of BMSCs and PRP may be more effective for accelerating diabetic ulcer healing remains unclear. Objective: We investigated the efficacy of BMSCs and PRP for the repair of refractory wound healing in a diabetic rat model. Methods: Forty-eight rats with diabetes mellitus induced by streptozotocin were divided into four groups: treatment with BMSCs plus PRP, BMSCs alone, PRP alone, phosphate buffered saline. The rate of wound closure was quantified. A histopathological study was conducted regarding wound depth and the skin edge at 7, 14, and 28 days after surgery. Results: Wound healing rates were significantly higher in the BMSC plus PRP group than in the other groups. The immunohistochemistry results showed that the expression of platelet/endothelial cell adhesion molecule 1, proliferating cell nuclear antigen, and transforming growth factor-β1 increased significantly in the BMSC plus PRP group compared to the other treatment groups. On day 7, CD68 expression increased significantly in the wounds of the BMSC plus PRP group, but decreased markedly at day 14 compared to the controls. Conclusion: The combination of BMSCs and PRP aids diabetic wound repair and regeneration. (Ann Dermatol 26(1) 1∼10, 2014)

Disruption of endothelial barrier function is linked with hyposecretion and lymphocytic infiltration in salivary glands of Sjögren's syndrome

Cong, Xin,Zhang, Xue-Ming,Zhang, Yan,Wei, Tai,He, Qi-Hua,Zhang, Li-Wei,Hua, Hong,Lee, Sang-Woo,Park, Kyungpyo,Yu, Guang-Yan,Wu, Li-Ling Elsevier 2018 Biochimica et biophysica acta. Molecular basis of Vol.1864 No.10

<P><B>Abstract</B></P> <P>Sjögren's syndrome (SS) is an inflammatory autoimmune disease that causes hyposecretion in salivary glands. Endothelial tight junctions (TJs) play crucial roles in salivation and barrier function of blood vessels. However, whether the alteration of endothelial TJs were involved in pathogenesis of SS was still unknown. Here, the ultrastructure and function of endothelial TJs in submandibular glands (SMGs) were detected by transmission electron microscopy and in vivo paracellular permeability assay in different aged NOD mouse model for SS. CFSE-labeled lymphocytes were injected into tail vein to trace the infiltration, while claudin-5 expression and distribution were detected by immunofluorescence, qRT-PCR, and western blot. Results showed that the stimulated salivary flow rate was gradually decreased and lymphocytic infiltration was found as age increased in 12- and 21-week-old NOD mice, but not 7-week-old NOD mice. Blood vessels were dilated, while endothelial TJ width and paracellular tracer transport were increased in 12-week-old NOD mice. Moreover, the injected CFSE-labeled lymphocytes were observed in SMGs of 12-week-old NOD mice. Claudin-5 level was increased and relocalized from the apical portion of neighboring endothelial cells to lateral membranes and cytoplasm in 12-week-old NOD mice. Additionally, the alteration of claudin-5 expression and distribution was further confirmed in labial salivary glands and bilateral parotid glands from SS patients. In cultured human microvessel endothelial cell line (HMEC-1), IFN-γ stimulation significantly increased claudin-5 expression. Taken together, we identified that the endothelial TJ barrier was disrupted and contributed to the development of salivary hyposecretion and lymphocytic infiltration in SS.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Endothelial tight junction barrier is disrupted in hyposecretory submandibular glands from Sjögren's syndrome mouse model </LI> <LI> The disrupted salivary endothelial barrier is linked with lymphocytic infiltration in Sjögren's syndrome mouse model </LI> <LI> The redistribution of claudin-5 is responsible for disrupted endothelial barrier in salivary glands from Sjögren's syndrome </LI> </UL> </P>

Bandwidth Management of WiMAX Systems and Performance Modeling

Li, Yue,He, Jian-Hua,Xing, Weixi Korean Society for Internet Information 2008 KSII Transactions on Internet and Information Syst Vol.2 No.2

WiMAX has been introduced as a competitive alternative for metropolitan broadband wireless access technologies. It is connection oriented and it can provide very high data rates, large service coverage, and flexible quality of services (QoS). Due to the large number of connections and flexible QoS supported by WiMAX, the uplink access in WiMAX networks is very challenging since the medium access control (MAC) protocol must efficiently manage the bandwidth and related channel allocations. In this paper, we propose and investigate a cost-effective WiMAX bandwidth management scheme, named the WiMAX partial sharing scheme (WPSS), in order to provide good QoS while achieving better bandwidth utilization and network throughput. The proposed bandwidth management scheme is compared with a simple but inefficient scheme, named the WiMAX complete sharing scheme (WCPS). A maximum entropy (ME) based analytical model (MEAM) is proposed for the performance evaluation of the two bandwidth management schemes. The reason for using MEAM for the performance evaluation is that MEAM can efficiently model a large-scale system in which the number of stations or connections is generally very high, while the traditional simulation and analytical (e.g., Markov models) approaches cannot perform well due to the high computation complexity. We model the bandwidth management scheme as a queuing network model (QNM) that consists of interacting multiclass queues for different service classes. Closed form expressions for the state and blocking probability distributions are derived for those schemes. Simulation results verify the MEAM numerical results and show that WPSS can significantly improve the network’s performance compared to WCPS.

Association Between the c.3751G>A Genetic Variant of MDR1 and Hepatocellular Carcinoma Risk in a Chinese Han Population

Li, Xiao-Fei,He, Hua-Bin,Zhu, Yan-Shuang,He, Jin-Ke,Ye, Wei-Wei,Chen, Yong-Xin,Lou, Lian-Qing Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.9

The objective of this study was to evaluate the influence of a genetic variant in the multidrug resistance 1 gene (MDR1) on hepatocellular carcinoma (HCC) risk. This case-control study was conducted in a Chinese population of 645 HCC cases and 658 cancer-free controls. The genotype of the c.3751G>A genetic variant in the MDR1 gene was investigated by created restriction site-polymerase chain reaction (CRS-PCR) and DNA sequencing methods. Our data demonstrated significantly differences detected in the allelic and genotypic frequencies between HCC cases and those of cancer-free controls. Association analyses indicated that there were statistically increased risk of HCC in the homozygote comparison (AA versus (vs.) GG: OR=2.22, 95% CI 1.51-3.27, ${\chi}^2$=16.90, P<0.001), dominant model (AA/GA vs. GG: OR=1.25, 95% CI 1.00-1.55, ${\chi}^2$=3.98, P=0.046), recessive model (AA vs. GA/GG: OR=2.14, 95% CI 1.47-3.09, ${\chi}^2$=16.68, P<0.001) and allele comparison (A vs. G: OR=1.33, 95% CI 1.13-1.57, ${\chi}^2$=11.66, P=0.001). The allele-A and genotype-AA may contribute to HCC susceptibility. These preliminary findings suggest that the c.3751G>A genetic variant in the MDR1 gene is potentially related to HCC susceptibility in a Chinese Han population, and might be used as a molecular marker for evaluating HCC susceptibility.