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Thermal deflection analysis of the solidified shell in continuous casting of slab

LIU Hongzhao, WANG Zhongmin

《机械工程前沿（英文）》 2007年第2卷第2期页码 175-179 doi: 10.1007/s11465-007-0029-3

摘要： The thermal deformation problem in the continuous casting of a slab subjected to thermal loading because of the temperature gradient along the solidified shell thickness is investigated. On the basis of the reciprocal theorem of work or Betti-Maxwell s reciprocal theorem and the superposition principle, the deflection expressions for a rectangular plate with the two opposite edges simply supported, and the other two opposite edges clamped under the action of the uniformly distributed load and nonuniform temperature field are derived respectively. The meaning of each term in the deflection expression obtained by the reciprocal theorem of work is explained. Then the practical example is given to calculate the thermal deformation and the bulging deformation of the solidified shell under three tension speeds. This research is useful for analyzing the bulging deformation in the continuous casting of a slab under the static pressure of the molten steel and the thermal loading because of the temperature gradient along the solidified shell thickness.

关键词： s reciprocal loading deflection expression reciprocal opposite

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Improved prediction of pile bending moment and deflection due to adjacent braced excavation

《结构与土木工程前沿（英文）》 doi: 10.1007/s11709-023-0961-2

摘要： Deep excavations in dense urban areas have caused damage to nearby existing structures in numerous past construction cases. Proper assessment is crucial in the initial design stages. This study develops equations to predict the existing pile bending moment and deflection produced by adjacent braced excavations. Influential parameters (i.e., the excavation geometry, diaphragm wall thickness, pile geometry, strength and small-strain stiffness of the soil, and soft clay thickness) were considered and employed in the developed equations. It is practically unfeasible to obtain measurement data; hence, artificial data for the bending moment and deflection of existing piles were produced from well-calibrated numerical analyses of hypothetical cases, using the three-dimensional finite element method. The developed equations were established through a multiple linear regression analysis of the artificial data, using the transformation technique. In addition, the three-dimensional nature of the excavation work was characterized by considering the excavation corner effect, using the plane strain ratio parameter. The estimation results of the developed equations can provide satisfactory pile bending moment and deflection data and are more accurate than those found in previous studies.

关键词： pile responses excavation prediction deflection bending moments

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Modeling of large-deflection links for compliant mechanisms

Zhonglei FENG, Yueqing YU, Wenjing WANG,

《机械工程前沿（英文）》 2010年第5卷第3期页码 294-301 doi: 10.1007/s11465-010-0019-8

摘要： The traditional pseudo-rigid-body model (PRBM) has one degree of freedom (DOF) and performs a good simulation to the tip locus of flexible links for compliant mechanisms on the basis of a parametric approximation method. In this study, a new approach of a two-DOF PRBM is proposed to simulate both the tip locus and tip deflection angle of large-deflection links for compliant mechanisms on the basis of the angular deflection approximation technique. A linear regression for the spring stiffness coefficient of the 2R PRBM using the optimization technique is presented. The advantage of the new model is well illustrated through a numerical comparison between the 1R and the 2R PRBM.

关键词： compliant mechanism pseudo-rigid-body model (PRBM) large-deflection link angular deflection approximation

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New nonlinear stiffness actuator with predefined torque‒deflection profile

《机械工程前沿（英文）》 2023年第18卷第1期 doi: 10.1007/s11465-022-0721-3

摘要： A nonlinear stiffness actuator (NSA) could achieve high torque/force resolution in low stiffness range and high bandwidth in high stiffness range, both of which are beneficial for physical interaction between a robot and the environment. Currently, most of NSAs are complex and hardly used for engineering. In this paper, oriented to engineering applications, a new simple NSA was proposed, mainly including leaf springs and especially designed cams, which could perform a predefined relationship between torque and deflection. The new NSA has a compact structure, and it is lightweight, both of which are also beneficial for its practical application. An analytical methodology that maps the predefined relationship between torque and deflection to the profile of the cam was developed. The optimal parameters of the structure were given by analyzing the weight of the NSA and the mechanic characteristic of the leaf spring. Though sliding friction force is inevitable because no rollers were used in the cam-based mechanism, the sliding displacement between the cam and the leaf spring is very small, and consumption of sliding friction force is very low. Simulations of different torque‒deflection profiles were carried out to verify the accuracy and applicability of performing predefined torque‒deflection profiles. Three kinds of prototype experiments, including verification experiment of the predefined torque‒deflection profile, torque tracking experiment, and position tracking experiment under different loads, were conducted. The results prove the accuracy of performing the predefined torque‒deflection profile, the tracking performance, and the interactive performance of the new NSA.

关键词： compliant actuator nonlinear stiffness actuator nonlinear spring predefined torque−deflection profile

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Instantaneous deflection of light-weight concrete slabs

Behnam VAKHSHOURI, Shami NEJADI

《结构与土木工程前沿（英文）》 2017年第11卷第4期页码 412-423 doi: 10.1007/s11709-017-0416-8

摘要： Construction loading before the age of 28 d can have the most significant effects on the slabs, especially for multi-story structures. The changing properties of the young concrete complicate the prediction of serviceability design requirements also. An experimental investigation is performed on four simply supported Light-Weight Concrete (LWC) one-way slabs subjected to immediate loading at 14 d. Effects of aggregate type, loading levels and cracking moment together with the influences of ultimate moment capacity and service moment on the instantaneous deflection of slabs are studied. Comparison of the obtained results with predictions of existing models in the literature shows considerable differences between the recorded and estimated instantaneous deflection of LWC slabs. Based on sensitivity analysis of the effective parameters, a new equation is proposed and verified to predict the instantaneous deflection of LWC slabs subjected to loading at the age of 14 d.

关键词： instantaneous deflection light-weight concrete expanded polystyrene effective moment of inertia cracking moment moment capacity service moment

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大型多支承回转窑托轮偏斜接触有限元分析

李学军,张美阳,褚福磊

《中国工程科学》 2007年第9卷第12期页码 16-20

摘要：

针对回转窑托轮偏斜对接触区应力分布的影响，运用赫兹接触理论，推导出托轮与滚圈最大接触应力比与托轮偏斜角的关系；采用有限元方法计算某支承结构托轮平行与呈最大偏斜角时的接触问题，得到支承部件接触应力和等效应力应变分布情况，并得出滚圈和托轮的危险易损部位；为回转窑的轴向调控提供了有效的理论依据。

关键词：大型多支承托轮偏斜接触应力有限元

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analysis of thin-walled box continuous girder with variable cross-sections in considering effect of large deflection

Yuji CHEN, Qizhi LUO,

《结构与土木工程前沿（英文）》 2009年第3卷第4期页码 352-356 doi: 10.1007/s11709-009-0057-7

摘要： In order to study the mechanics behavior of a thin-walled box continuous girder with variable cross-sections, using potential variation theories, considering the effect of shear lag of flange’s stress and the nonlinear geometry of vertical displacement, and evolving five generalized displacements with the spline function, the large deflection problem of the thin-walled box continuous girder with variable cross-section was transformed to a nonlinear algebraic equation, which was solved using the Newton-Raphon iterative method. The results of the calculation show that different shear lag warp functions to the cantilever, top and bottom plate should be taken to analyze the mechanics behavior of the thin-walled box continuous girder reliably. The thin-walled box continuous girder with variable cross-sections has more reasonable stress state and is more adaptable for the longitudinal change of internal forces than that with equal cross-sections. The effect of large deflection on the stress and displacement of the thin-walled box continuous girder with variable cross-sections depends on the values of the load.

关键词： thin-walled box girder with variable cross-sections potential variational theory shear lag large deflection problem

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粘贴玻璃钢加固混凝土组合梁挠度研究

段敬民,钱永久,曾宪桃

《中国工程科学》 2004年第6卷第10期页码 79-82

摘要：

将一定几何尺寸的玻璃钢板粘贴在混凝土梁的受拉区，能有效地提高混凝土梁的抗弯承载能力和混凝土梁的横向刚度。通过解析的方法，分别考虑组合梁在3种不同受力状态下，对玻璃钢板中拉力进行解析，得到了组合梁在不同载荷作用下的挠度表达式。

关键词：粘贴加固玻璃钢混凝土组合梁挠度

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Blockage of receptor-interacting protein 2 expression by small interfering RNA in murine macrophages

LIU Hongchun, CAO Zhongwei, JIN Jianjun, WANG Jiyao

《医学前沿（英文）》 2008年第2卷第2期页码 166-170 doi: 10.1007/s11684-008-0030-1

摘要： This study aims to demonstrate that blocking the receptor-interacting protein2 (Rip2) expression can decrease inflammatory cytokine production by macrophage and protect mice from endotoxin lethality. Murine Rip2 small interfering RNA (siRNA) plasmids were constructed and transfected into macrophage and Rip2 expression was detected with reverse transcription-polymerase chain reaction (RT-PCR) and western blot. Cell proliferation was assayed with MTT. TNF-? concentration was assayed with ELISA and high-mobility group box 1 protein (HMGB1) level with semi-quantitative western blot after lipopolysaccharide (LPS) stimulation. LPS challenge was given after the plasmids were injected into mice and the survival rate was calculated. Rip2 siRNA plasmid could block the mRNA and protein expression of Rip2 and promote cell proliferation. Blocking Rip2 could attenuate LPS-induced TNF-? and HMGB1 production. The HMGB1 expression in the liver decreased to (40.21 ± 11.03) pg/g, and serum TNF-? level decreased to (300.43 ± 59.26) ng/L ( < 0.05). The survival rate of mice from endotoxemia was also improved ( < 0.05). The results demonstrate that Rip2 siRNA plasmid can block the expression of Rip2, decrease the production of TNF-? and HMGB1 and protect mice from fatal endotoxemia.

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MSI/LOH and extron expression of the FHIT gene in gastric carcinoma

XIAO Yuping, MAO Lili, HAN Chengbo, LI Jinyi, XU Lei, XIN Yan

《医学前沿（英文）》 2007年第1卷第1期页码 99-103 doi: 10.1007/s11684-007-0019-1

摘要： We detected loss of heterozygosity (LOH) and microsatellite instabilities (MSI), as well as extron expression of the fragile histidine triad (FHIT) gene in gastric carcinoma (GC), in order to evaluate their association with clinicopathological processes in gastric carcinogenesis. LOH and MSI of the FHIT were detected by using PCR at 4 microsatellite loci: D3S 1300, D3S 4103, D3S 1481, D3S 1234 in cancer tissues from 50 patients with primary GC, with normal mucosa acting as matched controls. FHIT transcripts were detected by nested RT-PCR in 30 cases of GC and their products were sequenced. Results show that the average frequencies of LOH and MSI of the FHIT gene in GC were 32.4% and 26.4%, respectively. There was no correlation between LOH and MSI of the FHIT gene in GC and the histological characteristics of gastric carcinoma (Bormann s or Lauren s classification). LOH of the FHIT gene in GC was related to depth invasiveness, and its frequency in GC where serosa was penetrated was significantly higher than that in GC without serosa penetration (73.5% 37.5%, <0.05). The frequency of MSI in GC without lymph node metastasis was significantly higher than that in GC with lymph node metastasis (66.7% 34.3%, <0.05). Aberrant transcripts were found in 11/30 GC tissues. Sequencing analysis of the aberrant fragments found a RT-PCR product missing exons 5 7 in one case of GC, and another product missing exons 4 7. Four of 10 (40.0%) cases of primary GC showed absent or decreased expression of the FHIT protein as compared to their matched normal tissues. The findings in this study suggest that LOH and MSI of FHIT gene may induce aberrant extron expression, which might play a role in gastric carcinogenesis.

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Gene expression disparity in giant cell tumor of bone

Xiaohua PAN, Shuhua YANG, Deming XIAO, Yong DAI, Lili REN

《医学前沿（英文）》 2009年第3卷第1期页码 49-56 doi: 10.1007/s11684-009-0012-y

摘要： The aim of this paper was to study the differential gene expression of giant cell tumor of bone (GCTB) by gene chip technology. Total RNA of 8 fresh GCTB specimens (Jaffe I∶6 cases, II∶1 case, III∶1 case; Campanacci I∶6 cases, II∶1 case, III∶1 case; Enneking Staging G T M : 5 cases, G T M : 2 cases, G T M : 1 case) and 4 normal bony callus specimens (the control group) were extracted and purified to get mRNA and then reverse transcribed to complementary DNA, respectively. Microarray screening with a set of 8064 human cDNA genes was conducted to analyze the difference among the samples and the control. The hybridization signals were scanned. The gene expression disparity between the GCTB samples and normal bony callus was significantly different ( <0.01), and the disparity of over 5-fold was found in 47 genes in the GCTB specimens, with 25 genes up-regulated and 22 down-regulated including the extracellular matrix and transforming-related genes, oncogene and its homolog genes, cytokine and its receptor genes. Specific gene spectrum associated with GCTB can be identified by cDNA microarray, which will be the foundation of progressive etiology elucidation, diagnosis and treatment of GCTB.

关键词： giant cell tumor of bone gene microarray cDNA

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Distinct gene expression pattern of mutations coordinated by target repression and promoter hypermethylation

《医学前沿（英文）》 2022年第16卷第4期页码 627-636 doi: 10.1007/s11684-020-0815-4

摘要： Runt-related transcription factor 1 (RUNX1) is an essential regulator of normal hematopoiesis. Its dysfunction, caused by either fusions or mutations, is frequently reported in acute myeloid leukemia (AML). However, RUNX1 mutations have been largely under-explored compared with RUNX1 fusions mainly due to their elusive genetic characteristics. Here, based on 1741 patients with AML, we report a unique expression pattern associated with RUNX1 mutations in AML. This expression pattern was coordinated by target repression and promoter hypermethylation. We first reanalyzed a joint AML cohort that consisted of three public cohorts and found that RUNX1 mutations were mainly distributed in the Runt domain and almost mutually exclusive with NPM1 mutations. Then, based on RNA-seq data from The Cancer Genome Atlas AML cohort, we developed a 300-gene signature that significantly distinguished the patients with RUNX1 mutations from those with other AML subtypes. Furthermore, we explored the mechanisms underlying this signature from the transcriptional and epigenetic levels. Using chromatin immunoprecipitation sequencing data, we found that RUNX1 target genes tended to be repressed in patients with RUNX1 mutations. Through the integration of DNA methylation array data, we illustrated that hypermethylation on the promoter regions of RUNX1-regulated genes also contributed to dysregulation in RUNX1-mutated AML. This study revealed the distinct gene expression pattern of RUNX1 mutations and the underlying mechanisms in AML development.

关键词： RUNX1 gene mutation acute myeloid leukemia transcriptional repression DNA methylation

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Immunohistochemical measurement and expression of Mcl-1 in infertile testes

null

《医学前沿（英文）》 2015年第9卷第3期页码 361-367 doi: 10.1007/s11684-015-0395-x

摘要：

The diagnosis of azoospermia represents a major challenge to andrologists as this condition may occur despite normal spermatogenesis and genital tracts. Myeloid cell leukemia-1 (Mcl-1) is a member of the Bcl-2 family of proteins involved in regulation of apoptosis in various cell types. This study aimed to investigate the immunohistochemical expression of Mcl-1 in testicular biopsies of subjects with azoospermia. Eighty-six cases with azoospermia were obtained from 509 infertile patients admitted to the Andrology Unit of the Zagazig University Hospitals from January 2010 to December 2011. Biopsies were diagnosed and classified using H&E-stained slide sections. The specimens were subjected to immunohistochemical staining for Mcl-1 and examined through light microscopy. Forty-five cases of maturation arrest (25 at spermatids and 20 at the spermatocytes), 31 cases of hypospermatogenesis (20 moderate and 11 severe), 5 cases of Sertoli?cell-only syndrome, 2 cases of basement membrane hyalinization, and 1 case of tubular and peritubular sclerosis were observed. Normal spermatogenesis was detected in 2 cases. A strong positive immunoreaction in Leydig cells was observed among all investigated specimens. A moderate reaction was detected in spermatocytes and spermatozoa in cases of normal spermatogenesis and hypospermatogenesis, but a negative reaction was detected in cases of maturation arrest and germ cell aplasia. Apoptosis was found to be associated with decreased rate of spermatogenesis. High apoptosis rates may result in azoospermia, which can occur despite normal spermatogenesis and absence of duct obstruction.

关键词： spermatogenesis testis Mcl-1 expression immunohistochemical study infertility

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Construction of a universal recombinant expression vector that regulates the expression of human lysozyme

Shen LIU, Shengzhe SHANG, Xuezhen YANG, Huihua ZHANG, Dan LU, Ning LI

《农业科学与工程前沿（英文）》 2018年第5卷第3期页码 382-389 doi: 10.15302/J-FASE-2018211

摘要：

The mammary gland provides a novel method for producing recombinant proteins in milk of transgenic animals. A key component in the technology is the construction of an efficient milk expression vector. Here, we established a simple method to construct a milk expression vector, by a combination of homologous recombination and digestion-ligation. Our methodology is expected to have the advantages of both plasmid and bacterial artificial chromosome (BAC) vectors. The BAC of mouse whey acidic protein gene (mWAP) was modified twice by homologous recombination to produce a universal expression vector, and the human lysozyme gene (hLZ) was then inserted into the vector by a digestion-ligation method. The final vector containing the 8.5 kb mWAP 5′ promoter, 4.8 kb hLZ genomic DNA, and 8.0 kb mWAP 3′ genomic DNA was microinjected into pronuclei of fertilized mouse embryos, to successfully generate two transgenic mouse lines that expressed recombinant human lysozyme (rhLZ) in milk. The highest expression level of rhLZ was 0.45 g·L⁻¹, and rhLZ exhibited the same antibacterial activity as native hLZ. Our results have provided a simple approach to construct a universal milk expression vector, and demonstrated that the resulting vector regulates the expression of hLZ in milk.

关键词： BAC recombinant methods gene expression human lysozyme transgenic mice milk expression vector

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Relationship of adrenomedullin expression and microvessel density and prognosis in smooth muscle tumor

JIANG Yuan, TIAN Xuehong, YUAN Jie, JIN Yuemei, TAN Yusong

《医学前沿（英文）》 2007年第1卷第4期页码 398-400 doi: 10.1007/s11684-007-0077-4

摘要： The aim of this paper was to investigate the relationship between the expression of adrenomedullin (ADM) and microvessel density (MVD) and prognosis in smooth muscle tumor of uterus. The expression of ADM was detected using immunohistochemical staining in specimens from 15 normal controls, 28 cases of uterine leiomyoma (LE) and 19 cases of uterine leiomyosarcoma (LES). The MVD was assayed by immunostainting with CD. There was a positive correlation between the ADM expression and MVD in LE and LES respectively ( = 0.823, <0.01; = 0.793, <0.01). The expression of ADM in LE was statistically lower than that in LES (<0.05). There was a positive correlation between the ADM expression and mitotic figures in LES (<0.05): the more mitotic figures, the higher levels of the ADM expression and poor prognosis. The ADM is an important angiogenic factor in smooth muscle tumor of uterus. The ADM can be used as an accessory marker in estimating the malignant potency of LE and judging the pro gnosis of LES, and as a novel molecular target of anti-angiogenic and anticarcinogenic strategies.

关键词： anticarcinogenic microvessel density malignant potency muscle uterine leiomyosarcoma