Estimation of load and resistance factors based on the fourth moment method

Zhao-Hui Lu,Yan-gang Zhao,Alfredo H-S. Ang 국제구조공학회 2010 Structural Engineering and Mechanics, An Int'l Jou Vol.36 No.1

The load and resistance factors are generally obtained using the First Order Reliability Method (FORM), in which the design point should be determined and derivative-based iterations have to be used. In this paper, a simple method for estimating the load and resistance factors using the first four moments of the basic random variables is proposed and a simple formula for the target mean resistance is also proposed to avoid iteration computation. Unlike the currently used method, the load and resistance factors can be determined using the proposed method even when the probability density functions (PDFs) of the basic random variables are not available. Moreover, the proposed method does not need either the iterative computation of derivatives or any design points. Thus, the present method provides a more convenient and effective way to estimate the load and resistance factors in practical engineering. Numerical examples are presented to demonstrate the advantages of the proposed fourth moment method for determining the load and resistance factors.

Estimation of load and resistance factors based on the fourth moment method

Lu, Zhao-Hui,Zhao, Yan-Gang,Ang, Alfredo H.S. Techno-Press 2010 Structural Engineering and Mechanics, An Int'l Jou Vol.36 No.1

The load and resistance factors are generally obtained using the First Order Reliability Method (FORM), in which the design point should be determined and derivative-based iterations have to be used. In this paper, a simple method for estimating the load and resistance factors using the first four moments of the basic random variables is proposed and a simple formula for the target mean resistance is also proposed to avoid iteration computation. Unlike the currently used method, the load and resistance factors can be determined using the proposed method even when the probability density functions (PDFs) of the basic random variables are not available. Moreover, the proposed method does not need either the iterative computation of derivatives or any design points. Thus, the present method provides a more convenient and effective way to estimate the load and resistance factors in practical engineering. Numerical examples are presented to demonstrate the advantages of the proposed fourth moment method for determining the load and resistance factors.

Reliability-based assessment of American and European specifications for square CFT stub columns

Zhao-Hui Lu,Yan-gang Zhao,Zhi-wu Yu,Cheng Chen 국제구조공학회 2015 Steel and Composite Structures, An International J Vol.19 No.4

This paper presents a probabilistic investigation of American and European specifications (i.e., AISC and Eurocode 4) for square concrete-filled steel tubular (CFT) stub columns. The study is based on experimental results of 100 axially loaded square CFT stub columns from the literature. By comparing experimental results for ultimate loads with code-predicted column resistances, the uncertainty of resistance models is analyzed and it is found that the modeling uncertainty parameter can be described using random variables of lognormal distribution. Reliability analyses were then performed with/without considering the modeling uncertainty parameter and the safety level of the specifications is evaluated in terms of sufficient and uniform reliability criteria. Results show that: (1) The AISC design code provided slightly conservative results of square CFT stub columns with reliability indices larger than 3.25 and the uniformness of reliability indices is no better because of the quality of the resistance model; (2) The uniformness of reliability indices for the Eurocode 4 was better than that of AISC, but the reliability indices of columns designed following the Eurocode 4 were found to be quite below the target reliability level of Eurocode 4.

Intravenous Tenecteplase for Acute Ischemic Stroke Within 4.5–24 Hours of Onset (ROSE-TNK): A Phase 2, Randomized, Multicenter Study

Wang Lu,Dai Ying-Jie,Cui Yu,Zhang Hong,Jiang Chang-Hao,Duan Ying-Jie,Zhao Yong,Feng Ye-Fang,Geng Shi-Mei,Zhang Zai-Hui,Lu Jiang,Zhang Ping,Zhao Li-Wei,Zhao Hang,Ma Yu-Tong,Song Cheng-Guang,Zhang Yi,Ch 대한뇌졸중학회 2023 Journal of stroke Vol.25 No.3

Background and Purpose Intravenous tenecteplase (TNK) efficacy has not been well demonstrated in acute ischemic stroke (AIS) beyond 4.5 hours after onset. This study aimed to determine the effect of intravenous TNK for AIS within 4.5 to 24 hours of onset. Methods In this pilot trial, eligible AIS patients with diffusion-weighted imaging (DWI)-fluid attenuated inversion recovery (FLAIR) mismatch were randomly allocated to intravenous TNK (0.25 mg/kg) or standard care within 4.5–24 hours of onset. The primary endpoint was excellent functional outcome at 90 days (modified Rankin Scale [mRS] score of 0–1). The primary safety endpoint was symptomatic intracranial hemorrhage (sICH). Results Of the randomly assigned 80 patients, the primary endpoint occurred in 52.5% (21/40) of TNK group and 50.0% (20/40) of control group, with no significant difference (unadjusted odds ratio, 1.11; 95% confidence interval 0.46–2.66; <i>P</i>=0.82). More early neurological improvement occurred in TNK group than in control group (11 vs. 3, <i>P</i>=0.03), but no significant differences were found in other secondary endpoints, such as mRS 0–2 at 90 days, shift analysis of mRS at 90 days, and change in National Institutes of Health Stroke Scale score at 24 hours and 7 days. There were no cases of sICH in this trial; however, asymptomatic intracranial hemorrhage occurred in 3 of the 40 patients (7.5%) in the TNK group. Conclusion This phase 2, randomized, multicenter study suggests that intravenous TNK within 4.5–24 hours of onset may be safe and feasible in AIS patients with a DWI-FLAIR mismatch.

Analysis of Ferrous on Ten-Eleven Translocation Activity and Epigenetic Modifications of Early Mouse Embryos by Fluorescence Microscopy

Zhao, Ming-Hui,Liang, Shuang,Guo, Jing,Choi, Jeong-Woo,Kim, Nam-Hyung,Lu, Wen-Fa,Cui, Xiang-Shun Cambridge University Press 2016 Microscopy and Microanalysis Vol.22 No.2

<B>Abstract</B><P>Iron is an essential trace element that plays important roles in the cellular function of all organs and systems. However, the function of Fe(II) in mammalian embryo development is unknown. In this study, we investigated the role of Fe(II) during preimplantation embryo development. Depletion of Fe(II) using thiosemicarbazone-24 (TSC24), a specific Fe(II) chelator, rescued quenching of the Fe(II)-sensitive fluorophore phen green-SK. After <I>in vitro</I> fertilization, TSC24 significantly reduced the cleavage rate as well as blastocyst formation. The hatch rate of blastocysts was also reduced with 1 pM TSC24 treatment (20.25±1.86 versus 42.28±12.96%, <I>p</I><0.05). Blastocysts were cultured in leukemia inhibitory factor-free mouse embryonic stem cell culture medium with or without TSC24, and those with depleted Fe(II) displayed delayed attachment and lost the ability to induce embryoid body formation. To further explore the mechanism of Fe(II) in embryo development, we assessed the expression of 5-hydroxymethylcytosine (5hmC) and OCT4 in the pronuclear and blastocyst stages, respectively. We observed that Fe(II) reduced 5hmC and OCT4 expression, which could be explained by low ten-eleven translocation (TET) enzyme activity induced by TSC24 treatment. These findings demonstrate that Fe(II) is required for mammalian embryo development and that it facilitates the process via regulation of TET activity.</P>

MondoA Is Required for Normal Myogenesis and Regulation of the Skeletal Muscle Glycogen Content in Mice

Hui Ran,Yao Lu,Qi Zhang,Qiuyue Hu,Junmei Zhao,Kai Wang,Xuemei Tong,Qing Su 대한당뇨병학회 2021 Diabetes and Metabolism Journal Vol.45 No.3

Background: Skeletal muscle is the largest tissue in the human body, and it plays a major role in exerting force and maintaining metabolism homeostasis. The role of muscle transcription factors in the regulation of metabolism is not fully understood. MondoA is a glucose-sensing transcription factor that is highly expressed in skeletal muscle. Previous studies suggest that MondoA can influence systemic metabolism homeostasis. However, the function of MondoA in the skeletal muscle remains unclear. Methods: We generated muscle-specific MondoA knockout (MAKO) mice and analyzed the skeletal muscle morphology and glycogen content. Along with skeletal muscle from MAKO mice, C2C12 myocytes transfected with small interfering RNA against MondoA were also used to investigate the role and potential mechanism of MondoA in the development and glycogen metabolism of skeletal muscle. Results: MAKO caused muscle fiber atrophy, reduced the proportion of type II fibers compared to type I fibers, and increased the muscle glycogen level. MondoA knockdown inhibited myoblast proliferation, migration, and differentiation by inhibiting the phosphatase and tensin homolog (PTEN)/phosphoinositide 3-kinase (PI3K)/Akt pathway. Further mechanistic experiments revealed that the increased muscle glycogen in MAKO mice was caused by thioredoxin-interacting protein (TXNIP) downregulation, which led to upregulation of glucose transporter 4 (GLUT4), potentially increasing glucose uptake. Conclusion: MondoA appears to mediate mouse myofiber development, and MondoA decreases the muscle glycogen level. The findings indicate the potential function of MondoA in skeletal muscle, linking the glucose-related transcription factor to myogenesis and skeletal myofiber glycogen metabolism.

Complex dental anomalies in a belatedly diagnosed cleidocranial dysplasia patient

Lu, Hui,Zeng, Binghui,Yu, Dongsheng,Jing, Xiangyi,Hu, Bin,Zhao, Wei,Wang, Yiming Korean Academy of Oral and Maxillofacial Radiology 2015 Imaging Science in Dentistry Vol.46 No.1

Cleidocranial dysplasia (CCD) is a rare congenital disorder, typically characterized by persistently open skull sutures, aplastic or hypoplastic clavicles, and supernumerary teeth. Mutations in the gene encoding the runt-related transcription factor 2 (RUNX2) protein are responsible for approximately two thirds of CCD patients. We report a 20-year-old CCD patient presenting not only with typical skeletal changes, but also complex dental anomalies. A previously undiagnosed odontoma, 14 supernumerary teeth, a cystic lesion, and previously unreported fused primary teeth were discovered on cone-beam computed tomography (CBCT) scans. Mutation analysis identified the causal c.578G>A (p.R193Q) mutation in the RUNX2 gene. At 20 years of age, the patient had already missed the optimal period for dental intervention. This report describes the complex dental anomalies in a belatedly diagnosed CCD patient, and emphasizes the significance of CBCT assessment for the detection of dental anomalies and the importance of early treatment to achieve good outcomes.

Complex dental anomalies in a belatedly diagnosed cleidocranial dysplasia patient

Hui Lu,Binghui Zeng,Dongsheng Yu,Xiangyi Jing,Bin Hu,Wei Zhao,Yiming Wang 대한영상치의학회 2015 Imaging Science in Dentistry Vol.45 No.3

Cleidocranial dysplasia (CCD) is a rare congenital disorder, typically characterized by persistently open skull sutures, aplastic or hypoplastic clavicles, and supernumerary teeth. Mutations in the gene encoding the runt-related transcription factor 2 (RUNX2) protein are responsible for approximately two thirds of CCD patients. We report a 20-year-old CCD patient presenting not only with typical skeletal changes, but also complex dental anomalies. A previously undiagnosed odontoma, 14 supernumerary teeth, a cystic lesion, and previously unreported fused primary teeth were discovered on cone-beam computed tomography (CBCT) scans. Mutation analysis identified the causal c.578G>A (p.R193Q) mutation in the RUNX2 gene. At 20 years of age, the patient had already missed the optimal period for dental intervention. This report describes the complex dental anomalies in a belatedly diagnosed CCD patient, and emphasizes the significance of CBCT assessment for the detection of dental anomalies and the importance of early treatment to achieve good outcomes.

Cubic normal distribution and its significance in structural reliability

Zhao, Yan-Gang,Lu, Zhao-Hui Techno-Press 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.28 No.3

Information on the distribution of the basic random variable is essential for the accurate analysis of structural reliability. The usual method for determining the distributions is to fit a candidate distribution to the histogram of available statistical data of the variable and perform approximate goodness-of-fit tests. Generally, such candidate distribution would have parameters that may be evaluated from the statistical moments of the statistical data. In the present paper, a cubic normal distribution, whose parameters are determined using the first four moments of available sample data, is investigated. A parameter table based on the first four moments, which simplifies parameter estimation, is given. The simplicity, generality, flexibility and advantages of this distribution in statistical data analysis and its significance in structural reliability evaluation are discussed. Numerical examples are presented to demonstrate these advantages.

Treating urban dredged silt with ethanol improves settling and solidification properties

Guo-Lu Yang,Zhao-Hui Chai,Meng Chen 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.1

The organic matter content in urban dredged silt is high for the indraft of municipal sewage, and it seriously influences the utilization of urban dredged silt. It is necessary to find a method to solve this problem. This paper presents a method of treating the silt with ethanol (STE), considering that ethanol is a good organic solvent which can dissolve many kinds of organic matter, and optimizes the treatment conditions through Box-Benhnken design (BBD) experiment with organic matter removal efficiency as the response. The ideal conditions were as follows: action time, 47 min; ethanol concentration, 41%; ratio of ethanol to silt, 54 : 1 ml/g with organic matter removal efficiency of 51.12%. Then, settling and solidification properties of raw silt and STE were explored through laboratory experiments. The results show treating urban dredged silt improved the settling and solidification properties of silt.