Art of Lines

( Liangwang ) 한국기초조형학회 2019 한국기초조형학회 작품집 Vol.2019 No.2

Investigation of Self-assembly Structure and Properties of a Novel Designed Lego-type Peptide with Double Amphiphilic Surfaces

Liang Wang,Xiao-jun Zhao 대한화학회 2010 Bulletin of the Korean Chemical Society Vol.31 No.12

A typically designed ‘Peptide Lego’ has two distinct surfaces: a hydrophilic side that contains the complete charge distribution and a hydrophobic side. In this article, we describe the fabrication of a unique lego-type peptide with the AEAEYAKAK sequence. The novel peptide with double amphiphilic surfaces is different from typical peptides due to special arrangement of the residues. The results of CD, FT-IR, AFM and DLS demonstrate that the peptide with the random coil characteristic was able to form stable nanostructures that were mediated by non-covalent interactions in an aqueous solution. The data further indicated that despite its different structure, the peptide was able to undergo self-assembly similar to a typical peptide. In addition, the use of hydrophobic pyrene as a model allowed the peptide to provide a new type of potential nanomaterial for drug delivery. These efforts collectively open up a new direction in the fabrication of nanomaterials that are more perfect and versatile.

Dynamic Research of a Potential Carrier for Hydrophobic Compound Model Pyrene Using Amphiphilic Peptide EYK

Liang Wang,Xiao-jun Zhao 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.2

In recent years, the study of self-assembly peptide used in drug delivery system has been attracted great interest from scientists. In the category are self-assembly peptides in the structure either with one hydrophobic surface and another hydrophilic or a hydrophobic head and a hydrophilic tail. Here, we focus on a novel designed peptide EYK with double amphiphilic surfaces, investigating on the capability of peptide as a carrier for hydrophobic compound model pyrene. The fluorescence data presented the dynamic process of the transfer, showing that the pyrene was in the crystalline form in peptide solution, and molecularly migrated from its peptide encapsulations into the membrane bilayers when the peptide-pyrene suspension was mixed with liposome vesicles. The results indicated that the peptide EYK could stabilize hydrophobic pyrene in aqueous solution and delivered it into EPC liposome as a potential carrier.

Applications of acoustic radiation force impulse quantification in chronic kidney disease: a review

Liang Wang 대한초음파의학회 2016 ULTRASONOGRAPHY Vol.35 No.4

Acoustic radiation force impulse (ARFI) imaging is an emerging technique with great promise in the field of elastography. Previous studies have validated ARFI quantification as a method of estimating fibrosis in chronic liver disease. Similarly, fibrosis is the principal process underlying the progression of chronic kidney disease, which is the major cause of renal failure. However, the quantification of tissue stiffness using ARFI imaging is more complex in the kidney than in the liver. Moreover, not all previous studies are comparable because they employed different procedures. Therefore, subsequent studies are warranted, both in animal models and in clinical patients, in order to better understand the histopathological mechanisms associated with renal elasticity and to further improve this imaging method by developing a standardized guidelines for its implementation.

A Novel Adaptive High-order Sliding Mode Control based on Integral Sliding Mode

Liang Wang,Yongzhi Sheng,Xiangdong Liu 제어·로봇·시스템학회 2014 International Journal of Control, Automation, and Vol.12 No.3

This paper presents an adaptive high-order sliding mode control scheme targeting for uncertain minimum phase nonlinear single-input-single-output (SISO) systems, which can be equivalently formulated as the finite-time stabilization of high-order input-output dynamics subject to the uncertainties of parameters such as a chain of integrators. The proposed controller is derived from the concept of integral sliding mode and consists of two parts, one part of which achieves the finite-time stabilization of the high-order input-output dynamics without uncertainties by solving a finite-horizon optimal control problem with a free-final-state. The other part adopts the adaptive sliding mode control technique considering the practical bounded uncertainties, by which a modified switching gain adaptation algorithm is developed so that the on-line switching gain selection can be executed and the upper bounds of the uncertainties are not requisite in advance. As a result, a high-order sliding mode is established, ensuring the sliding variables and its high-order derivatives converge to an arbitrarily small vicinity of the origin in finite time. Therefore, the proposed controller achieves fixed convergence time and further improves strong robustness against bounded uncertainties with lower chattering and the easy implementation. Simulation results are presented in detail to verify the effectiveness and feasibility of the proposed algorithm.

Effects of positive and negative stretching on the structure and properties of polyacrylonitrile fibers in the pre-oxidation process

Liang Wang,Wei Lu,Li Zhang,Liwei Xue,Seung-Kon Ryu,Ri-guang Jin 한국탄소학회 2011 Carbon Letters Vol.12 No.2

Polyacrylonitrile (PAN) fibers were pre-oxidized in a temperature range of 180-275℃. The effects of positive and negative stretching on the structure and morphology of PAN fiber in the pre-oxidation process were studied by FTIR spectroscopy, XRD, and SEM. Mechanical property changes were also investigated. No changes in the movement and intensity of functional groups of PAN fibers were caused by positive stretching of up to 10% and negative stretching down to -8%. The crystal structure can be affected by the positive stretching and negative stretching. The maximum strength is 479.81 MPa when the stretching is positive, and the maximum strength is 420.55 MPa when the stretching is negative.

Optimized M9 Minimal Salts Medium for Enhanced Growth Rate and Glycogen Accumulation of Escherichia coli DH5α

( Liang Wang ),( Qinghua Liu ),( Yangguang Du ),( Daoquan Tang ),( Michael J. Wise ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 한국미생물·생명공학회지 Vol.46 No.3

Glycogen plays important roles in bacteria. Its structure and storage capability have received more attention recently because of the potential correlations with environmental durability and pathogenicity. However, the low level of intracellular glycogen makes extraction and structure characterization difficult, inhibiting functional studies. Bacteria grown in regular media such as lysogeny broth and tryptic soy broth do no accumulate large amounts of glycogen. Comparative analyses of bacterial media reported in literature for glycogen-related studies revealed that there was no consistency in the recipes reported. Escherichia coli DH5α is a convenient model organism for gene manipulation studies with respect to glycogen. Additionally, M9 minimal salts medium is widely used to improve glycogen accumulation, although its composition varies. In this study, we optimized the M9 medium by adjusting the concentrations of itrogen source, tryptone, carbon source, and glucose, in order to achieve a balance between the growth rate and glycogen accumulation. Our result showed that 1 × M9 minimal salts medium containing 0.4% tryptone and 0.8% glucose was a well-balanced nutrient source for enhancing the growth and glycogen storage in bacteria. This result will help future investigations related to bacterial physiology in terms of glycogen function.

RELIABILITY ANALYSIS FOR THE TWO-PARAMETER PARETO DISTRIBUTION UNDER RECORD VALUES

Liang Wang,Yimin Shi,Ping Chang 한국전산응용수학회 2011 Journal of applied mathematics & informatics Vol.29 No.5

In this paper the estimation of the parameters as well as survival and hazard functions are presented for the two-parameter Pareto distribution by using Bayesian and non-Bayesian approaches under upper record values. Maximum likelihood estimation (MLE) and interval estimation are derived for the parameters. Bayes estimators of reliability performances are obtained under symmetric (Squared error) and asymmetric (Linex and general entropy (GE)) losses, when two parameters have discrete and continuous priors, respectively. Finally, two numerical examples with real data set and simulated data, are presented to illustrate the proposed method. An algorithm is introduced to generate records data, then a simulation study is performed and different estimates results are compared.

Effects of Notch Radius and Thickness on the Tensile Strength and Fracture Mechanisms of Al6061-T6 Plate Specimens

Liang Wang,Xiao Du,Nak-Sam Choi 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.23 No.2

In this study, the tensile strength and fracture mechanisms of Al6061-T6 plate specimens were evaluated based on von Mises stress and triaxial tensile stress according to the specimen geometry. Stress states at four representative sites (center, position of the maximum stress triaxiality, skin, and notch tip) on the cross-section of the gauge portion were analyzed under tensile testing. The notch strength ratios of specimens with a small notch radius significantly increase with an increase in thickness, whereas those of specimens with a large notch radius change very little. The intensity and position of the maximum stress triaxiality change significantly with varying notch radii and thicknesses. Consequently, with an increase in the thickness and decrease in the notch radius, the shear fracture mode transforms into a tensile-shear mixed fracture mode through the evolution of the stress state and plastic deformation.

INTRINSIC MOTIVATORS AND PSYCHOLOGICAL BENEFITS OF CUSTOMER ENGAGEMENT IN TOURISM SOCIAL MEDIA SITES

Liang Wang,Henry Tsai,Tianyu Ying 글로벌지식마케팅경영학회 2018 Global Marketing Conference Vol.2018 No.07

Since the late 1980s, information communication and technology (ICT) have reshaped the landscape of the tourism industry (Buhalis & Law, 2008). Thanks to the Web 2.0 technology, tourism practitioners have never been this close to their customers over social media platforms. According to Kaplan and Haenlein (2010), social media refers to “a group of Internet-based applications which build on the ideological and technological foundations of Web 2.0 and that allow the creation and exchange of User Generated Content” (p. 61). In line with this definition, electronic social networks, user-generated content aggregators, as well as location-based applications are all typical social media platforms, across which enable customers to create, edit, and share content. The increasingly growing social media platforms have greatly facilitated implementations of customer engagement strategies for organizations. As a psychological state, customer engagement is featured by interactive customer experiences with an organization, which encourage psychological, emotional, and physical investment a customer has in the organization (Harrigan, Evers, Miles, & Daly, 2017). In the tourism and hospitality context, customer engagement strategies are as critical in strengthening customer loyalty, trust, and brand evaluations (So, King, & Sparks, 2016). Useful insights have been gained relating to conceptualization and measurement scale of customer engagement, organizational and cultural obstacles to consumer engagement within hotel organizations (Chathoth et al., 2014), customer engagement in a social media context alongside the process of recognition (Cabiddu et al., 2014). Underlying the practical and theoretical significance of customer engagement lies the subjective nature of views on the social media platforms. Goh, Heng, and Lin (2014) recognized that engagement in social media brand communities positively lead to enhanced purchase expenditures through embedded information and persuasion. Quantitively, the persuasive effect of user generated information is at least 22 times more than that of marketer’s in terms of marginal effect. Although previous research has examined consequences of consumer engagement, there has been less attention paid to its causes. Meanwhile, as far as Brodie et al. (2011) were concerned, the persistency of consumer-brand engagement is contingent on an assessment of tangible and intangible costs against possible benefits such as product news and offers. Therefore, identification of these benefits can offer supplementary insights into current literature of consumer engagement. The current study utilizes the self-determination theory to uncover how engagement in social media activities is facilitated by consumers’ intrinsic motivators and what psychological benefits can consumer obtain from such engagement, as either psychological state or process (Brodie et al., 2011). Research subjects in this study are Chinese social media users. According to eMarketer’s (2017) estimated that more than 80 percent of Internet users in China (i.e., around 626 million people) accessed social networks regularly in 2017. The importance of tapping this massive market can never be overestimated.