Improvement of Poly(γ-glutamic acid) Biosynthesis and Quantitative Metabolic Flux Analysis of a Two-stage Strategy for Agitation Speed Control in the Culture of Bacillus subtilis NX-2

Dan Zhang,Zongqi Xu,Hong Xu,Xiaohai Feng,Sha Li,Heng Cai,Yan Wei,Pingkai Ouyang 한국생물공학회 2011 Biotechnology and Bioprocess Engineering Vol.16 No.6

In this study, the production of poly(γ-glutamic acid) by Bacillus subtilis NX-2 (PGA) at different agitation speeds was investigated. Based on the analysis of specific cell growth rate (μ) and specific PGA formation rate (q_p),a two-stage strategy for agitation speed control was proposed. During the first 24 h, an agitation speed of 600rpm was used to maintain a high μ for better cell growth,which then reduced to 400 rpm after 24 h to maintain a high qp to enhance PGA production. Using this method, the maximum concentration of PGA reached 40.5 ± 0.91 g/L and the PGA productivity was 0.56 ± 0.012 g/L/h, which was 17.7 and 9.8% higher, respectively, than the best results obtained when a constant agitation speed was used. The flux distributions and the related enzymes of 2-oxoglutarate could be affected by this two-stage strategy for agitation speed. The activity of isocitrate dehydrogenase and glutamate dehydrogenase at the key node of 2-oxoglutarate increased, and more flux distribution was directed to glutamate. The flux distribution from extracellular to intracellular glutamate also increased and improved PGA production as the glutamate uptake rates increased using the agitation-shift control method.

Research on Collaborative Filtering Algorithm based on Cloud Computing

Dan Zhang 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.7

In order to solve this problem of cloud model, this paper presents another new collaborative filtering recommendation algorithm by combining the item classification and cloud model. Firstly the algorithm utilizes the item classification information and cloud model to compute items inner-similarity, and then gets the scores from neighbor items which have the highest similarity and uses their scores to forecast the unrated inner-class items. Secondly, the neighbors of user are obtained by computing the inner-class user similarities in the cloud model, providing the final forecast grade and carrying out the recommendation.

Chemical constituents and their acetyl cholinesterase inhibitory and antioxidant activities from leaves of Acanthopanax henryi: potential complementary source against Alzheimer's disease

Zhang, Xiao Dan,Liu, Xiang Qian,Kim, Yang Hee,Whang, Wan Kyunn 대한약학회 2014 Archives of Pharmacal Research Vol.37 No.5

The aim of this study was to investigate chemical constituents of the leaves of Acanthopanax henryi, and their antioxidant, acetyl cholinesterase inhibitory activities. Caffeoyl quinic acid derivates and flavonoids were obtained from A. henry, through column chromatography technologies, and the content of major constituents was determined by the HPLC-UV method. Anti-oxidant activity of the isolated metabolites was evaluated by free radical scavenging (DPPH, ABTS radicals) and superoxide anion scavenging. The results showed that di-caffeoyl quinic acid derivates had stronger antioxidant activity than positive controls (ascorbic acid, trolox and allopurinol). Acetyl cholinesterase inhibitory activity was estimated on the constituents, among which, quercetin, 4-caffeoyl-quinic acid and 4,5-caffeoyl quinic acid were found to have strong acetyl cholinesterase inhibitory activity with $IC_{50}$ values ranging from 62.6 to $121.9{\mu}M$. The present study showed that some of the tested constituents from the leaves of A. henryi exhibit strong antioxidant and acetyl cholinesterase inhibitory effects. This suggest that the leaves of A. henryi can be used as a new natural complementary source of acetyl cholinesterase inhibitors and anti-oxidant agents, thus being a promising potential complementary source against Alzheimer's disease.

Key role of peptidoglycan on acrylamide binding by lactic acid bacteria

Dan Zhang,Wei Liu,Liang Li,Hong-Yu Zhao,Hong-Yang Sun,Ming-Han Meng,Sheng Zhang,Mei-Li Shao 한국식품과학회 2017 Food Science and Biotechnology Vol.26 No.1

The primary purpose of this study was to analyze the ability of four peptidoglycan (PGN) from different lactic acid bacteria to bind acrylamide (AA) and to identify the binding mechanism. In this study, to clarify the possible binding interactions among AA and components of PGN, chemical components, surface structure, amino acids component, and functional groups of peptidoglycans were studied. It was found that PGN from Lactobacillus plantarum 1.0065 had the highest ability to bind AA with 87%. Furthermore, a significant positive relation was found between the carbohydrate content of PGN and percentage of bind AA, and the content of four specific amino acids of PGN and AA binding ability were also positive correlated. Thereinto, alanine of PGN had a significant impact on AA binding among four amino acids. Additionally, the C–O (carboxyl, polysaccharides, and arene), C=O amide, and N–H amines groups of PGN were involved in AA binding.

前衛時裝和前衛時裝革新

( Dan Zhang ),( C. Anthony Di Benedetto ) 한국마케팅과학회 2010 Journal of Global Fashion Marketing Vol.1 No.4

This is a study of the related concepts of radical fashion and radical fashion innovation. Radical fashions are defined here as those that may never enter the market at all, and exist primarily on runway shows, in exhibitions and in publicity; by contrast, radical fashion innovations may be very successful in the marketplace. Radical fashions represent a clear break from the old designs, as opposed to incremental fashions, which are defined as an extension or evolution of the old designs. Using this definition, radical fashion seems to be at odds with the definition of marketable fashion. Nevertheless, while most radical fashions do not enter the market at all and live only in runway shows, exhibitions, and museums, there are many examples of radical fashion innovations successful in the market. Accordingly, a series of questions rise: What is radical fashion? What is radical fashion innovation? What are the differences and similarities between these, and how are they connected? This study seeks to address these questions, using a foundation developed in the radical product innovation literature. Fashion innovations may be in terms form or function, or style, and can be radical (involving the breaking down of old ideas) or incremental (involving the evolution of new ideas from old ideas). We draw from the radical product innovation literature to build two related models. The first is a model of radical fashion and radical fashion innovation that illustrates the components of both concepts. The second is a model of radical fashion innovation diffusion, drawn from the general product innovation diffusion literature, which explores the evolution of and the connections between these two concepts from the beginning (i.e., the radical fashion) to the end (i.e., success in the mass market). Radical fashion may result in designs that are more suitable for the runway, catalogues, or even museum display, than for actual wear. Radical fashion has sometimes been called "new ideas before their marketing phase." Radical fashion may successfully enter the market, however, and gain wide acceptance among consumers. The transition from radical fashion to radical fashion innovation is not too different from the transition from invention to innovation, which is familiar to researchers in product innovation. Notable in this transition process is the fact that, for many product innovations, what drives the first customers to purchase (the "Visionaries," to use Moore`s terminology in his "crossing the chasm" model of innovation diffusion) may be very different from what drives the rest of the market (the "Pragmatists."). If this "chasm" or divide between the two market segments is not recognized, the innovating firm may find that their product stalls during the diffusion process and never effectively reaches the mass market. In the case of fashion products, visionaries (such as celebrities and the fashion press) prime the market and create favorable word of mouth; yet, at the same time, less-radical, wearable designs may be seen on the runway, or may be manufactured for the mass market and sold through department stores, specialty clothing stores, or even discounters. The most successful worldwide designers instinctively know this, and can continuously produce radically innovative fashion which also usually transitions to the mass market successfully. They recognize the need to reach the visionaries successfully to generate sufficient publicity and word of mouth, and also to use product design, promotion, and distribution strategies, as well as appropriate price lining policies, to reach the mass market (the pragmatists) effectively. We conclude with generalized findings and managerial implications for firms in the fashion industry. We attempt to bring the radical innovation literature, and its understanding of the process of radical innovation diffusion in the marketplace, to the expanding discussion of fashion marketing success strategic development.

Fatigue characteristics of distributed sensing cables under low cycle elongation

Dan Zhang,Jiacheng Wang,Bo li,Bin Shi 국제구조공학회 2016 Smart Structures and Systems, An International Jou Vol.18 No.6

When strain sensing cables are under long-term stress and cyclic loading, creep may occur in the jacket material and each layer of the cable structure may slide relative to other layers, causing fatigue in the cables. This study proposes a device for testing the fatigue characteristics of three types of cables operating under different conditions to establish a decay model for observing the patterns of strain decay. The fatigue characteristics of cables encased in polyurethane (PU), GFRP-reinforced, and wire rope-reinforced jackets were compared. The findings are outlined as follows. The cable strain decayed exponentially, and the decay process involved quick decay, slow decay, and stabilization stages. Moreover, the strain decay increased with the initial strain and tensile frequency. The shorter the unstrained period was, the more similar the initial strain levels of the strain decay curves were to the stabilized strain levels of the first cyclic elongation. As the unstrained period increased, the initial strain levels of the strain decay curves approached those of the first cyclic elongation. The tested sensing cables differed in the amount and rate of strain decay. The wire rope-reinforced cable exhibited the smallest amount and rate of decay, whereas the GFRP-reinforced cable demonstrated the largest.

Characterizing the strain transfer on the sensing cable-soil interface based on triaxial testing

Dan Zhang,Guan-Zhong Wu,Tai-Song Shan,Bin Shi,Yuan-Jiang Fang,Kang Ren 국제구조공학회 2022 Smart Structures and Systems, An International Jou Vol.30 No.1

The deformation coordination between a rock/soil mass and an optical sensing cable is an important issue for accurate deformation monitoring. A stress-controlled triaxial apparatus was retrofitted by introducing an optical fiber into the soil specimen. High spatial resolution optical frequency domain reflectometry (OFDR) was used for monitoring the strain distribution along the axial direction of the specimen. The results were compared with those measured by a displacement meter. The strain measured by the optical sensing cable has a good linear relationship with the strain calculated by the displacement meter for different confining pressures, which indicates that distributed optical fiber sensing technology is feasible for soil deformation monitoring. The performance of deformation coordination between the sensing cable and the soil during unloading is higher than that during loading based on the strain transfer coefficients. Three hypothetical strain distributions of the triaxial specimen are proposed, based on which theoretical models of the strain transfer coefficients are established. It appears that the parabolic distribution of specimen strain should be more reasonable by comparison. Nevertheless, the strain transfer coefficients obtained by the theoretical models are higher than the measured coefficients. On this basis, a strain transfer model considering slippage at the interface of the sensing cable and the soil is discussed.

A New Unsymmetrical Zinc Phthalocyanine as Photosensitizers for Dye-sensitized Solar Cells

Dan Zhang,Xue-Jun Zhang,Lei Zhang,Li-Jun Mao 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.4

A new unsymmetrical zinc phthalocyanine has been designed and synthesized based on the ‘push-pull’ and extended π-conjugation concept for the dye-sensitized solar cells. Three tert-butoxy groups, which act as electron releasing (‘push’), enhance the solubility of phthalocyanine in common organic solvents and reduce the aggregation. Hydroxy substituted 9,10-anthraquinones act as electron acceptors (‘pull’) for the study of photoinduced electron transfer processes as well as grafting onto nanocrystalline TiO2. The new unsymmetrical zinc phthalocyanine was fully characterized by FTIR, UV-vis, 1H NMR, cyclic voltammetry and differential pulse voltammetry. The new sensitizer was tested in dye-sensitized solar cells, and gave a better performance.

Residual detection of buparvaquone, nystatin, and etomidate in animal-derived food products in a single chromatographic run using liquid chromatography-tandem mass spectrometry

Zhang, Dan,Park, Jin-A.,Abd El-Aty, A.M.,Kim, Seong-Kwan,Cho, Sang-Hyun,Wang, Yanmei,Shim, Jae-Han,Jeong, Ji Hoon,Shin, Sung Chul,Kim, Jin-Suk,Chang, Byung-Joon,Shin, Ho-Chul Elsevier 2017 Food chemistry Vol.237 No.-

<P><B>Abstract</B></P> <P>A reliable and highly sensitive screening method based on liquid chromatography coupled withtriple-quadrupoleelectrospray tandemmass spectrometry (LC-MS/MS) analysis has been developed for the detection and quantification of three veterinary drugs, including buparvaquone, nystatin, and etomidate impurity B CRS. The tested drugs were extracted from samples of porcine muscle, pasteurized whole milk, and eggs using 10mM ammonium formate in acetonitrile followed by liquid-liquid purification with <I>n</I>-hexane. Chromatographic separation was achieved on a Phenomenex Luna C18 analytical column using 0.1% formic acid in ultrapure water (A) and acetonitrile (B) as mobile phases. All the matrix-matched calibration curves were linear (<I>R<SUP>2</SUP> </I> ≥0.9756) over the concentration levels of the drugs tested. Recovery at two spiking levels (equivalent to the limit of quantification (LOQ)=5ng/g and 2×LOQ) ranged from 72.88% to 92.59% with intra- and inter-day precisions <17%, except for porcine muscle spiked with 5ng/g nystatin (RSD=25.15%). Samples collected from markets located in Seoul, Republic of Korea, tested negative for all the drugs analyzed. In summary, this method is suitable for screening and quantifying the selected drugs in a single chromatographic run and with high selectivity in animal-derived food products meant for human consumption.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Buparvaquone, nystatin, and etomidate were analyzed in animal-derived food products using LC-MS/MS. </LI> <LI> A combination of 10mM ammonium formate in acetonitrile and <I>n</I>-hexane is sufficient to effectively extract the drugs without SPE. </LI> <LI> The performance parameters were satisfactory and acceptable. </LI> <LI> The target analytes were not detected in any of the market samples. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Study of Oleophobic Modification of Fiber Material Surface and Its Performance

Dan Zhang,Chanjuan Huang,Wei Luo,Yuhe Wu,Zhu Long 한국섬유공학회 2019 Fibers and polymers Vol.20 No.6

In recent years, remarkable development and progresses have been made on the study of oleophobic modificationof fibers. Modified oleophobic fibers have broad application prospects not only owing to their important uses in daily life, butalso their extraordinary use in the fields of defense science and technology, and medical health care. In this study, fluorinecontainingacrylate (FP) emulsion was synthesized via emulsion polymerization method using perfluorooctyl acrylate(PFOA) as the fluorine-containing monomer, and butyl acrylate (BA) and styrene (St) as the basic monomers. In addition,SiO2 hydrosol was also prepared by water-based sol-gel reaction using tetraethyl orthosilicate (TEOS) as the precursor. Fourier transform infrared spectroscopy, scanning electron microscopy, atomic force microscopy, particle size analysis,thermogravimetric analysis and contact angle measurement were used to characterize the structural morphology and thermalstability of the FP polymer. The as-obtained FP and SiO2/FP were coated on cotton fabrics by the impregnation-curingmethod, successfully affording the cotton fabrics with oleophobic property. The application performance of the fabrics beforeand after finishing were measured and analyzed, and the effect of rubbing and soap washing on the oleophobic property of thefabrics were investigated. Then property changes, such as the anti-ultraviolet property, whiteness, breathability, and breakingstrength, of the fabrics before and after finishing were investigated. The results showed that the FP finishing agent exhibitedexcellent thermal property and satisfied the basic requirements for the fabrics finishing agents. The oleophobic property ofthe fabrics after FP emulsion finishing achieved grade 5, with no wettability to n-dodecane. The oleophobic property of theSiO2/FP treated fabrics was better than those of the FP treated fabrics, indicating that the roughen treatment of cotton fabricssurfaces using silica sol first and then coating with FP improved the oleophobic property. The combined actions of the coarsesurface structure provided by SiO2 nanoparticles and the low surface energy of the fluorine-containing polymers afforded thecotton fabric surfaces with oleophobic property. The treated fabrics retained good oleophobic performance after multipletimes of water washing and rubbings, and the physical mechanical properties of the cotton fabrics did not change muchbefore and after finishing, and thus did not affect the clothing performance of the cotton fabrics.