Immobilization of hemoglobin on functionalized multi-walled carbon nanotubes-poly-l-histidine-zinc oxide nanocomposites toward the detection of bromate and H₂O₂

Vilian, A.,Chen, S.M.,Kwak, C.H.,Hwang, S.K.,Huh, Y.S.,Han, Y.K. Elsevier Sequoia 2016 Sensors and actuators. B Chemical Vol.224 No.-

A novel biocompatible sensing strategy has been developed based on functionalized multi-walled carbon nanotube (f-MWCNT), poly-l-histine (P-l-His), and ZnO nanocomposite film for the immobilization of hemoglobin (Hb). The direct electron transfer properties and bioelectrocatalytic activity of the Hb in f-MWCNT-P-l-His-ZnO composite film is further investigated. The apparent heterogeneous electron transfer rate constant (k<SUB>s</SUB>) of Hb confined to f-MWCNT-P-l-His-ZnO nanocomposite is found to be 5.16s<SUP>-1</SUP> using Laviron's equation. Moreover, the surface coverage concentration (Γ) of the electroactive Hb in the f-MWCNT-P-l-His-ZnO film is estimated to be 1.88x10<SUP>-9</SUP>molcm<SUP>-2</SUP>. The fabricated electrochemical biosensor based on the immobilized Hb revealed a fast response time (<3s) with a wide linear range (4-18,000μM and 2-15,000μM) and detection limit (as low as 0.01μM and 0.30μM) for the electrocatalytic determination of a mediator-free H<SUB>2</SUB>O<SUB>2</SUB> and bromate under optimal experimental conditions. The ca. apparent Michaelis-Menten constant is 0.14mM, which indicates that the Hb has a high affinity to H<SUB>2</SUB>O<SUB>2</SUB>. The high sensitivity, good reproducibility, and long-term stability of the proposed nanocomposite film indicates that it can serve as an electrode for the development of an amperometric H<SUB>2</SUB>O<SUB>2</SUB> and bromate-based biosensor. The proposed third-generation biosensor was successfully applied to milk and urine samples for the detection of H<SUB>2</SUB>O<SUB>2</SUB> and bromate.

Multilocus Sequence Typing and Virulence Factors Analysis of Escherichia coli O157 Strains in China

Xiao W. Ji,Ya L. Liao,Ye F. Zhu,Hai G. Wang,Ling Gu,Jiang Gu,Chen Dong,Hong L. Ding,Xu H. Mao,Feng C. Zhu,Quan M. Zou 한국미생물학회 2010 The journal of microbiology Vol.48 No.6

Escherichia coli O157:H7, an important food-borne pathogen, has become a major public health concern worldwide. The aim of this study was to investigate the molecular epidemiologic feature of E. coli O157:H7strains in China. 105 E. coli O157:H7 isolates were collected from various hosts and places over 9 years. A multilocus sequence typing scheme (MLST) was applied for bacteria genotyping and polymerase chain reaction (PCR) was used for virulence factor identification. Seven new MLST sequence types (STs), namely ST836, ST837, ST838, ST839, ST840, ST841, and ST842 were identified, which grouped into two lineages. Phylogenetic analysis suggested that the most two frequent STs in China, ST837 and ST836, may be the derivatives of E. coli O157:H7 Sakai or E. coli O157:H7 EDL933. Geographical diversity and host variety of E. coli O157:H7 were observed in China. In addition, the different distribution of tccp was detected. The data presented herein provide new insights into the molecular epidemiologic feature of E. coli O157:H7, and aid in the investigation of the transmission regularity and evolutionary mechanism of E. coli O157:H7.

New Evidence of Alleles (V199I and G52S) at the PRKAG3 (RN) Locus Affecting Pork Meat Quality

Chen, J.F.,Dai, L.H.,Peng, J.,Li, J.L.,Zheng, R.,Zuo, B.,Li, F.E.,Liu, M.,Yue, K.,Lei, M.G.,Xiong, Y.Z.,Deng, C.Y.,Jiang, S.W. Asian Australasian Association of Animal Productio 2008 Animal Bioscience Vol.21 No.4

The porcine PRKAG3 (RN) gene encodes the regulatory gamma subunit of adenosine monophosphate-activated protein kinase (AMPK), which is a good candidate gene affecting meat quality. In this study, the effects of two missense mutations A595G (Ile199Val) and G154A (Gly52Ser) in porcine PRKAG3 gene on meat quality traits were studied in M. Longissimus dorsi (LD), M. Semispinalis capitis (SC) and M. Biceps femoris (BF) from different populations of 326 pigs. The PRKAG3 alleles 199I, 199IV, 52S and 52G were identified with PCR-RFLPs and all genotypes - 199I/199I, 199I/199V, 199V/199V, 52S/52S, 52S/52G and 52G/52G - were found. The frequency of V allele was larger than that of I allele in all populations. I allele frequency was zero in Chinese Meishan pigs (population D) especially. G allele frequency was larger than that of S allele in all populations except Large White (population A). Both variations at the PRKAG3 locus significantly affected these meat quality traits. The pork meat quality has not previously been established in Meishan or crosses thereof. The results suggested that generally pH of LD, SC and BF was higher in Meishan pigs than that in other populations. Moreover, Meishan pigs showed higher water-holding capacity and intramuscular fat (IMF), lower water content and water loss percentage compared to other populations in terms of the two variations. The results present here supply new evidence that alleles V199I and G52S at the PRKAG3 locus affect pork meat quality and provide useful information on pork production.

Characterization and Formation Mechanism of Ni3Si–Al2O3 Nanocomposite Prepared by Mechanochemical Reduction Method

H. Chen,D. M. Zhou,L. Cai,Y. Y. Wang,K. Yu 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.2

In this present work, Ni3Si–Al2O3 nanocomposite powders were synthesized by mechanical milling using NiO, Si and Alas raw materials. The phase transformation, formation mechanism and microstructure evolution of the powders duringmechanical milling were investigated by X-ray difraction (XRD), diferential thermal analysis (DTA), scanning electronmicroscopy (SEM), transition electron microscopy (TEM) and microhardness measurements. Results showed that the Ni3Si,Al2O3 and Ni31Si12 phases formed after 5 h of milling with a rapid mechanically induced self-propagating synthesis mode. The average grain size and internal strain of Ni3Si and Al2O3 after 30 h of milling were (16.8 nm, 1.27%) and (19.6 nm,0.94%), respectively. The maximum microhardness value of 813 HV was obtained in the 30 h milled powder. The relationship between the hardness and grain size of the powders satisfes the Hall–Petch relationship. Ni3Si–Al2O3 nanocompositepowders are very stable during heating at 950 °C. By annealing of the milled powders leads to grain growth, internal strainand microhardness of Ni3Si powder decrease and transformation of disordered structure to an ordered state. A long-rangeordering parameter (LRO) of 0.97 for the ordered Ni3Si can be achieved after annealing at 950 °C for 2 h.

Studies on Cryopreservation of D-shaped and Umbo Larvae of Arkshel1(Scapharca broughtonii)

K.H. Kang,K. H. Kho,Z.T. Chen,Kim Y.H.,Kim J.M. 한국발생생물학회 2003 한국발생생물학회 학술발표대회 Vol.2003 No.1

The present study examined the possibility of cryopreservation of the D-shaped and umbo larvae of arkshell (Scapharca broughtonii), in terms of the survival rates after freezing and thawing. D-shaped and umbo larvae of arkshells were obtained from a shellfish farming on Yosu city. The average shell lengths were m and , respectively. Five cryoprotectants (CPAs), dimethyl sulfoxide (DMSO), glycerol, ethylene glycol (EG), propylene glycol (PG), and methanol, were tested at the concentrations of 1.5, 2.0 and 2.5 M. After larvae suspended in CPAs, cryoprotectants were loaded in 0.5 ml straws at a larval density of 50-100 larvae per straw, and epuilibrated for 10 and 20 minute at room temperature (), repectively. Straws were cooled at a rate of /min from to , held for 5 min at , and then cooled at /min to and equilibrated for 5 min followed by plunging in liquid nitrogen. After storage in liquid nitrogen for 1 day, straws were thawed in a water. As soon as straws were observed to melt, larvae were diluted with an equal volume of ASW and then washed twice with a large volume of ASW at an interval of 2 min to unload the CPAs. The results showed that after equilibration for 10 and 20 minute at room temperature, no larvae survived using methanol as CPAs, and it was observed that larval shells all open slightly, and larval flesh broke down and slopped over the shells. The highest survival rates (D-shaped larvae: 77.6%, umbo larvae: 59.3%) were obtained with 2M DMSO, and 1.5M glycerol yielded survival rates of 53.8% for D-shaped larvae and 37.5% for umbo larvae. The surviving D-shaped larvae showed active rotary motion and perfect membrane integrity and cytoplasmic normality, and the vigorous movement of veliger cilia was observed inside the closed shells. The breakdown of tissue occurred in the abnormal larvae, and the isolated cell often run out of shells.

Nitrate Reduction and Pigment Formation of Chinese-Style Sausage Mixes Caused by Micrococcaceae

Guo, H.L.,Chen, M.T.,Liu, D.C. Asian Australasian Association of Animal Productio 2000 Animal Bioscience Vol.13 No.8

This study investigated the nitrate reduction ability of Micrococcaceae on pigment formation in Chinese- style sausage. One hundred ppm sodium nitrite and 150 ppm sodium nitrate was added asepticly to ground pork which was then inoculated with $10^7CFU/g$ of either Micrococcus varians, Staphylococcus carnosus or Staphylococcus xylosus. All samples were cured at $20{^{\circ}C}$ or $30{^{\circ}C}$ for 3 days and then color, residue nitrite, nitrosyl pigment and residue nitrate were determined. The results indicated that samples inoculated with S. xylosus had higher a- and b- values due to nitrate reduction and pigment production after 3 days curing and these values were higher at the higher curing temperature. The nitrosyl pigment of the samples with S. xylosus had highest values after 3 days curing at both $20{^{\circ}C}$ and $30{^{\circ}C}$. However, sample inoculated with S. carnosus and S. xylosus had lower nitrate contents than the sample inoculated with M. varians. At $30{^{\circ}C}$ as well as S. carnosus and M. varians had a stronger decreasing in nitrate concentration during curing at $20{^{\circ}C}$. Moreover, samples inoculated with S. xylosus and S. carnosus had a higher residual nitrite content during curing at $20{^{\circ}C}$ or $30{^{\circ}C}$. In conclusion, two Staphylococci strains tested were most optimum starter cultures for improving pigment formation during Chinese-style sausage curing.

Osmotically driven membrane processes: Exploring the potential of branched polyethyleneimine as draw solute using porous FO membranes with NF separation layers

Cho, M.,Lee, S.H.,Lee, D.,Chen, D.P.,Kim, I.C.,Diallo, M.S. Elsevier Scientific Pub. Co 2016 Journal of membrane science Vol.511 No.-

Forward osmosis (FO) is a promising membrane process with the potential to offer more efficient separation technologies for various environmental and industrial applications including (i) water reuse, (ii) desalination, and (iii) resource recovery. However, a major and unresolved challenge in FO remains the availability of efficient draw solutions that could be (i) implemented using porous and high flux FO membranes and (ii) reconstituted using a low-energy separation process. This study investigates the potential use of a branched polyethyleneimine (PEI) macromolecule (M<SUB>w</SUB> of 25,000Da) as osmotic agent to formulate new draw solutions that could be deployed using porous FO membranes with nanofiltration (NF) selective layers. To asses the potential of PEI-based draw solutions, we combine (i) osmotic pressure measurements, (ii) membrane preparation and characterization, (iii) water flux and reverse solute permeation measurements and (iv) draw solution concentration experiments using NF. The overall results of this study suggest that branched PEI macromolecules (M<SUB>w</SUB> of 25,000Da) are promising building blocks for the development of draw solutions for osmotically-driven membrane processes using a nanofibrous composite (NFC) polyacrylonitrile (PAN) membrane with an NF selective layer and no polyethylene terephthalate (PET) microporous support.

Spectroscopic and molecular characterization of humic substances (HS) from soils and sediments in a watershed: comparative study of HS chemical fractions and the origins

Derrien, M.,Lee, Y. K.,Park, J. E.,Li, P.,Chen, M.,Lee, S. H.,Lee, S. H.,Lee, J. B.,Hur, J. Springer Science + Business Media 2017 Environmental Science and Pollution Research Vol.24 No.20

<P>Optical properties and molecular composition of humic substances (HS) can provide valuable information on the sources and the history of the associated biogeochemical processes. In this study, many well-known spectral and molecular characteristics were examined in eight different HS samples, which were extracted from soils and sediments located in a forested watershed, via two advanced tools including fluorescence excitation emission matrix-parallel factor analysis (EEM-PARAFAC) and high-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Two humic-like (C1 and C2) and one protein-like (C3) components were identified from EEM-PARAFAC. Irrespective of the origins, humic acid (HA) fractions were distinguished from fulvic acid (FA) fractions by the HS characteristics of specific UV absorbance (SUVA), the number of formulas, maximum fluorescence intensities of C1 and C2, condensed aromatics, tannins, and CHON, CHOS, and CHONS classes. In contrast, only five HS indices, including C3 intensity, H%, modified aromatic index (AI(mod)), the percentages of carbohydrates, and unsaturated hydrocarbons, were found to be significant factors in discriminating between the two HS origins (i.e., soils and sediments). The ordination of the Bray-Curtis dissimilarity matrix further confirmed that the HS chemical fraction (i.e., HA or FA) was the more important factor to determine the measured HS characteristics than the HS origin. Our results provided an in-depth insight into the chemical and structural heterogeneity of bulk HS, which could be even beyond the differences observed along the two HS origins. This study also delivers a cautious message that the two operationally defined HS chemical fractions should be carefully considered in tracking the origins of different HS samples.</P>

간호대생과 비보건계열 여대생의 미세먼지 위험에 대한 인식과 지식, 건강 관리행위 비교 연구

김선미,김슬기,김진선,박주형,배다희,유수빈,유영주,임지향,최유진,Chen Mengyao,양숙자,손지희 이화여자대학교 간호과학대학 2019 이화간호학회지 Vol.- No.53

Purpose: This study aimed to know whether there is a comparison of perception, knowledge and health promoting behaviors about particular matter between nursing students and non-health departments college students. Methods: A quantitative research is used. Data were collected from August 1 to 19. The study sample was nursing students and non-health departments students. For the similar condition of samples, this study excluded whose first language is not Korean. Independent T-test and pearson’s correlation was used for this study. Results: A significant positive correlation did not existed between difference of major and perception(t=0.017, p=0.986), knwledge(t=0.652, p=.516) and health promoting behaviors(t=-0.114, p=.910) about particular matters. Conclusion: Based on the study results, there is no significant correlation of perception and actions about particular matters between nursing students and non-health department college students.

Sparse feature selection identifies H2A.Z as a novel, pattern-specific biomarker for asymmetrically self-renewing distributed stem cells

Huh, Y.H.,Noh, M.,Burden, F.R.,Chen, J.C.,Winkler, D.A.,Sherley, J.L. Elsevier 2015 Stem cell research Vol.14 No.2

There is a long-standing unmet clinical need for biomarkers with high specificity for distributed stem cells (DSCs) in tissues, or for use in diagnostic and therapeutic cell preparations (e.g., bone marrow). Although DSCs are essential for tissue maintenance and repair, accurate determination of their numbers for medical applications has been problematic. Previous searches for biomarkers expressed specifically in DSCs were hampered by difficulty obtaining pure DSCs and by the challenges in mining complex molecular expression data. To identify such useful and specific DSC biomarkers, we combined a novel sparse feature selection method with combinatorial molecular expression data focused on asymmetric self-renewal, a conspicuous property of DSCs. The analysis identified reduced expression of the histone H2A variant H2A.Z as a superior molecular discriminator for DSC asymmetric self-renewal. Subsequent molecular expression studies showed H2A.Z to be a novel ''pattern-specific biomarker'' for asymmetrically self-renewing cells, with sufficient specificity to count asymmetrically self-renewing DSCs in vitro and potentially in situ.