Derivatization reaction-based surface-enhanced Raman scattering (SERS) for detection of trace acetone

Zheng, Y.,Chen, Z.,Zheng, C.,Lee, Y.I.,Hou, X.,Wu, L.,Tian, Y. Pergamon Press ; Elsevier Science Ltd 2016 Talanta Vol.155 No.-

<P>A facile method was developed for determination of trace volatile acetone by coupling a derivatization reaction to surface-enhanced Raman scattering (SERS). With iodide modified Ag nanoparticles (Ag IMNPs) as the SERS substrate, acetone without obvious Raman signal could be converted to SERS-sensitive species via a chemical derivatization reaction with 2,4-dinitrophenylhydrazine (2,4-DNPH). In addition, acetone can be effectively separated from liquid phase with a purge-sampling device and then any serious interference from sample matrices can be significantly reduced. The optimal conditions for the derivatization reaction and the SERS analysis were investigated in detail, and the selectivity and reproducibility of this method were also evaluated. Under the optimal conditions, the limit of detection (LOD) for acetone was 5 mg L-1 or 0.09 mM (3 sigma). The relative standard deviation (RSD) for 80 mg L-1 acetone (n=9) was 1.7%. This method was successfully used for the determination of acetone in artificial urine and human urine samples with spiked recoveries ranging from 92% to 110%. The present method is convenient, sensitive, selective, reliable and suitable for analysis of trace acetone, and it could have a promising clinical application in early diabetes diagnosis. (C) 2016 Elsevier B.V. All rights reserved.</P>

Evidence for the onset of color transparency in ρ⁰ electroproduction off nuclei

CLAS Collaboration,El Fassi, L.,Zana, L.,Hafidi, K.,Holtrop, M.,Mustapha, B.,Brooks, W.K.,Hakobyan, H.,Zheng, X.,Adhikari, K.P.,Adikaram, D.,Aghasyan, M.,Amaryan, M.J.,Anghinolfi, M.,Arrington, J.,Ava North-Holland Pub. Co 2012 Physics letters: B Vol.712 No.4

We have measured the nuclear transparency of the incoherent diffractive A(e,e<SUP>'</SUP>ρ<SUP>0</SUP>) process in <SUP>12</SUP>C and <SUP>56</SUP>Fe targets relative to <SUP>2</SUP>H using a 5 GeV electron beam. The nuclear transparency, the ratio of the produced ρ<SUP>0</SUP>@?s on a nucleus relative to deuterium, which is sensitive to ρA interaction, was studied as function of the coherence length (l<SUB>c</SUB>), a lifetime of the hadronic fluctuation of the virtual photon, and the four-momentum transfer squared (Q<SUP>2</SUP>). While the transparency for both <SUP>12</SUP>C and <SUP>56</SUP>Fe showed no l<SUB>c</SUB> dependence, a significant Q<SUP>2</SUP> dependence was measured, which is consistent with calculations that included the color transparency effects.

Topiramate stimulates glucose transport through AMP-activated protein kinase-mediated pathway in L6 skeletal muscle cells

Ha, E,Yim, S V,Jung, K H,Yoon, S H,Zheng, L T,Kim, M J,Hong, S J,Choe, B K,Baik, H H,Chung, J H,Kim, J W Nature Publishing Group 2006 The pharmacogenomics journal Vol.6 No.5

The use of topiramate (TPM) in the treatment of binge-eating disorder, bulimia nervosa, and antipsychotic-induced weight gain has recently increased, however, the exact molecular basis for its effects on body weight reduction and improved glucose homeostasis, is yet to be elucidated. Here we investigated the effect and signaling pathway of TPM on glucose uptake in L6 rat skeletal muscle cells, which account for >70% of glucose disposal in the body. Intriguingly, we found that TPM (10 μM) stimulated the rate of glucose uptake up to twofold increase. And TPM-stimulated glucose transport was inhibited with the overexpression of dominant-negative form of AMP-activated protein kinase (AMPK), an important mediator in glucose transport, implicating that AMPK-mediated pathway is involved. The TPM-stimulated glucose transport was blocked by SB203580, a specific inhibitor of AMPK downstream mediator, p38 mitogen-activated protein kinase (MAPK) protein. LY294002, an inhibitor of phosphatidylinositol (PI) 3-kinase, which is another crucial mediator in independent glucose transport pathway, did not inhibit TPM-stimulated glucose transport. We also found that TPM increased the phosphorylation level of AMPK and p38 MAPK, whereas no effect on the activity of PI 3-kinase of TPM, when assessed by PI 3-kinase assay, was observed. These results together suggest that TPM stimulates glucose transport, not via PI 3-kinase mediated, but via AMPK-mediated pathway in skeletal muscle cells, thereby contributing to the body weight regulation and glucose homeostasis.The Pharmacogenomics Journal (2006) 6, 327–332. doi:10.1038/sj.tpj.6500366; published online 17 January 2006

Effect of night light regimen on growth performance, antioxidant status and health of broiler chickens from 1 to 21 days of age

R.X. Zhao,C.H. Cai,P. Wang,L. Zheng,J.S. Wang,K.X. Li,W. Liu,X.Y. Guo,X. A. Zhan,K.Y. Wang 아세아·태평양축산학회 2019 Animal Bioscience Vol.32 No.6

Objective: The study was conducted to evaluate the effects of night light regimen on growth performance, antioxidant status and health of Lingnan Yellow broiler chickens from 1 to 21 days of age. Methods: A completely randomized factorial design involved 2 photoperiods (constant lighting [CL], 24 L:0 D and intermittent lighting [INL], 17 L:3 D:1 L:3 D)×2 light intensities (10 lx and 30 lx). A total of one thousand six hundred and eighty 1-d-old Lingnan Yellow broiler chicks were randomly divided into 4 treatments with 6 replicates (70 birds per replicate). The experiment lasted for 21 d. Results: Photoperiods and light intensities had no effect on average daily gain, feed conversion ratio, and mortality of the broiler chickens (p>0.05). The INL had a significant effect on average daily feed intake (p<0.05) of broiler chickens compared with CL. Photoperiod and light intensity had an interactive effect on melatonin (MT) concentration (p<0.05). At CL, reducing light intensity increased MT concentration; INL birds had higher MT but MT concentration was not affected by light intensity. There was an interactive effect on glutathione peroxidase (GPx) and catalase (CAT) in serum and total antioxidant capability (T-AOC) in liver between photoperiod and light intensity. With the decrease of light intensity, the activities of GPx and CAT in serum and T-AOC in liver increased in CL group (p<0.05). Broiler chickens reared under INL had better antioxidant status and 10 lx treatments had higher activities of CAT in serum than 30 lx (p<0.05). Different photoperiods and light intensities had no effect on malondialdehyde. There was an interaction between photoperiod and light intensity on serum creatine kinase (CK) concentration (p<0.05). At CL, the elevated light intensity resulted in an increase in CK content; INL birds had lower CK concentration especially in low light intensity group. Besides, INL and low light intensity significantly reduced the concentration of serum corticosterone and heat shock protein 70 (p<0.05). Serum immunoglobulin M contents were increased in broiler chickens reared under the INL compared with CL group (p<0.05). Conclusion: Results above suggest that the night light regimen of INL and 10 lx could be beneficial to the broiler chickens from 1 to 21 days of age due to the better health status and electricity savings.

An approach in analyzing the noise characteristics caused by inhomogeneity of media in optical disk

L. Li,Y. X. Zheng,J. Li,L. Y. Chen 한국물리학회 2004 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.44 No.32

In this paper, the optical-matrix method and Monte Carlo method are combined to analyze the characteristics of media noise, which is induced by inhomogeneity of optical constants of materials in a phase-change optical disk. We obtained the re ectivity of the optical disk with recorded domain, both in crystalline phase and in amorphous phase, by the use of an optical-matrix method. Adding a random variable to the refractive index of an arbitrary layer, we use the Monte Carlo method to analyze the noise characteristics contributed by the inhomogeneity of the materials of the optical disk. The results reveal that the noise level mostly depends on the Ge2Sb2Te5 material and the undercoat layer.

Stacked Hydrophilic Fibers Porous Surfaces Enables Self-water Supply Evaporative Cooling to Improve Thermoelectric Output Capability

L. J. Zheng(정량준),D. H. Kang(강동희),H. W. Kang(강현욱) Korean Society for Precision Engineering 2022 한국정밀공학회 학술발표대회 논문집 Vol.2022 No.10

Strain Sensitivity of Electric-Magnetic Coupling in Flexible Terahertz Metamaterials

Zheng, L.,Sun, X.,Xu, H.,Lu, Y.,Lee, Y.,Rhee, J. Y.,Song, W. SPRINGER SCIENCE + BUSINESS MEDIA 2015 PLASMONICS Vol.10 No.6

Fuzzy-sliding mode control of a full car semi-active suspension systems with MR dampers

Zheng, L.,Li, Y.N.,Baz, A. Techno-Press 2009 Smart Structures and Systems, An International Jou Vol.5 No.3

A fuzzy-sliding mode controller is presented to control the dynamics of semi-active suspension systems of vehicles using magneto-rheological (MR) fluid dampers. A full car model is used to design and evaluate the performance of the proposed semi-active controlled suspension system. Four mixed mode MR dampers are designed, manufactured, and integrated with four independent sliding mode controllers. The siding mode controller is designed to decrease the energy consumption and maintain robustness. In order to overcome the chattering of the sliding mode controllers, a fuzzy logic control strategy is merged into the sliding mode controller. The proposed fuzzy-sliding mode controller is designed and fabricated. The performance of the semi-active suspensions is evaluated in both the time and frequency domains. The obtained results demonstrate that the proposed fuzzy-sliding mode controller can effectively suppress the vibration of vehicles and improve their ride comfort and handling stability. Furthermore, it is shown that the "chattering" of the sliding mode controller is smoothed when it is integrated with a fuzzy logic control strategy. Although the cost function of the fuzzy-sliding mode control is a slightly higher than that of a classical LQR controller, the control effectiveness and robustness are enhanced considerably.

Anti-inflammatory effects of catechols in lipopolysaccharide-stimulated microglia cells: Inhibition of microglial neurotoxicity

Zheng, L.T.,Ryu, G.M.,Kwon, B.M.,Lee, W.H.,Suk, K. North-Holland ; Elsevier Science Ltd 2008 european journal of pharmacology Vol.588 No.1

Microglial activation plays a pivotal role in the pathogenesis of neurodegenerative diseases by producing various proinflammatory cytokines and nitric oxide (NO). In the present study, the anti-inflammatory and subsequent neuroprotective effects of catechol and its derivatives including 3-methylcatechol, 4-methylcatechol, and 4-tert-butylcatechol were investigated in microglia and neuroblastoma cells in culture. The four catechol compounds showed anti-inflammatory effects with different potency. The catechols significantly decreased lipopolysaccharide (LPS)-induced NO and tumor necrosis factor (TNF)-α production in BV-2 microglia cells. The catechols also inhibited the expression of inducible nitric oxide synthase (iNOS) and TNF-α at mRNA or protein levels in the LPS-stimulated BV-2 cells. In addition, the catechols inhibited LPS-induced nuclear translocation of p65 subunit of nuclear factor (NF)-κB, IκB degradation, and phosphorylation of p38 mitogen-activated protein kinase (MAPK) in BV-2 cells. Moreover, the catechols attenuated the cytotoxicity of LPS-stimulated BV-2 microglia toward co-cultured rat B35 neuroblastoma cells. The catechols, however, did not protect B35 cells against H<SUB>2</SUB>O<SUB>2</SUB> toxicity, indicating that the compounds exerted the neuroprotective effect by inhibiting the inflammatory activation of microglia in the co-culture. The anti-inflammatory and neuroprotective properties of the catechols in cultured microglia and neuroblastoma cells suggest a therapeutic potential of these compounds for the treatment of neurodegenerative diseases that are associated with an excessive microglial activation.

FATIGUE ASSESSMENT OF REAR AXLE UNDER SERVICE LOADING HISTORIES CONSIDERING THE STRENGTHENING AND DAMAGING EFFECTS OF LOADS BELOW FATIGUE LIMIT

L. H. ZHAO,S. L. ZHENG,J. Z. FENG,H. F. ZHOU,Y. F. XING 한국자동차공학회 2014 International journal of automotive technology Vol.15 No.5

Accurately predicting the fatigue life is the basis for the reliability and lightweight design of automobile parts. However, the predicted lives under service loadings on the basis of the S-N curve from constant amplitude loads from existingmethods often seems conservative compared with real lives, because of ignoring the strengthening effect of loads belowfatigue limit. In this paper, a fatigue damage model, which is modification of Miner's Rule, was established for the fatigueassessment under service loadings by means of taking into account the strengthening and damaging effects of loads belowfatigue limit. Then this model and conventional Miner's Rule are applied to the estimate the fatigue life of a torsion beam rearaxle using the loading history recorded on proving ground. Finally, verification tests are performed on MTS road loadsimulator test bed. Results of predicted lives and fatigue tests demonstrate that the accuracy of the predicted life could begreatly improved by taking into account the strengthening and damaging effect of loads below fatigue limit.