Investigation of energy transfer and concentration quenching of Dy³⁺ luminescence in Gd(BO₂)₃ by means of fluorescence dynamics

Zhang, X.,Meng, F.,Li, W.,Kim, S.I.,Yu, Y.M.,Seo, H.J. Elsevier Sequoia 2013 Journal of alloys and compounds Vol.578 No.-

In this paper, the photoluminescence (PL) properties of Dy<SUP>3+</SUP> activated Gd(BO<SUB>2</SUB>)<SUB>3</SUB> phosphors are presented by means of fluorescence dynamics excited by pulsed laser light (λ=266nm). Energy transfer from Gd<SUP>3+</SUP> to Dy<SUP>3+</SUP> and concentration quenching of the Dy<SUP>3+</SUP> luminescence are studied. From the PL spectra and decay curves the energy transfer from Gd<SUP>3+</SUP> to Dy<SUP>3+</SUP> is confirmed. The decay curves of Dy<SUP>3+4</SUP>F<SUB>9/2</SUB>→<SUP>6</SUP>H<SUB>13/2</SUB> transition exhibiting build-up and decay process confirm the energy transfer between Gd<SUP>3+</SUP> to Dy<SUP>3+</SUP>. The rise time becomes shorter as the Dy<SUP>3+</SUP> concentration increases. The theoretical luminescence decay curves of (Gd<SUB>1-x</SUB>Dy<SUB>x</SUB>)(BO<SUB>2</SUB>)<SUB>3</SUB> samples agree well with the experimental observations. The concentration quenching of the Dy<SUP>3+</SUP> ion emission can be ascribed to resonant cross-relaxation. The interaction between the Dy<SUP>3+</SUP> ions is probably of the electric dipole-dipole type through fitting the data with Inokuti-Hirayama (I-H) model. The energy transfer parameters and critical distance for the transfer processes are given.

Genome-wide association study in a Chinese population identifies a susceptibility locus for type 2 diabetes at 7q32 near <i>PAX4</i>

Ma, R. C. W.,Hu, C.,Tam, C. H.,Zhang, R.,Kwan, P.,Leung, T. F.,Thomas, G. N.,Go, M. J.,Hara, K.,Sim, X.,Ho, J. S. K.,Wang, C.,Li, H.,Lu, L.,Wang, Y.,Li, J. W.,Wang, Y.,Lam, V. K. L.,Wang, J.,Yu, W.,Ki Springer-Verlag 2013 Diabetologia Vol.56 No.6

<P><B>Aims/hypothesis</B></P><P>Most genetic variants identified for type 2 diabetes have been discovered in European populations. We performed genome-wide association studies (GWAS) in a Chinese population with the aim of identifying novel variants for type 2 diabetes in Asians.</P><P><B>Methods</B></P><P>We performed a meta-analysis of three GWAS comprising 684 patients with type 2 diabetes and 955 controls of Southern Han Chinese descent. We followed up the top signals in two independent Southern Han Chinese cohorts (totalling 10,383 cases and 6,974 controls), and performed in silico replication in multiple populations.</P><P><B>Results</B></P><P>We identified <I>CDKN2A/B</I> and four novel type 2 diabetes association signals with <I>p</I> < 1 × 10<SUP>−5</SUP> from the meta-analysis. Thirteen variants within these four loci were followed up in two independent Chinese cohorts, and rs10229583 at 7q32 was found to be associated with type 2 diabetes in a combined analysis of 11,067 cases and 7,929 controls (<I>p</I><SUB>meta</SUB> = 2.6 × 10<SUP>−8</SUP>; OR [95% CI] 1.18 [1.11, 1.25]). In silico replication revealed consistent associations across multiethnic groups, including five East Asian populations (<I>p</I><SUB>meta</SUB> = 2.3 × 10<SUP>−10</SUP>) and a population of European descent (<I>p</I> = 8.6 × 10<SUP>−3</SUP>). The rs10229583 risk variant was associated with elevated fasting plasma glucose, impaired beta cell function in controls, and an earlier age at diagnosis for the cases. The novel variant lies within an islet-selective cluster of open regulatory elements. There was significant heterogeneity of effect between Han Chinese and individuals of European descent, Malaysians and Indians.</P><P><B>Conclusions/interpretation</B></P><P>Our study identifies rs10229583 near <I>PAX4</I> as a novel locus for type 2 diabetes in Chinese and other populations and provides new insights into the pathogenesis of type 2 diabetes.</P><P><B>Electronic supplementary material</B></P><P>The online version of this article (doi:10.1007/s00125-013-2874-4) contains peer-reviewed but unedited supplementary material, which is available to authorised users.</P>

Improving mechanical and magnetocaloric responses of amorphous melt-extracted Gd-based microwires via nanocrystallization

Belliveau, H.F.,Yu, Y.Y.,Luo, Y.,Qin, F.X.,Wang, H.,Shen, H.X.,Sun, J.F.,Yu, S.C.,Srikanth, H.,Phan, M.H. Elsevier 2017 JOURNAL OF ALLOYS AND COMPOUNDS Vol.692 No.-

<P><B>Abstract</B></P> <P>We report on the structural, mechanical, and magnetocaloric properties of annealed melt-extracted Gd<SUB>53</SUB>Al<SUB>24</SUB>Co<SUB>20</SUB>Zr<SUB>3</SUB> amorphous microwires of ∼70 μm diameter. During heat treatment small islands of nanocrystallities are generated and isolated in the amorphous region for the wires. The size of the nanocrystallities ranges from 5 nm to 10 nm. The observed lattice distortion from the nanocrystallities causes changes in the magnetic properties of the wires. The annealing temperature of 100 °C has the largest strength (1845 MPa) as compared to wires annealed at other temperatures. This is likely to trigger nanophase transformation in the amorphous region and these nanocrystals have been preserved through the increase of annealing temperature. The formulation of the nanocrystalline islands is also verified by the selected-area electron diffraction (SAED). The microwires exhibit a large and reversible magnetocaloric effect (MCE), with the maximum isothermal magnetic entropy change (−Δ<I>S</I> <SUB>M</SUB>) and refrigerant capacity (<I>RC</I>) values of 9.5 J/kg K and 689 J/kg respectively for the microwire annealed at 100 °C. This <I>RC</I> is about 35%, 67%, and 91% larger than those of bulk Gd<SUB>53</SUB>Al<SUB>24</SUB>Co<SUB>20</SUB>Zr<SUB>3</SUB> (∼509 J/kg), Gd (∼410 J/kg), and Gd<SUB>5</SUB>Si<SUB>2</SUB>Ge<SUB>1.9</SUB>Fe<SUB>0.1</SUB> (∼360 J/kg) regardless of their ordering temperatures. These results demonstrate the ability to tune the mechanical and magnetic properties of the microwires by thermal annealing.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The impact of nanocrystallization in Gd<SUB>53</SUB>Al<SUB>24</SUB>Co<SUB>20</SUB>Zr<SUB>3</SUB> microwires. </LI> <LI> Enhanced mechanical strength. </LI> <LI> Enhanced magnetocaloric response. </LI> </UL> </P>

Impact of structural disorder on the magnetic ordering and magnetocaloric response of amorphous Gd-based microwires

Biswas, Anis,Yu, Y. Y.,Bingham, N. S.,Wang, H.,Qin, F. X.,Sun, J. F.,Yu, S. C.,Franco, V.,Srikanth, H.,Phan, M. H. American Institute of Physics 2014 JOURNAL OF APPLIED PHYSICS - Vol.115 No.17

<P>We have studied the impact of structural disorder on the magnetic ordering and magnetocaloric response of amorphous Gd68Ni32 and Gd53Al24Co20Zr3 microwires. We find that the presence of structural disorder significantly broadens the paramagnetic to ferromagnetic (PM-FM) transition and the temperature-dependent magnetic entropy change, while the nature of the second-order magnetic transition and long-range ferromagnetic order are not essentially affected by this effect. The large magnetic moment of Gd and the presence of the long-range ferromagnetic order are believed to result in a large magnetic entropy change, which together with the broadening of the PM-FM transition due to structural disorder contribute to a large refrigerant capacity. The excellent magnetocaloric properties of the amorphous microwires make them very promising candidates for active magnetic refrigeration. (C) 2014 AIP Publishing LLC.</P>

Luminescence properties of Eu³⁺ in gadolinium molybdate β'-Gd₂Mo₃O₁₂ phosphors

Meng, F.,Zhang, X.,Kim, S.I.,Yu, Y.M.,Seo, H.J. Wissenschaftliche Verlagsgesellschaft m. b. H 2014 OPTIK -STUTTGART- Vol.125 No.14

In this paper, we report the synthesis and photoluminescence (PL) properties of β'-Gd<SUB>2</SUB>Mo<SUB>3</SUB>O<SUB>12</SUB> doped with Eu<SUP>3+</SUP> ions. The relationship between Eu<SUP>3+</SUP> luminescence versus concentration and temperature is discussed. In order to investigate the mechanism of concentration quenching, luminescence decay curves are measured and the Inokuti-Hirayama model is used to analyze them. The activation energy for the thermal quenching is estimated by the Arrhenius fitting. The emission spectrum of β'-Gd<SUB>2</SUB>Mo<SUB>3</SUB>O<SUB>12</SUB> exhibits the strongest emission peak at 614.5nm due to electric-dipole transition. The excitation spectrum shows several sets of lines in the range of 350-425nm which are associated with the typical intra-configurational 4f<SUP>6</SUP> transitions of Eu<SUP>3+</SUP>. The spectral positions of these lines match well with the emission spectra of near-UV LEDs, which makes the phosphor find a potential application for white light-emitting-diodes.

Humidity-assisted selective reactivity between NO₂ and SO₂ gas on carbon nanotubes

Yao, Fei,Duong, Dinh Loc,Lim, Seong Chu,Yang, Seung Bum,Hwang, Ha Ryong,Yu, Woo Jong,Lee, Il Ha,Gü,ne&#x15f,, Fethullah,Lee, Young Hee Royal Society of Chemistry 2011 Journal of materials chemistry Vol.21 No.12

<P>In spite of the technical importance of detecting environmental SO<SUB><I>x</I></SUB> and NO<SUB><I>x</I></SUB> gases, a selective detection has not been realized because of their similar chemical properties. In this report, adsorption and desorption of SO<SUB>2</SUB> and NO<SUB>2</SUB> gas on carbon nanotubes are investigated in terms of different humidity levels at room temperature. A random-network single walled carbon nanotube (SWCNT) resistor is constructed by a dip-pen method using a SWCNT/dichloroethane (DCE) solution. In the case of SO<SUB>2</SUB> gas adsorption, the resistance increases at high humidity level (92%) and shows no obvious change at low humidity levels. On the other hand, in the case of NO<SUB>2</SUB> gas adsorption, the resistance always decreases independent of moisture levels. Our density functional theory (DFT) calculations show that this selective behavior originates from cooperative charge compensation between the SO<SUB>2</SUB>–<I>n</I>H<SUB>2</SUB>O complex and the p-type CNT resistor. The change of response time and recovery time with different moisture levels is further investigated. This humidity-assisted gas reaction provides a simple route to detect these two gases selectively.</P> <P>Graphic Abstract</P><P>Selective detection of SO<SUB>2</SUB> and NO<SUB>2</SUB> gas has been successfully realized on carbon nanotubes by introducing humidity in this study. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c0jm03227a'> </P>

Effects of Adding Super Dose Phytase to the Phosphorus-deficient Diets of Young Pigs on Growth Performance, Bone Quality, Minerals and Amino Acids Digestibilities

Zeng, Z.K.,Wang, D.,Piao, X.S.,Li, P.F.,Zhang, H.Y.,Shi, C.X.,Yu, S.K. Asian Australasian Association of Animal Productio 2014 Animal Bioscience Vol.27 No.2

Two experiments were conducted to evaluate the efficacy of feeding an Escherichia coli (E. coli) derived phytase to pigs fed P deficient, corn-soybean meal diets. In Exp. 1, one hundred and twenty crossbred piglets ($9.53{\pm}0.84$ kg) were allocated to one of five treatments which consisted of four low P diets (0.61% Ca, 0.46% total P and 0.24% non-phytate P) supplemented with 0, 500, 1,000, or 20,000 FTU/kg E. coli phytase as well as a positive control formulated to be adequate in all nutrients (0.77% Ca, 0.62% total P and 0.42% non-phytate P). The treatments were applied to six pens with four pigs per pen for 28 days. In Exp. 2, ten crossbred pigs ($19.66{\pm}1.16$ kg) fitted with ileal T-cannula were used in a nutrient balance study. The pigs were assigned to treatments similar to those used in Exp. 1 in a doubly replicated $5{\pm}4$ incomplete Latin square design (5 diets with 4 periods). Each period consisted of a 5-d adjustment period followed by a 3-d total collection of feces and urine and then a 2-d collection of ileal digesta. Supplementation with phytase linearly increased (p<0.05) weight gain, feed intake, feed efficiency, bone breaking strength and fat-free dry and ash bone weight. There were linear increases (p<0.01) in the apparent ileal digestibility (AID) of DM, GE, CP, Ca, total P, inositol hexaphosphate ($IP_6$) and some AA with increasing dose of E. coli phytase. Pigs fed 20,000 FTU/kg had a greater (p<0.05) AID of IP6 (80% vs 59% or 64%, respectively) than pigs fed diets with 500 or 1,000 FTU/kg phytase. There were linear increases (p<0.05) in the total tract digestibility of Ca, total P, Na, K, Mg, and Zn as well as in the retention of Mg and Zn with increased phytase dose. The retention and utilization of Cu, and the total tract digestibility of CP and Cu quadratic increased (p<0.05) with increased phytase dose. In conclusion, supplementation of 500 FTU of phytase/kg and above effectively hydrolyzed phytate in low-P corn-soybean diets for pigs. In addition, a super dose of phytase (20,000 FTU/kg) hydrolyzed most of the IP6 and consequently further improved mineral use, protein utilization and performance.

Physciosporin suppresses the proliferation, motility and tumourigenesis of colorectal cancer cells

Ta&#x15f,, &#x130,sa,Han, Jin,Park, So-Yeon,Yang, Yi,Zhou, Rui,Gamage, Chathurika D.B.,Van Nguyen, Tru,Lee, Ji-Yoon,Choi, Yong Jae,Yu, Young Hyun,Moon, Kyung-Sub,Kim, Kyung Keun,Ha, Hyung-Ho,Kim, Sang Elsevier 2019 Phytomedicine Vol.56 No.-

<P><B>Abstract</B></P> <P><B>Background</B></P> <P>Lichens, which represent symbiotic associations of fungi and algae, are potential sources of numerous natural products. Physciosporin (PHY) is a potent secondary metabolite found in lichens and was recently reported to inhibit the motility of lung cancer cells via novel mechanisms.</P> <P><B>Purpose</B></P> <P>The present study investigated the anticancer potential of PHY on colorectal cancer (CRC) cells.</P> <P><B>Methods</B></P> <P>PHY was isolated from lichen extract by preparative TLC. The effect of PHY on cell viability, motility and tumourigenicity was elucidated by MTT assay, hoechst staining, flow cytometric analysis, transwell invasion and migration assay, soft agar colony formation assay, Western blotting, qRT-PCR and PCR array <I>in vitro</I> as well as tumorigenicity study <I>in vivo</I>.</P> <P><B>Results</B></P> <P>PHY decreased the viability of various CRC cell lines (Caco2, CT26, DLD1, HCT116 and SW620). Moreover, PHY elicited cytotoxic effects by inducing apoptosis at toxic concentrations. At non-toxic concentrations, PHY dose-dependently suppressed the invasion, migration and colony formation of CRC cells. PHY inhibited the motility of CRC cells by suppressing epithelial-mesenchymal transition and downregulating actin-based motility markers. In addition, PHY downregulated β-catenin and its downstream target genes cyclin-D1 and c-Myc. Moreover, PHY modulated KAI1 C-terminal-interacting tetraspanin and KAI1 expression, and downregulated the downstream transcription factors c-jun and c-fos. Finally, PHY administration showed considerable bioavailability and effectively decreased the growth of CRC xenografts in mice without causing toxicity.</P> <P><B>Conclusion</B></P> <P>PHY suppresses the growth and motility of CRC cells via novel mechanisms.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

A CMOS Frequency divider for 2.4/5GHz WLAN Applications with a Simplified Structure

Yu, Q.,Liu, Y.,Yu, X.P.,Lim, W.M.,Yang, F.,Zhang, X.L.,Peng, Y. The Institute of Electronics and Information Engin 2011 Journal of semiconductor technology and science Vol.11 No.4

In this paper, a dual-band integer-N frequency divider is proposed for 2.4/5.2 GHz multi-standard wireless local area networks. It consists of a multi-modulus imbalance phase switching prescaler and two all-stage programmable counters. It is able to provide dual-band operation with high resolution while maintaining a low power consumption. This frequency divider is integrated with a 5 GHz VCO for multi-standard applications. Measurement results show that the VCO with frequency divider can work at 5.2 GHz with a total power consumption of 22 mW.

INTEGRATED VEHICLE CHASSIS CONTROL WITH A MAIN/SERVO-LOOP STRUCTURE

Li, D.,Shen, X.,Yu, F. The Korean Society of Automotive Engineers 2006 International journal of automotive technology Vol.7 No.7

In order to reduce the negative effects of dynamic coupling among vehicle subsystems and improve the handling performance of vehicle under severe driving conditions, a vehicle chassis control integration approach based on a main-loop and servo-loop structure is proposed. In the main-loop, in order to achieve satisfactory longitudinal, lateral and yaw response, a sliding mode controller is used to calculate the desired longitudinal, lateral forces and yaw moment of the vehicle; and in the servo-loop, a nonlinear optimizing method is adopted to compute the optimal control inputs, i.e. wheel control torques and active steering angles, and thus distributes the forces and moment to four tire/road contact patches. Simulation results indicate that significant improvement in vehicle handling and stability can be expected from the proposed chassis control integration.