The H,G_1,G_2 photometric system with scarce observational data

Science.gov (United States)

Penttilä, A.; Granvik, M.; Muinonen, K.; Wilkman, O.

2014-07-01

The H,G_1,G_2 photometric system was officially adopted at the IAU General Assembly in Beijing, 2012. The system replaced the H,G system from 1985. The 'photometric system' is a parametrized model V(α; params) for the magnitude-phase relation of small Solar System bodies, and the main purpose is to predict the magnitude at backscattering, H := V(0°), i.e., the (absolute) magnitude of the object. The original H,G system was designed using the best available data in 1985, but since then new observations have been made showing certain features, especially near backscattering, to which the H,G function has troubles adjusting to. The H,G_1,G_2 system was developed especially to address these issues [1]. With a sufficient number of high-accuracy observations and with a wide phase-angle coverage, the H,G_1,G_2 system performs well. However, with scarce low-accuracy data the system has troubles producing a reliable fit, as would any other three-parameter nonlinear function. Therefore, simultaneously with the H,G_1,G_2 system, a two-parameter version of the model, the H,G_{12} system, was introduced [1]. The two-parameter version ties the parameters G_1,G_2 into a single parameter G_{12} by a linear relation, and still uses the H,G_1,G_2 system in the background. This version dramatically improves the possibility to receive a reliable phase-curve fit to scarce data. The amount of observed small bodies is increasing all the time, and so is the need to produce estimates for the absolute magnitude/diameter/albedo and other size/composition related parameters. The lack of small-phase-angle observations is especially topical for near-Earth objects (NEOs). With these, even the two- parameter version faces problems. The previous procedure with the H,G system in such circumstances has been that the G-parameter has been fixed to some constant value, thus only fitting a single-parameter function. In conclusion, there is a definitive need for a reliable procedure to produce

A simple and highly selective ‘turn-on’ type fluorescence chemodosimeter for Hg2+ based on 1-(2-phenyl-2H-[1,2,3]triazole-4-carbonyl)thiosemicarbazide

International Nuclear Information System (INIS)

Lin, Hui; Shi, Wei; Tian, Yong; Ma, Fudong; Xu, Linxian; Ma, Junchi; Hui, Yonghai; Xie, Zhengfeng

2015-01-01

1-(2-phenyl-2H-[1,2,3]triazole-4-carbonyl)-4- (4-methylphenyl)thiosemicarbazide (M1) has been synthesized and investigated as a fluorescence chemodosimeter for Hg 2+ in dimethylsulfoxide. Highly selective ‘turn-on’ fluorescence alterations of M1 were observed upon the addition of Hg 2+ . Detection limit of Hg 2+ by M1 reaches ~3.7×10 −8 mol/L (evaluated by 3σ criteria).The coexistent metal ions rendered no obvious interference toward the optical response of M1 for Hg 2+ .The mechanism of M1 for the recognition of Hg 2+ has been investigated by FT-IR, 1 H NMR and MS analyses. - Highlights: • A type of thiosemicarbazide-derivatived compound (M1) was synthesized. • The fluorescence of M1 displayed highly selective ‘turn-on’ type fluorescence alteration with the presence of Hg 2+ . • Detection limit of ~3.7×10 −8 M for Hg 2+ can be obtained by this probing system. • Hg 2+ -induced intramolecular desulfurization and cyclization process of thiosemicarbazide moieties is the plausible probing mechanism

MODIS/Aqua Clouds 5-Min L2 Swath 1km and 5km V006

Data.gov (United States)

National Aeronautics and Space Administration — The MODIS/Aqua Clouds 5-Min L2 Swath 1km and 5km (MYD06_L2) product consists of cloud optical and physical parameters. These parameters are derived using remotely...

Efeito da temperatura, pH e vestígios de Hg2+ e Pb2+ na acti­vidade de desidrogenases e urease num solo da região de Évora Effect of temperature, pH and Hg2+ and Pb2+ traces in dehydrogenaseand urease activities of a soil from Évora region

Directory of Open Access Journals (Sweden)

M. R. Martins

2010-01-01

Full Text Available As actividades das enzimas no solo são um importante indicador da sua qualida­de. Neste estudo procedeu-se à caracteri­zação da actividade enzimática de desi­drogenases (EC 1.1.1 e da urease (EC 3.5.1.5 de um solo sob Olea europeae L. da região de Évora. As constantes cinéti­cas Km e Vmáx, foram determinadas usando como substratos o cloreto de p­-iodonitrotetrazolio (INT e a ureia, res­pectivamente. Foi avaliado o efeito nas referidas actividades provocado pelo pH, temperatura e vestígios de Hg2+ e de Pb2+. As actividades máximas obtiveram-se a pH = 8,5 e 40 ºC, com Km= 0,5 mM e Vmáx = 5,4 µmol min-1 g-1, para a activida­de de desidrogenases e a pH = 10 e 37 ºC, com Km = 25,7 mM e Vmáx = 2,0x10-2 µmol min-1 g-1, para a urease. Estas acti­vidades foram inibidas por diferentes concentrações de Hg2+, mas apenas a acti­vidade da urease foi inibida pelo Pb2+. Estes resultados são comparáveis com os referidos na literatura para estes enzimas.Enzyme activities are often used as in­dicator of soil quality. This study reports on dehydrogenase (EC 1.1.1 and urease (EC 3.5.1.5 activities of a soil under Olea europaea L. from Évora region. Kinetic constants Km and Vmax were determined using p-iodonitrotetrazolium chloride (INT and urea, respectively. Effects of pH, temperature and Hg2+ and Pb2+ traces on both activities were determined. Maximal activity was obtained at pH = 8.5 and 40ºC, Km = 0.5 mM and Vmax=5,4µmol min-1 g-1 , for dehydro­genase and at pH = 10 and 37 ºC, Km = 25.7 mM and Vmax = 2.0x10-2 µmol min-1 g-1, for urease. These activities were in­hibited by different concentrations of Hg2+, but only the urease activity was in­hibited by Pb2+. Results of this study are comparable to those reported in the litera­ture for these enzymes.

Uptake and clearance of mercury Hg (NO3)2-203Hg by the guppy (Lebistes reticulatus)

International Nuclear Information System (INIS)

Ferreira, J.R.; Rodrigues, N.S.; Nascimento Filho, V.F. do

1982-01-01

Fishes weighing between 20.6 and 536.9 mg were exposed to 25, 50 and 100 μg Hg.l -1 as Hg (NO 3 ) 2 labelled with 203 Hg, for 17 days in plastic aquaria containing 4 litre of soft aerated dechlorinated water. Whole body mercury contents were determined periodically by gamma counting, using a single channel spectrometer and a 3 in X 3 in NaI(Tl) well crystal. The highest bioconcentration of mercury was after 100 h of exposure for all the treatments. A further study on the clearance of mercury nitrate was carried out by transfering fishes to mercury-free water, after a period of 100 h of exposure in solutions of 35 and μg Hg.l -1 . The fishes were not sacrificed after the dose measurment, being returned to the aquaria for further sampling. The rate of clearance was similar for both concentrations. After 120 h exposure to uncontamined water, the fishes excreted the mercury previously absorbed. The correlation coefficient of the experimentals equations were 0.91 and 0.94, respectively, for the treatments 35 and 70 μg Hg.l -1 . Both experiments, uptake and clearance were made at same values of the water physico-chemical parameters (hardness = 36 mg CaCO 3 ; pH=7.2; O.D.=7.0 mg/l; temperature=23 +- 1 0 C). (Author) [pt

Galvanomagnetic effects in n-Hg1-x-yCdxMnyTe and n-Hg1-yMnyTe crystals with εg>0

International Nuclear Information System (INIS)

Gluzman, N.G.; Lerinman, N.K.; Sabirzyanova, L.D.; Bodnaruk, O.A.; Gorbatyuk, I.N.; Rarenko, I.M.

1989-01-01

Longitudinal ρ zz and transverse ρ xx magnetoresistances and R hall coefficient in H magnetic fields up to 100 kE at 1.2≤T≤300 K are measured at n-Hg 1-x-y Cd x Mn y Te and n-Hg 1-y Mn y Te crystals (100≤ε g ≤260 meV) with N D -N A ≅10 15 cm -3 . Shubnikov-de-Gaas (SG) oscillations were observed at all specimens. Maxima positions of SG oscillations depend on T. For Hg 1-y Mn y Te crystals the position of zero maximum is shifted to large H direction, it is caused by abrupt (as compared to zone one) reduction of summary g-factor. Magnetophonon oscillations are determined at longitudinal magnetoresistance. Transition from metal conductivity to activation one occuring in magnetic field is studied; activation energy in nonmetallic range is determined. Some peculiarities of galvanomagnetic phenomena in n-Hg 1-y Mn y Te specimens, which indicate presence of p-type inclusions in n-type crystals, are determined

2-HG Inhibits Necroptosis by Stimulating DNMT1-Dependent Hypermethylation of the RIP3 Promoter

Directory of Open Access Journals (Sweden)

Zhentao Yang

2017-05-01

Full Text Available 2-hydroxyglutarate-(2-HG-mediated inhibition of TET2 activity influences DNA hypermethylation in cells harboring mutations of isocitrate dehydrogenases 1 and 2 (IDH1/2. Here, we show that 2-HG also regulates DNA methylation mediated by DNA methyltransferase 1 (DNMT1. DNMT1-dependent hypermethylation of the RIP3 promoter occurred in both IDH1 R132Q knockin mutant mouse embryonic fibroblast (MEFs and 2-HG-treated wild-type (WT MEFs. We found that 2-HG bound to DNMT1 and stimulated its association with the RIP3 promoter, inducing hypermethylation that reduces RIP3 protein and consequently impaired RIP3-dependent necroptosis. In human glioma samples, RIP3 protein levels correlated negatively with IDH1 R132H levels. Furthermore, ectopic expression of RIP3 in transformed IDH1-mutated MEFs inhibited the growth of tumors derived from these cells following transplantation into nude mice. Thus, our research sheds light on a mechanism of 2-HG-induced DNA hypermethylation and suggests that impaired necroptosis contributes to the tumorigenesis driven by IDH1/2 mutations.

Mercury(II) and methylmercury(II) complexes of novel sterically hindered thiolates: 13C and 199Hg NMR studies and the crystal and molecular structures of [MeHg(SC6H2-2,4,6-Pri3)], [Hg(SC6H4-2-SiMe3)2], [Hg(2-SC5H3N-3-SiMe3)2], and [Hg{(2-SC6H4)2SiMe2}]2

International Nuclear Information System (INIS)

Block, E.; Brito, M.; Gernon, M.; McGowty, D.; Kang, Hyunkyu; Zubieta, J.

1990-01-01

Several series of complexes of the types [MeHg(SR)] and [Hg(SR) 2 ] have been synthesized, where the ligands are members of new classes of sterically hindered thiolates, including (triorganosilyl)methanethiols, 2-(triorganosilyl)benzenethiols, 3-(triorganosilyl)pyridine-2-thiols, and bis(2-mercaptophenyl) derivatives. Detailed 1 H, 13 C, and 199 Hg NMR studies revealed several general trends. The 199 Hg chemical shifts moved upfield in the order [MeHg(SR)] 2 ] 2 ] 2 ]. For the [MeHg(SR)] series of complexes, 1 J(Hg-C) correlates with δ( 13 C(methyl)) and with the type of thiolate ligand. Anomalous behavior is observed for oligomeric species. There is only a limited correlation of δ( 199 Hg) with steric cone angles for a subset of the complexes. Crystal data for the complexes are reported. 86 refs., 7 figs., 11 tabs

Design and synthesis of BODIPY-clickate based Hg(2+) sensors: the effect of triazole binding mode with Hg(2+) on signal transduction.

Science.gov (United States)

Vedamalai, Mani; Kedaria, Dhaval; Vasita, Rajesh; Mori, Shigeki; Gupta, Iti

2016-02-14

BODIPY-clickates, F1 and F2, for the detection of Hg(2+) have been designed, synthesized and characterized. Both F1 and F2 showed hyperchromic shifts in the UV-visible spectra in response to increasing Hg(2+) concentrations. Hg(2+) ion binding caused perturbation of the emission quenching process and chelation induced enhanced bathochromic emission of F1 and F2 to 620 nm and 660 nm, respectively. Job's plot clearly indicated that the binding ratio of F1 and F2 with Hg(2+) was 1 : 1. The NMR titration of BODIPY-clickates with Hg(2+) confirmed that aromatic amines and triazoles were involved in the binding event. Furthermore, HRMS data of F1-Hg(2+) and F2-Hg(2+) supported the formation of mercury complexes of BODIPY-clickates. The dissociation constant for the interaction between fluorescent probes F1 and F2 with Hg(2+) was found to be 24.4 ± 5.1 μM and 22.0 ± 3.9 μM, respectively. The Hg(2+) ion induced fluorescence enhancement was almost stable in a pH range of 5 to 8. Having less toxicity to live cells, both the probes were successfully used to map the Hg(2+) ions in live A549 cells.

Syntheses, crystal structures and fluorescent properties of Cd(II), Hg(II) and Ag(I) coordination polymers constructed from 1H-1,2,4-triazole-1-acetic acid

International Nuclear Information System (INIS)

Ding Degang; Xie Lixia; Fan Yaoting; Hou Hongwei; Xu Yan

2009-01-01

Three new d 10 coordination polymers, namely [Cd(taa)Cl] n 1, [Hg(taa)Cl] n 2, and [Ag 1.5 (taa)(NO 3 ) 0.5 ] n 3 (taa=1H-1,2,4-triazole-1-acatate anion) have been prepared and characterized by elemental analysis, IR, and single crystal X-ray diffraction. Compound 1 consists of two-dimensional layers constructed by carboxyl-linked helical chains, which are further linked through carboxyl group to generate a unique 3D open framework. Topological analysis reveals that the structure of 1 can be classified as an unprecedented (3,8)-connected network with the Schlaefli symbol (4.5 2 ) 2 (4 2 .5 8 .6 14 .7 3 .8). Compound 2 manifests a doubly interpenetrated decorated α-polonium cubic network with the Schlaefli symbol of (4 10 .6 2 .8 3 ). Compound 3 consists of 2D puckered layers made up of Ag centers and taa - bridges. In addition, all of these compounds are photoluminescent in the solid state with spectra that closely resemble those of the ligand precursor. - Graphical abstract: Three new compounds based on 1H-1,2,4-triazole-1-acetic acid and Cd(II), Hg(II) and Ag(I) salts display luminescent properties and may be potential candidates for luminescent materials.

Hg0 and HgCl2 Reference Gas Standards: ?NIST Traceability ...

Science.gov (United States)

EPA and NIST have collaborated to establish the necessary procedures for establishing the required NIST traceability of commercially-provided Hg0 and HgCl2 reference generators. This presentation will discuss the approach of a joint EPA/NIST study to accurately quantify the true concentrations of Hg0 and HgCl2 reference gases produced from high quality, NIST-traceable, commercial Hg0 and HgCl2 generators. This presentation will also discuss the availability of HCl and Hg0 compressed reference gas standards as a result of EPA's recently approved Alternative Methods 114 and 118. Gaseous elemental mercury (Hg0) and oxidized mercury (HgCl2) reference standards are integral to the use of mercury continuous emissions monitoring systems (Hg CEMS) for regulatory compliance emissions monitoring. However, a quantitative disparity of approximately 7-10% has been observed between commercial Hg0 and HgCl2 reference gases which currently limits the use of (HgCl2) reference gas standards. Resolving this disparity would enable the expanded use of (HgCl2) reference gas standards for regulatory compliance purposes.

Prunella vulgaris Suppresses HG-Induced Vascular Inflammation via Nrf2/HO-1/eNOS Activation

Directory of Open Access Journals (Sweden)

Ho Sub Lee

2012-01-01

Full Text Available Vascular inflammation is an important factor which can promote diabetic complications. In this study, the inhibitory effects of aqueous extract from Prunella vulgaris (APV on high glucose (HG-induced expression of cell adhesion molecules in human umbilical vein endothelial cells (HUVEC are reported. APV decreased HG-induced expression of intercellular adhesion molecule-1 (ICAM-1, vascular cell adhesion molecule-1 (VCAM-1, and E-selectin. APV also dose-dependently inhibited HG-induced adhesion of HL-60 monocytic cells. APV suppressed p65 NF-κB activation in HG-treated cells. APV significantly inhibited the formation of intracellular reactive oxygen species (ROS. HG-stimulated HUVEC secreted gelatinases, however, APV inhibited it. APV induced Akt phosphorylation as well as activation of heme oxygenase-1 (HO-1, eNOS, and nuclear factor E2-related factor 2 (Nrf2, which may protect vascular inflammation caused by HG. In conclusion, APV exerts anti-inflammatory effect via inhibition of ROS/NF-κB pathway by inducing HO-1 and eNOS expression mediated by Nrf2, thereby suggesting that Prunella vulgaris may be a possible therapeutic approach to the inhibition of diabetic vascular diseases.

Sensitized fluorescence in thallium induced in collisions with Hg(6/sup 3/P/sub 1/) atoms

Energy Technology Data Exchange (ETDEWEB)

Wade, M K; Czajkowski, M; Krause, L [Windsor Univ., Ontario (Canada). Dept. of Physics

1978-07-01

The transfer of excitation from excited mercury atoms to ground-state thallium atoms was investigated using techniques of sensitized fluorescence. A Hg-Tl vapor mixture contained in a quartz cell was irradiated with Hg 2537 A resonance radiation which caused the mercury atoms to become excited to the 6/sup 3/P/sub 1/ state. Subsequent collisions between the Hg(6/sup 3/P/sub 1/) and Tl(6/sup 2/Psub(1/2)) atoms resulted in the population of the 8/sup 2/Ssub(1/2), 6/sup 2/D, and 7/sup 2/Ssub(1/2) thallium states, whose decay gave rise to sensitized fluorescence of wavelengths 3231, 3520, 3776, and 5352 A. Intensity measurements on the sensitized fluorescence and on the Hg 2537 A resonance fluorescence, observed at right angles to the direction of excitation, yielded cross sections of 3.0, 0.3, and 0.05 A/sup 2/ for collisional excitation transfer from Hg(6/sup 3/P/sub 1/) to the 8/sup 2/Ssub(1/2), 6/sup 2/D, and 7/sup 2/Ssub(1/2) states in thallium, respectively. The results are fully consistent with previously determined cross sections for excitation transfer in other binary metallic vapor systems.

Formation of Dirac point and the topological surface states inside the strained gap for mixed 3D Hg1-xCdx Te

Science.gov (United States)

Marchewka, Michał

2016-10-01

In this paper the results of the numerical calculation obtained for the three-dimensional (3D) strained Hg1-xCdx Te layers for the x-Cd composition from 0.1 to 0.155 and a different mismatch of the lattice constant are presented. For the investigated region of the Cd composition (x value) the negative energy gap (Eg =Γ8 -Γ6) in the Hg1-xCdx Te is smaller than in the case of pure HgTe which, as it turns out, has a significant influence on the topological surface states (TSS) and the position of the Dirac point. The numerical calculation based on the finite difference method applied for the 8×8 kp model with the in-plane tensile strain for (001) growth oriented structure shows that the Dirac cone inside the induced insulating band gap for non zero of the Cd composition and a bigger strain caused by the bigger lattice mismatch (than for the 3D HgTe TI) can be obtained. It was also shown how different x-Cd compounds move the Dirac cone from the valence band into the band gap. The presented results show that 75 nm wide 3D Hg1-xCdx Te structures with x ≈ 0.155 and 1.6% lattice mismatch make the system a true topological insulator with the dispersion of the topological surface states similar to those ones obtained for the strained CdTe/HgTe QW.

A benzothiazole-based fluorescent probe for distinguishing and bioimaging of Hg{sup 2+} and Cu{sup 2+}

Energy Technology Data Exchange (ETDEWEB)

Gu, Biao; Huang, Liyan; Su, Wei; Duan, Xiaoli; Li, Haitao, E-mail: haitao-li@hunnu.edu.cn; Yao, Shouzhuo

2017-02-15

A new benzothiazole-based fluorescent probe 2-(benzo[d]thiazol-2-yl)-4-(1,3- dithian-2-yl)phenol (BT) with two different reaction sites, a thioacetal group (site 1 for Hg{sup 2+}), and O and N atoms of the benzothiazole dye (site 2 for Cu{sup 2+}), was designed and synthesized. The probe BT showed ratiometric fluorescent response to Hg{sup 2+} and fluorescence quenching behavior to Cu{sup 2+}, which induces naked-eye fluorescent color changes from green to blue and colorless, respectively. Moreover, it displayed highly sensitivity and selectivity toward Hg{sup 2+} and Cu{sup 2+} without interference from other metal ions. The sensing mechanisms were also confirmed by {sup 1}H NMR titration, mass spectrum and Job's plot analyses. Finally, probe BT was successfully used for fluorescent imaging of Hg{sup 2+} and Cu{sup 2+} in living cells, demonstrating its potential applications in biological science. - Highlights: • A benzothiazole-based probe for multiple metal ions has been firstly developed. • The differential sensing mechanisms of Hg{sup 2+} and Cu{sup 2+} relied on different reaction. • The probe could be used to monitor Hg{sup 2+} and Cu{sup 2+}in vitro and in vivo with distinct fluorescence changes.

Chemical stabilization and high pressure synthesis of Ba-free Hg-based superconductors, (Hg,M)Sr{sub 2}Ca{sub n-1}Cu{sub n}O{sub y}(N=1{approximately}3)

Energy Technology Data Exchange (ETDEWEB)

Kishio, K. [Univ. of Tokyo (Japan)]|[Kyoto Univ. (Japan); Shimoyama, J.; Hahakura, S. [Univ. of Tokyo (Japan)] [and others

1994-12-31

A homologous series of new Hg-based HTSC compounds, (Hg,M)Sr{sub 2}Ca{sub n-1}Cu{sub n}O{sub y} with n=1 to 3, have been synthesized. The stabilization of the pure phases have been accomplished by chemical doping of third elements such as M=Cr, Mo and Re. While the Hg1201(n=1) phase was readily obtained in this way, it was necessary to simultaneously dope Y into the Ca site to stabilize the Hg1212(n=2) phase. On the other hand, single-phase Y-free Hg1212(n=2) and Hg1223(n=3) samples were synthesized only under a high pressure of 6 GPa. In sharp contrast to the Ba-containing compounds, all the samples prepared in the present study have been quite stable during the synthesis and no deterioration in air has been observed after the preparation.

Study of the pseudo-ternary Ag2SAs2S3HgI2 vitreous system

Science.gov (United States)

Boidin, R.; Le Coq, D.; Cuisset, A.; Hindle, F.; Brubach, J.-B.; Michel, K.; Bychkov, E.

2013-03-01

Chalcogenide alloys in the Ag2SAs2S3HgI2 pseudo-ternary system were synthesized and their vitreous nature was verified by X-ray diffraction. The glass transition and crystallization temperatures (Tg and Tc), the density (d), and the total electrical conductivity (σ) were measured for all samples of three series, A, B, and C corresponding to (Ag2S)50-x/2(As2S3)50-x/2(HgI2)x, (Ag2S)y(As2S3)80-y(HgI2)20 and (Ag2S)z(As2S3)50(HgI2)50-z, respectively. The maximum of Tg was approximately 160 °C for glasses with low HgI2 content whereas the maximum of density (5.75 g cm-3) was obtained for the sample in the B-series with the highest Ag2S concentration (z=60 mol%). This composition also possesses the highest conductivity at 298 K (σ298 K≈10-3 S cm-1). Unexpectedly the conductivity of the A-series samples was observed to decrease as a function of the Ag2S content. The far-infrared transmission in the 100-600 cm-1 window range (3.3-18.2 THz, 100-16.6 μm) was also given for a few glass compositions highlighting the strong influence of the HgI2 content.

Evidence of Hg-chain formation in HgxTiS2: a 199mHg-TDPAC study

International Nuclear Information System (INIS)

Troeger, W.; Butz, T.; Ouvrard, G.

1993-01-01

We determined the 199m Hg nuclear quadrupole interaction in the ''misfit'' or ''superstoichiometric'' compound Hg x TiS 2 by time differential perturbed angular correlation. A unique Hg-site with ν Q = 511(1) MHz and η = 0.410(4) was observed, irrespective of the Hg-uptake (2/3 ≤ x ≤ 4/3). We propose a model of Hg-Hg zig-zag chains which accounts for these observations as well as for the X-ray diffraction data. (orig.)

Formation Dirac point and the topological surface states for HgCdTe-QW and mixed 3D HgCdTe TI

OpenAIRE

Marchewka Michał

2017-01-01

In this paper the results of numerical calculations based on the finite difference method (FDM) for the 2D and 3D TI with and without uniaxial tensile strain for mixed Hg1-xCdxTe structures are presented. The numerical calculations were made using the 8×8 model for x from 0 up to 0.155 and for the wide range for the thickness from a few nm for 2D up to 150 nm for 3D TI as well as for different mismatch of the lattice constant and different barrier potential in the case of the QW. For the inve...

Peculiarity of electron optical orientation in Hg1-xMnxTe and Hg1-xCdxTe alloys

International Nuclear Information System (INIS)

Georgitseh, E.I.; Ivanov-Omskij, V.I.; Pogorletskij, V.M.

1991-01-01

To clarify the effect of exchange interaction of electrons with manganese ions on electron spin relaxation, a study was made on optical orientation in Hg 1-x Mn x Te alloy and Hg 1-x Cd x Te alloys with similar parameters of energy spectrum at 4.2 K. It is shown that exchange interaction in semimagnetic Hg 1-x Mn x Te solutions, caused by the presence of manganese ions, reduced the time of spin relaxation. However, this reduction is not sufficient make optical orientation of electrons not observable

46 CFR 53.05-1 - Safety valve requirements for steam boilers (modifies HG-400 and HG-401).

Science.gov (United States)

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Safety valve requirements for steam boilers (modifies HG-400 and HG-401). 53.05-1 Section 53.05-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... requirements for steam boilers (modifies HG-400 and HG-401). (a) The pressure relief valve requirements and the...

Non-Controlled Biogenic Emission of CO, H2S, NH3 and Hg0 from Lazareto's Landfill, Tenerife, Canary Islands

Science.gov (United States)

Nolasco, D.; Lima, R.; Salazar, J.; Hernández, P. A.; Pérez, N. M.

2002-12-01

Landfills are important sources of contaminant gases to the surrounding environment and a significant amount of them could be released to the atmosphere through the surface environment in a diffuse form, also known as non-controlled emission of landfill gases. CH4 and CO2 are major components in landfill gases and other gas species are only present in minor amounts. Trace compounds include both inorganic and a large number of volatile organic components. The goal of this study is to evaluate the non-controlled biogenic emission of inorganic toxic gases from Lazareto's landfill. Which is located in the city of Santa Cruz de Tenerife, with a population of about 150,000, and is used as a Palm tree park. Lazareto's landfill has an extension of 0.22 Km2 and it is not operative since 1980. A non-controlled biogenic gas emission survey of 281 sampling sites was carried out from February tod March, 2002. Surface CO2 efflux measurements were performed by means of a portable NDIR sensor according with the accumulation chamber method. Surface CO2 efflux ranged from negligible values up to 30,600 gm-2d-1. At each sampling site, surface landfill gas samples were collected at 40 cm depth using a metallic soil probe. These gas samples were analyzed within 24 hours for major and inorganic toxic gas species by means of microGC and specific electrochemical sensors. The highest concentrations of CO, H2S, NH3 and Hg0 were 3, 20, 2,227, 0.010 ppmV, respectively. Non-controlled biogenic emission rate of CO, H2S, NH3, and Hg0 were estimated by multiplying the observed surface CO2 efflux times (Inorganic Toxic Gas)i/CO2 weight ratio at each sampling site, respectively. The highest surface inorganic toxic gas efllux rates were 699 gm-2d-1 for NH3, 81, 431 and 4 mgm-2d-1 for CO, H2S and Hg0, respectively. Taking into consideration the spatial distribution of the inorganic toxic gas efflux values as well as the extension of the landfill, the non-controlled biogenic emission of CO, H2S, NH3

Fourier transform nuclear magnetic resonance studies of 199Hg

International Nuclear Information System (INIS)

Krueger, H.; Lutz, O.; Nolle, A.; Schwenk, A.

1975-01-01

199 Hg Fourier Transform NMR studies of various solutions of diverse mercury salts in H 2 O and D 2 O or in the appropriate protonated and deuterated acids are reported for both Hg 2 ++ and Hg ++ . In the different solutions investigated the 199 Hg line positions depend on the concentration of the solution, on the solvents and their isotopic composition and on the temperature of the sample. A ratio of the Larmor frequency of 199 Hg and of 2 H in a Hg(NO 3 ) 2 solution in dilute DNO 3 is given. Using this ratio and the measured chemical shifts, a ratio of the Larmor frequencies of 199 Hg for infinite dilution relative to 2 H in pure D 2 O is given. From this a g 1 -factor for 199 Hg is derived and compared with the g 1 -factor of an optical pumping experiment. The resulting shielding constant is sigma (hydrated 199 Hg ++ versus 199 Hg atom) = -24.32(5) x 10 -4 . This yields an atomic reference scale for all measured NMR line shifts of mercury. (orig.) [de

Urinary excretion of furosemide in rats with HgCl sub 2 -induced acute renal damage

Energy Technology Data Exchange (ETDEWEB)

Fujimura, Akio; Sudoh, Toshiaki; Ohashi, Kyoichi; Ebihara, Akio (Jichi Medical School, Tochigi (Japan))

1992-01-01

To examine the influence of mercuric chloride (HgCl{sub 2})-induced acute renal damage on urinary excretion of furosemide, HgCl{sub 2} or its vehicle along was given intraperitoneally to Wistar rats. The following two experiments were done. Study 1: three percent body weight (b.w.) of 1% NaCl solution or furosemide in 3% b.w. of 1% NaCl solution was given orally before and after HgCl{sub 2} treatment, and an 8-hour urine was collected. Study 2: furosemide was given orally, and blood samples were obtained at 1, 2, 3, 4, 6 and 8 hours after administration. Urinary excretion of N-acetyl-{beta}-D-glucosaminidase increased, and urine volume and urinary excretions of furosemide and sodium decreased in the HgCl{sub 2}-treated rats. There were significant correlations between the urinary furosemide and its diuretic effects. Regression lines after HgCl{sub 2} were significantly different from those before treatment. The values of absorption as well as elimination rate constant were smaller, while the time to maximum concentration and the elimination half-life were longer in the HgCl{sub 2}-treated rats compared to vehicle-treated animals. These results suggest that the urinary excretion of furosemide and the responsiveness of renal tubular cells to this agent are impaired in rats with HgCl{sub 2}-induced acute renal damage.

Electrochemical Detection of Ultratrace (Picomolar) Levels of Hg2+ Using a Silver Nanoparticle-Modified Glassy Carbon Electrode.

Science.gov (United States)

Suherman, Alex L; Ngamchuea, Kamonwad; Tanner, Eden E L; Sokolov, Stanislav V; Holter, Jennifer; Young, Neil P; Compton, Richard G

2017-07-05

Ultratrace levels of Hg 2+ have been quantified by undertaking linear sweep voltammetry with a silver nanoparticle-modified glassy carbon electrode (AgNP-GCE) in aqueous solutions containing Hg 2+ . This is achieved by monitoring the change in the silver stripping peak with Hg 2+ concentration resulting from the galvanic displacement of silver by mercury: Ag(np) + 1/2Hg 2+ (aq) → Ag + (aq) + 1/2Hg(l). This facile and reproducible detection method exhibits an excellent linear dynamic range of 100.0 pM to 10.0 nM Hg 2+ concentration with R 2 = 0.982. The limit of detection (LoD) based on 3σ is 28 pM Hg 2+ , while the lowest detectable level for quantification purposes is 100.0 pM. This method is appropriate for routine environmental monitoring and drinking water quality assessment since the guideline value set by the US Environmental Protection Agency (EPA) for inorganic mercury in drinking water is 0.002 mg L -1 (10 nM).

Efficacy of a Community-Based Physical Activity Program KM2H2 for Stroke and Heart Attack Prevention among Senior Hypertensive Patients: A Cluster Randomized Controlled Phase-II Trial.

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Jie Gong

Full Text Available To evaluate the efficacy of the program Keep Moving toward Healthy Heart and Healthy Brain (KM2H2 in encouraging physical activities for the prevention of heart attack and stroke among hypertensive patients enrolled in the Community-Based Hypertension Control Program (CBHCP.Cluster randomized controlled trial with three waves of longitudinal assessments at baseline, 3 and 6 months post intervention.Community-based and patient-centered self-care for behavioral intervention in urban settings of China.A total of 450 participants diagnosed with hypertension from 12 community health centers in Wuhan, China were recruited, and were randomly assigned by center to receive either KM2H2 plus standard CBHCP care (6 centers and 232 patients or the standard care only (6 centers and 218 patients.KM2H2 is a behavioral intervention guided by the Transtheoretical Model, the Model of Personalized Medicine and Social Capital Theory. It consists of six intervention sessions and two booster sessions engineered in a progressive manner. The purpose is to motivate and maintain physical activities for the prevention of heart attack and stroke.Heart attack and stroke (clinically diagnosed, primary outcome, blood pressure (measured, secondary outcome, and physical activity (self-report, tertiary outcome were assessed at the individual level during the baseline, 3- and 6-month post-intervention.Relative to the standard care, receiving KM2H2 was associated with significant reductions in the incidence of heart attack (3.60% vs. 7.03%, p < .05 and stroke (5.11% vs. 9.90%, p<0.05, and moderate reduction in blood pressure (-3.72 mmHg in DBP and -2.92 mmHg in DBP at 6-month post-intervention; and significant increases in physical activity at 3- (d = 0.53, 95% CI: 0.21, 0.85 and 6-month (d = 0.45, 95% CI: 0.04, 0.85 post-intervention, respectively.The program KM2H2 is efficacious to reduce the risk of heart attack and stroke among senior patients who are on anti

Structure cristalline du composé Hg3-xSbx(S+Se2+xI2-x (x ≃ 0.1

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Mohammed Kars

2016-03-01

Full Text Available Single crystals of the mercury chalcohalide Hg3-xSbx(S+Se2+xI2-x (x ≃ 0.1 (mercury antimony sulfide selenide iodide, were grown by a chemical transport reaction. The structure contains three independent A (Hg/Sb atoms; each atom is strongly covalently bonded with two X (Se/S atoms to form approximately linear X–A–X units. The X–A–X units link to form A4X4 rings, which are combined into infinite crankshaft-type bands running along the [100] direction. Four equatorial E (I/X = Se,S atoms at relatively long distances complete the distorted octahedral coordination of A (Hg/Sb. The crystal under investigation was twinned by non-merohedry with a refined twin domain fraction of 0.814 (6:0.186 (6. The structure is isotypic with Hg3Se2I2 [Beck & Hedderich (2000. J. Solid State Chem. 151, 73–76], but the current determination reveals a coupled substitution, with partial replacement of Hg+2 by Sb+3, balanced by the equivalent substitution of I−1 by S−2 and Se−2. Bond-valence calculations are consistent with this relative substitution model.

Importance of Dissolved Neutral Hg-Sulfides, Energy Rich Organic Matter and total Hg Concentrations for Methyl Mercury Production in Sediments

Science.gov (United States)

Drott, A.; Skyllberg, U.

2007-12-01

Methyl mercury (MeHg) is the mercury form that biomagnifies to the greatest extent in aquatic food webs. Therefore information about factors determining MeHg concentrations is critical for accurate risk assessment of contaminated environments. The concentration of MeHg in wetlands and sediments is the net result of: 1) methylation rates, 2) demethylation rates, and 3) input/output processes. In this study, the main controls on Hg methylation rates and total concentrations of MeHg, were investigated at eight sites in Sweden with sediments that had been subjected to local Hg contamination either as Hg(0), or as phenyl-Hg. Sediments were selected to represent a gradient in total Hg concentration, temperature climate, salinity, primary productivity, and organic C content and quality. Most sediments were high in organic matter content due to wood fibre efflux from pulp and paper industry. The pore water was analysed for total Hg, MeHg, DOC, H2S(aq), pH, DOC, Cl and Br. The chemical speciation of Hg(II) and MeHg in pore water was calculated using equilibrium models. Potential methylation and demethylation rates in sediments were determined in incubation experiments at 23° C under N2(g) for 48 h, after addition of isotopically enriched 201Hg(II) and Me204Hg. In all surface (0-20 cm) sediments there was a significant (pdetermined specific potential methylation rate constant (Km, day-1) and % MeHg (concentrations of MeHg normalized to total Hg) in the sediment. This indicates that MeHg production overruled degradation and input/output processes of MeHg in surface sediments, and that % MeHg in surface sediments may be used as a proxy for net production of MeHg. To our knowledge, these are the first data showing significant positive relationships between short term (48 h) MeHg production and longer term accumulation of MeHg, across a range of sites with different properties (1). If MeHg was not normalized to total Hg, the relationship was not significant. For sub-sets of

Crystallographic isomorphism in the structural type of α-HgI{sub 2} by example of KHgI{sub 3} · H{sub 2}O, β-Ag{sub 2}HgI{sub 4}, and β-Cu{sub 2}HgI{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Borisov, S. V., E-mail: borisov@niic.nsc.ru; Magarill, S. A.; Pervukhina, N. V. [Russian Academy of Sciences, Nikolaev Institute of Inorganic Chemistry, Siberian Branch (Russian Federation)

2017-03-15

The structure of KHgI{sub 3} · H{sub 2}O is assigned to the family of crystal structures having the three-layer cubic packing of iodine anions with cations in the tetrahedral voids (the structures of α-HgI{sub 2}, β-Ag{sub 2}HgI{sub 4}, and β-Cu{sub 2}HgI{sub 4} among them). Crystallographic analysis shows that the nodes of the three-layer close packing are populated by iodine anions and K cations in the ratio 3/4: 1/4. Transformation of the structure of α-HgI{sub 2} into the structure of KHgI{sub 3} · H{sub 2}O can be formally represented as the replacement of (HgI){sub n}{sup +} fragments by (KH{sub 2}O){sub n}{sup +} fragments: (Hg{sub 2}I{sub 4})–(HgI){sup +} + (KH{sub 2}O){sub n}{sup +} = KHgI{sub 3} · H{sub 2}O. Perforated layers of vertex-sharing HgI{sub 4} tetrahedra break down into parallel isolated chains. Channels formed in place of I–Hg–I–Hg–fragments are occupied by–H{sub 2}O–K–-H{sub 2}-O-K-H{sub 2}O-chains weakly bound to neighbors.

The Ag2Se-HgSe-GeSe2 system and crystal structures of the compounds

International Nuclear Information System (INIS)

Parasyuk, O.V.; Gulay, L.D.; Romanyuk, Ya.E.; Olekseyuk, I.D.; Piskach, L.V.

2003-01-01

The phase diagram of the quasi-ternary Ag 2 Se-HgSe-GeSe 2 system at 298 K was investigated using X-ray phase analysis and metallography. The formation of five intermediate quaternary phases β (Ag ∼7.12-∼6.32 Hg ∼0.44-∼0.82 GeSe 6 ), γ (Ag ∼6.08-∼4.00 Hg ∼0.96-∼2.00 GeSe 6 ), δ (Ag 3.4 Hg 2.3 GeSe 6 ), ε (Ag ∼2.24-∼2.00 Hg ∼2.88-∼3.00 GeSe 6 ) and ∼Ag 1.4 Hg 1.3 GeSe 6 was established. The crystal structure of the β-phase (for the Ag 6.504 Hg 0.912 GeSe 6 composition) was determined using X-ray single crystal diffraction. It crystallizes in a cubic structure (space group F4-bar 3m) with the lattice parameter a=1.09026(4) nm. The crystal structure of the δ-phase (Ag 3.4 Hg 2.3 GeSe 6 ) was determined using X-ray powder diffraction (space group F4-bar 3m, a=1.07767(8) nm). The crystal structure determination of the γ-phase (space group Pmn2 1 ) was performed for the compositions Ag 5.6 Hg 1.2 GeSe 6 , Ag 4.8 Hg 1.6 GeSe 6 and Ag 4 Hg 2 GeSe 6 using X-ray powder diffraction. The crystal structure of the LT-Hg 2 GeSe 4 compound (space group I4-bar , a=0.56786(2), c=1.12579(5) nm) was confirmed by powder diffraction also.

Density of liquid Hg(1-x)Cd(x)Te

Science.gov (United States)

Chandra, D.; Holland, L. R.

1983-01-01

Negative thermal expansion has been established in liquid Hg(1-x)Cd(x)Te for x less than 0.2 employing a pycnometric method. Pure HgTe increases in density from its melting point at 670 C to a maximum value at 750 C, where normal thermal expansion progressively resumes. The dependence of density on temperature for liquid Hg(1-x)Cd(x)Te arises almost exclusively from the HgTe portion of the melt, while CdTe acts as a diluent. The temperature corresponding to the maximum density changes slightly with composition, increasing by about 5 C for x = 0.1.

Extraction, partial characterization and susceptibility to Hg2+ of acid phosphatase from the microalgae Pseudokirchneriella subcapitata Extração, caracterização parcial e susceptibilidade ao Hg2+ da fosfatase ácida da microalga Pseudokirchneriella subcapitata

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Claudio Martín Jonsson

2009-10-01

Full Text Available Pseudokirchneriella subcapitata is a unicellular green algae widely distributed in freshwater and soils. Due to its cosmopolitan characteristic, its use is recommended by national and international protocols in ecotoxicity studies. The alteration of phosphatase activities by agriculture pollutants like heavy metals has been extensively used as a biomarker in risk assessment and biomonitoring. In this study, we compared the extraction of acid phosphatase from P. subcapitata by different procedures and we studied the stability, substrates specificity, kinetics and the effect of Hg2+ in the crude extract. The freezing and thawing technique associated with probe sonication was the most suitable method of extraction. The enzyme was stable when frozen at -20ºC for at least six months, showed an optimum pH of 5 and a Km value of 0.27 mM for p-nitrophenylphosphate (pNPP as substrate. Some natural organic substrates were cleaved by a similar extent as the synthetic substrate pNPP. Short term exposure (24 hours to Hg2+ had little effect but inhibition of the specific activity was observed after 7 days with EC50 (concentration of Hg2+ that promotes 50% decrease of specific activity value of 12.63 μM Hg2+.Pseudokirchneriella subcapitata é uma alga verde unicelular amplamente distribuída em corpos d´agua e solos. Devido a sua natureza cosmopolita, seu uso é recomendado por protocolos nacionais e internacionais na realização de estudos de ecotoxicidade. A alteração da atividade de fosfatases por agentes poluentes de origem agrícola, como metais pesados, tem sido largamente usada como um biomarcador na avaliação de risco e biomonitoramento. No presente trabalho foi comparada a extração da fosfatase ácida de P. subcapitata por diferentes métodos e estudada a sua estabilidade, especificidade por substratos, cinética e efeito do Hg2+ no extrato bruto. O congelamento e descongelamento, associado com ultrassom, foi o método que proporcionou maior

199Hg Moessbauer measurements on mercury, alloys and Hg-fluorides

International Nuclear Information System (INIS)

Wurtinger, W.; Kankeleit, E.

1979-01-01

The Moessbauer effect on the 158 keV 5/2 - -1/2 - transition in 199 Hg, of the order of 10 ppm, has been studied using the current integration technique. The isomer shift between the Hg(I)- and Hg(II)-fluorides as well as the quadrupole splitting in Hg 2 Pt and Hg 2 F 2 are interpreted in terms of relativistic Hartree-Fock-Slater and Molecular Orbital calculations. The following nuclear parameters could be derived: Δ[r 2 ] = (3.2+-1.1) 10 -3 fm 2 and Q(5/2 - ) = (-0.8+-0.4)b. Evidence for an oblate triaxially deformed 199 Hg nucleus is derived from particle plus rotor calculations. (orig.)

Compton profiles and electronic structure of HgBr{sub 2} and HgI{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Ahmed, G.; Dashora, Alpa [Department of Physics, University College of Science, M.L. Sukhadia University, Udaipur, 313001 Rajasthan (India); Sharma, M. [Physics Division, State Forensic Science Laboratory, Jaipur, 302016 Rajasthan (India); Ahuja, B.L. [Department of Physics, University College of Science, M.L. Sukhadia University, Udaipur, 313001 Rajasthan (India)], E-mail: blahuja@yahoo.com

2010-02-15

In this paper, we present the first-ever experimental Compton line shapes of HgBr{sub 2} and HgI{sub 2} using {sup 137}Cs Compton spectrometer. To compare our experimental momentum densities, we have computed the Compton profiles using Hartree-Fock and density functional theory within linear combination of atomic orbitals. We have also computed the energy bands and density of states using the linear combination of atomic orbitals and full potential linearized augmented plane wave method. On the basis of equal-valence-electron-density profiles, it is seen that HgI{sub 2} is more covalent than HgBr{sub 2} which is in agreement with the valence charge densities. The experimental isotropic profiles are found to be relatively in better agreement with the Hartree-Fock data. We have also discussed the photoluminescence and detection properties of both the halides.

Water Soluble Cationic Porphyrin Sensor for Detection of Hg2+, Pb2+, Cd2+, and Cu2+

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Matibur Zamadar

2016-01-01

Full Text Available Here we report the sensing properties of the aqueous solution of meso-tetra(N-methyl-4-pyridylporphine tetrachloride (1 for simultaneous detection of toxic metal ions by using UV-vis spectroscopy. Cationic porphyrin 1 displayed different electronic absorptions in UV-vis region upon interacting with Hg2+, Pb2+, Cd2+, and Cu2+ ions in neutral water solution at room temperature. Quite interestingly, the porphyrin 1 showed that it can function as a single optical chemical sensor and/or metal ion receptor capable of detecting two or more toxic metal ions, particularly Hg2+, Pb2+, and Cd2+ ions coexisting in a water sample. Porphyrin 1 in an aqueous solution provides a unique UV-vis sensing system for the determination of Cd2+ in the presence of larger metal ions such as Hg2+, or Pb2+. Finally, the examination of the sensing properties of 1 demonstrated that it can operate as a Cu2+ ion selective sensor via metal displacement from the 1-Hg2+, 1-Pb2+, and 1-Cd2+.

Synthesis, structural and physico-chemical studies of the monocrystal superconductor oxides Hg Ba{sub 2} Ca{sub n-1} Cu{sub n} O{sub 2n+2+{delta}}; Synthese, etudes structurales et physico-chimiques de monocristaux d`oxydes supraconducteurs Hg Ba{sub 2} Ca{sub n-1} Cu{sub n} O{sub 2n+2+{delta}}

Energy Technology Data Exchange (ETDEWEB)

Viallet-Guillen, Virginie [Dept. de Recherche sur l` Etat Condense, CEA Centre d` Etudes de Saclay, 91 - Gif-sur-Yvette (France)

1998-01-01

The thesis presents the synthesis and the structural and physico-chemical properties of the mercury-based monocrystal superconductor oxides. The results reported in the first chapter refer to the first three members of the mercury cuprate series Hg-1201, Hg-1212 and Hg-1223. In the second chapter detailed results concerning the structure of these compounds are given highlighting the features common to all cuprates and pointing out the peculiarities of mercury phases. The third chapter presents the phase diagrams ({delta}, T, p(O{sub 2})) of the compounds HgBa{sub 2}CuO{sub 4+{delta}} and HgBa{sub 2}Ca{sub 2}Cu{sub 3}O{sub 8+{delta}} obtained by thermogravimetry under controlled atmosphere between 150 deg.C and 500 deg.C and thermodynamic equilibrium conditions. In the case of Hg-1201, the critical temperature shows a variation close to a parabolic law, with an optimal Tc of 96 K ({delta}{approx_equal}0.10) while in Hg-1223 the Tc increases linearly with the O content up to the optimal Tc of 135 K ({delta}{approx_equal}0.19) and decreases only by 2 K in the over-doped regime. Finally, in the fourth chapter different physical properties are reviewed. The obtained monocrystals allowed studying the resistive transitory anisotropy, the torque, the specific heat, the nuclear magnetic resonance and the Raman diffusion 212 refs., 106 figs., 30 tabs.

A ratiometric electrochemical biosensor for sensitive detection of Hg2+ based on thymine-Hg2+-thymine structure.

Science.gov (United States)

Xiong, Erhu; Wu, Liang; Zhou, Jiawan; Yu, Peng; Zhang, Xiaohua; Chen, Jinhua

2015-01-01

In this paper, a simple, selective and reusable electrochemical biosensor for the sensitive detection of mercury ions (Hg(2+)) has been developed based on thymine (T)-rich stem-loop (hairpin) DNA probe and a dual-signaling electrochemical ratiometric strategy. The assay strategy includes both "signal-on" and "signal-off" elements. The thiolated methylene blue (MB)-modified T-rich hairpin DNA capture probe (MB-P) firstly self-assembled on the gold electrode surface via Au-S bond. In the presence of Hg(2+), the ferrocene (Fc)-labeled T-rich DNA probe (Fc-P) hybridized with MB-P via the Hg(2+)-mediated coordination of T-Hg(2+)-T base pairs. As a result, the hairpin MB-P was opened, the MB tags were away from the gold electrode surface and the Fc tags closed to the gold electrode surface. These conformation changes led to the decrease of the oxidation peak current of MB (IMB), accompanied with the increase of that of Fc (IFc). The logarithmic value of IFc/IMB is linear with the logarithm of Hg(2+) concentration in the range from 0.5 nM to 5000 nM, and the detection limit of 0.08 nM is much lower than 10nM (the US Environmental Protection Agency (EPA) limit of Hg(2+) in drinking water). What is more, the developed DNA-based electrochemical biosensor could be regenerated by adding cysteine and Mg(2+). This strategy provides a simple and rapid approach for the detection of Hg(2+), and has promising application in the detection of Hg(2+) in real environmental samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Two Zn and Hg bromide salts based on 1-ethyl-3-methyl imidazolium ionic liquid: Ionothermal synthesis, structures and supramolecular organization

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Xiu-Cheng Zhang

2012-12-01

Full Text Available Two Zn(II and Hg(II bromide salts, [EMI]2[ZnBr4] (1 and [EMI][HgBr3] (2, have been synthesized under ionothermal conditions using 1-ethyl-3-methyl imidazolium bromide ([EMI]Br as solvents. 1 consists of tetrahedral anion [ZnBr4]2− and 2 consists of 1D double chain locating in the cavities surrounded by [EMI]+ cations. Both compounds exhibit 3D supramolecular architectures organized by the C-H•••Br hydrogen bondings and alkyl-alkyl interactions.DOI: http://dx.doi.org/10.4314/bcse.v26i3.9

Investigation of characteristics of sup 2 sup 0 sup 1 Tl -> sup 2 sup 0 sup 1 Hg

CERN Document Server

Kharitonov, V V

2002-01-01

The estimated intensities of transitions on the ground and first-excited levels in the sup 2 sup 0 sup 1 Hg at the decay of sup 2 sup 0 sup 1 Tl and estimated constants lg ft are obtained from the analysis of the relative intensities of the mercury M sub 4 N sub 6 sub , sub 7 N sub 6 sub , sub 7 Auger-electron line, initiated by the e-capture and of the conversion O sub 3 -mercury line, due to the nuclear transition with the energy 1.56 keV

The simplest representative of a complex series. The Hg-rich amalgam Yb_1_1Hg_5_4

International Nuclear Information System (INIS)

Tambornino, Frank; Hoch, Constantin

2017-01-01

Yb_1_1Hg_5_4 is a new member of a series of amalgams with composition close to MHg_5. Its crystal structure was solved and refined on the basis of single crystal data. The structure model was confirmed with a Rietveld refinement. Yb_1_1Hg_5_4 has the first crystal structure in this family in which no disorder effects such as mixed occupation, split positions or superstructure formation is observed. It therefore can be regarded as a parent structure for all other amalgams. The crystal structure of Yb_1_1Hg_5_4 can be derived from the Gd_1_4Ag_5_1 structure type, the aristotype of this family. We give a detailed crystal structure description for Yb_1_1Hg_5_4 and discuss it in the context of the further known crystal structures closely related. A ranking within this structure family can be established by calculating features for the structural complexity for all structures, including the individual disorder phenomena.

The new barium zinc mercurides Ba3ZnHg10 and BaZn0.6Hg3.4 – Synthesis, crystal and electronic structure

International Nuclear Information System (INIS)

Schwarz, Michael; Wendorff, Marco; Röhr, Caroline

2012-01-01

The title compounds Ba 3 ZnHg 10 and BaZn 0.6 Hg 3.4 were synthesized from stoichiometric ratios of the elements in Ta crucibles. Their crystal structures, which both represent new structure types, have been determined using single crystal X-ray data. The structure of Ba 3 ZnHg 10 (orthorhombic, oP28, space group Pmmn, a=701.2(3), b=1706.9(8), c=627.3(3)pm, Z=2, R1=0.0657) contains folded 4 4 Hg nets, where the meshes form the bases of flat rectangular pyramids resembling the structure of BaAl 4 . The flat pyramids are connected via Hg–Zn/Hg bonds, leaving large channels at the folds, in which Ba(1) and Hg(2) atoms alternate. Whereas the remaining Hg/Zn atoms form a covalent 3D network of three- to five-bonded atoms with short M–M distances (273–301 pm; CN 9–11), the Hg(2) atoms in the channels adopt a comparatively large coordination number of 12 and increased distances (317–348 pm) to their Zn/Hg neighbours. In the structure of BaZn 0.6 Hg 3.4 (cubic, cI320, space group I4 ¯ 3d, a=2025.50(7) pm, Z=64, R1=0.0440), with a chemical composition not much different from that of Ba 3 ZnHg 10 , the Zn/Hg atoms of the mixed positions M(1/2) are arranged in an slightly distorted primitive cubic lattice with a 4×4×4 subcell relation to the unit cell. The 24 of the originating 64 cubes contain planar cis tetramers Hg(5,6) 4 with Hg in a nearly trigonal planar or tetrahedral coordination. In another 24 of the small cubes, two opposing faces are decorated by Hg(3,4) 2 dumbbells, two by Ba(2) atoms respectively. The third type of small cubes are centered by Ba(1) atoms only. The complex 3D polyanionic Hg/Zn network thus formed is compared with the Hg partial structure in Rb 3 Hg 20 applying a group-subgroup relation. Despite their different overall structures, the connectivity of the negatively charged Hg atoms, the rather metallic Zn bonding characteristic (as obtained from FP-LAPW band structure calculations) and the coordination number of 16 for all Ba cations

A global catalogue of Ceres impact craters ≥ 1 km and preliminary analysis

Science.gov (United States)

Gou, Sheng; Yue, Zongyu; Di, Kaichang; Liu, Zhaoqin

2018-03-01

The orbital data products of Ceres, including global LAMO image mosaic and global HAMO DTM with a resolution of 35 m/pixel and 135 m/pixel respectively, are utilized in this research to create a global catalogue of impact craters with diameter ≥ 1 km, and their morphometric parameters are calculated. Statistics shows: (1) There are 29,219 craters in the catalogue, and the craters have a various morphologies, e.g., polygonal crater, floor fractured crater, complex crater with central peak, etc.; (2) The identifiable smallest crater size is extended to 1 km and the crater numbers have been updated when compared with the crater catalogue (D ≥ 20 km) released by the Dawn Science Team; (3) The d/D ratios for fresh simple craters, obviously degraded simple crater and polygonal simple crater are 0.11 ± 0.04, 0.05 ± 0.04 and 0.14 ± 0.02 respectively. (4) The d/D ratios for non-polygonal complex crater and polygonal complex crater are 0.08 ± 0.04 and 0.09 ± 0.03. The global crater catalogue created in this work can be further applied to many other scientific researches, such as comparing d/D with other bodies, inferring subsurface properties, determining surface age, and estimating average erosion rate.

Influence of defect structure on magnetic and electronic properties of Hg1-x Crx Se and Hg1-x Cox Se

International Nuclear Information System (INIS)

Prozorovskij, V.D.; Reshidova, I.Yu.; Puzynya, A.I.; Paranchich, Yu.S.

1996-01-01

The results of experimental investigations of the Shubnikov-de Haas oscillations at superhigh frequencies, electron spin resonance, magnetic susceptibility, relaxation dielectric losses, and galvanomagnetic measurements in the Hg 1-x Cr x Se and Hg 1-x Co x Se single crystal samples are presented. Analysis of the results Hg 1-x Cr x Se and Hg 1-x Co x Se depend on the defect structure of the substance and the type of defects making this structure. The manifestation of critical phenomena in Hg 1-x Cr x Se also depends on the defect structure

Distinct toxicological characteristics and mechanisms of Hg2+ and MeHg in Tetrahymena under low concentration exposure.

Science.gov (United States)

Liu, Cheng-Bin; Qu, Guang-Bo; Cao, Meng-Xi; Liang, Yong; Hu, Li-Gang; Shi, Jian-Bo; Cai, Yong; Jiang, Gui-Bin

2017-12-01

Inorganic divalent mercury complexes (Hg 2+ ) and monomethylmercury complexes (MeHg) are the main mercury species in aquatic systems and their toxicity to aquatic organisms is of great concern. Tetrahymena is a type of unicellular eukaryotic protozoa located at the bottom of food chain that plays a fundamental role in the biomagnification of mercury. In this work, the dynamic accumulation properties, toxicological characteristics and mechanisms of Hg 2+ and MeHg in five Tetrahymena species were evaluated in detail. The results showed that both Hg 2+ and MeHg were ingested and exhibited inhibitory effects on the proliferation or survival of Tetrahymena species. However, the ingestion rate of MeHg was significantly higher than that of Hg 2+ . The mechanisms responsible for the toxicity of MeHg and Hg 2+ were different, although both chemicals altered mitochondrial membrane potential (MMP). MeHg disrupted the integrity of membranes while Hg 2+ had detrimental effects on Tetrahymena as a result of the increased generation of reactive oxygen species (ROS). In addition, the five Tetrahymena species showed different capacities in accumulating Hg 2+ and MeHg, with T. corlissi exhibiting the highest accumulations. The study also found significant growth-promoting effect on T. corlissi under low concentration exposure (0.003 and 0.01μg Hg/mL (15 and 50nM)), suggesting different effect and mechanism that should be more closely examined when assessing the bioaccumulation and toxicity of mercury in aquatic ecosystems. Copyright © 2017 Elsevier B.V. All rights reserved.

Injury of Hg2+ and DBS on Lemna minor%Hg2+、DBS对浮萍的伤害研究

Institute of Scientific and Technical Information of China (English)

马剑敏; 王琳; 杜晋立; 吴晶敏

2001-01-01

The injury degree of Lemna minor by the stress of Hg2+ and DBSare reported.The concentrations of chlorophyll and dissolved protein decrease with the increase of Hg2+ and DBS concentrations or as treatment time is continued,dead percentage increase with the increase of Hg2+ and DBS concentrations or as treatment time is continued.When the concentrations of HgCl2 is 6mg/L or DBS is 12mg/L,about 70% of Lemna minor can live for 10 days at least.%研究了在Hg2+、DBS胁迫下，浮萍(LemnaminorL.)植株的枯死率、叶绿素含量和可溶性蛋白质含量的变化。植株的枯死率随Hg2+、DBS浓度升高和处理时间的延长而增加；叶绿素和蛋白质含量随Hg2+和DBS浓度升高和处理时间的延长而逐渐下降。在HgCl2、DBS浓度分别为6mg/L、12mg/L时，约70%的浮萍10d内仍存活。

Beer Law Constants and Vapor Pressures of HgI2 over HgI2(s,l)

Science.gov (United States)

Su, Ching-Hua; Zhu, Shen; Ramachandran, N.; Burger, A.

2002-01-01

Optical absorption spectra of the vapor phase over HgI2(s,l) were measured at sample temperatures between 349 and 610 K for wavelengths between 200 and 600 nm. The spectra show the samples sublimed congruently into HGI2 without any observed Hg or I2 absorption spectra. The Beer's Law constants for 15 wavelengths between 200 and 440 nm were derived. From these constants the vapor pressure of HgI2, P, was found to be a function of temperature for the liquid and the solid beta-phases: ln P(atm) = -7700/T(K) + 12.462 (liquid phase) and ln P(atm) = -10150/T(K) + 17.026 (beta-phase). The expressions match the enthalpies of vaporization and sublimation of 15.30 and 20.17 kcal/mole respectively, for the liquid and the beta-phase HgI2. The difference in the enthalpies gives an enthalpy of fusion of 4.87 kcal/mole, and the intersection of the two expressions gives a melting point of 537 K.

Stability studies of Hg implanted YBa$_{2}$Cu$_{3}$O$_{6+x}$

CERN Document Server

Araújo, J P; Wahl, U; Marques, J G; Alves, E; Amaral, V S; Lourenço, A A; Galindo, V; Von Papen, T; Senateur, J P; Weiss, F; Vantomme, A; Langouche, G; Melo, A A; Da Silva, M F A; Soares, J C; Sousa, J B

1999-01-01

High quality YBa$_{2}$Cu$_{3}$O$_{6+x}$ (YBCO) superconducting thin films were implanted with the radioactive $^{197m}$Hg (T$_{1/2}$ = 24 h) isotope to low fluences of 10$^{13}$ atoms/cm$^{2}$ and 60 keV energy. The lattice location and stability of the implanted Hg were studied combining the Perturbed Angular Correlation (PAC) and Emission Channeling (EC) techniques. We show that Hg can be introduced into the YBCO lattice by ion implantation into unique regular sites. The EC data show that Hg is located on a highly symmetric site on the YBCO lattice, while the PAC data suggests that Hg occupies the Cu(1) site. Annealing studies were performed under vacuum and O$_{2}$ atmosphere and show that Hg starts to diffuse only above 653 K.

Triaxiality in the even-mass Hg isotopes: A discontinuity at 200Hg

International Nuclear Information System (INIS)

Morrison, I.; Spear, R.H.

1981-01-01

The mass dependence of excitation energies of the 2 + 1 , 2 + 2 , and 4 + 1 states of the even-mass Hg isotopes, and of some related B(E2) values, shows a marked discontinuity at 200 Hg. Analysis of B(E2;0 + 1 →2 + 1 ) values in terms of an extended interacting boson approximation model suggests that this discontinuity is due to a change in the proton and neutron distributions at 200 Hg. Apart from 200 Hg, the data favor γ-soft models rather than the rigid triaxial-rotor model

Activation of the Hg-C Bond of Methylmercury by [S2]-Donor Ligands.

Science.gov (United States)

Karri, Ramesh; Banerjee, Mainak; Chalana, Ashish; Jha, Kunal Kumar; Roy, Gouriprasanna

2017-10-16

Here we report that [S 2 ]-donor ligands Bmm OH , Bmm Me , and Bme Me bind rapidly and reversibly to the mercury centers of organomercurials, RHgX, and facilitate the cleavage of Hg-C bonds of RHgX to produce stable tetracoordinated Hg(II) complexes and R 2 Hg. Significantly, the rate of cleavage of Hg-C bonds depends critically on the X group of RHgX (X = BF 4 - , Cl - , I - ) and the [S 2 ]-donor ligands used to induce the Hg-C bonds. For instance, the initial rate of cleavage of the Hg-C bond of MeHgI induced by Bme Me is almost 2-fold higher than the initial rate obtained by Bmm OH or Bmm Me , indicating that the spacer between the two imidazole rings of [S 2 ]-donor ligands plays a significant role here in the cleavage of Hg-C bonds. Surprisingly, we noticed that the initial rate of cleavage of the Hg-C bond of MeHgI induced by Bme Me (or Bmm Me ) is almost 10-fold and 100-fold faster than the cleavage of Hg-C bonds of MeHgCl and [MeHg]BF 4 respectively, under identical reaction conditions, suggesting that the Hg-C bond of [MeHg]BF 4 is highly inert at room temperature (21 °C). We also show here that the nature of the final stable cleaved products, i.e. Hg(II) complexes, depends on the X group of RHgX and the [S 2 ]-donor ligands. For instance, the reaction of Bmm Me with MeHgCl (1:1 molar ratio) afforded the formation of the 16-membered metallacyclic dinuclear mercury compound (Bmm Me ) 2 Hg 2 Cl 4 , in which the two Cl atoms are located inside the ring, whereas due to the large size of the I atom, a similar reaction with MeHgI yielded polymeric [(Bmm Me ) 2 HgI 2 ] m ·(MeHgI) n . However, the treatment of Bmm Me with ionic [RHg]BF 4 led to the formation of the tetrathione-coordinated mononuclear mercury compound [(Bmm Me ) 2 Hg](BF 4 ) 2 , where BF 4 - serves as a counteranion.

Electron beam induced Hg desorption and the electronic structure of the Hg depleted surface of Hg1/sub -//sub x/Cd/sub x/Te

International Nuclear Information System (INIS)

Shih, C.K.; Friedman, D.J.; Bertness, K.A.; Lindau, I.; Spicer, W.E.; Wilson, J.A.

1986-01-01

Auger electron spectroscopy (AES), x-ray photoemission spectroscopy (XPS), low energy electron diffraction (LEED), and angle-resolved ultraviolet photoemission spectroscopy (ARPES) were used to study the electron beam induced Hg desorption from a cleaved (110)Hg/sub 1-//sub x/Cd/sub x/Te surface and the electronic structure of the Hg depleted surface. Solid state recrystallized Hg/sub 1-//sub x/Cd/sub x/Te single crystals were used. It was found that the electron beam heating dominated the electron beam induced Hg desorption on Hg/sub 1-//sub x/Cd/sub x/Te. At the electron beam energy used, the electron beam heating extended several thousand angstroms deep. However, the Hg depletion saturated after a few monolayers were depleted of Hg atoms. At the initial stage of Hg loss (only 3%), the surface band bends upward (more p type). The ARPES spectrum showed the loss of some E vs k dispersion after 22% Hg atoms were removed from the surface region, and no dispersion was observed after 43% Hg atoms were removed. These results have important implications on the electronic structure of the surfaces and interfaces of which the stoichiometry is altered

M-theory solutions invariant under D(2,1; γ) + D(2,1;γ)

International Nuclear Information System (INIS)

Bachas, C.; D'Hoker, E.; Estes, J.; Krym, D.

2014-01-01

We simplify and extend the construction of half-BPS solutions to 11-dimensional supergravity, with isometry superalgebra D(2,1;γ) + D(2,1;γ). Their space-time has the form AdS 3 x S 3 x S 3 warped over a Riemann surface Σ. It describes near-horizon geometries of M2 branes ending on, or intersecting with, M5 branes along a common string. The general solution to the BPS equations is specified by a reduced set of data (γ, h, G), where γ is the real parameter of the isometry superalgebra, and h and G are functions on Σ whose differential equations and regularity conditions depend only on the sign of γ. The magnitude of γ enters only through the map of h,G onto the supergravity fields, thereby promoting all solutions into families parametrized by vertical stroke γ vertical stroke. By analyzing the regularity conditions for the supergravity fields, we prove two general theorems: (i) that the only solution with a 2-dimensional CFT dual is AdS 3 x S 3 x S 3 x R 2 , modulo discrete identifications of the flat R 2 , and (ii) that solutions with γ 4 /Z 2 or AdS 7 ' regions; highly-curved M5-branes; and a coordinate singularity called the ''cap''. By putting these ''Lego'' pieces together we recover all known global regular solutions with the above symmetry, including the self-dual strings on M5 for γ 0, but now promoted to families parametrized by vertical stroke γ vertical stroke. We also construct exactly new regular solutions which are asymptotic to AdS 4 /Z 2 for γ 0 solutions with highly curved M5-brane regions, which are the formal continuation of the self-dual string solutions across the decompactification point at γ = 0. (Copyright copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

A Theoretical Study of the Oxidation of Hg0 to HgBr2 in the Troposphere

DEFF Research Database (Denmark)

Goodsite, M. E.; Plane, J. M C; Skov, H.

2004-01-01

The oxidation of elemental mercury (Hg0) to the divalent gaseous mercury dibromide (HgBr2) has been proposed to account for the removal of Hg0 during depletion events in the springtime Arctic. The mechanism of this process is explored in this paper by theoretical calculations of the relevant rate...... coefficients. Rice-Ramsberger-Kassel-Marcus (RRKM) theory, together with ab initio quantum calculations where required, are used to estimate the following: recombination rate coefficients of Hg with Br, I, and O; the thermal dissociation rate coefficient of HgBr; and the recombination rate coefficients of Hg......Br with Br, I, OH, and O2. A mechanism based on the initial recombination of Hg with Br, followed by the addition of a second radical (Br, I, or OH) in competition with thermal dissociation of HgBr, is able to account for the observed rate of Hg 0 removal, both in Arctic depletion events and at lower...

Turn-On Fluorescent Chemosensor for Hg2+ Based on Multivalent Rhodamine Ligands

Science.gov (United States)

Wang, Xuemei; Iqbal, Mudassir; Huskens, Jurriaan; Verboom, Willem

2012-01-01

Rhodamine-based fluorescent chemosensors 1 and 2 exhibit selective fluorescence enhancement to Fe3+ and Hg2+ over other metal ions at 580 nm in CH3CN/H2O (3/1, v/v) solution. Bis(rhodamine) chemosensor 1, under optimized conditions (CH3CN/HEPES buffer (0.02 M, pH = 7.0) (95/5, v/v)), shows a high selectivity and sensitivity to Hg2+, with a linear working range of 0–50 μM, a wide pH span of 4–10, and a detection limit of 0.4 μM Hg2+. PMID:23222686

Synthesis, structural and physico-chemical studies of the monocrystal superconductor oxides Hg Ba2 Can-1 Cun O2n+2+δ

International Nuclear Information System (INIS)

Viallet-Guillen, Virginie

1998-01-01

The thesis presents the synthesis and the structural and physico-chemical properties of the mercury-based monocrystal superconductor oxides. The results reported in the first chapter refer to the first three members of the mercury cuprate series Hg-1201, Hg-1212 and Hg-1223. In the second chapter detailed results concerning the structure of these compounds are given highlighting the features common to all cuprates and pointing out the peculiarities of mercury phases. The third chapter presents the phase diagrams (δ, T, p(O 2 )) of the compounds HgBa 2 CuO 4+δ and HgBa 2 Ca 2 Cu 3 O 8+δ obtained by thermogravimetry under controlled atmosphere between 150 deg.C and 500 deg.C and thermodynamic equilibrium conditions. In the case of Hg-1201, the critical temperature shows a variation close to a parabolic law, with an optimal Tc of 96 K (δ≅0.10) while in Hg-1223 the Tc increases linearly with the O content up to the optimal Tc of 135 K (δ≅0.19) and decreases only by 2 K in the over-doped regime. Finally, in the fourth chapter different physical properties are reviewed. The obtained monocrystals allowed studying the resistive transitory anisotropy, the torque, the specific heat, the nuclear magnetic resonance and the Raman diffusion

Synthesis, crystal and band structures, and properties of a new supramolecular complex (Hg2As)2(CdI4)

International Nuclear Information System (INIS)

Zou Jianping; Wu Dongsheng; Huang Shuping; Zhu Jing; Guo Guocong; Huang Jinshun

2007-01-01

A new quaternary supramolecular complex (Hg 2 As) 2 (CdI 4 ) (1) has been prepared by the solid-state reaction and structurally characterized by single crystal X-ray diffraction analysis. Compound 1 crystallizes in the space group P2 1 of the monoclinic system with two formula units in a cell: a=7.945(4), b=12.934(6), c=8.094(4) A, β=116.898 o (1), V=741.7(6) A 3 . The structure of 1 is characterized by a tridymite-like three-dimensional cationic framework, which is composed of mercury and arsenic atoms, with the channels being occupied by discrete CdI 4 2- tetrahedral guest-anions. The optical properties were investigated in terms of the diffuse reflectance and Fourier transform infrared spectra. The electronic band structure along with density of states (DOS) calculated by DFT method indicates that the present compound is a semiconductor with a direct band gap, and that the optical absorption is mainly originated from the charge transitions from I-5p and As-4p to Cd-5s and Hg-6s states. - Graphical abstract: A new quaternary supramolecular complex (Hg 2 As) 2 (CdI 4 ) (1) has been prepared by the solid-state reaction, and structurally characterized by single crystal X-ray diffraction analysis. The structure of 1 is characterized by a 3-D tridymite-like cationic framework with the channels being occupied by discrete CdI 4 2- tetrahedral guest-anions

Highly sensitive optical sensor that detects Hg"2"+ and Cu"2"+ by immobilizing dicarboxylate 1,5-diphenyl-3-thiocarbazone on surface functionalized PVA microspheres

International Nuclear Information System (INIS)

Bai, Xue; Gu, Haixin; Hua, Zulin; Dai, Zhangyan; Yang, Bei; Li, Yulong

2015-01-01

Highlights: • PVA microspheres were chosen as carrier and DDT groups were chosen as chromophores. • The DDT–PVA microspheres could detect Hg"2"+ and Cu"2"+ simultaneously within 120 s. • The DDT–PVA microspheres had excellent detection for Hg"2"+ and Cu"2"+ ions. • The DDT–PVA microspheres had preeminent selectivity and reusability. - Abstract: A novel optical sensor to detect Hg"2"+ and Cu"2"+ is prepared by immobilizing a synthesized dicarboxylate 1,5-diphenyl-3-thiocarbazone (DDT) group on functionalized polyvinyl alcohol (PVA) microspheres. This optical sensor is successfully fabricated by extensive characterization with Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Its colorimetric properties, selectivity, sensitivity, and reversibility are investigated as well. In this sensing system, DDT–PVA selectively recognized multiple heavy metal ions, as indicated by the changes in color from orange to scarlet for Hg"2"+ and from orange to gray for Cu"2"+. In particular, this optical sensor exhibits the most apparent color changes at pH levels of 12 and 2. Hence, Hg"2"+ and Cu"2"+ can be detected in aqueous solution at minimum detection limits of 0.053 and 0.132 μM, respectively, with a UV-vis spectrometer. Furthermore, the sensor can be regenerated by ethylene diamine tetraacetic acid and reused several times. Therefore, the optical sensor can detect Hg"2"+ because of its selectivity, sensitivity, and reversibility.

Characterization of the Fermi surface of BEDT-TTF4[Hg2Cl6].PhCl by electronic band structure calculations

International Nuclear Information System (INIS)

Veiros, L.F.; Canadell, E.

1994-01-01

Tight-binding band structure calculations for the room temperature structure of BEDT-TTF 4 [Hg 2 Cl 6 ]-PhCl show the existence of closed electron and hole Fermi surfaces, in agreement with the 2D metallic conductivity of this salt. It is shown that these closed Fermi surfaces result from the hybridization of two hidden 1D Fermi surfaces. However, our study also shows that a transition associated with either a usual or a hidden nesting type mechanism is unlikely. This explains why this salt retains its metallic properties without any resistivity anomaly down to 1.3 K. Our study suggests that BEDT-TTF 4 [Hg 2 Cl 6 ]-PhCl is somewhat anisotropic 2D semimetal and should exhibit Shubnikov-de Haas oscillations corresponding to a cross-sectional area of approximately 13% of the first Brillouin zone. (orig.)

The sea-air exchange of mercury (Hg) in the marine boundary layer of the Augusta basin (southern Italy): concentrations and evasion flux.

Science.gov (United States)

Bagnato, E; Sproveri, M; Barra, M; Bitetto, M; Bonsignore, M; Calabrese, S; Di Stefano, V; Oliveri, E; Parello, F; Mazzola, S

2013-11-01

The first attempt to systematically investigate the atmospheric mercury (Hg) in the MBL of the Augusta basin (SE Sicily, Italy) has been undertaken. In the past the basin was the receptor for Hg from an intense industrial activity which contaminated the bottom sediments of the Bay, making this area a potential source of pollution for the surrounding Mediterranean. Three oceanographic cruises have been thus performed in the basin during the winter and summer 2011/2012, where we estimated averaged Hgatm concentrations of about 1.5±0.4 (range 0.9-3.1) and 2.1±0.98 (range 1.1-3.1) ng m(-3) for the two seasons, respectively. These data are somewhat higher than the background Hg atm value measured over the land (range 1.1±0.3 ng m(-3)) at downtown Augusta, while are similar to those detected in other polluted regions elsewhere. Hg evasion fluxes estimated at the sea/air interface over the Bay range from 3.6±0.3 (unpolluted site) to 72±0.1 (polluted site of the basin) ng m(-2) h(-1). By extending these measurements to the entire area of the Augusta basin (~23.5 km(2)), we calculated a total sea-air Hg evasion flux of about 9.7±0.1 g d(-1) (~0.004 tyr(-1)), accounting for ~0.0002% of the global Hg oceanic evasion (2000 tyr(-1)). The new proposed data set offers a unique and original study on the potential outflow of Hg from the sea-air interface at the basin, and it represents an important step for a better comprehension of the processes occurring in the marine biogeochemical cycle of this element. Copyright © 2013 Elsevier Ltd. All rights reserved.

Positive gain measurements on the 3350-A continuum band of Hg2

International Nuclear Information System (INIS)

Schlie, L.A.; Guenther, B.D.; Rathge, R.D.

1976-01-01

A He-Cd + laser operating at 3250 A and an Ar + laser at 3511 A and 3638 A have been used to probe for gain on both sides of the Hg 2 3350-A (A 3 1/subu/→X 1 Σ/subg/ + ) continuum band in Hg vapor at a pressure of 3.75 atm that was pumped by a 1.5-MeV 600-J 20-ns electron beam. This letter presents the first observation of positive gain on this 3350-A band of Hg 2 . The results indicate that the stimulated emission cross section for this band is larger than any associated photoionization process in the Hg vapor and has a magnitude of approximately 10 -18 cm 2 . Also, raising the temperature of the vapor above its saturation value increases the maximum value and duration of the observed gain, indicating that the population of the upper level of this transition is being fed by a temperature-dependent internal energy reservoir in the Hg

Interpretation of the vacancy-ordering controlled growth morphology of Hg5In2Te8 precipitates in Hg3In2Te6 single crystals by TEM observation and crystallographic calculation

International Nuclear Information System (INIS)

Sun, Jie; Fu, Li; Liu, Hongwei; Ringer, S.P.; Liu, Zongwen

2015-01-01

Graphical abstract: The growth morphology and detailed crystallography of Hg 5 In 2 Te 8 precipitates in Hg 3 In 2 Te 6 matrix to has been interpreted by means of transmission electron microscopy and invariant element deformation model. Three crystallographic equivalent variants of Hg 5 In 2 Te 8 precipitates in Hg 3 In 2 Te 6 matrix were found to have different growth directions and habit planes. Such growth morphology is fully attributed to the lattice shrinkage induced by vacancy ordering under high temperature in Hg 5 In 2 Te 8 . Through near coincident site lattice and invariant strain calculation, the morphology and crystallographic features of the precipitate has been successfully interpreted. - Highlights: • The growth morphology of Hg 5 In 2 Te 8 precipitates in Hg 3 In 2 Te 6 was observed by TEM. • Near-CSL calculation show 0.7577% lattice shrinkage of Hg 5 In 2 Te 8 at high temperature. • All the involved factors have inverse relationship with the move speed of interface. • The calculated crystallography features of Hg 5 In 2 Te 8 agree well with the TEM results. - Abstract: Generally, the crystal growth morphology in liquid or vapor was controlled by chemical potential, while that in solid solute was restricted by 3D strain matching between matrix and secondary phase. It is already known that the growth and evolution of the morphology of secondary phase during the solid phase transformation are highly determined by the variation of interface energy induced by lattice mismatch. In this work, the growth morphology and crystallography of Hg 5 In 2 Te 8 precipitates in Hg 3 In 2 Te 6 matrix were investigated by means of transmission electron microscopy (TEM). It was found that the growth of Hg 5 In 2 Te 8 precipitates displayed an unusual growth morphology which contain three crystallographically equivalent variants with different growth directions in Hg 3 In 2 Te 6 matrix, suggesting a slight lattice constant variation of Hg 5 In 2 Te 8 precipitate

Crystal structure of HgGa{sub 2}Se{sub 4} under compression

Energy Technology Data Exchange (ETDEWEB)

Gomis, Oscar, E-mail: osgohi@fis.upv.es [Centro de Tecnologías Físicas: Acústica, Materiales y Astrofísica, MALTA Consolider Team, Universitat Politècnica de València, 46022 València (Spain); Vilaplana, Rosario [Centro de Tecnologías Físicas: Acústica, Materiales y Astrofísica, MALTA Consolider Team, Universitat Politècnica de València, 46022 València (Spain); Manjón, Francisco Javier [Instituto de Diseño para la Fabricación y Producción Automatizada, MALTA Consolider Team, Universitat Politècnica de València, 46022 València (Spain); Santamaría-Pérez, David [Departamento de Química Física I, Universidad Complutense de Madrid, MALTA Consolider Team, Avenida Complutense s/n, 28040 Madrid (Spain); Departamento de Física Aplicada-ICMUV, MALTA Consolider Team, Universidad de Valencia, Edificio de Investigación, C/Dr. Moliner 50, Burjassot, 46100 Valencia (Spain); Errandonea, Daniel [Departamento de Física Aplicada-ICMUV, MALTA Consolider Team, Universidad de Valencia, Edificio de Investigación, C/Dr. Moliner 50, Burjassot, 46100 Valencia (Spain); and others

2013-06-01

Highlights: ► Single crystals of HgGa{sub 2}Se{sub 4} with defect-chalcopyrite structure were synthesized. ► HgGa{sub 2}Se{sub 4} exhibits a phase transition to a disordered rock salt structure at 17 GPa. ► HgGa{sub 2}Se{sub 4} undergoes a phase transition below 2.1 GPa to a disordered zinc blende. - Abstract: We report on high-pressure x-ray diffraction measurements up to 17.2 GPa in mercury digallium selenide (HgGa{sub 2}Se{sub 4}). The equation of state and the axial compressibilities for the low-pressure tetragonal phase have been determined and compared to related compounds. HgGa{sub 2}Se{sub 4} exhibits a phase transition on upstroke toward a disordered rock-salt structure beyond 17 GPa, while on downstroke it undergoes a phase transition below 2.1 GPa to a phase that could be assigned to a metastable zinc-blende structure with a total cation-vacancy disorder. Thermal annealing at low- and high-pressure shows that kinetics plays an important role on pressure-driven transitions.

Effect of layer composition on band spectrum of CdxHg1-xTe - CdyHg1-yTe-type superlattices

International Nuclear Information System (INIS)

Gerchikov, L.G.; Subashiev, A.V.; Salman Dalla

1993-01-01

Evolution of energy spectrum of Cd x Hg 1-x Te -Cd y Hg 1-y Te superlattices at variation of layer composition is considered. Transition from 3 type superlattice to 1 type superlattice occurring for y=0.16 is studied comprehensively. In this case, dependence of the width of superlattice forbidden zone on layer thickness is shown to become more smooth, than in CdTe - HgTe superlattice and it gives more possibilities to use such superlattices for making IR phototransistors. 10 refs., 4 figs

R-2HG Exhibits Anti-tumor Activity by Targeting FTO/m6A/MYC/CEBPA Signaling.

Science.gov (United States)

Su, Rui; Dong, Lei; Li, Chenying; Nachtergaele, Sigrid; Wunderlich, Mark; Qing, Ying; Deng, Xiaolan; Wang, Yungui; Weng, Xiaocheng; Hu, Chao; Yu, Mengxia; Skibbe, Jennifer; Dai, Qing; Zou, Dongling; Wu, Tong; Yu, Kangkang; Weng, Hengyou; Huang, Huilin; Ferchen, Kyle; Qin, Xi; Zhang, Bin; Qi, Jun; Sasaki, Atsuo T; Plas, David R; Bradner, James E; Wei, Minjie; Marcucci, Guido; Jiang, Xi; Mulloy, James C; Jin, Jie; He, Chuan; Chen, Jianjun

2018-01-11

R-2-hydroxyglutarate (R-2HG), produced at high levels by mutant isocitrate dehydrogenase 1/2 (IDH1/2) enzymes, was reported as an oncometabolite. We show here that R-2HG also exerts a broad anti-leukemic activity in vitro and in vivo by inhibiting leukemia cell proliferation/viability and by promoting cell-cycle arrest and apoptosis. Mechanistically, R-2HG inhibits fat mass and obesity-associated protein (FTO) activity, thereby increasing global N 6 -methyladenosine (m 6 A) RNA modification in R-2HG-sensitive leukemia cells, which in turn decreases the stability of MYC/CEBPA transcripts, leading to the suppression of relevant pathways. Ectopically expressed mutant IDH1 and S-2HG recapitulate the effects of R-2HG. High levels of FTO sensitize leukemic cells to R-2HG, whereas hyperactivation of MYC signaling confers resistance that can be reversed by the inhibition of MYC signaling. R-2HG also displays anti-tumor activity in glioma. Collectively, while R-2HG accumulated in IDH1/2 mutant cancers contributes to cancer initiation, our work demonstrates anti-tumor effects of 2HG in inhibiting proliferation/survival of FTO-high cancer cells via targeting FTO/m 6 A/MYC/CEBPA signaling. Copyright © 2017 Elsevier Inc. All rights reserved.

Single crystal growth, electronic structure and optical properties of Cs2HgBr4

Science.gov (United States)

Lavrentyev, A. A.; Gabrelian, B. V.; Vu, V. T.; Shkumat, P. N.; Parasyuk, O. V.; Fedorchuk, A. O.; Khyzhun, O. Y.

2015-10-01

We report on successful synthesis of high-quality single crystal of cesium mercury tetrabromide, Cs2HgBr4, by using the vertical Bridgman-Stockbarger method as well as on studies of its electronic structure. For the Cs2HgBr4 crystal, we have recorded X-ray photoelectron spectra for both pristine and Ar+ ion-bombarded surfaces. Our data indicate that the Cs2HgBr4 single crystal surface is rather sensitive with respect to Ar+ ion-bombardment. In particular, such a treatment of the Cs2HgBr4 single crystal surface alters its elemental stoichiometry. To explore peculiarities of the energy distribution of total and partial densities of states within the valence band and the conduction band of Cs2HgBr4, we have made band-structure calculations based on density functional theory (DFT) employing the augmented plane wave+local orbitals (APW+lo) method as incorporated in the WIEN2k package. The APW+lo calculations allow for concluding that the Br 4p states make the major contributions in the upper portion of the valence band, while its lower portion is dominated by contributors of the Hg 5d and Cs 5p states. Further, the main contributors to the bottom of the conduction band of Cs2HgBr4 are the unoccupied Br p and Hg s states. In addition, main optical characteristics of Cs2HgBr4 such as dispersion of the absorption coefficient, real and imaginary parts of dielectric function, electron energy-loss spectrum, refractive index, extinction coefficient and optical reflectivity have been explored from the first-principles band-structure calculations.

Sudden change of quadrupole moment between the first 5/2- states of 197Hg and 199Hg

International Nuclear Information System (INIS)

Herzog, P.; Krien, K.; Freitag, M.; Reuschenbach, M.; Walitzki, H.

1980-01-01

Low-temperature time differential perturbed angular correlation experiments with the 164 KeV-134 keV cascade of sup(197m)Hg in a zinc matrix give evidence that the hitherto accepted value of the quadrupole moment of the first 5/2 - state of 197 Hg is erroneous. A new value is derived from a time differential perturbed angular correlation experiment with the 374 keV-158 keV cascade of sup(199m)Hg implanted into a Be single crystal and comparison with an analogous experiment for sup(197m)Hg. Taking Q(5/2 - , 199 Hg) = +0.95(7) b we derive Q(5/2 - , 197 Hg) = 0.081(6) b. This change of quadrupole moment is discussed in the framework of the shell model. (orig.)

Floodplain simulation for Musi River using integrated 1D/2D hydrodynamic model

Directory of Open Access Journals (Sweden)

Al Amin Muhammad B.

2017-01-01

Full Text Available This paper presents the simulation of floodplain at Musi River using integrated 1D and 2D hydrodynamic model. The 1D flow simulation was applied for the river channel with flow hydrograph as upstream boundary condition. The result of 1D flow simulation was integrated into 2D flow simulation in order to know the area and characteristics of flood inundation. The input data of digital terrain model which was used in this research had grid resolution of 10m×10m, but for 2D simulation the resolution was with grid resolution 50 m × 50 m so as to limit simulation time since the model size was big enough. The result of the simulation showed that the inundated area surrounding Musi River is about 107.44 km2 with maximum flood depth is 3.24 m, water surface velocity ranges from 0.00 to 0.83 m/s. Most of floodplain areas varied from middle to high flood hazard level, and only few areas had very high level of flood hazard especially on river side. The structural flood control measurement to be recommended to Palembang is to construct flood dike and flood gate. The non structural measurement one is to improve watershed management and socialization of flood awareness.

Measurement of core level and band offsets at the interface of ITO/Hg_3In_2Te_6(1 1 0) heterojunction by synchrotron radiation photoelectron spectroscopy

International Nuclear Information System (INIS)

Li, Yapeng; Fu, Li; Sun, Jie; Ibrahim, Kurash; Wang, Jia-ou

2016-01-01

Highlights: • The valence band maximum of ITO film and MIT were measured to be 1.6 eV and 0.6 eV, respectively. • The concentration of In element presented a trend of increasing first and then decreasing from MIT to ITO. • The valence band offsets of the ITO/MIT(1 1 0) heterojunction was confirmed to be a type-II band alignment phenomenon. - Abstract: The Indium Tin Oxide (ITO) film was deposited on the surface of Hg_3In_2Te_6 (short for MIT) (1 1 0) for the fabrication of ITO/MIT(1 1 0) heterojunction by using the pulsed laser deposition method. In situ X-ray photoelectron spectroscopy was utilized to examine the band offsets and core level of ITO/MIT(1 1 0) heterojunctions. The result showed that the valence band maximum of ITO films and MIT(1 1 0) were 1.6 eV and 0.6 eV, respectively. Meanwhile, it was found that the binding energy of Te 3d, Sn 3d and Hg 4f remained unchanged during the ITO deposition process. However, the binding energy of O 1s and In 3d_5_/_2 increased about 0.3 eV and 0.2 eV, respectively, with the thickness increasing of ITO film from 3.5 nm to 5 nm. This may due to the elements diffusion at the interface region during the film growing process. According to the core level spectrum, it can be speculated that no significant chemical reaction occurred at the interface of ITO/MIT(1 1 0). In addition, the valence band offset of the ITO/MIT(1 1 0) heterojunction can be calculated to be −1 ± 0.15 eV by the means of the photoelectron spectroscopy methods. The conduction band offset is deduced to be −3.96 ± 0.15 eV from the known valence band offset value, indicating that the band offsets of ITO/MIT(1 1 0) heterojunction is a type-II band alignment.

A dansyl-rhodamine ratiometric fluorescent probe for Hg2+ based on FRET mechanism.

Science.gov (United States)

Xie, Puhui; Guo, Fengqi; Wang, Lingyu; Yang, Sen; Yao, Denghui; Yang, Guoyu

2015-03-01

Based on resonance energy transfer (FRET) from dansyl to rhodamine 101, a new fluorescent probe (compound 1) containing rhodamine 101 and a dansyl unit was synthesized for detecting Hg(2+) through ratiometric sensing in DMSO aqueous solutions. This probe shows a fast, reversible and selective response toward Hg(2+) in a wide pH range. Hg(2+) induced ring-opening reactions of the spirolactam rhodamine moiety of 1, leading to the formation of fluorescent derivatives that can serve as the FRET acceptors. Very large stokes shift (220 nm) was observed in this case. About 97-fold increase in fluorescence intensity ratio was observed upon its binding with Hg(2+).

Enhanced Hg{sup 2+} removal and Hg{sup 0} re-emission control from wet fuel gas desulfurization liquors with additives

Energy Technology Data Exchange (ETDEWEB)

Tingmei Tang; Jiang Xu; Rongjie Lu; Jingjing Wo; Xinhua Xu [Zhejiang University, Hangzhou (China). Department of Environmental Engineering

2010-12-15

Secondary atmospheric pollutions may result from wet flue gas desulfurization (FGD) systems caused by the reduction of Hg{sup 2+} to Hg{sup 0}. The present study employed three agents: Na{sub 2}S, 2,4,6-trimercaptotiazine, trisodium salt nonahydrate (TMT) and sodium dithiocarbamate (DTCR) to precipitate aqueous Hg{sup 2+} in simulated desulfurization solutions. The effects of the precipitator's dosing quantity, the initial pH value, the reaction temperature, the concentrations of Cl{sup -} and other metal ions (e.g. Cu{sup 2+} and Pb{sup 2+}) on Hg{sup 2+} removal were studied. A linear relationship was observed between Hg{sup 2+} removal efficiency and the increasing precipitator's doses along with initial pH. The addition of chloride and metal ions impaired the Hg{sup 2+} removal from solutions due to the complexation of Cl{sup -} and Hg{sup 2+} as well as the chelating competition between Hg{sup 2+} and other metal ions. Based on a comprehensive comparison of the treatment effects, DTCR was found to be the most effective precipitating agent. Moreover, all the precipitating agents were potent enough to inhibit Hg{sup 2+} reduction as well as Hg{sup 0} re-emission from FGD liquors. More than 90% Hg{sup 2+} was captured by precipitating agents while Hg{sup 2+} reduction efficiency decreased from 54% to just less than 3%. The additives could efficiently control the secondary Hg{sup 0} pollution from FGD liquors. 21 refs., 6 figs.

Stability and diffusion of Hg implanted YBa2Cu3O6+x

International Nuclear Information System (INIS)

Araujo, J.P.; Correia, J.G.; Wahl, U.; Marques, J.G.; Alves, E.; Amaral, V.S.; Lourenco, A.A.; Galindo, V.; Papen, T. von; Senateur, J.P.; Weiss, F.; Vantomme, A.; Langouche, G.; Melo, A.A.; Silva, M.F. da; Soares, J.C.; Sousa, J.B.

1999-01-01

The radioactive isotope 197m Hg was implanted at 60 keV with low fluences (10 13 ions/cm 2 ) into YBa 2 Cu 3 O 6+x (YBCO) superconducting thin films at ISOLDE/CERN. We report on the Hg dynamics and stability inside the YBCO lattice as a function of annealing temperature up to 890 K in a vacuum or O 2 atmosphere. The perturbed angular correlation (PAC) technique was used for probing the Hg behavior at the atomic scale, while by monitoring the sample's activity in situ the Hg outdiffusion was studied. We found that Hg ions occupy unique lattice sites and that Hg should be bound to two apical oxygens. Hg diffusion occurs only for annealing temperatures above 653 K, in vacuum. The Hg migration energy was estimated to be E M =1.58±0.15 eV

High energy proton-induced radioactivity in HgI2 crystals

International Nuclear Information System (INIS)

Porras, E.; Ferrero, J.L.; Sanchez, F.; Ruiz, J.A.; Lei, F.

1995-01-01

Mercuric iodide (HgI 2 ) semiconductor crystals are generating a lot of interest as room temperature solid state detectors for hard X-ray astronomy observations. For these applications one of the most important background sources is the cosmic proton induced radioactivity in the detector material. In order to study this background noise contribution a 1x1x1 cm HgI 2 crystal was irradiated with high energy protons. The resulting long-lived unstable isotopes and their production rates have been identified and compared with Monte Carlo simulations. ((orig.))

Novel Hg2+-Induced Nephropathy in Rats and Mice Lacking Mrp2: Evidence of Axial Heterogeneity in the Handling of Hg2+ Along the Proximal Tubule

Science.gov (United States)

Zalups, Rudolfs K.; Joshee, Lucy; Bridges, Christy C.

2014-01-01

The role of the multi-resistance protein 2 (Mrp2) in the nephropathy induced by inorganic mercuric mercury (Hg2+) was studied in rats (TR−) and mice (Mrp2−/−), which lack functional Mrp2, and control animals. Animals were exposed to nephrotoxic doses of HgCl2. Forty-eight or 24 hours after exposure, tissues were harvested and analyzed for Hg content and markers of injury. Histological analyses revealed that the proximal tubular segments affected pathologically by Hg2+ were significantly different between Mrp2-deficient animals and controls. In the absence of Mrp2, cellular injury localized almost exclusively in proximal tubular segments in the subcapsular (S1) to midcortical regions (early S2) of the kidney. In control animals, cellular death occurred mainly in the proximal tubular segments in the inner cortex (late S2) and outer stripe of the outer medulla (S3). These differences in renal pathology indicate that axial heterogeneity exists along the proximal tubule with respect to how mercuric ions are handled. Total renal and hepatic accumulation of mercury was also greater in animals lacking Mrp2 than in controls, indicating that Mrp2 normally plays a significant role in eliminating mercuric ions from within proximal tubular cells and hepatocytes. Analyses of plasma creatinine, BUN, and renal expression of Kim-1 and Ngal tend to support the severity of the nephropathies detected histologically. Collectively, our findings indicate that a fraction of mercuric ions is normally secreted by Mrp2 in early portions of proximal tubules into the lumen and then is absorbed downstream in straight portions, where mercuric species typically induce toxic effects. PMID:25145654

Tracing aquatic bioavailable Hg in three different regions of China using fish Hg isotopes.

Science.gov (United States)

Liu, Cheng-Bin; Hua, Xiu-Bing; Liu, Hong-Wei; Yu, Ben; Mao, Yu-Xiang; Wang, Ding-Yong; Yin, Yong-Guang; Hu, Li-Gang; Shi, Jian-Bo; Jiang, Gui-Bin

2018-04-15

To trace the most concerned bioavailable mercury (Hg) in aquatic environment, fish samples were collected from three typical regions in China, including 3 rivers and 1 lake in the Tibetan Plateau (TP, a high altitude background region with strong solar radiation), the Three Gorges Reservoir (TGR, the largest artificial freshwater reservoir in China), and the Chinese Bohai Sea (CBS, a heavily human-impacted semi-enclosed sea). The Hg isotopic compositions in fish muscles were analyzed. The results showed that anthropogenic emissions were the main sources of Hg in fish from TGR and CBS because of the observed negative δ 202 Hg and positive Δ 199 Hg in these two regions (TGR, δ 202 Hg: - 0.72 to - 0.29‰, Δ 199 Hg: 0.15 - 0.52‰; CBS, δ 202 Hg: - 2.09 to - 0.86‰, Δ 199 Hg: 0.07 - 0.52‰). The relatively higher δ 202 Hg and Δ 199 Hg (δ 202 Hg: - 0.37 - 0.08‰, Δ 199 Hg: 0.50 - 1.89‰) in fish from TP suggested the insignificant disturbance from local anthropogenic activities. The larger slopes of Δ 199 Hg/Δ 201 Hg in fish from TGR (1.29 ± 0.14, 1SD) and TP (1.25 ± 0.06, 1SD) indicated methylmercury (MeHg) was produced and photo-reduced in the water column before incorporation into the fish. In contrast, the photoreduction of Hg 2+ was the main process in CBS (slope of Δ 199 Hg/Δ 201 Hg: 1.06 ± 0.06, 1SD). According to the fingerprint data of Hg isotopes, the most important source for aquatic bioavailable Hg in TP should be the long-range transported Hg, contrasting to the anthropogenic originated MeHg from surface sediments and runoffs in TGR and inorganic Hg from continental inputs in CBS. Therefore, the isotopic signatures of Hg in fish can provide novel clues in tracing sources and behaviors of bioavailable Hg in aquatic systems, which are critical for further understanding the biogeochemical cycling of Hg. Copyright © 2017 Elsevier Inc. All rights reserved.

Detailed Assessment of the Kinetics of Hg-Cell Association, Hg Methylation, and Methylmercury Degradation in Several Desulfovibrio Species

Science.gov (United States)

Graham, Andrew M.; Bullock, Allyson L.; Maizel, Andrew C.; Elias, Dwayne A.

2012-01-01

The kinetics of inorganic Hg [Hg(II)i] association, methylation, and methylmercury (MeHg) demethylation were examined for a group of Desulfovibrio species with and without MeHg production capability. We employed a detailed method for assessing MeHg production in cultures, including careful control of medium chemistry, cell density, and growth phase, plus mass balance of Hg(II)i and MeHg during the assays. We tested the hypothesis that differences in Hg(II)i sorption and/or uptake rates drive observed differences in methylation rates among Desulfovibrio species. Hg(II)i associated rapidly and with high affinity to both methylating and nonmethylating species. MeHg production by Hg-methylating strains was rapid, plateauing after ∼3 h. All MeHg produced was rapidly exported. We also tested the idea that all Desulfovibrio species are capable of Hg(II)i methylation but that rapid demethylation masks its production, but we found this was not the case. Therefore, the underlying reason why MeHg production capability is not universal in the Desulfovibrio is not differences in Hg affinity for cells nor differences in the ability of strains to degrade MeHg. However, Hg methylation rates varied substantially between Hg-methylating Desulfovibrio species even in these controlled experiments and after normalization to cell density. Thus, biological differences may drive cross-species differences in Hg methylation rates. As part of this study, we identified four new Hg methylators (Desulfovibrio aespoeensis, D. alkalitolerans, D. psychrotolerans, and D. sulfodismutans) and four nonmethylating species (Desulfovibrio alcoholivorans, D. tunisiensis, D. carbinoliphilus, and D. piger) in our ongoing effort to generate a library of strains for Hg methylation genomics. PMID:22885751

Chemical doping and improved flux pinning in Hg-based superconductors

International Nuclear Information System (INIS)

Kishio, K.; Shimoyama, J.; Yoshikawa, A.; Kitazawa, K.

1996-01-01

Chemical doping of a small amount (0.02∼0.3) of rhenium (Re) ion into HgBa 2 Ca n-1 Cu n O y (n=1∼4) has been studied. The flux pinning strength in these Hg-based superconductors is significantly enhanced compared to the undoped parent materials. Neutron diffraction analysis of representative samples (n=3) revealed that Re partially substitutes the Hg-site with octahedrally fully coordinated oxygen atoms, giving rise to the stabilization of Hg(Re)O layer and reduction of this blocking layer thickness. Associated with the expected hybridization of Re-5d and O-2p orbitals and possible metallization of the Hg(Re)O layer, the improved flux pinning behavior is considered to be caused by the decrease of the electromagnetic anisotropy and the enhanced interlayer superconducting coupling strength

Adsorption of Hg2+ from aqueous solution onto polyacrylamide/attapulgite

International Nuclear Information System (INIS)

Zhao Yijiang; Chen Yan; Li Meisheng; Zhou Shouyong; Xue Ailian; Xing Weihong

2009-01-01

Polyacrylamide/attapulgite (PAM/ATP) was prepared by the solution polymerization of acrylamide (AM) onto γ-methacryloxypropyl trimethoxy silane (KH-570)-modified attapulgite (ATP). PAM/ATP was characterized using Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS). The effects of contact time, adsorbent dosage, and pH of the initial solution on the adsorption capacities for Hg 2+ were investigated. The adsorption process was rapid; 88% of adsorption occurred within 5 min and equilibrium was achieved at around 40 min. The equilibrium data fitted the Langmuir sorption isotherms well, and the maximum adsorption capacity of Hg 2+ onto PAM/ATP was found to be 192.5 mg g -1 . The adsorption kinetics of PAM/ATP fitted a pseudo-second-order kinetic model. Our results suggest that chemisorption processes could be the rate-limiting steps in the process of Hg 2+ adsorption. Hg 2+ adsorbed onto PAM/ATP could be effectively desorbed in hot acetic acid solution, and the adsorption capacity of the regenerated adsorbents could still be maintained at 95% by the sixth cycle.

Comment on 'Thermodynamic description of the Hg-Te system' [Journal of Alloys and Compounds 494 (1-2) (2010) 102-108

Energy Technology Data Exchange (ETDEWEB)

Kang, Youn-Bae, E-mail: ybkang@postech.ac.k [Graduate Institute of Ferrous Technology (GIFT), Pohang University of Science and Technology, Hyojadong, Pohang, Kyungbuk 790-784 (Korea, Republic of)

2010-09-03

Recently Gierlotka [Journal of Alloys and Compounds 494 (1-2) (2010) 102-108] reported on thermodynamic assessments of the Hg-Te binary system using (1) two-sublattice ionic model, (2) associate model, and (3) random mixing model for the liquid phase. And a conclusion was made such that the two-sublattice ionic model and the associate model are superior to the random mixing model in describing thermodynamic properties and phase diagram of the Hg-Te system, and the two-sublattice ionic model seems to be more suitable for describing Hg-Te binary system due to ionic behavior of the Hg-Te liquid. Purpose of the present letter is to point out that (1) the two-sublattice ionic model and the associate model can be made mathematically the same in a binary system as in the Hg-Te system, therefore two different assessments using either the two-sublattice ionic model or the associate model by Gierlotka are essentially very similar as long as the parameters used in both models are similar, and (2) the two models can also be made mathematically equivalent even in higher order system under certain conditions.

Impact of D2O/H2O Solvent Exchange on the Emission of HgTe and CdTe Quantum Dots: Polaron and Energy Transfer Effects.

Science.gov (United States)

Wen, Qiannan; Kershaw, Stephen V; Kalytchuk, Sergii; Zhovtiuk, Olga; Reckmeier, Claas; Vasilevskiy, Mikhail I; Rogach, Andrey L

2016-04-26

We have studied light emission kinetics and analyzed carrier recombination channels in HgTe quantum dots that were initially grown in H2O. When the solvent is replaced by D2O, the nonradiative recombination rate changes highlight the role of the vibrational degrees of freedom in the medium surrounding the dots, including both solvent and ligands. The contributing energy loss mechanisms have been evaluated by developing quantitative models for the nonradiative recombination via (i) polaron states formed by strong coupling of ligand vibration modes to a surface trap state (nonresonant channel) and (ii) resonant energy transfer to vibration modes in the solvent. We conclude that channel (i) is more important than (ii) for HgTe dots in either solution. When some of these modes are removed from the relevant spectral range by the H2O to D2O replacement, the polaron effect becomes weaker and the nonradiative lifetime increases. Comparisons with CdTe quantum dots (QDs) served as a reference where the resonant energy loss (ii) a priori was not a factor, also confirmed by our experiments. The solvent exchange (H2O to D2O), however, is found to slightly increase the overall quantum yield of CdTe samples, probably by increasing the fraction of bright dots in the ensemble. The fundamental study reported here can serve as the foundation for the design and optimization principles of narrow bandgap quantum dots aimed at applications in long wavelength colloidal materials for infrared light emitting diodes and photodetectors.

Fluorescent Gold Nanoprobes for the Sensitive and Selective Detection for Hg2+

Directory of Open Access Journals (Sweden)

Chai Fang

2010-01-01

Full Text Available Abstract A simple, cost-effective yet rapid and sensitive sensor for on-site and real-time Hg2+ detection based on bovine serum albumin functionalized fluorescent gold nanoparticles as novel and environmentally friendly fluorescent probes was developed. Using this probe, aqueous Hg2+ can be detected at 0.1 nM in a facile way based on fluorescence quenching. This probe was also applied to determine the Hg2+ in the lake samples, and the results demonstrate low interference and high sensitivity.

Reduced Limit on the Permanent Electric Dipole Moment of ^{199}Hg.

Science.gov (United States)

Graner, B; Chen, Y; Lindahl, E G; Heckel, B R

2016-04-22

This Letter describes the results of the most recent measurement of the permanent electric dipole moment (EDM) of neutral ^{199}Hg atoms. Fused silica vapor cells containing enriched ^{199}Hg are arranged in a stack in a common magnetic field. Optical pumping is used to spin polarize the atoms orthogonal to the applied magnetic field, and the Faraday rotation of near-resonant light is observed to determine an electric-field-induced perturbation to the Larmor precession frequency. Our results for this frequency shift are consistent with zero; we find the corresponding ^{199}Hg EDM d_{Hg}=(-2.20±2.75_{stat}±1.48_{syst})×10^{-30}e cm. We use this result to place a new upper limit on the ^{199}Hg EDM |d_{Hg}|<7.4×10^{-30}e cm (95% C.L.), improving our previous limit by a factor of 4. We also discuss the implications of this result for various CP-violating observables as they relate to theories of physics beyond the standard model.

M-theory solutions invariant under D(2,1; γ) + D(2,1;γ)

Energy Technology Data Exchange (ETDEWEB)

Bachas, C. [Laboratoire de Physique Theorique de l' Ecole Normale Superieure Unite mixte (UMR 8549) du CNRS et de l' ENS, Paris (France); D' Hoker, E. [Department of Physics and Astronomy, University of California, Los Angeles, CA (United States); Estes, J. [Blackett Laboratory, Imperial College, London (United Kingdom); Krym, D. [Physics Department, New York City College of Technology, The City University of New York, Brooklyn, NY (United States)

2014-03-06

We simplify and extend the construction of half-BPS solutions to 11-dimensional supergravity, with isometry superalgebra D(2,1;γ) + D(2,1;γ). Their space-time has the form AdS{sub 3} x S{sup 3} x S{sup 3} warped over a Riemann surface Σ. It describes near-horizon geometries of M2 branes ending on, or intersecting with, M5 branes along a common string. The general solution to the BPS equations is specified by a reduced set of data (γ, h, G), where γ is the real parameter of the isometry superalgebra, and h and G are functions on Σ whose differential equations and regularity conditions depend only on the sign of γ. The magnitude of γ enters only through the map of h,G onto the supergravity fields, thereby promoting all solutions into families parametrized by vertical stroke γ vertical stroke. By analyzing the regularity conditions for the supergravity fields, we prove two general theorems: (i) that the only solution with a 2-dimensional CFT dual is AdS{sub 3} x S{sup 3} x S{sup 3} x R {sup 2}, modulo discrete identifications of the flat R {sup 2}, and (ii) that solutions with γ < 0 cannot have more than one asymptotic higher-dimensional AdS region. We classify the allowed singularities of h and G near the boundary of Σ, and identify four local solutions: asymptotic AdS{sub 4}/Z{sub 2} or AdS{sub 7}' regions; highly-curved M5-branes; and a coordinate singularity called the ''cap''. By putting these ''Lego'' pieces together we recover all known global regular solutions with the above symmetry, including the self-dual strings on M5 for γ <0, and the Janus solution for γ > 0, but now promoted to families parametrized by vertical stroke γ vertical stroke. We also construct exactly new regular solutions which are asymptotic to AdS{sub 4}/Z{sub 2} for γ < 0, and conjecture that they are a different superconformal limit of the self-dual string. Finally, we construct exactly γ > 0 solutions with highly curved M5

A dansyl group modified SBA-15 INHIBIT logic gate with [Hg2+ and Cl-] or [Hg2+ and Br-] as inputs

Science.gov (United States)

Wang, Xiaoyu; Yang, Honglei

2013-07-01

We developed a SBA-15-based INHIBIT logic gate (DA-SBA-15) which was prepared by covalent immobilization of a dansylamide derivative into the channels of the mesoporous silica material (SBA-15) via (3-aminopropyl)triethoxysilane (APTES) groups. A series of characteristic results proved that the fluorescent ligand was successfully grafted into the mesopores of SBA-15. The fluorescent characterization revealed excellent selectivity of DA-SBA-15 to the Hg2+ ion. Moreover, DA-SBA-15 can be considered as a selective fluorescent probe for Cl- and Br-. The fluorescent changes of DA-SBA-15 upon the addition of ions (Hg2+, Cl- and Br-) were utilized as an INH logic gate at the molecular level, using [Hg2+ and Cl-] or [Hg2+ and Br-] as chemical inputs and the fluorescence intensity signal as output.

Relationship between herbaceous biomass and 1km (2) advanced very high resolution radiometer (AVHRR) NDVI in Kruger National Park, South Africa

CSIR Research Space (South Africa)

Wessels, Konrad J

2006-03-01

Full Text Available biomass and 1-km2 Advanced Very High Resolution Radiometer (AVHRR) NDVI in Kruger National Park, South Africa K. J. WESSELS*{, S. D. PRINCE{, N. ZAMBATIS{, S. MACFADYEN{, P. E. FROST§" and D. VAN ZYL§ {Department of Geography, University of Maryland... production (Prince and Justice 1991, Tucker et al. 1991a,b, Myneni et al. *Corresponding author. Email: wessels@geog.umd.edu International Journal of Remote Sensing Vol. 27, No. 5, 10 March 2006, 951–973 International Journal of Remote Sensing ISSN 0143...

The organic anion transport polypeptide 1d1 (Oatp1d1) mediates hepatocellular uptake of phalloidin and microcystin into skate liver.

Science.gov (United States)

Meier-Abt, F; Hammann-Hänni, A; Stieger, B; Ballatori, N; Boyer, J L

2007-02-01

Organic anion transporting polypeptides (rodent Oatp; human OATP) mediate cellular uptake of numerous organic compounds including xenobiotic toxins into mammalian hepatocytes. In the little skate Leucoraja erinacea a liver-specific Oatp (Oatp1d1, also called sOatp) has been identified and suggested to represent an evolutionarily ancient precursor of the mammalian liver OATP1B1 (human), Oatp1b2 (rat), and OATP1B3 (human). The present study tested whether Oatp1d1 shares functional transport activity of the xenobiotic oligopeptide toxins phalloidin and microcystin with the mammalian liver Oatps/OATPs. The phalloidin analogue [(3)H]-demethylphalloin was taken up into skate hepatocytes with high affinity (Km approximately 0.4 microM), and uptake could be inhibited by phalloidin and a variety of typical Oatp/OATP substrates such as bromosulfophthalein, bile salts, estrone-3-sulfate, cyclosporine A and high concentrations of microcystin-LR (Ki approximately 150 microM). When expressed in Xenopus laevis oocytes Oatp1d1 increased uptake of demethylphalloin (Km approximately 2.2 microM) and microcystin-LR (Km approximately 27 microM) 2- to 3-fold over water-injected oocytes, whereas the alternative skate liver organic anion transporter, the dimeric Ostalpha/beta, exhibited no phalloidin and only minor microcystin-LR transport. Also, the closest mammalian Oatp1d1 orthologue, the human brain and testis OATP1C1, did not show any phalloidin transport activity. These results demonstrate that the evolutionarily ancient Oatp1d1 is able to mediate uptake of cyclic oligopeptide toxins into skate liver. The findings support the notion that Oatp1d1 is a precursor of the liver-specific mammalian Oatps/OATPs and that its transport properties are closely associated with certain forms of toxic liver injury such as for example protein phosphatase inhibition by the water-borne toxin microcystin.

The organic anion transport polypeptide 1d1 (Oatp1d1) mediates hepatocellular uptake of phalloidin and microcystin into skate liver

International Nuclear Information System (INIS)

Meier-Abt, F.; Hammann-Haenni, A.; Stieger, B.; Ballatori, N.; Boyer, J.L.

2007-01-01

Organic anion transporting polypeptides (rodent Oatp; human OATP) mediate cellular uptake of numerous organic compounds including xenobiotic toxins into mammalian hepatocytes. In the little skate Leucoraja erinacea a liver-specific Oatp (Oatp1d1, also called sOatp) has been identified and suggested to represent an evolutionarily ancient precursor of the mammalian liver OATP1B1 (human), Oatp1b2 (rat), and OATP1B3 (human). The present study tested whether Oatp1d1 shares functional transport activity of the xenobiotic oligopeptide toxins phalloidin and microcystin with the mammalian liver Oatps/OATPs. The phalloidin analogue [ 3 H]-demethylphalloin was taken up into skate hepatocytes with high affinity (Km ∼ 0.4 μM), and uptake could be inhibited by phalloidin and a variety of typical Oatp/OATP substrates such as bromosulfophthalein, bile salts, estrone-3-sulfate, cyclosporine A and high concentrations of microcystin-LR (Ki ∼ 150 μM). When expressed in Xenopus laevis oocytes Oatp1d1 increased uptake of demethylphalloin (Km ∼ 2.2 μM) and microcystin-LR (Km ∼ 27 μM) 2- to 3-fold over water-injected oocytes, whereas the alternative skate liver organic anion transporter, the dimeric Ostα/β, exhibited no phalloidin and only minor microcystin-LR transport. Also, the closest mammalian Oatp1d1 orthologue, the human brain and testis OATP1C1, did not show any phalloidin transport activity. These results demonstrate that the evolutionarily ancient Oatp1d1 is able to mediate uptake of cyclic oligopeptide toxins into skate liver. The findings support the notion that Oatp1d1 is a precursor of the liver-specific mammalian Oatps/OATPs and that its transport properties are closely associated with certain forms of toxic liver injury such as for example protein phosphatase inhibition by the water-borne toxin microcystin

Hg0 and HgCl2 Reference Gas Standards: NIST Traceability and Comparability (And EPA ALT Methods for Hg and HCl )

Science.gov (United States)

EPA and NIST have collaborated to establish the necessary procedures for establishing the required NIST traceability of commercially-provided Hg0 and HgCl2 reference generators. This presentation will discuss the approach of a joint EPA/NIST study to accurately quantify the tru...

Intense charge transfer surface based on graphene and thymine-Hg(II)-thymine base pairs for detection of Hg(2.).

Science.gov (United States)

Li, Jiao; Lu, Liping; Kang, Tianfang; Cheng, Shuiyuan

2016-03-15

In this article, we developed an electrochemiluminescence (ECL) sensor with a high-intensity charge transfer interface for Hg(2+) detection based on Hg(II)-induced DNA hybridization. The sensor was fabricated by the following simple method. First, graphene oxide (GO) was electrochemically reduced onto a glassy carbon electrode through cyclic voltammetry. Then, amino-labeled double-stranded (ds)DNA was assembled on the electrode surface using 1-pyrenebutyric acid N-hydroxysuccinimide as a linker between GO and DNA. The other terminal of dsDNA, which was labeled with biotin, was linked to CdSe quantum dots via biotin-avidin interactions. Reduced graphene oxide has excellent electrical conductivity. dsDNA with T-Hg(II)-T base pairs exhibited more facile charge transfer. They both accelerate the electron transfer performance and sensitivity of the sensor. The increased ECL signals were logarithmically linear with the concentration of Hg(II) when Hg(2+) was present in the detection solution. The linear range of the sensor was 10(-11) to 10(-8)mol/L (R=0.9819) with a detection limit of 10(-11)mol/L. This biosensor exhibited satisfactory results when it was used to detect Hg(II) in real water samples. The biosensor with high-intense charge transfer performance is a prospect avenue to pursue more and more sensitive detection method. Copyright © 2015 Elsevier B.V. All rights reserved.

Preparation of CdxHg1-xTe films by the method of vapour-phase epitaxy of HgTe on CdTe substrates with subsequent mutual diffusion

International Nuclear Information System (INIS)

Varavin, V.S.; Sidorov, Yu.G.; Remesnik, V.G.; Chikichev, S.I.; Nis, I.E.

1994-01-01

Mirror-like HgTe films have been grown on CdTe substrates of various orientations by vapor deposition of HgTe in temperature gradient. Deposition rates fell in the range of 5-12 μm/h. Subsequent annealing has permitted production of Hg 1-x Cd x Te layers about 15 μm in thickness. Canier density in annealed n-type specimens has been found to constitute (1-20)x10 15 cm -3 at carrier mobility of (2-5)x10 4 cm 2 xV -1 xs -1 and in p-type films - (1-5)x10 16 cm -3 and 200-350 cm 2 xV -1 xs -1 (77 K) respectively

Hg Storage and Mobility in Tundra Soils of Northern Alaska

Science.gov (United States)

Olson, C.; Obrist, D.

2017-12-01

Atmospheric mercury (Hg) can be transported over long distances to remote regions such as the Arctic where it can then deposit and temporarily be stored in soils. This research aims to improve the understanding of terrestrial Hg storage and mobility in the arctic tundra, a large receptor area for atmospheric deposition and a major source of Hg to the Arctic Ocean. We aim to characterize spatial Hg pool sizes across various tundra sites and to quantify the mobility of Hg from thawing tundra soils using laboratory mobility experiments. Active layer and permafrost soil samples were collected in the summer of 2014 and 2015 at the Toolik Field Station in northern Alaska (68° 38' N) and along a 200 km transect extending from Toolik to the Arctic Ocean. Soil samples were analyzed for total Hg concentration, bulk density, and major and trace elements. Hg pool sizes were estimated by scaling up Hg soil concentrations using soil bulk density measurements. Mobility of Hg in tundra soils was quantified by shaking soil samples with ultrapure Milli-Q® water as an extracting solution for 24 and 72 hours. Additionally, meltwater samples were collected for analysis when present. The extracted supernatant was analyzed for total Hg, dissolved organic carbon, cations and anions, redox, and ph. Mobility of Hg from soil was calculated using Hg concentrations determined in solid soil samples and in supernatant of soil solution samples. Results of this study show Hg levels in tundra mineral soils that are 2-5 times higher than those observed at temperate sites closer to pollution sources. Most of the soil Hg was located in mineral horizons where Hg mass accounted for 72% of the total soil pool. Soil Hg pool sizes across the tundra sites were highly variable (166 - 1,365 g ha-1; avg. 419 g ha-1) due to the heterogeneity in soil type, bulk density, depth to frozen layer, and soil Hg concentration. Preliminary results from the laboratory experiment show higher mobility of Hg in mineral

Highly sensitive optical sensor that detects Hg{sup 2+} and Cu{sup 2+} by immobilizing dicarboxylate 1,5-diphenyl-3-thiocarbazone on surface functionalized PVA microspheres

Energy Technology Data Exchange (ETDEWEB)

Bai, Xue, E-mail: baixue@hhu.edu.cn; Gu, Haixin; Hua, Zulin; Dai, Zhangyan; Yang, Bei; Li, Yulong

2015-11-15

Highlights: • PVA microspheres were chosen as carrier and DDT groups were chosen as chromophores. • The DDT–PVA microspheres could detect Hg{sup 2+} and Cu{sup 2+} simultaneously within 120 s. • The DDT–PVA microspheres had excellent detection for Hg{sup 2+} and Cu{sup 2+} ions. • The DDT–PVA microspheres had preeminent selectivity and reusability. - Abstract: A novel optical sensor to detect Hg{sup 2+} and Cu{sup 2+} is prepared by immobilizing a synthesized dicarboxylate 1,5-diphenyl-3-thiocarbazone (DDT) group on functionalized polyvinyl alcohol (PVA) microspheres. This optical sensor is successfully fabricated by extensive characterization with Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Its colorimetric properties, selectivity, sensitivity, and reversibility are investigated as well. In this sensing system, DDT–PVA selectively recognized multiple heavy metal ions, as indicated by the changes in color from orange to scarlet for Hg{sup 2+} and from orange to gray for Cu{sup 2+}. In particular, this optical sensor exhibits the most apparent color changes at pH levels of 12 and 2. Hence, Hg{sup 2+} and Cu{sup 2+} can be detected in aqueous solution at minimum detection limits of 0.053 and 0.132 μM, respectively, with a UV-vis spectrometer. Furthermore, the sensor can be regenerated by ethylene diamine tetraacetic acid and reused several times. Therefore, the optical sensor can detect Hg{sup 2+} because of its selectivity, sensitivity, and reversibility.

Synthesis, crystal and electronic structures and optical properties of (HIm)₂ Hg₃Cl₈ and (HIm)HgI₃ (HIm = imidazolium)

Energy Technology Data Exchange (ETDEWEB)

Nhalil, Hariharan [Univ. of Oklahoma, Norman, OK (United States). Dept. of Chemistry and Biochemistry; Whiteside, Vincent R. [Univ. of Oklahoma, Norman, OK (United States). Homer L. Dodge Dept. of Physics & Astronomy; Sellers, Ian R. [Univ. of Oklahoma, Norman, OK (United States). Homer L. Dodge Dept. of Physics & Astronomy; Ming, Wenmei [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science & Technology Division; Du, Mao-Hua [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science & Technology Division; Saparov, Bayrammurad [Univ. of Oklahoma, Norman, OK (United States). Dept. of Chemistry and Biochemistry

2017-11-22

Here, we report synthesis, crystal and electronic structures, and optical properties of two new Hg-based zero-dimensional hybrid organic-inorganic halides (HIm)2Hg3Cl8 and (HIm)HgI3 (HIm = imidazolium). (HIm)₂Hg₃Cl₈ crystallizes in the triclinic P-1 space group with a pseudo-layered structure made of organic imidazolium cation layers and anionic inorganic layers containing [Hg₂Cl₆]^2- units and linear [HgCl₂]⁰ molecules. (HIm)HgI₃ crystallizes in the monoclinic P2₁/c space group featuring anionic [HgI₃]- units that are surrounded by imidazolium cations. Based on density functional theory calculations, (HIm)₂Hg₃Cl₈ has an indirect band gap, whereas (HIm)HgI₃ has a direct band gap with the measured onsets of optical absorption at 3.43 and 2.63 eV, respectively. (HIm)₂Hg₃Cl₈ and (HIm)HgI₃ are broadband light emitters with broad photoluminescence peaks centered at 548 nm (2.26 eV) and 582 nm (2.13 eV), respectively. In conclusion, following the crystal and electronic structure considerations, the PL peaks are assigned to self-trapped excitons.

Functionalized layered double hydroxide with nitrogen and sulfur co-decorated carbondots for highly selective and efficient removal of soft Hg2+ and Ag+ ions.

Science.gov (United States)

Asiabi, Hamid; Yamini, Yadollah; Shamsayei, Maryam; Molaei, Karam; Shamsipur, Mojtaba

2018-05-28

A facile composite was fabricated via direct assembly of nitrogen and sulfur co-decorated carbon dots with abundant oxygen-containing functional groups on the surface of the positively charged layered double hydroxide (N,S-CDs-LDH). The novel N,S-CDs-LDH demonstrates highly selective bindings (M-S) and an extremely efficient removal capacity for soft metal ions such as Ag + and Hg 2+ ions. N,S-CDs-LDH displayed a selectivity order of Ag + > Hg 2+ > Cu 2+ > Pb 2+ > Zn 2+ > Cd 2+ for their adsorption. The enormous capacities for Hg 2+ (625.0 mg g -1 ) and Ag + (714.3 mg g -1 ) and very high distribution coefficients (K d ) of 9.9 × 10 6 mL g -1 (C 0  = 20 mg L -1 ) and 2.0 × 10 7 mL g -1 (C 0  = 20 mg L -1 ) for Hg 2+ and Ag + , respectively, place the N,S-CDs-LDH at the top of LDH based materials known for such removal. The adsorption kinetic curves for Hg 2+ and Ag + fitted well with the pseudo-second order model. For Hg 2+ and Ag + , an exceptionally rapid capture with removal ∼100% within 80 min was observed (C ions  = 30 mg L -1 and V/m ratio of 1000). The adsorption isotherms were well described using Langmuir isotherm. The N,S-CDs-LDH was successfully applied to highly efficient removal of Hg 2+ and Ag + from aqueous solutions. Copyright © 2018 Elsevier B.V. All rights reserved.

Specific inhibition of p97/VCP ATPase and kinetic analysis demonstrate interaction between D1 and D2 ATPase domains.

Science.gov (United States)

Chou, Tsui-Fen; Bulfer, Stacie L; Weihl, Conrad C; Li, Kelin; Lis, Lev G; Walters, Michael A; Schoenen, Frank J; Lin, Henry J; Deshaies, Raymond J; Arkin, Michelle R

2014-07-29

The p97 AAA (ATPase associated with diverse cellular activities), also called VCP (valosin-containing protein), is an important therapeutic target for cancer and neurodegenerative diseases. p97 forms a hexamer composed of two AAA domains (D1 and D2) that form two stacked rings and an N-terminal domain that binds numerous cofactor proteins. The interplay between the three domains in p97 is complex, and a deeper biochemical understanding is needed in order to design selective p97 inhibitors as therapeutic agents. It is clear that the D2 ATPase domain hydrolyzes ATP in vitro, but whether D1 contributes to ATPase activity is controversial. Here, we use Walker A and B mutants to demonstrate that D1 is capable of hydrolyzing ATP and show for the first time that nucleotide binding in the D2 domain increases the catalytic efficiency (kcat/Km) of D1 ATP hydrolysis 280-fold, by increasing kcat 7-fold and decreasing Km about 40-fold. We further show that an ND1 construct lacking D2 but including the linker between D1 and D2 is catalytically active, resolving a conflict in the literature. Applying enzymatic observations to small-molecule inhibitors, we show that four p97 inhibitors (DBeQ, ML240, ML241, and NMS-873) have differential responses to Walker A and B mutations, to disease-causing IBMPFD mutations, and to the presence of the N domain binding cofactor protein p47. These differential effects provide the first evidence that p97 cofactors and disease mutations can alter p97 inhibitor potency and suggest the possibility of developing context-dependent inhibitors of p97. Copyright © 2014 Elsevier Ltd. All rights reserved.

Environmental impact of CO2, Rn, Hg degassing from the rupture zones produced by Wenchuan M s 8.0 earthquake in western Sichuan, China.

Science.gov (United States)

Zhou, Xiaocheng; Chen, Zhi; Cui, Yueju

2016-10-01

The concentrations and flux of CO2, (222)Radon (Rn), and gaseous elemental mercury (Hg) in soil gas were investigated based on the field measurements in June 2010 at ten sites along the seismic rupture zones produced by the May 12, 2008, Wenchuan M s 8.0 earthquake in order to assess the environmental impact of degassing of CO2, Rn and Hg. Soil gas concentrations of 344 sampling points were obtained. Seventy measurements of CO2, Rn and Hg flux by the static accumulation chamber method were performed. The results of risk assessment of CO2, Rn and Hg concentration in soil gas showed that (1) the concentration of CO2 in the epicenter of Wenchuan M s 8.0 earthquake and north end of seismic ruptures had low risk of asphyxia; (2) the concentrations of Rn in the north segment of seismic ruptures had high levels of radon, Maximum was up to level 4, according to Chinese code (GB 50325-2001); (3) the average geoaccumulation index I geo of soil Hg denoted the lack of soil contamination, and maximum values classified the soil gas as moderately to strongly polluted in the epicenter. The investigation of soil gas CO2, Rn and Hg degassing rate indicated that (1) the CO2 in soil gas was characterized by a mean [Formula: see text] of -20.4 ‰ and by a mean CO2 flux of 88.1 g m(-2) day(-1), which were in the range of the typical values for biologic CO2 degassing. The maximum of soil CO2 flux reached values of 399 g m(-2) day(-1) in the epicenter; (2) the soil Rn had higher exhalation in the north segment of seismic ruptures, the maximum reached value of 1976 m Bq m(-2) s(-1); (3) the soil Hg flux was lower, ranging from -2.5 to 18.7 n g m(-2) h(-1) and increased from south to north. The mean flux over the all profiles was 4.2 n g m(-2) h(-1). The total output of CO2 and Hg degassing estimated along seismic ruptures for a survey area of 18.17 km(2) were approximately 0.57 Mt year(-1) and 688.19 g year(-1). It is recommended that land-use planners should

Study of the decay /sup 184/Hg. -->. /sup 184/Au (Tsub(1/2)=30s). [Lifetime, upper limits

Energy Technology Data Exchange (ETDEWEB)

Nettles, W G; Beraud, R; Cole, J D; Hamilton, J H; Ramayya, A V; Kawakami, H [Vanderbilt Univ., Nashville, TN (USA). Dept. of Physics; Sastry, K S.R. [Massachusetts Univ., Amherst (USA); Spejewski, E H

1978-04-01

The radioactive decay of /sup 184/Hg to /sup 184/Au was studied on line with the UNISOR isotope separator. The 184 mass chain was entered at /sup 184/Tl and /sup 184/Hg by bombarding an isotopically-enriched target of /sup 180/W with /sup 14/N ions of 177 MeV. Multiscale singles and ..gamma..-..gamma..-time coincidence studies were carried out. No previous levels have been assigned to /sup 184/Au. From the coincidence data eight levels at 156.2, 159.1, 247.7, 282.8, 295.1, 392.4, 418.0 and 412.4 keV are assigned and two tentative levels at 534.0 and 551.6 keV are proposed. By using the delayed coincidence technique, a half-life of 36+-6 nanoseconds was measured for the 156.2 keV first-excited level and upper limits of 2 nanoseconds were determined for the half-lives of levels at 159.1, 247.7, 295.1 and 392.4 keV.

HD 66051, an eclipsing binary hosting a highly peculiar, HgMn-related star.

Science.gov (United States)

Niemczura, Ewa; Hümmerich, Stefan; Castelli, Fiorella; Paunzen, Ernst; Bernhard, Klaus; Hambsch, Franz-Josef; Hełminiak, Krzysztof

2017-07-19

HD 66051 is an eclipsing system with an orbital period of about 4.75 d that exhibits out-of-eclipse variability with the same period. New multicolour photometric observations confirm the longevity of the secondary variations, which we interpret as a signature of surface inhomogeneities on one of the components. Using archival and newly acquired high-resolution spectra, we have performed a detailed abundance analysis. The primary component is a slowly rotating late B-type star (T eff  = 12500 ± 200 K; log g = 4.0, v sin i = 27 ± 2 km s -1 ) with a highly peculiar composition reminiscent of the singular HgMn-related star HD 65949, which seems to be its closest analogue. Some light elements as He, C, Mg, Al are depleted, while Si and P are enhanced. Except for Ni, all the iron-group elements, as well as most of the heavy elements, and in particular the REE elements, are overabundant. The secondary component was estimated to be a slowly rotating A-type star (T eff  ~ 8000 K; log g = 4.0, v sin i ~ 18 km s -1 ). The unique configuration of HD 66051 opens up intriguing possibilities for future research, which might eventually and significantly contribute to the understanding of such diverse phenomena as atmospheric structure, mass transfer, magnetic fields, photometric variability and the origin of chemical anomalies observed in HgMn stars and related objects.

Rhodamine-based chemodosimeter for fluorescent determination of Hg(2+) in 100% aqueous solution and in living cells.

Science.gov (United States)

Li, Dan; Li, Chun-Yan; Li, Yong-Fei; Li, Zhi; Xu, Fen

2016-08-31

A rhodamine spirolactam derivative (1) bearing a hydrophilic carboxylic acid group is developed as a fluorescent chemodosimeter for bivalent mercury ions (Hg(2+)) in 100% aqueous solution. It exhibits a highly sensitive "turn-on" fluorescent response toward Hg(2+) with a 42-fold fluorescence intensity enhancement under 1 equiv. of Hg(2+) added. The chemodosimeter can be applied to the quantification of Hg(2+) with a linear range covering from 3.0 × 10(-7) to 1.0 × 10(-5) M and a detection limit of 9.7 × 10(-8) M. Most importantly, the fluorescence changes of the chemodosimeter are remarkably specific for Hg(2+) in the presence of other metal ions, which meet the selective requirements for practical application. Moreover, the experiment results show that the response behavior of 1 towards Hg(2+) is pH independent in neutral condition (pH 5.0-8.0) and the response is fast (response time less than 3 min). Furthermore, the ring-opening mechanism of the rhodamine spirolactam induced by Hg(2+) was supported by NMR, MS, and DFT theoretical calculations. In addition, the proposed chemodosimeter has been used to detect Hg(2+) in water samples and image Hg(2+) in living cells with satisfying results. Copyright © 2016 Elsevier B.V. All rights reserved.

46 CFR 53.05-3 - Materials (modifies HG-401.2).

Science.gov (United States)

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Materials (modifies HG-401.2). 53.05-3 Section 53.05-3... Pressure Relieving Devices (Article 4) § 53.05-3 Materials (modifies HG-401.2). Materials for valves must be in accordance with HG-401.2 of section IV of the ASME Boiler and Pressure Vessel Code...

Band spectrum transformation and temperature dependences of thermoelectric power of Hg1-xRxBa2Ca2Cu3O8+δ system

Directory of Open Access Journals (Sweden)

M. Vasyuk

2011-03-01

Full Text Available Temperature dependences of thermoelectric power S(T at T>Tc of the Hg-based high temperature superconductors Hg1-xRxBa2Ca2Cu3O8+δ (R=Re, Pb have been analyzed with accounting for strong scattering of charge carriers. Transformation of parameters of a narrow conducting band in the region of the Fermi level was studied. The existence of correlation between the effective bandwidth and the temperature of a superconductive transition Tc is shown.

Photoluminescence from CdxHg1-xTe

International Nuclear Information System (INIS)

Breivik, M; Selvig, E; Tonheim, C R; Brendhagen, E; Brudevoll, T; Rheenen, A D van; Steen, H; Nicolas, S; Lorentzen, T; Haakenaasen, R

2008-01-01

We present important aspects of photoluminescence (PL) of Cd x Hg 1-x Te in the infrared part of the spectrum where background thermal radiation significantly affects the PL spectrum. We show how the background spectrum can be removed from the data. We also show how the wavelength of the excitation laser affects the relative intensity of the PL peaks from a multi-layer structure. Finally, we present temperature dependent PL of a Cd 0.36 Hg 0.64 Te/Cd 0.61 Hg 0.39 Te multiple quantum well structure grown on a 4 μm thick Cd 0.36 Hg 0.64 Te buffer layer. We attribute the low temperature peak from the buffer layer to impurities. The impurity levels are depopulated as the temperature increases, resulting in a decreased PL peak intensity. Above ∼200 K a band-to-band peak from the buffer layer is observed. The quantum well peak persists up to ∼200 K

La cartografia de la flora del Montseny en reticle UTM d'1 km. de costat: plantejament i primers resultats

OpenAIRE

Panareda i Clopés, Josep M. (Josep Maria), 1945-; Nuet i Badia, Josep

1983-01-01

El present treball és un primer escrit sobre la cartografia corològica de les plantes vasculars en el massis del Montseny (Serralada Pre-litoral), en el qual exposem el plantejament del projecte i oferim uns primers résultats. Hi incloem també un mapa per espècie prenent com a unitat espacial el quadrat d'1 km de costat del reticle UTM. La presència de 1'espècie a cada quadrat és indicada en très graus d'abundància: espècie présent o rara, espècie fréquent i espècie abundant. L'àrea estudiada...

Positive cooperativity of the specific binding between Hg2+ ion and T:T mismatched base pairs in duplex DNA

International Nuclear Information System (INIS)

Torigoe, Hidetaka; Miyakawa, Yukako; Ono, Akira; Kozasa, Tetsuo

2012-01-01

Highlights: ► Hg 2+ specifically bound with the T:T mismatched base pair at 1:1 molar ratio. ► The binding constant between Hg 2+ and the T:T mismatched base pair was 10 6 M −1 . ► The binding constant was larger than those for nonspecific metal–DNA interactions. ► The binding constant for the second Hg 2+ was larger than that for the first Hg 2+ . ► The positive cooperative binding was observed between Hg 2+ and multiple T:T. - Abstract: Metal-mediated base pairs by the interaction between metal ions and artificial bases in oligonucleotides have been developed for their potential applications in nanotechnology. We recently found that a natural T:T mismatched base pair bound with Hg 2+ ion to form a novel T–Hg–T base pair. Here, we examined the thermodynamic properties of the binding between Hg 2+ and each of the single and double T:T mismatched base pair duplex DNAs by isothermal titration calorimetry. Hg 2+ specifically bound with the T:T mismatched base pair at 1:1 molar ratio with 10 6 M −1 binding constant, which was significantly larger than those for nonspecific metal ion–DNA interactions. In the Hg 2+ –double T:T mismatched base pair interaction, the affinity for the second Hg 2+ binding was significantly larger than that for the first Hg 2+ binding. The positively cooperative binding may be favorable to align multiple Hg 2+ in duplex DNA for the application of the metal-mediated base pairs in nanotechnology.

Simple-structured, hydrazinecarbothioamide derivatived dual-channel optical probe for Hg{sup 2+} and Ag{sup +}

Energy Technology Data Exchange (ETDEWEB)

Shi, Wei [Oil & Gas Field Applied Chemistry Key Laboratory of Sichuan Province, School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500 (China); Key Laboratory of Oil & Gas Fine Chemicals, Ministry of Education, College of Chemistry and Chemical Engineering, Xinjiang University, Urumqi 83004 (China); Chen, Yabin [Key Laboratory of Oil & Gas Fine Chemicals, Ministry of Education, College of Chemistry and Chemical Engineering, Xinjiang University, Urumqi 83004 (China); Chen, Xin [Oil & Gas Field Applied Chemistry Key Laboratory of Sichuan Province, School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500 (China); Xie, Zhengfeng, E-mail: xiezhf@swpu.edu.cn [Oil & Gas Field Applied Chemistry Key Laboratory of Sichuan Province, School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500 (China); Key Laboratory of Oil & Gas Fine Chemicals, Ministry of Education, College of Chemistry and Chemical Engineering, Xinjiang University, Urumqi 83004 (China); Hui, Yonghai [Key Laboratory of Oil & Gas Fine Chemicals, Ministry of Education, College of Chemistry and Chemical Engineering, Xinjiang University, Urumqi 83004 (China)

2016-06-15

A type of simple-structured, hydrazinecarbothioamide-containing Schiff-base derivative, 2-(4-(diphenylamino)benzylidene)hydrazinecarbothioamide (M1), was synthesized through condensation reaction between 4-(diphenylamino)benzaldehyde and thiosemicarbazide. In the mixture of DMSO/H{sub 2}O (DMSO/H{sub 2}O=9:1(v:v), pH=4.5), distinct “turn-off” fluorescence alterations of M1 were observed upon the addition of Hg{sup 2+}, and the addition of Ag{sup +} induced fluorescence bathochromic shift. The detection limits of Hg{sup 2+} and Ag{sup +} reach~0.19 μM and ~0.59 μM, respectively, as evaluated by the detailed fluorescence response of M1 toward incremental target ions. The different extent of photo-induced electron transfer (PET) between M1 and these two ions might be the plausible reason for such different optical response behaviors. - Highlights: • Hydrazinecarbothioamide-containing Schiff-base derivative (M1) was synthesized. • “Turn-off” fluorescence alterations of M1 were observed upon the addition of Hg{sup 2+}. • The addition of Ag{sup +} induced fluorescence bathochromic shift of M1. • Detection limits of Hg{sup 2+} and Ag{sup +} reaches ~0.19 μM and ~0.59 μM, respectively. • Hg{sup 2+} and Ag{sup +} can be detected in independent channels by M1 thus.

Theoretical studies on the interaction and dynamics in the colisional systems Hg+Li,Na,P and Ar*(4s3P2,0)+Hg,H

International Nuclear Information System (INIS)

Thiel, L.

2004-01-01

The central aim of this work is the detailed theoretical characterization of the autoionization process in collisions of metastable argon atoms with mercury and hydrogen atoms, Ar * (4s 3 P 2,0 ) + Hg and Ar * (4s 3 P 2,0 ) + H(1s). The autoionization process in the collision complexes Ar * (4s 3 P 2,0 ) + Hg und Ar * (4s 3 P 2,0 ) + H(1s) was investigated using the local complex potential approximation. Within this approach the entrance channel is described by a complex resonance potential whose imaginary part - the socalled autoionization width describes the ionization probability as a function of the internuclear distance. For both investigated systems, this work presents the first ab initio treatment of the autoionization process. In the collision complex Ar * + Hg, the asymptote of the entrance channel lies energetically above the asymptote of the exit channel Ar + Hg + . Both Penning ionization (PI) Ar * + Hg → Ar + Hg + + e - and associative ionization (AI) Ar * + Hg → ArHg + + e - are possible at thermal collision energies. The resonance potential and the autoionization width which describe the entrance channel were determined in MRCI calculations in which the resonance state was de- fined through Feshbach projection based on orbital occupancy. Taking the spin-orbit interaction in the Ar + core into account, the calculated complex potentials are able to reproduce the available experimental data such as the absolute ionization cross sections, the collision energy dependence of the relative cross sections for Penning and assoziative ionization and the electron energy spectra. (orig.)

The determination of the surface potential for the CdxHg1-xTe crystals and the V-CdxHg1-xTe and Ni-V-CdxMg1-xTe structures

International Nuclear Information System (INIS)

Veliyulin, Eh.I.; Ragimova, R.A.; Mamedov, A.A.

1996-01-01

Surface potential of semiconductor crystals n-Cd x Hg 1-x Te (unannealed and annealed in mercury vapors) and of the structures V-Cd x Hg 1-x Te, Ni-V-Cd x Hg 1-x Te has been defined using spectroscopy of weak-field electric reflection. It is shown that a deep penetration of vanadium atoms in near the surface region of the crystal occurs in the structures on the basis of unannealed Cd x Hg 1-x Te. 1 ref.; 4 figs

A thermodynamic stability of bulk and epitaxial CdHgTe, ZnHgTe and MnHgTe solid solutions

International Nuclear Information System (INIS)

Dejbuk, V.G.; Dremlyuzhenko, S.G.; Ostapov, S.Eh.

2005-01-01

A thermodynamics of Cd 1-x Hg x Te, Zn x Hg 1-x Te and Mg x Hg 1-x Te alloys has been investigated for a delta-lattice parameter model. The phase diagrams obtained show the stability of Cd 1-x Hg x Te, Zn x Hg 1-x Te in the whole range of compositions, alongside with a miscibility gap for Mn x Hg 1-x Te being of 0.35 x Hg 1-x Te/CdTe and Mn x Hg 1-x Te/Cd 0.96 Zn 0.04 Te epitaxial films result in lowering critical temperatures and narrowing the miscibility gap [ru

SoilGrids1km--global soil information based on automated mapping.

Directory of Open Access Journals (Sweden)

Tomislav Hengl

Full Text Available BACKGROUND: Soils are widely recognized as a non-renewable natural resource and as biophysical carbon sinks. As such, there is a growing requirement for global soil information. Although several global soil information systems already exist, these tend to suffer from inconsistencies and limited spatial detail. METHODOLOGY/PRINCIPAL FINDINGS: We present SoilGrids1km--a global 3D soil information system at 1 km resolution--containing spatial predictions for a selection of soil properties (at six standard depths: soil organic carbon (g kg-1, soil pH, sand, silt and clay fractions (%, bulk density (kg m-3, cation-exchange capacity (cmol+/kg, coarse fragments (%, soil organic carbon stock (t ha-1, depth to bedrock (cm, World Reference Base soil groups, and USDA Soil Taxonomy suborders. Our predictions are based on global spatial prediction models which we fitted, per soil variable, using a compilation of major international soil profile databases (ca. 110,000 soil profiles, and a selection of ca. 75 global environmental covariates representing soil forming factors. Results of regression modeling indicate that the most useful covariates for modeling soils at the global scale are climatic and biomass indices (based on MODIS images, lithology, and taxonomic mapping units derived from conventional soil survey (Harmonized World Soil Database. Prediction accuracies assessed using 5-fold cross-validation were between 23-51%. CONCLUSIONS/SIGNIFICANCE: SoilGrids1km provide an initial set of examples of soil spatial data for input into global models at a resolution and consistency not previously available. Some of the main limitations of the current version of SoilGrids1km are: (1 weak relationships between soil properties/classes and explanatory variables due to scale mismatches, (2 difficulty to obtain covariates that capture soil forming factors, (3 low sampling density and spatial clustering of soil profile locations. However, as the SoilGrids system is

Imobilisasi TiO2 ke dalam Resin Penukar Kation dan Aplikasinya sebagai Fotokatalis dalam Proses Fotoreduksi Ion Hg2+

Directory of Open Access Journals (Sweden)

Rosyid Ridho

2017-03-01

Full Text Available Abstrak Dalam rangka mengembangkan bahan fotokatalitis TiO2 pada penelitian ini telah dilakukan preparasi fotokatalis TiO2-Resin yang disertai dengan karakterisasi dan uji aktivitas untuk proses fotoreduksi ion Hg(II. Preparasi imobilisasi ini dilakukan dengan metode pertukaran ion yang di ikuti dengan kalsinasi pada suhu tertentu. Pada preparasi telah dipelajari pengaruh konsentrasi Titanium Isopropoksida sebagai sumber ion Ti(IV terhadap TiO2-Resin yang dikarakterisasi dengan menggunakan Difraksi Sinar X (XRD dan Thermografimetri (TGA. Pada proses fotoreduksi ion Hg(II dipelajari pengaruh massa fotokatalis, kadar TiO2 yang terimobilisasi ke dalam resin, konsentrasi Ion Hg(II, dan pengaruh pH. Proses fotoreduksi dilakukan dalam suatu reaktor tertutup yang dilengkapi dengan lampu UV, yaitu dengan cara menyinari campuran yang terdiri dari larutan ion Hg(II dan serbuk fotokatalis TiO2-Resin, disertai dengan pengadukan selama waktu tertentu. Hasil fotoreduksi dihitung berdasarkan selisih antara konsentrasi ion Hg(II awal dengan ion Hg(II yang tak tereduksi. Penentuan konsentrasi ion Hg(II yang tak tereduksi dilakukan dengan menggunakan Spektrofotometer Serapan Atom (SSA teknik pembangkitan uap dingin atau Cold Vapor Atomic Absorption Spectrophotometry(CV-AAS. Hasil preparasi menunjukkan semakin tinggi konsentrasi Titanium Isopropoksida yang ditambahkan pada resin semakin tinggi juga kadar TiO2 yang terbentuk pada TiO2-Resin. Hasil uji fotokatalis menunjukkan bahwa penggunaan fotokatalis TiO¬2-Resin dapat meningkatkan hasil fotoreduksi ion Hg(II yang peningkatannya lebih tinggi dibandingkan TiO2 serbuk. Penambahan fotokatalis dengan massa yang semakin besar menambah efektivitas fotoreduksi terhadap ion Hg(II yang semakin besar, namun jika ditambahkan massa fotokatalis yang lebih tinggi lagi akan menurunkan efektivitas fotoreduksi terhadap ion Hg(II. Kenaikan konsentrasi Hg(II menyebabkan efektivitas fotoreduksi semakin rendah. Pada pH 1-4 terjadi

EuCARD-Del-D3.1.2

CERN Document Server

Palladino, V

2013-01-01

The European accelerator neutrino community submitted end of July 2012 to the European Strategy in Particle Physics (ESPP) 2012 Symposium its proposal of the next global accelerator neutrino () facility for Europe to build or help build (NEu2012 D3.3.1): a new giant European underground home for mega  detectors in Finland 2300 Km from CERN, served by MW CERN  beams, ultimately a 10 GeV Neutrino Factory. Early in 2013, NEu2012 D3.2.1 documented further the analysis of performance and physics potential of upgrades and/or of major additions to existing neutrino facilities as evaluated in the NEu2012 years. Since, the Draft ESPP 2012 Strategy Upgrade Document re-emphasised the strong scientific case for a long-baseline (LBL)  programme, the need of a CERN programme for a substantial European role, possibly major participation in leading  projects in the US and Japan. Last contribution of the Network, taking stock of developments (the emergence of a ESS  option, the EUROnu costing report, a state...

Thiol-functionalization of metal-organic framework by a facile coordination-based postsynthetic strategy and enhanced removal of Hg2+ from water

International Nuclear Information System (INIS)

Ke, Fei; Qiu, Ling-Guang; Yuan, Yu-Peng; Peng, Fu-Min; Jiang, Xia; Xie, An-Jian; Shen, Yu-Hua; Zhu, Jun-Fa

2011-01-01

Highlights: ► A novel type of functionalized MOF for heavy metal removal. ► Functionalization of MOF by a facile coordination-based postsynthetic strategy. ► Thiol-functionalization of MOF has been realized for the first time. ► Enhanced removal of Hg 2+ by thiol-functionalized MOFs. - Abstract: The presence of coordinatively unsaturated metal centers in metal-organic frameworks (MOFs) provides an accessible way to selectively functionalize MOFs through coordination bonds. In this work, we describe thiol-functionalization of MOFs by choosing a well known three-dimensional (3D) Cu-based MOF, i.e. [Cu 3 (BTC) 2 (H 2 O) 3 ] n (HKUST-1, BTC = benzene-1,3,5-tricarboxylate), by a facile coordination-based postsynthetic strategy, and demonstrate their application for removal of heavy metal ion from water. A series of [Cu 3 (BTC) 2 ] n samples stoichiometrically decorated with thiol groups has been prepared through coordination bonding of coordinatively unsaturated metal centers in HKUST-1 with –SH group in dithioglycol. The obtained thiol-functionalized samples were characterized by powder X-ray diffraction, scanning electron microscope, energy dispersive X-ray spectroscopy, infrared spectroscopy, and N 2 sorption–desorption isothermal. Significantly, the thiol-functionalized [Cu 3 (BTC) 2 ] n exhibited remarkably high adsorption affinity (K d = 4.73 × 10 5 mL g −1 ) and high adsorption capacity (714.29 mg g −1 ) for Hg 2+ adsorption from water, while the unfunctionalized HKUST-1 showed no adsorption of Hg 2+ under the same condition.

Lattice defects in semiconducting Hg/1-x/Cd/x/Te alloys. I - Defect structure of undoped and copper doped Hg/0.8/Cd/0.2/Te. II - Defect structure of indium-doped Hg/0.8/Cd/0.2/Te

Science.gov (United States)

Vydyanath, H. R.

1981-01-01

Hall effect and mobility measurements were conducted on undoped Hg(0.8)Cd(0.2)Te crystals which were quenched to room temperature after being subjected to equilibration at temperatures ranging from 400 to 655 C in various Hg atmospheres. The variation of the hole concentration in the cooled crystals at 77 K as a function of Hg's partial pressure at the equilibration temperature, together with a comparison of the hole mobility in the undoped samples with that in copper-doped ones, yields a defect model for the undoped crystals according to which they are intrinsic at the equilibration temperatures and the native acceptor defects are doubly ionized. In the second part of this paper, the effects of indium doping are considered. The concentration of electrons obtained in the cooled crystals was found to be lower than the intrinsic carrier concentration at the equilibration temperatures. A defect model is proposed according to which most of the indium is incorporated as In2Te3(s) dissolved in the crystal, with only a small fraction of indium acting as single donors occupying Hg lattice sites.

[Adsorption and removal of gas-phase Hg(0) over a V2O5/AC catalyst in the presence of SO2].

Science.gov (United States)

Wang, Jun-wei; Yang, Jian-li; Liu, Zhen-yu

2009-12-01

The adsorption and removal behaviors of gas-phase Hg(0) over V2O5/AC and AC were studied under a simulated flue gas (containing N2, SO2, O2) in a fixed-bed reactor. The influences of the V2O5, loading, SO2 concentration and adsorption temperature on Hg0 adsorption were investigated. The speciation of mercury adsorbed was determined by X-ray photoelectron spectroscopy (XPS). It was found that the V2O5/AC catalyst has a much higher capability than AC for Hg(0) adsorption and removal, mainly because of the catalytic oxidation activity of V2O5. The Hg(0) adsorption capability depends on the V2O5 content of the V2O5/AC catalyst. The amounts of mercury adsorbed increase from 75.9 microg x g(-1) to 89.6 microg x g(-1) (in the absence of O2) and from 115.9 microg x g(-1) to 185.5 microg x g(-1) (in the presence of O2) as the V2O5 loading increases from 0.5% to 1.0%, which are much higher than those over AC under the same conditions (9.6 microg x g(-1) and 23.3 microg x g(-1)). SO2 in the flue gas enhances Hg(0) adsorption over the V2O5/AC catalyst, which is due to the reaction of SO2 and Hg(0) on V2O3/AC. But as the SO2 concentration increases from 500 x 10(-6) to 2000 x 10(-6), the amount of mercury adsorbed has only a slight increase. The optimal temperature for Hg(0) adsorption over the V2O5/AC catalyst is around 150 degrees C, at which the amounts of mercury adsorbed are up to 98.5 microg x g(-1) (in the absence of O2) and 187.7 microg x g(-1) (in the presence of O2). The XPS results indicate the formation of Hg(0) and HgSO4 on the surface of the V2O5/AC catalyst, which confirms the role of V2O5 and SO2.

Raman study of HgBa 2Ca n-1 Cu nO 2 n+2+ δ ( n=1,2,3,4 and 5) superconductors

Science.gov (United States)

Zhou, Xingjiang; Cardona, M.; Chu, C. W.; Lin, Q. M.; Loureiro, S. M.; Marezio, M.

1996-02-01

Polarized micro-Raman scattering measurements have been performed on the five members of the HgBa 2Ca n-1 Cu nO 2 n+2+ δ ( n=1,2,3,4 and 5) high- Tc superconductor family using different laser frequencies. Local laser annealing measurements were carried out to investigate the variation of the Raman spectra with the excess oxygen content, δ. A systematic evolution of the spectra, which display mainly peaks near 590, 570, 540 and 470 cm -1, with increasing number of CuO 2 layers has been observed; its origin has been shown to lie in the variation of the interstitial oxygen content. In addition to confirming that the 590 cm -1 mode represents vibration of apical oxygens in the absence of neighboring excess oxygen, the 570 cm -1 mode, which may be composed of some finer structures, has been assigned to the vibration of the apical oxygen modified by the presence of the neighboring excess oxygens. The 540 and 470 cm -1 modes may represent the direct vibration of excess oxygens. The implication of possible different distribution sites of excess oxygens is discussed. All other observed lower-frequency modes are also assigned.

Aqueous Hg(2+) associates with TiO2 nanoparticles according to particle size, changes particle agglomeration, and becomes less bioavailable to zebrafish.

Science.gov (United States)

Boran, Halis; Boyle, David; Altinok, Ilhan; Patsiou, Danae; Henry, Theodore B

2016-05-01

Engineered nanoparticles (NPs) have unique physicochemistry and potential to interact with other substances in the aqueous phase. Here, gene [metallothionein 2 (mt2)] expression changes in larval zebrafish were used to evaluate the association between aqueous Hg(2+) and TiO2 (NPs and bulk particle size control) to investigate the relationship between changes in Hg(2+) behavior and TiO2 size. During 24h exposures, TiO2 agglomerates increased in size and in the presence of 25μg Hg(2+)/L, greater increases in size were observed. The concentration of Hg(2+) in suspension also decreased in the presence of TiO2-NPs. Mercury increased expression of mt2 in larval zebrafish, but this response was lessened when zebrafish were exposed to Hg(2+) in the presence of TiO2-NPs, and which suggests that TiO2-NPs alter the bioavailability of Hg(2+) to zebrafish larvae. This ameliorative effect of TiO2 was also likely due to surface binding of Hg(2+) because a greater decrease in mt2 expression was observed in the presence of 1mg/L TiO2-NPs than 1mg/L TiO2-bulk. In conclusion, the results show that Hg(2+) will associate with TiO2-NPs, TiO2-NPs that have associated Hg(2+) will settle out of the aqueous phase more rapidly, and agglomerates will deliver associated Hg(2+) to sediment surfaces. Copyright © 2016 Elsevier B.V. All rights reserved.

Design of a peptidic turn with high affinity for HgII

DEFF Research Database (Denmark)

Pires, Sara; Habjanic, Jelena; Sezer, Murat

2012-01-01

A four amino acid peptide containing the ß-turn template dPro-Pro in the middle and two cysteines (Cys) in the terminal positions (CdPPC) has been synthesized and its mercury(II) coordination properties studied using different spectroscopic methods. The UV-vis, CD, (199m)Hg PAC, and Raman...... spectroscopic studies indicate the binding of Hg(II) to the two Cys, forming the dithiolatemercury(II) complex Hg(CdPPC). Electrospray ionization mass spectrometry corroborates the 1:1 complex formation. A log K = 40.0 was determined for the formation constant of the Hg(CdPPC) complex using competition...... potentiometric studies. Replacement of the dPro-Pro motif by a Pro-Pro unit generated a peptide (CPPC) capable of forming a similar species [Hg(CPPC)] but showing a lower affinity for Hg(II) (at least 3-3.5 orders of magnitude lower). The introduction of the dPro-Pro motif is crucial to induce the folding...

Collective structures in 185Hg

International Nuclear Information System (INIS)

Bourgeois, C.; Hildingsson, L.; Perrin, N.; Sergolle, H.; Hannachi, F.; Bastin, G.; Porquet, M.G.; Thibaud, J.P.; Beck, F.A.; Merdinger, J.C.

1988-01-01

Excited states of 185 Hg have been investigated via the 161 Dy ( 28 Si, 4n) reaction at 145 MeV. In-beam gamma-ray spectroscopy studies have been performed with the ''Chateau de Cristal'' 4π-multidetector array. Level scheme of 185 Hg has been established. Shape coexistence, still present in 185 Hg like in the neighbouring Hg isotopes, manifests itself through a weakly populated decoupled band built on the 13/2+ isomer and three strongly-coupled bands built on the prolate 1/2-[521], 7/2-[514], and 9/2+[624] Nilsson states

Consumption of NADPH for 2-HG Synthesis Increases Pentose Phosphate Pathway Flux and Sensitizes Cells to Oxidative Stress

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Susan J. Gelman

2018-01-01

Full Text Available Summary: Gain-of-function mutations in isocitrate dehydrogenase 1 (IDH1 occur in multiple types of human cancer. Here, we show that these mutations significantly disrupt NADPH homeostasis by consuming NADPH for 2-hydroxyglutarate (2-HG synthesis. Cells respond to 2-HG synthesis, but not exogenous administration of 2-HG, by increasing pentose phosphate pathway (PPP flux. We show that 2-HG production competes with reductive biosynthesis and the buffering of oxidative stress, processes that also require NADPH. IDH1 mutants have a decreased capacity to synthesize palmitate and an increased sensitivity to oxidative stress. Our results demonstrate that, even when NADPH is limiting, IDH1 mutants continue to synthesize 2-HG at the expense of other NADPH-requiring pathways that are essential for cell viability. Thus, rather than attempting to decrease 2-HG synthesis in the clinic, the consumption of NADPH by mutant IDH1 may be exploited as a metabolic weakness that sensitizes tumor cells to ionizing radiation, a commonly used anti-cancer therapy. : Using liquid chromatography/mass spectrometry (LC/MS and stable isotope tracing, Gelman et al. find that 2-HG production in cells with IDH1 mutations leads to increased pentose phosphate pathway activity to generate NADPH. Production of 2-HG competes with other NADPH-dependent pathways and sensitizes cells to redox stress. Keywords: 2-hydroxyglutarate, cancer metabolism, LC/MS, metabolomcis, pentose phosphate pathway, redox regulation

Microbial Oxidation of Hg(0) - Its Effect on Hg Stable Isotope Fractionation and Methylmercury Production

Energy Technology Data Exchange (ETDEWEB)

Yee, Nathan [Rutgers Univ., New Brunswick, NJ (United States); Barkay, Tamar [Rutgers Univ., New Brunswick, NJ (United States); Reinfelder, John [Rutgers Univ., New Brunswick, NJ (United States)

2016-06-28

Mercury (Hg) associated with mixed waste generated by nuclear weapons manufacturing has contaminated vast areas of the Oak Ridge Reservation (ORR). Neurotoxic methylmercury (MeHg) has been formed from the inorganic Hg wastes discharged into headwaters of East Fork Poplar Creek (EFPC). Thus, understanding the processes and mechanisms that lead to Hg methylation along the flow path of EFPC is critical to predicting the impacts of the contamination and the design of remedial action at the ORR. In part I of our project, we investigated Hg(0) oxidation and methylation by anaerobic bacteria. We discovered that the anaerobic bacterium Desulfovibrio desulfuricans ND132 can oxidize elemental mercury [Hg(0)]. When provided with dissolved elemental mercury, D. desulfuricans ND132 converts Hg(0) to Hg(II) and neurotoxic methylmercury [MeHg]. We also demonstrated that diverse species of subsurface bacteria oxidizes dissolved elemental mercury under anoxic conditions. The obligate anaerobic bacterium Geothrix fermentans H5, and the facultative anaerobic bacteria Shewanella oneidensis MR-1 and Cupriavidus metallidurans AE104 can oxidize Hg(0) to Hg(II) under anaerobic conditions. In part II of our project, we established anaerobic enrichment cultures and obtained new bacterial strains from the DOE Oak Ridge site. We isolated three new bacterial strains from subsurface sediments collected from Oak Ridge. These isolates are Bradyrhizobium sp. strain FRC01, Clostridium sp. strain FGH, and a novel Negativicutes strain RU4. Strain RU4 is a completely new genus and species of bacteria. We also demonstrated that syntrophic interactions between fermentative bacteria and sulfate-reducing bacteria in Oak Ridge saprolite mediate iron reduction via multiple mechanisms. Finally, we tested the impact of Hg on denitrification in nitrate reducing enrichment cultures derived from subsurface sediments from the Oak Ridge site, where nitrate is a major contaminant. We showed that there is an inverse

Chronologically matched toenail-Hg to hair-Hg ratio: temporal analysis within the Japanese community (U.S.

Directory of Open Access Journals (Sweden)

Hinners Thomas

2012-10-01

Full Text Available Abstract Background Toenail-Hg levels are being used as a marker of methylmercury (MeHg exposure in efforts to associate exposure with effects such as cardiovascular disease. There is a need to correlate this marker with more established biomarkers that presently underlie existing dose–response relationships in order to compare these relationships across studies. Methods As part of the Arsenic Mercury Intake Biometric Study, toenail clippings were collected at three time points over a period of one year amongst females from within the population of Japanese living near Puget Sound in Washington State (US. Variability in temporal intra-individual toenail-Hg levels was examined and chronologically matched hair and toenail samples were compared to more accurately define the toxicokinetic variability of Hg levels observed between the two compartments. Results Mean toenail-Hg values (n=43 for the 1st, 2nd and 3rd visits were 0.60, 0.60 and 0.56 ng/mg. Correlations were as follows: r=0.92 between 1st and 2nd clinic visits, r=0.75 between 1st and 3rd visits and r=0.87 between 2nd and 3rd visits. With few exceptions, toenail-Hg values from any visit were within 50-150% of the individual’s mean toenail-Hg level. Nearly all participants had less than a two-fold change in toenail-Hg levels across the study period. A regression model of the relationship between toenail-Hg and hair-Hg (n = 41 levels representing the same time period of exposure, gave a slope (Hg ng/mg of 2.79 for hair relative to toenail (r=0.954. Conclusions A chronologically matched hair-Hg to toenail-Hg ratio has been identified within a population that consumes fish regularly and in quantity. Intra-individual variation in toenail-Hg levels was less than two-fold and may represent dietary-based fluctuations in body burden for individuals consuming various fish species with different contaminant levels. The chronologically matched ratio will be useful for relating MeHg exposure and

Uptake of Hg2+ by picocyanobacteria in natural water from four Andean lakes

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Diéguez M.C.

2014-07-01

Full Text Available In lake food webs, planktonic bacteria and algae represent the greatest bioconcentration step for Hg2+ and monomethyl-Hg (MeHg. As they are the most abundant organisms in planktonic trophic webs and also the main food resource for herbivorous plankton, they can mobilize large amounts of Hg to higher trophic levels. In Andean Patagonian lakes (Argentina, dissolved organic matter (DOM concentration and character, coupled with photo-reactions, play a central role in the complexation of Hg2+ in the water column and can even regulate the uptake of Hg2+ by planktonic algae. In this investigation we evaluated the DOM character of natural waters (NW from four Andean lakes and studied its influence on the uptake of 197Hg2+ in a strain of the picocyanobacteria Synechococcus by using Hg2+ labeled with 197Hg2+. The uptake of radiolabeled Hg2+ by Synechococcus showed different magnitude in NW of lakes Moreno, El Trébol, Morenito and Escondido. Increasing lake DOM concentration reduced the bioavailability of Hg2+ as indicated by the lower uptakes rates found in NW with higher complexity and concentration of the DOM pool. Uptakes of Hg2+ by this picocyanobacteria contrasted among NW from pelagic (surface and bottom and littoral compartments of Lake Escondido which suggest that the entry of this metal may be highly variable even in the same environment. The study of the uptake of radiolabeled Hg2+ in a set of dilutions of NW from Lake Escondido demonstrated that the bioavailability of Hg2+ decrease with increasing DOM concentration.

Evidence for the frequency-shift of the OA A_1g mode in Hg-based superconductors

Science.gov (United States)

Yang, In-Sang; Lee, Hye-Gyong

1996-03-01

The Hg-based superconductors, HgBa_2Ca_n-1Cu_nO_2n+2+δ (n=1,2,3) have two strong Raman peaks at ~ 570 and 590 cm-1 in the high-frequency region. From the results of Raman measurements of Tl-doped Hg-1223 system, it is concluded that the peak at ~ 570 cm-1 does not arise from the vibration of the interstitial oxygen O_δ in the Hg/Tl-O plane, but from the frequency-shift of the A_1g-type vibration of the apical oxygen O_A. The peak at 570 cm-1 is from the O_As surrounded by the O_δs in the nearest neighbor, while the 590 cm-1 mode is from the O_As without the O_δs in the immediate neighbor. The intensity of the 570 cm-1 mode increases with the O_δ content, but the Raman frequencies of both modes do not change significantly. This suggests that the increase of the frequency of the OA A_1g mode under high pressure (I.-S. Yang et al., Phys. Rev. B 51, 644 (1995)) is independent from the O_δ content, in the Hg-based superconductors.

Characterization of Phenotypic and Transcriptional Differences in Human Pluripotent Stem Cells under 2D and 3D Culture Conditions.

Science.gov (United States)

Kamei, Ken-Ichiro; Koyama, Yoshie; Tokunaga, Yumie; Mashimo, Yasumasa; Yoshioka, Momoko; Fockenberg, Christopher; Mosbergen, Rowland; Korn, Othmar; Wells, Christine; Chen, Yong

2016-11-01

Human pluripotent stem cells hold great promise for applications in drug discovery and regenerative medicine. Microfluidic technology is a promising approach for creating artificial microenvironments; however, although a proper 3D microenvironment is required to achieve robust control of cellular phenotypes, most current microfluidic devices provide only 2D cell culture and do not allow tuning of physical and chemical environmental cues simultaneously. Here, the authors report a 3D cellular microenvironment plate (3D-CEP), which consists of a microfluidic device filled with thermoresponsive poly(N-isopropylacrylamide)-β-poly(ethylene glycol) hydrogel (HG), which enables systematic tuning of both chemical and physical environmental cues as well as in situ cell monitoring. The authors show that H9 human embryonic stem cells (hESCs) and 253G1 human induced pluripotent stem cells in the HG/3D-CEP system maintain their pluripotent marker expression under HG/3D-CEP self-renewing conditions. Additionally, global gene expression analyses are used to elucidate small variations among different test environments. Interestingly, the authors find that treatment of H9 hESCs under HG/3D-CEP self-renewing conditions results in initiation of entry into the neural differentiation process by induction of PAX3 and OTX1 expression. The authors believe that this HG/3D-CEP system will serve as a versatile platform for developing targeted functional cell lines and facilitate advances in drug screening and regenerative medicine. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of Novel Fluorescent Sensors Based on Naphthalimide Fluorophores for the Highly Selective Hg2+-Sensing

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Yordkhuan Tachapermpon

2015-01-01

Full Text Available With an aim to develop the new sensors for optical detection of Hg2+ ions, two novel fluorometric sensors were designed and successfully prepared using 2-(3-(2-aminoethylsulfanylpropylsulfanylethanamine and one or two N-methylnaphthalimide moieties (1 and 2. Sensor 1 was obtained via N-alkylation, N-imidation and a one-pot nucleophilic aromatic substitution, and N-formylation of the amine, while sensor 2 was prepared via N-alkylation, N-imidation, and nucleophilic aromatic substitution. The characterization, including 1H NMR, 13C NMR, and mass spectrometry, was then performed for 1 and 2. The Hg2+-binding behaviors of the sensors were investigated in terms of sensitivity and selectivity by fluorescence spectroscopy. Sensor 1 especially provided the reversible and highly Hg2+-selective ON-OFF fluorescence behavior by discriminating various interfering ions such as Pb2+, Co2+, Cd2+, Mn2+, Fe2+, K+, Na+, and in particular Cu2+ and Ag+ with a detection limit of 22 ppb toward Hg2+ ions.

Mercury (I) nitroprusside: A 2D structure supported on homometallic interactions

Energy Technology Data Exchange (ETDEWEB)

Osiry, H.; Cano, A. [Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Unidad Legaria, Instituto Politécnico Nacional, México (Mexico); Reguera, L. [Facultad de Química, Universidad de La Habana (Cuba); Lemus-Santana, A.A. [Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Unidad Legaria, Instituto Politécnico Nacional, México (Mexico); Reguera, E., E-mail: edilso.reguera@gmail.com [Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Unidad Legaria, Instituto Politécnico Nacional, México (Mexico)

2015-01-15

The pentacyanonitrosylferrate complex anion, [Fe(CN){sub 5}NO]{sup 2−}, forms an insoluble solid with Hg(I) ion, of formula unit Hg{sub 2}[Fe(CN){sub 5}NO]·2H{sub 2}O, whose crystal structure and related properties are unknown. This contribution reports the preparation of that compound by the precipitation method and its structural study from X-ray powder patterns complemented with spectroscopic information from IR, Raman, and UV–vis techniques. The crystal structure was solved ab initio and then refined using the Rietveld method. The solid crystallizes with a triclinic unit cell, in the P−1 space group, with cell parameters a=10.1202(12), b=10.1000(13), c=7.4704(11) Å; α=110.664(10), β=110.114(10), γ=104.724(8) °. Within the unit cell, two formula units are accommodated (Z=2). It adopts a layered structure related with the coordination of the equatorial CN groups at their N end to the Hg atoms while the axial CN ligand remains unlinked. Within the layers neighboring Hg{sub 2}[Fe(CN){sub 5}NO] building units remain linked through four relatively strong Hg–Hg interactions, with an interatomic distance of 2.549(3) Å. The charge donation from the equatorial CN groups through their 5σ orbitals results into an increase for the electron density on the Hg atoms, which strengths the Hg–Hg bond. In the Raman spectrum, that metal–metal bond is detected as a stretching vibration band at 167 cm{sup −1}. The available free volume between neighboring layers accommodates two water molecules, which are stabilized within the framework through hydrogen bonds with the N end of the unlinked axial CN group. The removal of these weakly bonded water molecules results in structural disorder for the material 3D framework. - Graphical abstract: Assembling of Hg{sub 2}[Fe(CN){sub 5}NO] units through Hg–Hg interactions. - Highlights: • Homometallic Hg–Hg interactions in metal nitroprusside. • 2D structure supported on metal–metal interactions. • Crystal

Measurement of core level and band offsets at the interface of ITO/Hg{sub 3}In{sub 2}Te{sub 6}(1 1 0) heterojunction by synchrotron radiation photoelectron spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Li, Yapeng [State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072 (China); Fu, Li, E-mail: fuli@nwpu.edu.cn [State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072 (China); Sun, Jie [State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072 (China); Ibrahim, Kurash; Wang, Jia-ou [Laboratory of Synchrotron Radiation, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100039 (China)

2016-02-15

Highlights: • The valence band maximum of ITO film and MIT were measured to be 1.6 eV and 0.6 eV, respectively. • The concentration of In element presented a trend of increasing first and then decreasing from MIT to ITO. • The valence band offsets of the ITO/MIT(1 1 0) heterojunction was confirmed to be a type-II band alignment phenomenon. - Abstract: The Indium Tin Oxide (ITO) film was deposited on the surface of Hg{sub 3}In{sub 2}Te{sub 6} (short for MIT) (1 1 0) for the fabrication of ITO/MIT(1 1 0) heterojunction by using the pulsed laser deposition method. In situ X-ray photoelectron spectroscopy was utilized to examine the band offsets and core level of ITO/MIT(1 1 0) heterojunctions. The result showed that the valence band maximum of ITO films and MIT(1 1 0) were 1.6 eV and 0.6 eV, respectively. Meanwhile, it was found that the binding energy of Te 3d, Sn 3d and Hg 4f remained unchanged during the ITO deposition process. However, the binding energy of O 1s and In 3d{sub 5/2} increased about 0.3 eV and 0.2 eV, respectively, with the thickness increasing of ITO film from 3.5 nm to 5 nm. This may due to the elements diffusion at the interface region during the film growing process. According to the core level spectrum, it can be speculated that no significant chemical reaction occurred at the interface of ITO/MIT(1 1 0). In addition, the valence band offset of the ITO/MIT(1 1 0) heterojunction can be calculated to be −1 ± 0.15 eV by the means of the photoelectron spectroscopy methods. The conduction band offset is deduced to be −3.96 ± 0.15 eV from the known valence band offset value, indicating that the band offsets of ITO/MIT(1 1 0) heterojunction is a type-II band alignment.

IDH1 and IDH2 mutations as novel therapeutic targets: current perspectives

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Mondesir J

2016-09-01

Full Text Available Johanna Mondesir1,2 Christophe Willekens3–5 Mehdi Touat6,7 Stéphane de Botton3–5 1Service d’Immunopathologie Clinique, Hôpital Saint Louis, 2CNRS UMR8104, INSERM U1016, Institut Cochin, Université Paris Descartes, Paris, 3Gustave Roussy, Université Paris-Saclay, Service d’Hématologie Clinique, 4INSERM U1170, Gustave Roussy, Université Paris-Saclay, Villejuif, 5Faculté de médecine Paris-Sud, Kremlin-Bicêtre, 6AP-HP, Hôpitaux Universitaires La Pitié Salpêtrière – Charles Foix, Service de Neurologie 2-Mazarin, Paris, 7Gustave Roussy, Université Paris‑Saclay, Département d’Innovation Thérapeutique et d’Essais Précoces, Villejuif, France Abstract: Isocitrate dehydrogenase 1 and 2 (IDH1 and IDH2 are key metabolic enzymes that convert isocitrate to α-ketoglutarate. IDH1/2 mutations define distinct subsets of cancers, including low-grade gliomas and secondary glioblastomas, chondrosarcomas, intrahepatic cholangiocarcinomas, and hematologic malignancies. Somatic point mutations in IDH1/2 confer a gain-of-function in cancer cells, resulting in the accumulation and secretion in vast excess of an oncometabolite, the D-2-hydroxyglutarate (D-2HG. Overproduction of D-2HG interferes with cellular metabolism and epigenetic regulation, contributing to oncogenesis. Indeed, high levels of D-2HG inhibit α-ketoglutarate-dependent dioxygenases, including histone and DNA demethylases, leading to histone and DNA hypermethylation and finally a block in cell differentiation. Furthermore, D-2HG is a biomarker suitable for the detection of IDH1/2 mutations at diagnosis and predictive of the clinical response. Finally, mutant-IDH1/2 enzymes inhibitors have entered clinical trials for patients with IDH1/2 mutations and represent a novel drug class for targeted therapy. Keywords: tumor metabolism, epigenetic, oncogene, IDH1, IDH2, glioma, acute myeloid leukemia, 2-HG, targeted therapies

An Effective Hg2+-Selective Fluorescent Chemosensor Based on a Calix[4]arene Bearing Four Dansyl Amides

Institute of Scientific and Technical Information of China (English)

LI Guang-Ke; LIU Min; YANG Guo-Qiang; CHEN Chuan-Feng; HUANG Zhi-Tang

2008-01-01

A new calix[4]arene-based fluorescent chemosensor bearing four dansyl amides on the upper rim (1) was con- veniently synthesized, which showed high sensitivity and selectivity toward Hg2+ over a wide range of metal ions in 50% aqueous acetonitrile. The complexation of Hg2+ ion induced a strong fluorescence quenching of 1 due to a well-defined electron transfer process from the dansyl group(s) to the metal center. Compared with compounds 2 and 3, tetradansyl amide substituted calix[4]arene 1 showed a preorganized and coordinated complexing site for metal ions. Moreover, the detection limit for Hg2. was found to be 3.41×10-6 mol·L-1, which might make 1 a po-tentially practical Hg2+-selective fluorescent sensor in aqueous system.

Facile sysnthesis of fluorescent silver nanoclusters as simultaneous detection and remediation for Hg2+

International Nuclear Information System (INIS)

Li, Dan; Li, Biao; Lee, Go Eun; Yang, Sung Ik

2015-01-01

Mercury is one of the most toxic metals to the environment and human life. 1 This metal can cause serious health problems because it easily passes through skin, respiratory tract, and gastrointestinal tissues into the human body, which will damage kidney, central nervou s system, and endocrine system. A facile synthetic strategy for the preparation of highly fluorescent AgNCs with red emission (λ em = 671 nm, quantum yield = 3.3%) has been developed. AgNCs showed a high sensitivity and selectivity toward the Hg 2+ ions over other metal ions in spiked tap water. The detection limit was determined to be 1.3 ppb, which met the requirement of the USEPA standards for the maximum allowable level of Hg 2+ in drinking water. AgNCs also showed applicability for remediation of Hg 2+ in polluted water with high removal efficiencies. The employment of AgNCs could be used to monitor and remediate Hg 2+ for the water analysis and purification.

Electronic structure and optical properties of Cs2HgI4: Experimental study and band-structure DFT calculations

Science.gov (United States)

Lavrentyev, A. A.; Gabrelian, B. V.; Vu, V. T.; Shkumat, P. N.; Myronchuk, G. L.; Khvyshchun, M.; Fedorchuk, A. O.; Parasyuk, O. V.; Khyzhun, O. Y.

2015-04-01

High-quality single crystal of cesium mercury tetraiodide, Cs2HgI4, has been synthesized by the vertical Bridgman-Stockbarger method and its crystal structure has been refined. In addition, electronic structure and optical properties of Cs2HgI4 have been studied. For the crystal under study, X-ray photoelectron core-level and valence-band spectra for pristine and Ar+-ion irradiated surfaces have been measured. The present X-ray photoelectron spectroscopy (XPS) results indicate that the Cs2HgI4 single crystal surface is very sensitive with respect to Ar+ ion-irradiation. In particular, Ar+ bombardment of the single crystal surface alters the elemental stoichiometry of the Cs2HgI4 surface. To elucidate peculiarities of the energy distribution of the electronic states within the valence-band and conduction-band regions of the Cs2HgI4 compound, we have performed first-principles band-structure calculations based on density functional theory (DFT) as incorporated in the WIEN2k package. Total and partial densities of states for Cs2HgI4 have been calculated. The DFT calculations reveal that the I p states make the major contributions in the upper portion of the valence band, while the Hg d, Cs p and I s states are the dominant contributors in its lower portion. Temperature dependence of the light absorption coefficient and specific electrical conductivity has been explored for Cs2HgI4 in the temperature range of 77-300 K. Main optical characteristics of the Cs2HgI4 compound have been elucidated by the first-principles calculations.

Zn2+, Cd2+, Hg2+ thiolates - derivatives of 2, 3, 5-trifluoro-4,6-bis(trifluoromethyl)thiophenol and heptafluoro-2-thionaphthol

International Nuclear Information System (INIS)

Larionov, S.V.; Kirichenko, V.N.; Platonov, V.E.; Maksimov, A.M.; Rodionov, P.P.; Fadeeva, V.P.; Oglezneva, I.M.; Lisojvan, V.I.; AN SSSR, Novosibirsk

1992-01-01

Zn 2+ , Cd 2+ , Hg 2+ coordination compounds with 2, 3, 5 -trifluoro- 4,6 bis(trifluoromethyl)trhiophenol (MHal) and heptafluoro-2-thionophthal (HT) of ZnHal 2 (CH 3 OH), CdHal 2 , HgHal 2 and MT 2 (M=Zn, Cd, Hg) composition, are obtained. Complexes are studied using thermal and X-ray phase analysis, vapour phase osmometry and IR spectroscopy, ZnHal 2 (CH 3 OH), CdHal 2 , ZnT 2 , HgHfl 2 , HgT 2 compounds in acetone solutions are in monomeric state, while in CdT 2 commeric particles. Frequencies of mostly valent vibrations of Cd-S bond are observed at 241 (CdHal 2 ), 225 (CdT 2 )

Protective effect of Moringa oleifera oil against HgCl2-induced hepato- and nephro-toxicity in rats.

Science.gov (United States)

Abarikwu, Sunny O; Benjamin, Sussan; Ebah, Sunday Godspower; Obilor, Godbless; Agbam, Goodluck

2017-07-26

Various parts of the Moringa oleifera (M. oleifera) tree are widely accepted to have ameliorative effects against metal toxicity. In the present study, M. oleifeira oil (MO) was tested against HgCl2-induced tissue pathologies and oxidative stress. Male Wistar rats were administered MO (1.798 mg/kg p.o.) or HgCl2 (5 mg/kg body wt) alone or in combination (5 mg/kg HgCl2+1.798 mg/kg MO p.o.) three times per week for 21 days. After exposure and treatment periods, rats were sacrificed; blood collected and the oxidative status of the liver and kidney homogenates were evaluated. In the liver, malondialdehyde (MDA) level, glutathione (GSH), and superoxide dismutase (SOD) activities were higher whereas catalase (CAT) activity was lower in the HgCl2 group than in the control group. In the kidney, MDA level, SOD, and CAT activities were higher whereas GSH activity was unchanged in the HgCl2 group compared to the control group. In the liver, MDA level, SOD, and CAT activities were lower in the HgCl2+MO group than in the HgCl2 group. In the kidney, MDA level, SOD and CAT activities were lower in the HgCl2+MO than in the HgCl2 group. Furthermore, Hg-induced increases in creatinine and bilirubin levels as well as the increase in γ-glutamyl transferase, lactate dehydrogenase, and alkaline phosphatase activities were attenuated in the combine exposure group and the animals showed improvement in the histology of the liver and kidney. MO decreased the negative effects of Hg-induced oxidative stress in rats.

First principles study of elemental mercury (Hg0) adsorption on low index CoMnO3 surfaces

International Nuclear Information System (INIS)

Ji, Wenchao; Su, Pingru; Tang, Qingli; Cheng, Zhiwen; Shen, Zhemin; Fan, Maohong

2017-01-01

Highlights: • Hg 0 adsorption on low index CoMnO 3 surface was predicted by DFT method. • Hg 0 is adsorbed on the CoMnO 3 surface with chemisorption interaction. • Hg 0 has highest adsorption energy on CoMnO 3 (1 0 0) surface with Hg-Mn mechanism. • The electron transfer of Hg 0 has positive relationship with adsorption energy. - Abstract: The density functional theory (DFT) is applied to predict elemental mercury (Hg 0 ) adsorption on CoMnO 3 surface for the first time. GGA/PBE functional were selected to determine the potential Hg 0 capture mechanisms. The results show that Hg 0 has good affinity with CoMnO 3 surfaces with chemical adsorption. The adsorption energy of Hg 0 -CoMnO 3 (1 0 0), Hg 0 -CoMnO 3 (1 0 1) and Hg 0 -CoMnO 3 (1 1 0) are −85.225, −72.305 and −70.729 kJ/mol, respectively. The Hg-Mn and Hg-Co mechanisms were revealed on low index surfaces. Hg 0 was oxidized to its valence state of 0.236 on Mn site in CoMnO 3 (1 0 0) surface. The Hg-Co interaction mechanism occurred on Hg 0 -CoMnO 3 (1 0 1) and Hg 0 -CoMnO 3 (1 1 0) with 0.209e − and 0.189e − transformation, respectively. The PDOS analysis shows that Hg-Mn interaction depends on the hybridization of Hg(s- and d-orbitals) and Mn (s-, p- and d- orbitals). However, Hg-Co interaction stems from s- and d- orbitals of Hg, which only overlapping with d- and p- orbital of Co. Both the adsorption energy and electronic structure analysis indicated that CoMnO 3 catalyst performed excellent in Hg 0 oxidation. Exposing CoMnO 3 (1 0 0) is most favorable in Hg 0 control, which provides theoretical instruction on certain crystal plane synthesis in experiment.

Long-distance transport of Hg, Sb, and As from a mined area, conversion of Hg to methyl-Hg, and uptake of Hg by fish on the Tiber River basin, west-central Italy

Science.gov (United States)

Gray, John E.; Rimondi, Valentina; Costagliola, Pilario; Vaselli, Orlando; Lattanzi, Pierfranco

2014-01-01

Stream sediment, stream water, and fish were collected from a broad region to evaluate downstream transport and dispersion of mercury (Hg) from inactive mines in the Monte Amiata Hg District (MAMD), Tuscany, Italy. Stream sediment samples ranged in Hg concentration from 20 to 1,900 ng/g, and only 5 of the 17 collected samples exceeded the probable effect concentration for Hg of 1,060 ng/g, above which harmful effects are likely to be observed in sediment-dwelling organisms. Concentrations of methyl-Hg in Tiber River sediment varied from 0.12 to 0.52 ng/g, and although there is no established guideline for sediment methyl-Hg, these concentrations exceeded methyl-Hg in a regional baseline site (water varied from 1.2 to 320 ng/L, all of which were below the 1,000 ng/L Italian drinking water Hg guideline and the 770 ng/L U.S. Environmental Protection Agency (USEPA) guideline recommended to protect against chronic effects to aquatic wildlife. Methyl-Hg concentrations in stream water varied from water samples contained concentrations of As (drinking water guidelines to protect human health (10 μg/L for As and 20 μg/L for Sb) and for protection against chronic effects to aquatic wildlife (150 μg/L for As and 5.6 μg/L for Sb). Concentrations of Hg in freshwater fish muscle ranged from 0.052–0.56 μg/g (wet weight), mean of 0.17 μg/g, but only 17 % (9 of 54) exceeded the 0.30 μg/g (wet weight) USEPA fish muscle guideline recommended to protect human health. Concentrations of Hg in freshwater fish in this region generally decreased with increasing distance from the MAMD, where fish with the highest Hg concentrations were collected more proximal to the MAMD, whereas all fish collected most distal from Hg mines contained Hg below the 0.30 μg/g fish muscle guideline. Data in this study indicate some conversion of inorganic Hg to methyl-Hg and uptake of Hg in fish on the Paglia River, but less methylation of Hg and Hg uptake by freshwater fish in the larger Tiber River.

Thiol-functionalization of metal-organic framework by a facile coordination-based postsynthetic strategy and enhanced removal of Hg2+ from water.

Science.gov (United States)

Ke, Fei; Qiu, Ling-Guang; Yuan, Yu-Peng; Peng, Fu-Min; Jiang, Xia; Xie, An-Jian; Shen, Yu-Hua; Zhu, Jun-Fa

2011-11-30

The presence of coordinatively unsaturated metal centers in metal-organic frameworks (MOFs) provides an accessible way to selectively functionalize MOFs through coordination bonds. In this work, we describe thiol-functionalization of MOFs by choosing a well known three-dimensional (3D) Cu-based MOF, i.e. [Cu(3)(BTC)(2)(H(2)O)(3)](n) (HKUST-1, BTC=benzene-1,3,5-tricarboxylate), by a facile coordination-based postsynthetic strategy, and demonstrate their application for removal of heavy metal ion from water. A series of [Cu(3)(BTC)(2)](n) samples stoichiometrically decorated with thiol groups has been prepared through coordination bonding of coordinatively unsaturated metal centers in HKUST-1 with -SH group in dithioglycol. The obtained thiol-functionalized samples were characterized by powder X-ray diffraction, scanning electron microscope, energy dispersive X-ray spectroscopy, infrared spectroscopy, and N(2) sorption-desorption isothermal. Significantly, the thiol-functionalized [Cu(3)(BTC)(2)](n) exhibited remarkably high adsorption affinity (K(d)=4.73 × 10(5)mL g(-1)) and high adsorption capacity (714.29 mg g(-1)) for Hg(2+) adsorption from water, while the unfunctionalized HKUST-1 showed no adsorption of Hg(2+) under the same condition. Copyright © 2011 Elsevier B.V. All rights reserved.

Sensitive Determination of Onco-metabolites of D- and L-2-hydroxyglutarate Enantiomers by Chiral Derivatization Combined with Liquid Chromatography/Mass Spectrometry Analysis

Science.gov (United States)

Cheng, Qing-Yun; Xiong, Jun; Huang, Wei; Ma, Qin; Ci, Weimin; Feng, Yu-Qi; Yuan, Bi-Feng

2015-01-01

2-hydroxyglutarate (2HG) is a potent competitor of α-ketoglutarate (α-KG) and can inhibit multiple α-KG dependent dioxygenases that function on the epigenetic modifications. The accumulation of 2HG contributes to elevated risk of malignant tumors. 2HG carries an asymmetric carbon atom in its carbon backbone and differentiation between D-2-hydroxyglutarate (D-2HG) and L-2-hydroxyglutarate (L-2HG) is crucially important for accurate diagnosis of 2HG related diseases. Here we developed a strategy by chiral derivatization combined with liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) analysis for highly sensitive determination of D-2HG and L-2HG enantiomers. N-(p-toluenesulfonyl)-L-phenylalanyl chloride (TSPC) was used to derivatize 2HG. The formed diastereomers by TSPC labeling can efficiently improve the chromatographic separation of D-2HG and L-2HG. And derivatization by TSPC could also markedly increase the detection sensitivities by 291 and 346 folds for D-2HG and L-2HG, respectively. Using the developed method, we measured the contents of D-2HG and L-2HG in clear cell renal cell carcinoma (ccRCC) tissues. We observed 12.9 and 29.8 folds increase of D-2HG and L-2HG, respectively, in human ccRCC tissues compared to adjacent normal tissues. The developed chiral derivatization combined with LC-ESI-MS/MS analysis offers sensitive determination of D-2HG and L-2HG enantiomers, which benefits the precise diagnosis of 2HG related metabolic diseases. PMID:26458332

Hg{sup 2+}-induced self-assembly of a naphthalimide derivative by selective 'turn-on' monomer/excimer emissions

Energy Technology Data Exchange (ETDEWEB)

Wanichacheva, Nantanit, E-mail: wanichacheva.nantanit@gmail.com [Department of Chemistry, Faculty of Science, Silpakorn University, Nakorn Pathom 73000 (Thailand); Prapawattanapol, Narupon [Petrochemistry and Polymer Science Program, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Sanghiran Lee, Vannajan [Department of Chemistry, Faculty of Science, University of Malaya 50603, Kuala Lumpur (Malaysia); Grudpan, Kate [Department of Chemistry, Center for Innovation in Chemistry, Faculty of Science, and Center of Excellence in Innovation for Analytical Science and Technology, Chiang Mai 50200 (Thailand); Petsom, Amorn [Research Centre for Bioorganic Chemistry, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand)

2013-02-15

A novel fluorescent sensor bearing two naphthalimide fluorophores based on 2-(3-(2-aminoethylsulfanyl)propylsulfanyl)ethanamine, 1, was readily synthesized for the recognition of Hg{sup 2+}. The sensitive and selective binding behaviors of 1 were investigated by fluorescence spectroscopy. Sensor 1 selectively binds Hg{sup 2+} by exhibiting OFF-ON fluorescence enhancement behaviors of the monomer and excimer bands. The sensor provides excellent Hg{sup 2+}-selectivity in the presence of high concentrations of competitive ions, particularly Cu{sup 2+} and Pb{sup 2+} as well as Na{sup +}, K{sup +}, Mn{sup 2+}, Cd{sup 2+}, Ni{sup 2+}, Ca{sup 2+}, Li{sup +}, Zn{sup 2+} and Co{sup 2+}, with an available detection limit of 2.1 Multiplication-Sign 10{sup -7} M or 42 ppb. - Highlights: Black-Right-Pointing-Pointer Multidentate sulfide-containing ligand bounded to naphthalimide as new Hg{sup 2+} sensor. Black-Right-Pointing-Pointer Sensor is prepared by a straightforward two-step synthesis. Black-Right-Pointing-Pointer Sensor shows high sensitivity and selectivity to Hg{sup 2+} with detection limit of 42 ppb. Black-Right-Pointing-Pointer Hg{sup 2+}-binding is indicated by fluorescence enhancement Black-Right-Pointing-Pointer Sensor 'turns-on' both monomeric and excimer emissions by the addition of Hg{sup 2+}.

Novel methodology for the study of mercury methylation and reduction in sediments and water using 197Hg radiotracer.

Science.gov (United States)

Ribeiro Guevara, Sergio; Zizek, Suzana; Repinc, Urska; Pérez Catán, Soledad; Jaćimović, Radojko; Horvat, Milena

2007-03-01

Mercury tracers are powerful tools that can be used to study mercury transformations in environmental systems, particularly mercury methylation, demethylation and reduction in sediments and water. However, mercury transformation studies using tracers can be subject to error, especially when used to assess methylation potential. The organic mercury extracted can be as low as 0.01% of the endogenous labeled mercury, and artefacts and contamination present during methylmercury (MeHg) extraction processes can cause interference. Solvent extraction methods based on the use of either KBr/H2SO4 or HCl were evaluated in freshwater sediments using 197Hg radiotracer. Values obtained for the 197Hg tracer in the organic phase were up to 25-fold higher when HCl was used, which is due to the coextraction of 197Hg2+ into the organic phase during MeHg extraction. Evaluations of the production of MeHg gave similar results with both MeHg extraction procedures, but due to the higher Hg2+ contamination of the controls, the uncertainty in the determination was higher when HCl was used. The Hg2+ contamination of controls in the HCl extraction method showed a nonlinear correlation with the humic acid content of sediment pore water. Therefore, use of the KBr/H2SO4 method is recommended, since it is free from these interferences. 197Hg radiotracer (T1/2=2.673 d) has a production rate that is about 50 times higher than that of 203Hg (T1/2=46.595 d), the most frequently used mercury radiotracer. Hence it is possible to obtain a similar level of performance to 203Hg when it is used it in short-term experiments and produced by the irradiation of 196Hg with thermal neutrons, using mercury targets with the natural isotopic composition. However, if the 0.15% natural abundance of the 196Hg isotope is increased, the specific activity of the 197Hg tracer can be significantly improved. In the present work, 197Hg tracer was produced from mercury 51.58% enriched in the 196Hg isotope, and a 340-fold

A new fluorescent pyrene–pyridine dithiocarbamate probe: A chemodosimeter to detect Hg2+ in pure aqueous medium and in live cells

International Nuclear Information System (INIS)

Singh, Vikram; Srivastava, Priyanka; PrakashVerma, Shiv; Misra, Arvind; Das, Parimal; Singh, Nanhai

2014-01-01

A new pyrene–pyridine dithiocarbamate based fluorescent chemodosimeter, potassium (pyren-1-ylmethyl)(pyridin-2-ylmethyl)dithiocarbamate (L1) has been designed and synthesized. The chemodosimeter shows high selectivity and sensitivity (5.2 ppb) for Hg 2+ in pure aqueous medium in which emission intensity was quenched by ≈80% due to the formation of new cyclized species, 1. The probe behaves as a chemodosimeter for Hg 2+ ions and forms Hg 2+ triggered cyclised imidazoline species with approximate detection time of 50 s and exhibits both colorimetric and fluorometric changes on detection of Hg 2+ ion. Color of the probe (L1) changed from green to colorless visible to the naked eye and from green to dark blue upon the addition of Hg 2+ ions under UV light. The Hg 2+ triggered cyclization reaction was confirmed by spectral data analysis and a single crystal structure determination of the cyclised entity 2 obtained from the model compound potassium benzyl(pyridin-2-ylmethyl) dithiocarbamate (L2). L1 finds its application for detection of Hg 2+ ions on paper strips, and in BSA (bovine serum albumin) medium. L1 is also applicable for the monitoring of Hg 2+ ion in NIH3T3 live cells. - Highlights: • Efficient chemodosimeter to detect Hg 2+ ions in pure aqueous medium. • Hg 2+ triggered cyclisation and formation of imidazoline species. • Probe exhibit both colorimetric and fluorometric changes • Probe is applicable to detect Hg 2+ in live cells and on cellulose paper strips

Photocatalysis of Hg2+ y Cr6+ in waste waters

International Nuclear Information System (INIS)

Franco, Alexander; Ortiz, Natalia; Mejia, Gloria; Restrepo, Gloria; Penuela, Gustavo

2001-01-01

This work was carried out to propose a treatment for the elimination of Hg 2 + and Cr 6 + ions that are present in wastewaters of the CIA and ISA laboratories. These ions are present in waste waters because in these laboratories analysis of chemical oxygen demand (COD), are performed in which HgSO 4 and K 2 Cr 2 O 7 are used. COD is a parameter very important to evaluate. In this paper water pollution results of chemical reduction of Hg 2 + and Cr 6 + ions using photo catalysis are reported and the elimination of both ions by using an adsorbent

Cytotoxicity of dental composite (co)monomers and the amalgam component Hg{sup 2+} in human gingival fibroblasts

Energy Technology Data Exchange (ETDEWEB)

Reichl, Franz-Xaver; Simon, Sabine; Esters, Magalie; Seiss, Mario [Ludwig-Maximilians-University of Munich, Walther-Straub-Institute of Pharmacology and Toxicology, Munich (Germany); Kehe, Kai [Bundeswehr Institute of Pharmacology and Toxicology, Munich (Germany); Kleinsasser, Norbert [University of Regensburg, Department of Otolaryngology - Head and Neck Surgery, Regensburg (Germany); Hickel, Reinhard [Ludwig-Maximilians-University, Department of Operative Dentistry and Periodontology, Munich (Germany)

2006-08-15

Unpolymerized resin (co)monomers or mercury (Hg) can be released from restorative dental materials (e.g. composites and amalgam). They can diffuse into the tooth pulp or the gingiva. They can also reach the gingiva and organs by the circulating blood after the uptake from swallowed saliva. The cytotoxicity of dental composite components hydroxyethylmethacrylate (HEMA), triethyleneglycoldimethacrylate (TEGDMA), urethanedimethacrylate (UDMA), and bisglycidylmethacrylate (Bis-GMA) as well as the amalgam component Hg{sup 2+} (as HgCl{sub 2}) and methyl mercury chloride (MeHgCl) was investigated on human gingival fibroblasts (HGFs) at two time intervals. To test the cytotoxicity of substances, the bromodeoxyuridine (BrdU) assay and the lactate dehydrogenase (LDH) assay were used. The test substances were added in various concentrations and cells were incubated for 24 or 48 h. The EC{sub 50} values were obtained as half-maximum-effect concentrations from fitted curves. Following EC{sub 50} values were found [BrdU: mean (mmol/l); SEM in parentheses; n=12]: (24 h/48 h) HEMA 8.860 (0.440)/6.600(0.630), TEGDMA 1.810(0.130)/1.220(0.130), UDMA 0.120(0.010)/0.140(0.010), BisGMA 0.060(0.004)/0.040(0.002), HgCl{sub 2} 0.015(0.001)/0.050(0.006), and MeHgCl 0.004(0.001)/0.005(0.001). Following EC{sub 50} values were found [LDH: mean (mmol/l); SEM in parentheses; n=12]: (24 h/48 h) HEMA 9.490(0.300)/7.890(1.230), TEGDMA 2.300(0.470)/1.950(0.310), UDMA 0.200(0.007)/0.100(0.007), BisGMA 0.070(0.005)/0.100(0.002), and MeHgCl 0.014(0.006)/0.010(0.003). In both assays, the following range of increased toxicity was found for composite components (24 and 48 h): HEMA < TEGDMA < UDMA < BisGMA. In both assays, MeHgCl was the most toxic substance. In the BrdU assay, Hg{sup 2+} was about fourfold less toxic than MeHgCl but Hg{sup 2+} was about fourfold more toxic than BisGMA. In the BrdU test, a significantly (P<0.05) decreased toxicity was observed for Hg{sup 2+} at 48 h, compared to the 24 h

Evaluating the role of re-adsorption of dissolved Hg(2+) during cinnabar dissolution using isotope tracer technique.

Science.gov (United States)

Jiang, Ping; Li, Yanbin; Liu, Guangliang; Yang, Guidi; Lagos, Leonel; Yin, Yongguang; Gu, Baohua; Jiang, Guibin; Cai, Yong

2016-11-05

Cinnabar dissolution is an important factor controlling mercury (Hg) cycling. Recent studies have suggested the co-occurrence of re-adsorption of the released Hg during the course of cinnabar dissolution. However, there is a lack of feasible techniques that can quantitatively assess the amount of Hg re-adsorbed on cinnabar when investigating cinnabar dissolution. In this study, a new method, based on isotope tracing and dilution techniques, was developed to study the role of Hg re-adsorption in cinnabar dissolution. The developed method includes two key components: (1) accurate measurement of both released and spiked Hg in aqueous phase and (2) estimation of re-adsorbed Hg on cinnabar surface via the reduction in spiked (202)Hg(2+). By adopting the developed method, it was found that the released Hg for trials purged with oxygen could reach several hundred μgL(-1), while no significant cinnabar dissolution was detected under anaerobic condition. Cinnabar dissolution rate when considering Hg re-adsorption was approximately 2 times the value calculated solely with the Hg detected in the aqueous phase. These results suggest that ignoring the Hg re-adsorption process can significantly underestimate the importance of cinnabar dissolution, highlighting the necessity of applying the developed method in future cinnabar dissolution studies. Copyright © 2016 Elsevier B.V. All rights reserved.

Novel methodology for the study of mercury methylation and reduction in sediments and water using 197Hg radiotracer

International Nuclear Information System (INIS)

Ribeiro Guevara, Sergio; Perez Catan, Soledad; Zizek, Suzana; Repinc, Urska; Jacimovic, Radojko; Horvat, Milena

2007-01-01

Mercury tracers are powerful tools that can be used to study mercury transformations in environmental systems, particularly mercury methylation, demethylation and reduction in sediments and water. However, mercury transformation studies using tracers can be subject to error, especially when used to assess methylation potential. The organic mercury extracted can be as low as 0.01% of the endogenous labeled mercury, and artefacts and contamination present during methylmercury (MeHg) extraction processes can cause interference. Solvent extraction methods based on the use of either KBr/H 2 SO 4 or HCl were evaluated in freshwater sediments using 197 Hg radiotracer. Values obtained for the 197 Hg tracer in the organic phase were up to 25-fold higher when HCl was used, which is due to the coextraction of 197 Hg 2+ into the organic phase during MeHg extraction. Evaluations of the production of MeHg gave similar results with both MeHg extraction procedures, but due to the higher Hg 2+ contamination of the controls, the uncertainty in the determination was higher when HCl was used. The Hg 2+ contamination of controls in the HCl extraction method showed a nonlinear correlation with the humic acid content of sediment pore water. Therefore, use of the KBr/H 2 SO 4 method is recommended, since it is free from these interferences. 197 Hg radiotracer (T 1/2 = 2.673 d) has a production rate that is about 50 times higher than that of 203 Hg (T 1/2 46.595 d), the most frequently used mercury radiotracer. Hence it is possible to obtain a similar level of performance to 203 Hg when it is used it in short-term experiments and produced by the irradiation of 196 Hg with thermal neutrons, using mercury targets with the natural isotopic composition. However, if the 0.15% natural abundance of the 196 Hg isotope is increased, the specific activity of the 197 Hg tracer can be significantly improved. In the present work, 197 Hg tracer was produced from mercury 51.58% enriched in the 196 Hg

Thiol-functionalization of metal-organic framework by a facile coordination-based postsynthetic strategy and enhanced removal of Hg{sup 2+} from water

Energy Technology Data Exchange (ETDEWEB)

Ke, Fei [Laboratory of Advanced Porous Materials, School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China); Qiu, Ling-Guang, E-mail: lgqiu@ahu.edu.cn [Laboratory of Advanced Porous Materials, School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China); Yuan, Yu-Peng; Peng, Fu-Min; Jiang, Xia; Xie, An-Jian; Shen, Yu-Hua [Laboratory of Advanced Porous Materials, School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China); Zhu, Jun-Fa [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029 (China)

2011-11-30

Highlights: Black-Right-Pointing-Pointer A novel type of functionalized MOF for heavy metal removal. Black-Right-Pointing-Pointer Functionalization of MOF by a facile coordination-based postsynthetic strategy. Black-Right-Pointing-Pointer Thiol-functionalization of MOF has been realized for the first time. Black-Right-Pointing-Pointer Enhanced removal of Hg{sup 2+} by thiol-functionalized MOFs. - Abstract: The presence of coordinatively unsaturated metal centers in metal-organic frameworks (MOFs) provides an accessible way to selectively functionalize MOFs through coordination bonds. In this work, we describe thiol-functionalization of MOFs by choosing a well known three-dimensional (3D) Cu-based MOF, i.e. [Cu{sub 3}(BTC){sub 2}(H{sub 2}O){sub 3}]{sub n} (HKUST-1, BTC = benzene-1,3,5-tricarboxylate), by a facile coordination-based postsynthetic strategy, and demonstrate their application for removal of heavy metal ion from water. A series of [Cu{sub 3}(BTC){sub 2}]{sub n} samples stoichiometrically decorated with thiol groups has been prepared through coordination bonding of coordinatively unsaturated metal centers in HKUST-1 with -SH group in dithioglycol. The obtained thiol-functionalized samples were characterized by powder X-ray diffraction, scanning electron microscope, energy dispersive X-ray spectroscopy, infrared spectroscopy, and N{sub 2} sorption-desorption isothermal. Significantly, the thiol-functionalized [Cu{sub 3}(BTC){sub 2}]{sub n} exhibited remarkably high adsorption affinity (K{sub d} = 4.73 Multiplication-Sign 10{sup 5} mL g{sup -1}) and high adsorption capacity (714.29 mg g{sup -1}) for Hg{sup 2+} adsorption from water, while the unfunctionalized HKUST-1 showed no adsorption of Hg{sup 2+} under the same condition.

Electronic structure and optical properties of defect chalcopyrite HgGa2Se4

Science.gov (United States)

Gabrelian, B. V.; Lavrentyev, A. A.; Vu, Tuan V.; Parasyuk, O. V.; Khyzhun, O. Y.

2018-01-01

We report on studies from an experimental and theoretical viewpoint of the electronic structure of mercury digallium selenide, HgGa2Se4, a very promising optoelectronic material. In particular, the method of X-ray photoelectron spectroscopy (XPS) was used to evaluate binding energies of the constituent element core electrons and the shape of the valence band for pristine and Ar+-ion bombarded surfaces of HgGa2Se4 single crystal. First principles band-structure calculations were performed in the present work using the augmented plane wave + local orbitals (APW+lo). These calculations indicate that the Se 4p states are the main contributors at the top and in the upper portion of the valence band with slightly smaller contributions of the Ga 4p states in the upper portion of the band as well. Further, the central portion of the valence band is determined mainly by contributions of the Ga 4s states, and the Hg 5d states are the principal contributors to the bottom of the valence band. These theoretical data are in fair agreement when matching on a common energy scale of the X-ray emission bands giving information on the energy distribution of the Se 4p and Ga 4p states and the XPS valence-band spectrum of the HgGa2Se4 crystal. The principal optical constants are elucidated from the DFT calculations.

Ultra-sensitive and selective Hg{sup 2+} detection based on fluorescent carbon dots

Energy Technology Data Exchange (ETDEWEB)

Liu, Ruihua; Li, Haitao; Kong, Weiqian; Liu, Juan [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China); Liu, Yang, E-mail: yangl@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China); Tong, Cuiyan, E-mail: tongcy959@nenu.edu.cn [Chemisty Department, Northeast Normal University, Changchun 130024 (China); Zhang, Xing [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China); Kang, Zhenhui, E-mail: zhkang@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China)

2013-07-15

Graphical abstract: Fluorescent carbon dots were efficiently synthesized by one-step sodium hydroxide-assisted reflux method from PEG and demonstrated to show high selectivity toward Hg2+ ions detection. - Highlights: • FCDs were synthesized by one-step sodium hydroxide-assisted reflux method from PEG. • The FCDs emit blue photoluminescence and have upconversion fluorescent property. • The FCDs show ultra-sensitive detective ability for Hg{sup 2+} ions. - Abstract: Fluorescent carbon dots (FCDs) were efficiently synthesized by one-step sodium hydroxide-assisted reflux method from poly(ethylene glycol) (PEG). The obtained FCDs exhibit excellent water-solubility and high stability. Under the UV irradiation, the FCDs could emit bright blue photoluminescence, and also they were found to show excellent up-conversion fluorescence. It was further demonstrated that such FCDs can serve as effective fluorescent sensing platform for Hg{sup 2+} ions detection with ultra-sensitivity and selectivity. The sensing system achieved a limit of detection as low as 1 fM, which is much lower than all the previous reported sensing systems for Hg{sup 2+} ions detection. This FCDs sensing system has been successfully applied for the analysis of Hg{sup 2+} ions in water samples from river, lake, and tap water, showing good practical feasibility.

Influence of spironolactone on the excretion of 203Hg2+ in rats

International Nuclear Information System (INIS)

Cikrt, M.; Tichy, M.

1975-01-01

The effect of spironolactone (SPL) on 203 Hg 2+ excretion was studied in rats with a special emphasis in biliary excretion. No correlation was found between the number of doses of SPL pretreatment (1-5 doses of 5 mg/100 g body weight) and the biliary excretion of 203 Hg 2+ within 6 hours after intravenous administration of 120 μg Hg 2+ per rat. After the SPL pretreatment there was a significantly increased mercury stool excretion 24 hours after intravenous administration. Concurrent oral administration of SH-groups containing sorbent had no effect on mercury stool excretion. Repeated administration of 203 Hg 2+ (5 hours after the first dose) induced significantly increased biliary excretion of mercury in rats pretreated with SPL. On the other hand, repeated administration of SPL (4 hours after intravenous administration of mercury) did not influence the biliary excretion of mercury. The results indicate that the effect of SPL on biliary excretion of mercury could be limited by the level of ''mercury available'' in the organism and might be determined by a direct interaction of mercury molecule with the molecule of SPL

Methylation of Hg downstream from the Bonanza Hg mine, Oregon

Science.gov (United States)

Gray, John E.; Hines, Mark E.; Krabbenhoft, David P.; Thoms, Bryn

2012-01-01

Speciation of Hg and conversion to methyl-Hg were evaluated in stream sediment, stream water, and aquatic snails collected downstream from the Bonanza Hg mine, Oregon. Total production from the Bonanza mine was >1360t of Hg, during mining from the late 1800s to 1960, ranking it as an intermediate sized Hg mine on an international scale. The primary objective of this study was to evaluate the distribution, transport, and methylation of Hg downstream from a Hg mine in a coastal temperate climatic zone. Data shown here for methyl-Hg, a neurotoxin hazardous to humans, are the first reported for sediment and water from this area. Stream sediment collected from Foster Creek flowing downstream from the Bonanza mine contained elevated Hg concentrations that ranged from 590 to 71,000ng/g, all of which (except the most distal sample) exceeded the probable effect concentration (PEC) of 1060ng/g, the Hg concentration above which harmful effects are likely to be observed in sediment-dwelling organisms. Concentrations of methyl-Hg in stream sediment collected from Foster Creek varied from 11 to 62ng/g and were highly elevated compared to regional baseline concentrations (0.11-0.82ng/g) established in this study. Methyl-Hg concentrations in stream sediment collected in this study showed a significant correlation with total organic C (TOC, R2=0.62), generally indicating increased methyl-Hg formation with increasing TOC in sediment. Isotopic-tracer methods indicated that several samples of Foster Creek sediment exhibited high rates of Hg-methylation. Concentrations of Hg in water collected downstream from the mine varied from 17 to 270ng/L and were also elevated compared to baselines, but all were below the 770ng/L Hg standard recommended by the USEPA to protect against chronic effects to aquatic wildlife. Concentrations of methyl-Hg in the water collected from Foster Creek ranged from 0.17 to 1.8ng/L, which were elevated compared to regional baseline sites upstream and downstream

Hg tolerance and biouptake of an isolated pigmentation yeast Rhodotorula mucilaginosa.

Science.gov (United States)

Liu, Bing; Wang, Chaogang; Liu, Danxia; He, Ning; Deng, Xu

2017-01-01

A pigmented yeast R1 with strong tolerance to Hg2+ was isolated. Phylogenetic identification based on the analysis of 26S rDNA and ITS revealed R1 is a Rhodotorula mucilaginosa species. R1 was able to grow in the presence of 80 mg/L Hg2+, but the lag phase was much prolonged compared to its growth in the absence of Hg2+. The maximum Hg2+ binding capacity of R1 was 69.9 mg/g, and dead cells could bind 15% more Hg2+ than living cells. Presence of organic substances drastically reduced bioavailability of Hg2+ and subsequently decreased Hg2+ removal ratio from aqueous solution, but this adverse effect could be remarkably alleviated by the simultaneous process of cell propagation and Hg2+ biouptake with actively growing R1. Furthermore, among the functional groups involved in Hg2+ binding, carboxyl group contributed the most, followed by amino & hydroxyl group and phosphate group. XPS analysis disclosed the mercury species bound on yeast cells was HgCl2 rather than HgO or Hg0.

Phonons and their dispersion in model ferroelastics Hg2Hal2

Science.gov (United States)

Roginskii, E. M.; Kvasov, A. A.; Markov, Yu. F.; Smirnov, M. B.

2012-05-01

Dispersion relations of the acoustic and optical phonon frequencies have been calculated and plotted, and the density of states of the phonon spectrum of Hg2Cl2 and Hg2Br2 crystals has been derived. The effect of hydrostatic pressure on the frequencies of acoustic and optical phonons and their dispersion has been theoretically analyzed. It has been found that an increase in the pressure leads to a strong softening of the slowest acoustic TA branch (the soft mode) at the X point of the Brillouin zone boundary, which is consistent with the phenomenological Landau theory and correlates with experiment.

HgTe based topological insulators

International Nuclear Information System (INIS)

Bruene, Christoph

2014-01-01

This PhD thesis summarizes the discovery of topological insulators and highlights the developments on their experimental observations. The work focuses on HgTe. The thesis is structured as follows: - The first chapter of this thesis will give a brief overview on discoveries in the field of topological insulators. It focuses on works relevant to experimental results presented in the following chapters. This includes a short outline of the early predictions and a summary of important results concerning 2-dimensional topological insulators while the final section discusses observations concerning 3-dimensional topological insulators. - The discovery of the quantum spin Hall effect in HgTe marked the first experimental observation of a topological insulator. Chapter 2 focuses on HgTe quantum wells and the quantum spin Hall effect. The growth of high quality HgTe quantum wells was one of the major goals for this work. In a final set of experiments the spin polarization of the edge channels was investigated. Here, we could make use of the advantage that HgTe quantum well structures exhibit a large Rashba spin orbit splitting. - HgTe as a 3-dimensional topological insulator is presented in chapter 3. - Chapters 4-6 serve as in depth overviews of selected works: Chapter 4 presents a detailed overview on the all electrical detection of the spin Hall effect in HgTe quantum wells. The detection of the spin polarization of the quantum spin Hall effect is shown in chapter 5 and chapter 6 gives a detailed overview on the quantum Hall effect originating from the topological surface state in strained bulk HgTe.

Ultra-sensitive and selective detection of mercury ion (Hg2+) using free-standing silicon nanowire sensors

Science.gov (United States)

Jin, Yan; Gao, Anran; Jin, Qinghui; Li, Tie; Wang, Yuelin; Zhao, Jianlong

2018-04-01

In this paper, ultra-sensitive and highly selective Hg2+ detection in aqueous solutions was studied by free-standing silicon nanowire (SiNW) sensors. The all-around surface of SiNW arrays was functionalized with (3-Mercaptopropyl)trimethoxysilane serving as Hg2+ sensitive layer. Due to effective electrostatic control provided by the free-standing structure, a detection limit as low as 1 ppt was obtained. A linear relationship (R 2 = 0.9838) between log(CHg2+ ) and a device current change from 1 ppt to 5 ppm was observed. Furthermore, the developed SiNW sensor exhibited great selectivity for Hg2+ over other heavy metal ions, including Cd2+. Given the extraordinary ability for real-time Hg2+ detection, the small size and low cost of the SiNW device, it is expected to be a potential candidate in field detection of environmentally toxic mercury.

Eco-toxicology effect on Moina mongolica Daday exposed to Cd2+, Pb2+, and Hg2+ by the food chain.

Science.gov (United States)

Wang, Meiru; Zhao, Wen; Jia, Xuying; Wei, Jie; Wang, Shan

2018-03-28

As one of the most important contaminants, heavy metals can seriously influence human health via the food chain. In this study, the eco-toxicological effects of Cd 2+ , Pb 2+ , and Hg 2+ on Moina mongolica Daday were investigated by feeding them Chlorella sp. that contained heavy metals. The relative body lengths of the M. mongolica changed rapidly, peaking at 2 days for Hg 2+ , 6 days for Cd 2+ , and 8 days for Pb 2+ . Moreover, grazing and clearance rates of the experimental group were apparently lower than those of the control group after immersion in heavy metals. Additionally, Cd 2+ and Pd 2+ in the food significantly influenced the mean lifespan of M. mongolica of the P and F 1 generations. Egg production per brood was also significantly impacted by Cd 2+ and Pb 2+ in the food in generation P. Interestingly, Pb 2+ was the only metal that significantly influenced the reproduction times of F 2 , while the reproductive times were significantly influenced by Cd 2+ for generation P. Moreover, Cd 2+ , Pb 2+ , and Hg 2+ in the food significantly influenced the fecundity of generation P. Evaluation of the population growth parameters of M. mongolica revealed that the intrinsic rate of increase, net reproduction rate, and finite rate of increase were significantly influenced by Cd 2+ , Pb 2+ , and Hg 2+ in the food in generation P. Additionally, Hg 2+ slightly impacted generation time for generation P. Finally, the acute toxicity toward M. mongolica was Hg 2+  > Cd 2+  > Pb 2+ . Overall, heavy metals in the food were likely to influence the growth, survival, and population growth of M. mongolica through the food chain.

Evidence for genetic heterogeneity in D-2-hydroxyglutaric aciduria

DEFF Research Database (Denmark)

Kranendijk, Martijn; Struys, Eduard A; Gibson, K Michael

2010-01-01

We performed molecular, enzyme, and metabolic studies in 50 patients with D-2-hydroxyglutaric aciduria (D-2-HGA) who accumulated D-2-hydroxyglutarate (D-2-HG) in physiological fluids. Presumed pathogenic mutations were detected in 24 of 50 patients in the D-2-hydroxyglutarate dehydrogenase (D2HGD...

Facile sysnthesis of fluorescent silver nanoclusters as simultaneous detection and remediation for Hg{sup 2+}

Energy Technology Data Exchange (ETDEWEB)

Li, Dan; Li, Biao; Lee, Go Eun; Yang, Sung Ik [Dept. of Applied Chemistry, Kyung Hee University, Yongin (Korea, Republic of)

2015-06-15

Mercury is one of the most toxic metals to the environment and human life. 1 This metal can cause serious health problems because it easily passes through skin, respiratory tract, and gastrointestinal tissues into the human body, which will damage kidney, central nervou s system, and endocrine system. A facile synthetic strategy for the preparation of highly fluorescent AgNCs with red emission (λ em = 671 nm, quantum yield = 3.3%) has been developed. AgNCs showed a high sensitivity and selectivity toward the Hg{sup 2+} ions over other metal ions in spiked tap water. The detection limit was determined to be 1.3 ppb, which met the requirement of the USEPA standards for the maximum allowable level of Hg{sup 2+} in drinking water. AgNCs also showed applicability for remediation of Hg{sup 2+} in polluted water with high removal efficiencies. The employment of AgNCs could be used to monitor and remediate Hg{sup 2+} for the water analysis and purification.

Hg/HgO electrode and hydrogen evolution potentials in aqueous sodium hydroxide

Energy Technology Data Exchange (ETDEWEB)

Nickell, Ryan A.; Zhu, Wenhua H.; Payne, Robert U.; Cahela, Donald R.; Tatarchuk, Bruce J. [Center for Microfibrous Materials Manufacturing, Department of Chemical Engineering, 230 Ross Hall, Auburn University, Auburn, AL 36849 (United States)

2006-10-27

The Hg/HgO electrode is usually utilized as a reference electrode in alkaline solution such as for development of an alkaline hydrogen electrode. The reference electrode provides a suitable reference point but is available from few commercial vendors and suffers from inadequate documentation on potential in varying electrolytes. A new numerical method uses activity, activity coefficients, and a few correlated empirical equations to determine the potential values in both dilute and concentrated sodium hydroxide solutions at temperatures of 0-90{sup o}C and at concentrations of 0.100-12.8mol kg{sub H{sub 2}O}{sup -1}. The computed potentials of the Hg/HgO electrodes versus a normal hydrogen electrode (NHE) at 25{sup o}C and 1atm are 0.1634V for 0.100m, 0.1077V for 1.00m, and 0.0976V for 1.45m NaOH solutions. The Hg/HgO reduction potential further changes to -0.0751V versus NHE and hydrogen evolution potential changes to -0.9916V versus NHE in a solution of 30.0wt.% NaOH at 80{sup o}C. The calculated values are compared with the measured data at 25 and 75{sup o}C. The experimental data agree well with the numerical values computed from the theoretical and empirical equations. (author)

Mercury coordination polymers with flexible ethane-1,2-diyl-bis-(pyridyl-3-carboxylate): Synthesis, structures, thermal and luminescent properties

Energy Technology Data Exchange (ETDEWEB)

Vallejos, Javier [Departamento de Química, Universidad Católica del Norte, Av. Angamos 0610, Antofagasta (Chile); Brito, Iván, E-mail: ivanbritob@yahoo.com [Departamento de Quimica, Universidad de Antofagasta, Av. Angamos 601, Antofagasta (Chile); Cárdenas, Alejandro [Departamento de Física, Universidad de Antofagasta, Av. Angamos 601, Antofagasta (Chile); Llanos, Jaime [Departamento de Química, Universidad Católica del Norte, Av. Angamos 0610, Antofagasta (Chile); Bolte, Michael [Institut für Anorganische Chemie der Goethe—Universität Frankfurt, Max-von-Laue-Strasse 7, D-60438 Frankfurt am Main (Germany); López-Rodríguez, Matías [Instituto de Bio-Orgánica “Antonio González”, Universidad de La Laguna, Astrofísico Francisco Sánchez N° 2, La Laguna, Tenerife (Spain)

2015-03-15

The reaction of the flexible ligand, ethane-1,2-diyl-bis-(pyridyl-3-carboxylate), (L) with HgI{sub 2} and HgBr{sub 2} salts under the same experimental conditions leads to the formation of two coordination polymers with different motifs: ([Hg(L)(Br{sub 2})]){sub n}(1) and ([Hg(L)(I{sub 2})]){sub n}(2). In both compounds, the ligand, (L) acts in a μ2-N:N′-bidentate fashion to link HgBr{sub 2} and HgI{sub 2} units to form a linear and helical chain motif, along [1 0 0] for (1) and [0 0 1] for (2). The ethylene moiety of (L) has gauche and trans conformation in compounds (1) and (2), respectively. The flexible conformation of L produces differences in the optical and crystal properties of the two compounds. - Graphical abstract: This work demonstrates how the HgX{sub 2} units are coordinates by bi-dentate ligand forming polymeric coordination complexes by self-assembly of both chemical units.- Highlights: • News 1-D d{sup 10} transition metal coordination polymers. • The photoluminescent properties have been measured. • The thermal properties have been measured.

A new fluorescent pyrene–pyridine dithiocarbamate probe: A chemodosimeter to detect Hg{sup 2+} in pure aqueous medium and in live cells

Energy Technology Data Exchange (ETDEWEB)

Singh, Vikram; Srivastava, Priyanka [Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi-221005 (India); PrakashVerma, Shiv [Centre for Genetic Disorders, Faculty of Science, Banaras Hindu University, Varanasi-221005 (India); Misra, Arvind [Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi-221005 (India); Das, Parimal [Centre for Genetic Disorders, Faculty of Science, Banaras Hindu University, Varanasi-221005 (India); Singh, Nanhai, E-mail: nsinghbhu@gmail.com [Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi-221005 (India)

2014-10-15

A new pyrene–pyridine dithiocarbamate based fluorescent chemodosimeter, potassium (pyren-1-ylmethyl)(pyridin-2-ylmethyl)dithiocarbamate (L1) has been designed and synthesized. The chemodosimeter shows high selectivity and sensitivity (5.2 ppb) for Hg{sup 2+} in pure aqueous medium in which emission intensity was quenched by ≈80% due to the formation of new cyclized species, 1. The probe behaves as a chemodosimeter for Hg{sup 2+} ions and forms Hg{sup 2+} triggered cyclised imidazoline species with approximate detection time of 50 s and exhibits both colorimetric and fluorometric changes on detection of Hg{sup 2+} ion. Color of the probe (L1) changed from green to colorless visible to the naked eye and from green to dark blue upon the addition of Hg{sup 2+} ions under UV light. The Hg{sup 2+} triggered cyclization reaction was confirmed by spectral data analysis and a single crystal structure determination of the cyclised entity 2 obtained from the model compound potassium benzyl(pyridin-2-ylmethyl) dithiocarbamate (L2). L1 finds its application for detection of Hg{sup 2+} ions on paper strips, and in BSA (bovine serum albumin) medium. L1 is also applicable for the monitoring of Hg{sup 2+} ion in NIH3T3 live cells. - Highlights: • Efficient chemodosimeter to detect Hg{sup 2+} ions in pure aqueous medium. • Hg{sup 2+} triggered cyclisation and formation of imidazoline species. • Probe exhibit both colorimetric and fluorometric changes • Probe is applicable to detect Hg{sup 2+} in live cells and on cellulose paper strips.

Quadrupole moments of the 12+ isomers in 188Hg and 190Hg

International Nuclear Information System (INIS)

Dracoulis, G.D.; Lonnroth, T.; Vajda, S.; Dafni, E.; Schatz, G.

1984-01-01

The electric quadrupole interaction of the 12 + isomers in 188 Hg and 190 Hg has been measured in solid Hg. The quadrupole moments deduced, vertical strokeQ[ 188 Hg(12 + )]vertical stroke = 91(11) e fm 2 and vertical strokeQ[ 190 Hg(12 + )]vertical stroke = 117(14) e fm 2 suggest a possible change in γ-deformation due to the rotation alignment of the isub(13/2) quasi-neutrons. The temperature dependence of the electric field gradient tensor in Hg was also determined. (orig.)

Oblate shapes of 200,202,204Hg

International Nuclear Information System (INIS)

Bockisch, A.; Bharuth-Ram, K.; Kleinfeld, A.M.; Lieb, K.P.

1979-01-01

Measurements of the reorientation effect for the first excited 2 + states in 200 , 202 , 204 Hg were performed by exploiting the dependence of the γ-ray yield on Q 2 + for different projectiles. For 200 Hg, a positive quadrupole moment of Q 2 = 0.96 +- 0.11 eb (for negative interference) or Q 2 = 1.11 +- 0.11 eb (for positive interference) was determined indicating an oblate shape. Small positive Q 2 values were also found for 202 Hg and 204 Hg. Nine B(E2) values for excitation of the 2 + , 2 + ' and 4 + states in 196-204 Hg were measured. (orig.) [de

A Dansyl-Rhodamine Based Fluorescent Probe for Detection of Hg2+ and Cu2.

Science.gov (United States)

Yuan, Shizhuang; Su, Wei; Wang, Enju

2017-09-01

A novel fluorescent probe based on dansyl-appended rhodamine B was developed. The probe can selectively recognize and sense Hg2+ and Cu2+ from other common metal ions by showing unique fluorescence and absorption characteristics. In MeCN/HEPES buffer solution, the probe gives a ratiometric fluorescent response to Hg2+, which was ascribed to the fluorescence resonance energy transfer from dansyl moiety to the ring-opened rhodamine B moiety, while the presence of Cu2+ causes fluorescence quenching. Beside the fluorescence change, the presence of Cu2+ and Hg2+ can induce intensive absorption at about 555 nm, which resulted in a color change from colorless to pink.

DAMAGE TO DNA PRIMARY STRUCTURE AND ANTIOXIDANT ENZYMES IN LEMNA MINOR INDUCED BY HG2+%Hg2+ 胁迫对浮萍体细胞DNA一级结构和抗氧化酶系的损伤

Institute of Scientific and Technical Information of China (English)

徐楠; 施国新; 曾晓敏; 丁小余; 徐勤松; 陈源

2003-01-01

主要从DNA一级结构及抗氧化酶系变化两方面,研究了Hg2+胁迫下浮萍体细胞的损伤.结果表明:运用随机扩增多态性DNA法(Random amplified polymorphism DNA, RAPD)和DNA梯法(DNA Ladder),5～10 mg*L-1 Hg2+处理组可检测到基因组DNA的明显损伤,20 mg*L-1Hg2+已导致细胞坏死;RAPD法较DNA Ladder法更灵敏.本文还发现,活性氧和抗氧化酶系很可能参与了浮萍体细胞凋亡过程.低浓度的Hg2+胁迫可刺激抗氧化酶活性升高,以清除体内活性氧,而一旦活性氧水平超出一定域值,抗氧化酶活性急速下降,导致细胞凋亡.%The damage to Lemna minor cells induced by Hg2+ was studied in this article. Most damage occurred to DNA primary structure and changes in antioxidant enzyme activities were investigated by using RAPD and DNA ladder methods. The results showed that obvious damage to DNA was found in the process of apoptosis induced by 5-10 mg*L-1 Hg2+, and 20 mg*L-1 Hg2+ had already caused necrotic injury. The RAPD method was the more sensitive of the two methods, and so could be considered as an important method for monitoring apoptosis. The results also indicated that reactive oxygen species (ROS) and antioxidant enzymes are involved in the process of apoptosis. The activities of antioxidant enzymes could be stimulated to eliminate active oxygen by exposing the Lemna minor to low Hg2+ concentration; the cells declined rapidly when ROS were unable to be eliminated effectively.

Lattice parameters of the Hg1-xFexSe and Cd1-xFexTe semimagnetic semiconductors

International Nuclear Information System (INIS)

Sarem, A.; Soulayman, S.

2004-01-01

Full text.Hg 1-x Fe x Se and Cd 1-x Fe x Te are members of a family of semiconducting alloys referred to as diluted magnetic semiconductors (DMS), i.e., ternary alloys whose lattice is made up in part of substitutional magnetic ions (in the present case, fe 2+ ). These materials are of considerable interest because, apart from the opportunities provided by the ternary nature of these compounds (e.g., tunability of the energy gap or the lattice constant), they display interesting magnetic properties as well as exchange interaction between the localized Fe 2+ moments and band electrons, resulting in a host of novel effects. In this paper we investigate the behavior of the crystal lattice of Hg 1-x Fe x Se and Cd 1-x Fe x Te, grown using modified Bridgman method. The purpose of the study is providing precise quantitative data for the lattice parameter as a function of x, which can then be used as a means of determining composition. The results of lattice parameter measurements on the ternary semiconductor alloys Hg 1-x Fe x Se over the range (0≤x≤0.15) and Cd 1-x Fe x Te in the range (0≤x≤0.03) are reports. Each sample was subjected to chemical analysis for determining the real concentration of iron. Here it was found that the differences between the nominal compositions and the real ones for all investigated samples are negligible. The powdered samples of Hg 1-x Fe x Se and Cd 1-x Fe x Te with different nominal compositions were studied using a DRON diffractometer with filtered Cο radiation (λ kα1 =1.78892A; λ kα2 =1.79278A). The diffraction patterns with a scan rate of 1 degree 2θ/min were taken. Precise measurements of the line position diffracted and extrapolation method to determine a to value θ=90 degree were made by Least Square Method. This method allowed determining cell parameters foe each sample with accuracy ±0.0001A. The crystal structure of these compounds was determined as a cubic one of the zinc blede type. The structural homogeneity of

Elastic, dynamical, and electronic properties of LiHg and Li3Hg: First-principles study

Science.gov (United States)

Wang, Yan; Hao, Chun-Mei; Huang, Hong-Mei; Li, Yan-Ling

2018-04-01

The elastic, dynamical, and electronic properties of cubic LiHg and Li3Hg were investigated based on first-principles methods. The elastic constants and phonon spectral calculations confirmed the mechanical and dynamical stability of the materials at ambient conditions. The obtained elastic moduli of LiHg are slightly larger than those of Li3Hg. Both LiHg and Li3Hg are ductile materials with strong shear anisotropy as metals with mixed ionic, covalent, and metallic interactions. The calculated Debye temperatures are 223.5 K and 230.6 K for LiHg and Li3Hg, respectively. The calculated phonon frequency of the T2 g mode in Li3Hg is 326.8 cm-1. The p states from the Hg and Li atoms dominate the electronic structure near the Fermi level. These findings may inspire further experimental and theoretical study on the potential technical and engineering applications of similar alkali metal-based intermetallic compounds.

Hg isotopes reveal in-stream processing and legacy inputs in East Fork Poplar Creek, Oak Ridge, Tennessee, USA.

Science.gov (United States)

Demers, Jason D; Blum, Joel D; Brooks, Scott C; Donovan, Patrick M; Riscassi, Ami L; Miller, Carrie L; Zheng, Wang; Gu, Baohua

2018-04-25

Natural abundance stable Hg isotope measurements were used to place new constraints on sources, transport, and transformations of Hg along the flow path of East Fork Poplar Creek (EFPC), a point-source contaminated headwater stream in Oak Ridge, Tennessee. Particulate-bound Hg in the water column of EFPC within the Y-12 National Security Complex, was isotopically similar to average metallic Hg(0) used in industry, having a mean δ202Hg value of -0.42 ± 0.09‰ (1SD) and near-zero Δ199Hg. On average, particulate fraction δ202Hg values increased downstream by 0.53‰, while Δ199Hg decreased by -0.10‰, converging with the Hg isotopic composition of the fine fraction of streambed sediment along the 26 km flow path. The dissolved fraction behaved differently. Although initial Δ199Hg values of the dissolved fraction were also near-zero, these values increased transiently along the flow path. Initial δ202Hg values of the dissolved fraction were more variable than in the particulate fraction, ranging from -0.44 to 0.18‰ among three seasonal sampling campaigns, but converged to an average δ202Hg value of 0.01 ± 0.10‰ (1SD) downstream. Dissolved Hg in the hyporheic and riparian pore water had higher and lower δ202Hg values, respectively, compared to dissolved Hg in stream water. Variations in Hg isotopic composition of the dissolved and suspended fractions along the flow path suggest that: (1) physical processes such as dilution and sedimentation do not fully explain decreases in total mercury concentrations along the flow path; (2) in-stream processes include photochemical reduction, but microbial reduction is likely more dominant; and (3) additional sources of dissolved mercury inputs to EFPC at baseflow during this study predominantly arise from the hyporheic zone.

SoilGrids1km — Global Soil Information Based on Automated Mapping

Science.gov (United States)

Hengl, Tomislav; de Jesus, Jorge Mendes; MacMillan, Robert A.; Batjes, Niels H.; Heuvelink, Gerard B. M.; Ribeiro, Eloi; Samuel-Rosa, Alessandro; Kempen, Bas; Leenaars, Johan G. B.; Walsh, Markus G.; Gonzalez, Maria Ruiperez

2014-01-01

Background Soils are widely recognized as a non-renewable natural resource and as biophysical carbon sinks. As such, there is a growing requirement for global soil information. Although several global soil information systems already exist, these tend to suffer from inconsistencies and limited spatial detail. Methodology/Principal Findings We present SoilGrids1km — a global 3D soil information system at 1 km resolution — containing spatial predictions for a selection of soil properties (at six standard depths): soil organic carbon (g kg−1), soil pH, sand, silt and clay fractions (%), bulk density (kg m−3), cation-exchange capacity (cmol+/kg), coarse fragments (%), soil organic carbon stock (t ha−1), depth to bedrock (cm), World Reference Base soil groups, and USDA Soil Taxonomy suborders. Our predictions are based on global spatial prediction models which we fitted, per soil variable, using a compilation of major international soil profile databases (ca. 110,000 soil profiles), and a selection of ca. 75 global environmental covariates representing soil forming factors. Results of regression modeling indicate that the most useful covariates for modeling soils at the global scale are climatic and biomass indices (based on MODIS images), lithology, and taxonomic mapping units derived from conventional soil survey (Harmonized World Soil Database). Prediction accuracies assessed using 5–fold cross-validation were between 23–51%. Conclusions/Significance SoilGrids1km provide an initial set of examples of soil spatial data for input into global models at a resolution and consistency not previously available. Some of the main limitations of the current version of SoilGrids1km are: (1) weak relationships between soil properties/classes and explanatory variables due to scale mismatches, (2) difficulty to obtain covariates that capture soil forming factors, (3) low sampling density and spatial clustering of soil profile locations. However, as the Soil

Metabolism of chlorofluorocarbons and polybrominated compounds by Pseudomonas putida G786(pHG-2) via an engineered metabolic pathway.

Science.gov (United States)

Hur, H G; Sadowsky, M J; Wackett, L P

1994-11-01

The recombinant bacterium Pseudomonas putida G786(pHG-2) metabolizes pentachloroethane to glyoxylate and carbon dioxide, using cytochrome P-450CAM and toluene dioxygenase to catalyze consecutive reductive and oxidative dehalogenation reactions (L.P. Wackett, M.J. Sadowsky, L.N. Newman, H.-G. Hur, and S. Li, Nature [London] 368:627-629, 1994). The present study investigated metabolism of brominated and chlorofluorocarbon compounds by the recombinant strain. Under anaerobic conditions, P. putida G786(pHG-2) reduced 1,1,2,2-tetrabromoethane, 1,2-dibromo-1,2-dichloroethane, and 1,1,1,2-tetrachloro-2,2-difluoroethane to products bearing fewer halogen substituents. Under aerobic conditions, P. putida G786(pHG-2) oxidized cis- and trans-1,2-dibromoethenes, 1,1-dichloro-2,2-difluoroethene, and 1,2-dichloro-1-fluoroethene. Several compounds were metabolized by sequential reductive and oxidative reactions via the constructed metabolic pathway. For example, 1,1,2,2-tetrabromoethane was reduced by cytochrome P-450CAM to 1,2-dibromoethenes, which were subsequently oxidized by toluene dioxygenase. The same pathway metabolized 1,1,1,2-tetrachloro-2,2-difluoroethane to oxalic acid as one of the final products. The results obtained in this study indicate that P. putida G786(pHG-2) metabolizes polyfluorinated, chlorinated, and brominated compounds and further demonstrates the value of using a knowledge of catabolic enzymes and recombinant DNA technology to construct useful metabolic pathways.

Evaluating the role of re-adsorption of dissolved Hg{sup 2+} during cinnabar dissolution using isotope tracer technique

Energy Technology Data Exchange (ETDEWEB)

Jiang, Ping [Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199 (United States); Li, Yanbin [Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education/Qingdao Collaborative Innovation Center of Marine Science and Technology, Ocean University of China, Qingdao 266100 (China); Liu, Guangliang [Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199 (United States); Southeast Environmental Research Center, Florida International University, Miami, FL 33199 (United States); Yang, Guidi [College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002 (China); Lagos, Leonel [Applied Research Center, Florida International University, Miami, FL 33199 (United States); Yin, Yongguang [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Gu, Baohua [Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge TN 37831 (United States); Jiang, Guibin [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Cai, Yong, E-mail: cai@fiu.edu [Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199 (United States); Southeast Environmental Research Center, Florida International University, Miami, FL 33199 (United States)

2016-11-05

Highlights: • Develop a new method to study Hg re-adsorption in cinnabar. • Both isotope dilution and tracer techniques were adopted. • The presence of O{sub 2} can significantly enhance the dissolution of cinnabar. • Prove the necessity of including re-adsorption in estimating cinnabar dissolution. - Abstract: Cinnabar dissolution is an important factor controlling mercury (Hg) cycling. Recent studies have suggested the co-occurrence of re-adsorption of the released Hg during the course of cinnabar dissolution. However, there is a lack of feasible techniques that can quantitatively assess the amount of Hg re-adsorbed on cinnabar when investigating cinnabar dissolution. In this study, a new method, based on isotope tracing and dilution techniques, was developed to study the role of Hg re-adsorption in cinnabar dissolution. The developed method includes two key components: (1) accurate measurement of both released and spiked Hg in aqueous phase and (2) estimation of re-adsorbed Hg on cinnabar surface via the reduction in spiked {sup 202}Hg{sup 2+}. By adopting the developed method, it was found that the released Hg for trials purged with oxygen could reach several hundred μg L{sup −1}, while no significant cinnabar dissolution was detected under anaerobic condition. Cinnabar dissolution rate when considering Hg re-adsorption was approximately 2 times the value calculated solely with the Hg detected in the aqueous phase. These results suggest that ignoring the Hg re-adsorption process can significantly underestimate the importance of cinnabar dissolution, highlighting the necessity of applying the developed method in future cinnabar dissolution studies.

Observation of Hg-diffusion in CdTe using heavy ion (40MeV-O5+) backscattering

International Nuclear Information System (INIS)

Otake, H.; Takita, K.; Murakami, K.; Masuda, K.; Kudo, H.; Seki, S.

1984-01-01

Diffusion of Hg in the near-surface region of CdTe crystals was observed by means of 40MeV-O 5+ ion backscattering. CdTe crystals immersed in Hg were kept in furnace at 280 -- 340 0 C for 2 -- 240hours. The backscattering spectra of these crystals were measured. The concentration of the diffused Hg atoms in the surface reached to 4 x 10 20 cm -3 , and Hg distribution was observed up to 1.4 μm from surface. Temperature dependence of the diffusion coefficients was determined as D = 5 x 10 3 exp (-2.0 +- 0.3eV/kT) cm 2 /sec. Hg-diffusion was not observed in the case of CdTe kept in Hg with a small amount of Cd. These facts suggest that Hg diffusion is controlled by the diffusion of Cd-vacancy. A method of observing the Hg-atoms profile in the near-surface region of the semiconductor was established. (author)

Temperature lidar measurements from 1 to 105 km altitude using resonance, Rayleigh, and Rotational Raman scattering

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M. Alpers

2004-01-01

Full Text Available For the first time, three different temperature lidar methods are combined to obtain time-resolved complete temperature profiles with high altitude resolution over an altitude range from the planetary boundary layer up to the lower thermosphere (about 1–105 km. The Leibniz-Institute of Atmospheric Physics (IAP at Kühlungsborn, Germany (54° N, 12° E operates two lidar instruments, using three different temperature measurement methods, optimized for three altitude ranges: (1 Probing the spectral Doppler broadening of the potassium D1 resonance lines with a tunable narrow-band laser allows atmospheric temperature profiles to be determined at metal layer altitudes (80–105 km. (2 Between about 20 and 90 km, temperatures were calculated from Rayleigh backscattering by air molecules, where the upper start values for the calculation algorithm were taken from the potassium lidar results. Correction methods have been applied to account for, e.g. Rayleigh extinction or Mie scattering of aerosols below about 32 km. (3 At altitudes below about 25 km, backscattering in the Rotational Raman lines is strong enough to obtain temperatures by measuring the temperature dependent spectral shape of the Rotational Raman spectrum. This method works well down to about 1 km. The instrumental configurations of the IAP lidars were optimized for a 3–6 km overlap of the temperature profiles at the method transition altitudes. We present two night-long measurements with clear wave structures propagating from the lower stratosphere up to the lower thermosphere.

An investigation of mercury sources in the Puyango-Tumbes River: Using stable Hg isotopes to characterize transboundary Hg pollution.

Science.gov (United States)

Schudel, Gary; Miserendino, Rebecca Adler; Veiga, Marcello M; Velasquez-López, P Colon; Lees, Peter S J; Winland-Gaetz, Sean; Davée Guimarães, Jean Remy; Bergquist, Bridget A

2018-07-01

Mercury (Hg) concentrations and stable isotopes along with other trace metals were examined in environmental samples from Ecuador and Peru's shared Puyango-Tumbes River in order to determine the extent to which artisanal- and small-scale gold mining (ASGM) in Portovelo-Zaruma, Ecuador contributes to Hg pollution in the downstream aquatic ecosystem. Prior studies investigated the relationship between ASGM activities and downstream Hg pollution relying primarily on Hg concentration data. In this study, Hg isotopes revealed an isotopically heavy Hg signature with negligible mass independent fractionation (MIF) in downstream sediments, which was consistent with the signature observed in the ASGM source endmember. This signature was traced as far as ∼120 km downstream of Portovelo-Zaruma, demonstrating that Hg stable isotopes can be used as a tool to fingerprint and trace sources of Hg over vast distances in freshwater environments. The success of Hg isotopes as a source tracer in fresh waters is largely due to the particle-reactive nature of Hg. Furthermore, the magnitude and extent of downstream Hg, lead, copper and zinc contamination coupled with the Hg isotopes suggest that it is unlikely that the smaller artisanal-scale activities, which do not use cyanidation, are responsible for the pollution. More likely it is the scale of ores processed and the cyanide leaching, which can release other metals and enhance Hg transport, used during small-scale gold mining that is responsible. Thus, although artisanal- and small-scale gold mining occur in tandem in Portovelo-Zaruma, a distinction should be made between these two activities. Copyright © 2018 Elsevier Ltd. All rights reserved.

G1SST, 1km blended SST

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A daily, global Sea Surface Temperature (SST) data set is produced at 1-km (also known as ultra-high resolution) by the JPL ROMS (Regional Ocean Modeling System)...

Hg+ ion density in low-pressure Ar-Hg discharge plasma used for liquid crystal display back-lighting

International Nuclear Information System (INIS)

Goto, Miki; Arai, Toshihiko

1995-01-01

The positive column of a low-pressure Ar-Hg discharge has been applied as a fluorescent light source for illumination. Many studies on the diagnostics and fundamental mechanisms have been carried out on both the classical fluorescent lamp (d=36 mm) and the compact fluorescent lamp (d=12 mm). On the other hand, a lamp of extremely narrow diameter (usually below 6 mm) has been recently developed for liquid crystal display (LCD) back-lighting and its importance is undoubtedly increasing. Some characteristics or mechanisms of the narrow-diameter lamp may be similar to those of the 36 mm one; however the similarity rule does not hold between them due to the contributions from a stepwise ionization process. Therefore, in order to clarify the excitation mechanism in the narrow-diameter lamp quantitatively, various parameters must be measured directly and some analysis must be done. The Hg + ion density and electron density are important parameters for the purpose of clarifying the excitation mechanism quantitatively. In this work, we have measured the Hg + ion density using the modified absorption method, and the electron density using the probe method in the Ar-Hg discharge of the 4 mm bore tube on bath temperature. Moreover, with combining the modified absorption method and the probe method, the Hg 2 + molecular ion density has been determined

Speciation of aquatic Hg2+ in humic substances by time differential perturbed angular correlation

International Nuclear Information System (INIS)

Franke, K.; Kupsch, H.; Troger, W.; Butz, T.

1997-01-01

Humic substances are ubiquitous in waters and soils and act as complexing agents for different heavy metals, e.g. Cd, Hg. Toxicity, reactivity, fixation, and migration are therefore strongly influenced by the interactions between heavy metals and humic substances. Humic substances derive from postmortal materials such as rotten plants, have dark colours and usually a molecular weight between 500 and 10.000 Dalton. Complex formation studies with different heavy metal ions indicate at least two different kinds of metal sites. Usually, these studies are restricted to heavy metal concentrations 2 to 3 orders of magnitude higher that the natural heavy metal abundance (i.e. 10 -10 molar). This serious limitation can be overcome by the use of suitable radioisotope techniques capable of metal speciation at extreme sensitivity levels such as TDPAC (Time Differential Perturbed Angular Correlation of γ-Rays). Thus, we studied the interaction of heavy metals with humic substances by monitoring the nuclear quadrupole interaction (NQI)of the short-lived radioisotopes 111m Cd (τ l/2 = 49 min) and 199m Hg (τ 1/2 = 43 min) supplied by ISOLDE via γ-γ -TDPAC and compared the 111m Cd/ 199m Hg-NQIs in humic substances with the known NQI of model compounds (i.e. metal proteins, organometallic compounds). At lowest Hg(II) concentrations (10 -10 molar) only linear Hg(ll) coordinations with nitrogen and/or sulfur were observed, with increasing Hg(II) concentration additional distorted trigonal (at 2.5.10 -10 molar) and tetrahedral coordinations (at 2.5.10 -8 molar) with various ligands show up and start to become dominant at Hg(II) concentrations of 10 -7 molar and higher. Contrary to Hg(II), we observed unspecific binding for Cd(lI) in the 111m Cd-TDPAC experiments only, even in the 10 -10 molar concentration range

Simultaneous removal of SO2, NO and Hg0 from flue gas by ferrate (VI) solution

International Nuclear Information System (INIS)

Zhao, Yi; Han, Yinghui; Guo, Tianxiang; Ma, Tianzhong

2014-01-01

Simultaneously removing SO 2 , NO and Hg 0 from flue gas was examined by ferrate (VI) solution at a bubbling reactor. The removal efficiencies of 100% for SO 2 , 64.8% for NO and 81.4% for Hg 0 were achieved respectively, under the optimum experimental conditions, in which concentration of ferrate (VI) solution was 0.25 mmol/L, solution pH was 8.0, flue gas flow rate was 1 L/min and reaction temperature was 320 K. Based on the discussions of the ferrate (VI) solution characteristics, the comparisons of the standard electrode potential (E 0 ) of ferrate (VI) solution with E 0 values of reactant, and the analysis of the reaction products, a mechanism of simultaneous removal was proposed. In the process of simultaneous removal, FeO 4 2− and HFeO 4 − as the dominant species of ferrate (VI), could rapidly oxidize SO 2 , NO, and Hg 0 into SO 4 2− , NO 3 − and Hg 2+ . - Highlights: • Prepared ferrate (VI) absorbent has excellent property of removing SO 2 , NO and Hg 0 . • 100% of SO 2 , 63.8% of NO and 83.6% of Hg 0 were simultaneously removed. • The simultaneous removal mechanism of SO 2 , NO and Hg 0 was proposed

A highly sensitive fluorescent probe based on BODIPY for Hg2+ in aqueous solution

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ZHAO Junwei

2016-12-01

Full Text Available A highly sensitive fluorescent probe based on BODIPY and hydrazine for Hg2+ was designed and synthesized.This probe could detect mercury ions in aqueous solutions within 5 min.With the increase of Hg2+ mole concentration,an obvious red shift of UV-Vis absorption wavelength was observed and the fluorescence intensity significantly enhanced.It was found that the fluorescence intensity of an aqueous solution containing 0.1 μmol/L Hg2+ is much stronger than that of blank solution,which indicats that the fluorescent probe has high sensitivity.In addition,other metal ions could not cause the change of fluorescent spectra,which means this probe has good selectivity,as well.

A solvent-dependent fluorescent detection method for Fe(3+) and Hg(2+) based on a rhodamine B derivative.

Science.gov (United States)

Li, Xutian; Yin, Yue; Deng, Junjie; Zhong, Huixian; Tang, Jian; Chen, Zhi; Yang, Liting; Ma, Li-Jun

2016-07-01

A new rhodamine B-benzofurazan based fluorescent probe (1) for Fe(3+) and Hg(2+) was synthesized. In aqueous solution containing 30% (v/v) ethanol, probe 1 shows a high selective fluorescent enhancement recognition to Fe(3+) with a binding ratio of 1:1 (probe 1: Fe(3+)), when the concentration of Fe(3+) is less than that of the probe. When the concentration of Fe(3+) is higher than that of the probe, it shows fluorescent "turn-on" response to Fe(3+) by opening the rhodamine spirolactam with a binding ratio of 1:2 (probe 1: Fe(3+)). Furthermore, probe 1 displays a high selectivity and a hypersensitivity (detection limit is 4.4nM) to Hg(2+) with a binding ratio of 1:1 in ethanol. NMR and UV-vis experiments indicate that the different fluorescent recognition signals to Fe(3+) and Hg(2+) are derived from different binding modes of 1-Fe(3+) and 1-Hg(2+). Copyright © 2016 Elsevier B.V. All rights reserved.

Inorganic mercury (Hg2+ uptake by different plankton fractions of Andean Patagonian lakes (Argentina

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Diéguez M.C.

2014-07-01

Full Text Available The species composition and the size structure of natural planktonic food webs may provide essential information to understand the fate of mercury and, in particular, the bioaccumulation pattern of Hg2+ in the water column of lake ecosystems. Heterotrophic and autotrophic picoplankton and phytoplankton are the most important entry points for Hg in aquatic ecosystems since they concentrate Hg2+ and MeHg from ambient water, making them available to planktonic consumers at higher trophic levels of lake food webs. In this investigation we studied the uptake of 197Hg2+ in natural plankton assemblages from four Andean lakes (Nahuel Huapi National Park, Patagonia, Argentina, comprised in the size fractions 0.2-2.7 μm (picoplankton, 0.2-20 μm (pico and nanoplankton and 20-50 μm (microplankton through experiments using Hg2+ labeled with 197Hg2+. The experimental results showed that the uptake of Hg2+ was highest in the smallest plankton fractions (0.2-2.7 μm and 0.2-20 μm compared to the larger fraction comprising microplankton (20-50 um. This pattern was consistent in all lakes, reinforcing the idea that among pelagic organisms, heterotrophic and autotrophic bacteria with the contribution of nanoflagellates and dinoflagellates constitute the main entry point of Hg2+ to the pelagic food web. Moreover, a significant direct relationship was found between the Hg2+ uptake and surface index of the planktonic fractions (SIf. Thus, the smaller planktonic fractions which bore the higher SI were the major contributors to the Hg2+ passing from the abiotic to the biotic pelagic compartments of these Andean lakes.

Electric structure of the Copahue Volcano (Neuquén Province, Argentina), from magnetotelluric soundings: 1D and 2D modellings

Science.gov (United States)

Mamaní, M. J.; Borzotta, E.; Venencia, J. E.; Maidana, A.; Moyano, C. E.; Castiglione, B.

2000-05-01

Four magnetotelluric soundings were carried out in 1993 in the region of the Copahue active volcano located at the border between Chile and Argentina (37°45'S, 71°18'W). Three soundings were located inside the caldera of the ancient stratovolcano (east of Copahue) and the fourth outside it. The soundings inside the caldera were situated at about 6, 11, and 14 km from the volcano. Digital data were obtained covering the range of periods from 1 sec to 10,000 sec using induction coils and a flux-gate magnetometer to obtain the magnetic data and Cu-SO 4Cu electrodes for electric field measurements. The apparent resistivity curves corresponding to principal directions were analyzed in conjunction with the geological background in order to eliminate distortion — which is very important in this hot volcanic region. Then, 1D modellings were performed using the "normal" curves — i.e., curves without distortions. Using the apparent resistivity curves with distortions, 2D modelling was also performed along a profile perpendicular to the regional tectonic trend suggested by MT soundings into the caldera. Results show low resistivity values of about 3-15 Ωm between 9 km to 20 km depth in the crust, suggesting high temperatures, with minimum values of about 700°C with partially melted zones in the upper crust between 9 km to 20 km depth under the caldera. The presence of a possible sulphide-carbonaceous layer (SC layer) in the upper basement could play an important role in lowering the electrical resistivities because of its high electronic conductivity.

Variation of the mean square amplitude with concentration in Hg1-xCdxTe

International Nuclear Information System (INIS)

Sadaiyandi, K.; Ramachandran, K.

1989-01-01

The mean square displacements (MSD) of Hg and Te in the mixed system Hg 1-x Cd x Te have been calculated for various concentrations of Cd atoms (x = 0.20, 0.40, 0.60, 0.80, 1.00) at 4, 77, and 300 K by means of the virtual crystal approximation. An unusual trend in MSD is found for x below 0.2: the higher mass has higher value of MS amplitude

Buprofezin Is Metabolized by CYP353D1v2, a Cytochrome P450 Associated with Imidacloprid Resistance in Laodelphax striatellus

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Mohammed Esmail Abdalla Elzaki

2017-11-01

Full Text Available CYP353D1v2 is a cytochrome P450 related to imidacloprid resistance in Laodelphax striatellus. This work was conducted to examine the ability of CYP353D1v2 to metabolize other insecticides. Carbon monoxide difference spectra analysis indicates that CYP353D1v2 was successfully expressed in insect cell Sf9. The catalytic activity of CYP353D1v2 relating to degrading buprofezin, chlorpyrifos, and deltamethrin was tested by measuring substrate depletion and analyzing the formation of metabolites. The results showed the nicotinamide–adenine dinucleotide phosphate (NADPH-dependent depletion of buprofezin (eluting at 8.7 min and parallel formation of an unknown metabolite (eluting 9.5 min. However, CYP353D1v2 is unable to metabolize deltamethrin and chlorpyrifos. The recombinant CYP353D1v2 protein efficiently catalyzed the model substrate p-nitroanisole with a maximum velocity of 9.24 nmol/min/mg of protein and a Michaelis constant of Km = 6.21 µM. In addition, imidacloprid was metabolized in vitro by the recombinant CYP353D1v2 microsomes (catalytic constant Kcat 0.064 pmol/min/pmol P450, Km = 6.41 µM. The mass spectrum of UPLC-MS analysis shows that the metabolite was a product of buprofezin, which was buprofezin sulfone. This result provided direct evidence that L. striatellus cytochrome P450 CYP353D1v2 is capable of metabolizing imidacloprid and buprofezin.

Buprofezin Is Metabolized by CYP353D1v2, a Cytochrome P450 Associated with Imidacloprid Resistance in Laodelphax striatellus.

Science.gov (United States)

Elzaki, Mohammed Esmail Abdalla; Miah, Mohammad Asaduzzaman; Han, Zhaojun

2017-11-29

CYP353D1v2 is a cytochrome P450 related to imidacloprid resistance in Laodelphax striatellus . This work was conducted to examine the ability of CYP353D1v2 to metabolize other insecticides. Carbon monoxide difference spectra analysis indicates that CYP353D1v2 was successfully expressed in insect cell Sf9. The catalytic activity of CYP353D1v2 relating to degrading buprofezin, chlorpyrifos, and deltamethrin was tested by measuring substrate depletion and analyzing the formation of metabolites. The results showed the nicotinamide-adenine dinucleotide phosphate (NADPH)-dependent depletion of buprofezin (eluting at 8.7 min) and parallel formation of an unknown metabolite (eluting 9.5 min). However, CYP353D1v2 is unable to metabolize deltamethrin and chlorpyrifos. The recombinant CYP353D1v2 protein efficiently catalyzed the model substrate p -nitroanisole with a maximum velocity of 9.24 nmol/min/mg of protein and a Michaelis constant of Km = 6.21 µM. In addition, imidacloprid was metabolized in vitro by the recombinant CYP353D1v2 microsomes (catalytic constant Kcat) 0.064 pmol/min/pmol P450, Km = 6.41 µM. The mass spectrum of UPLC-MS analysis shows that the metabolite was a product of buprofezin, which was buprofezin sulfone. This result provided direct evidence that L. striatellus cytochrome P450 CYP353D1v2 is capable of metabolizing imidacloprid and buprofezin.

Absence of Hg transpiration by shoot after Hg uptake by roots of six terrestrial plant species

International Nuclear Information System (INIS)

Greger, Maria; Wang Yaodong; Neuschuetz, Clara

2005-01-01

In this paper we investigated if, and to what extent, six different plant species accumulate, translocate and emit mercury (Hg) into the air. The Hg uptake by roots, distribution of Hg to the shoot and release of Hg via shoots of garden pea, spring wheat, sugar beet, oil-seed rape, white clover and willow were investigated in a transpiration chamber. The airborne Hg was trapped in a Hopcalite trap or a gold trap. Traps and plant materials were analysed for content of Hg by CVAAS. The results show that all plant species were able to take up Hg to a large extent from a nutrient solution containing 200 μg L -1 Hg. However, the Hg translocation to the shoot was low (0.17-2.5%) and the Hg that reached the leaves was trapped and no release of the absorbed Hg to the air was detected. - Mercury translocation to shoots was low

Effect of 24,25-dihydroxyvitamin D3 on 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] metabolism in vitamin D-deficient rats infused with 1,25-(OH)2D3

International Nuclear Information System (INIS)

Yamato, H.; Matsumoto, T.; Fukumoto, S.; Ikeda, K.; Ishizuka, S.; Ogata, E.

1989-01-01

Previous studies revealed that administration of 24,25-dihydroxyvitamin D3 [24,25-(OH)2D3] to calcium (Ca)-deficient rats causes a dose-dependent reduction in markedly elevated serum 1,25-(OH)2D3 level. Although the results suggested that the metabolism of 1,25-(OH)2D3 was accelerated by 24,25-(OH)2D3, those experiments could not define whether the enhanced metabolism of 1,25-(OH)2D3 played a role in the reduction in the serum 1,25-(OH)2D3 level. In the present study, in order to address this issue more specifically, serum 1,25-(OH)2D3 was maintained solely by exogenous administration through miniosmotic pumps of 1,25-(OH)2D3 into vitamin D-deficient rats. Thus, by measuring the serum 1,25-(OH)2D3 concentration, the effect of 24,25-(OH)2D3 on the MCR of 1,25-(OH)2D3 could be examined. Administration of 24,25-(OH)2D3 caused a dose-dependent enhancement in the MCR of 1,25-(OH)2D3, and 1 microgram/100 g rat.day 24,25-(OH)2D3, which elevated serum 24,25-(OH)2D3 to 8.6 +/- 1.3 ng/ml, significantly increased MCR and suppressed serum levels of 1,25-(OH)2D3. The effect of 24,25-(OH)2D3 on 1,25-(OH)2D3 metabolism developed with a rapid time course, and the recovery of iv injected [1 beta-3H]1,25-(OH)2D3 in blood was significantly reduced within 1 h. In addition, there was an increase in radioactivity in the water-soluble fraction of serum as well as in urine, suggesting that 1,25-(OH)2D3 is rapidly degraded to a water-soluble metabolite(s). Furthermore, the reduction in serum 1,25-(OH)2D3 was associated with a reduction in both serum and urinary Ca levels. Because the conversion of [3H]24,25-(OH)2D3 to [3H]1,24,25-(OH)2D3 or other metabolites was minimal in these rats, 24,25-(OH)2D3 appears to act without being converted into other metabolites. These results demonstrate that 24,25-(OH)2D3 rapidly stimulates the metabolism of 1,25-(OH)2D3 and reduces its serum level

Highly selective and sensitive optical sensor for determination of Pb2+and Hg2+ ions based on the covalent immobilization of dithizone on agarose membrane

Science.gov (United States)

Zargoosh, Kiomars; Babadi, Fatemeh Farhadian

2015-02-01

A highly sensitive and selective optical membrane for determination of Hg2+ and Pb2+ was prepared by covalent immobilization of dithizone on agarose membrane. In addition to its high stability, reproducibility and relatively long lifetime, the proposed optical sensor revealed good selectivity for target ions over a large number of alkali, alkaline earth, transition, and heavy metal ions. The proposed optical membrane displays linear responses from 1.1 × 10-8 to 2.0 × 10-6 mol L-1 and 1.2 × 10-8 to 2.4 × 10-6 mol L-1 for Hg2+ and Pb2+, respectively. The limits of detection (LOD) were 2.0 × 10-9 mol L-1 and 4.0 × 10-9 mol L-1 for Hg2+ and Pb2, respectively. The prepared optical membrane was successfully applied to the determination of Hg2+ and Pb2+ in industrial wastes, spiked tap water and natural waters without any preconcentration step.

Interactions of Hg(ii) with oligonucleotides having thymine-thymine mispairs. Optimization of an impedimetric Hg(ii) sensor.

Science.gov (United States)

Kamal, Ajar; She, Zhe; Sharma, Renu; Kraatz, Heinz-Bernhard

2017-05-21

The present work describes the effect of the number of thymine-thymine mispairs in single strand DNA probes on Hg(ii) interactions and further to develop a highly sensitive DNA based impedimetric sensor for Hg(ii) detection. To achieve this goal, the influence of the number of T-T mispairs on the signal response prompted by DNA-Hg(ii) binding interactions was examined on three designed DNA probes: 5'-OH-(CH 2 ) 6 -S-S-(CH 2 ) 6 -AGTCCACACGTTCCTTACGC-3', 5'-OH-(CH 2 ) 6 -S-S-(CH 2 ) 6 -AGTCCACATTTTCCTTTTGC-3', 5'-OH-(CH 2 ) 6 -S-S-(CH 2 ) 6 -AGTCCATTTTTTCCTTTTTT-3' having 2T-T, 4T-T and 6T-T mispairs with identical length, respectively. This study revealed that the number of T-T mispairs plays a critical role in maximizing the signal intensity of DNA-Hg(ii) binding interactions. Based on these results, DNA comprising maximum number of T-T mispairs was further utilized for construction of the Hg(ii) sensor, which exhibited a linear correlation between the change in charge transfer resistance (ΔR CT ) and the concentration of Hg(ii) over the range of 1.0 × 10 -5 M to 1.0 × 10 -10 M with a lower detection limit of 3.2 × 10 -11 M. The selectivity was tested against 12 different metal ions including Hg(ii). The ΔR CT response from Hg(ii) is 3 times higher than the nearest competitor Pb(ii) and approximately 10 times than other ions. The potential application of such a robust and label-free DNA sensor was demonstrated by analyzing environmental samples collected from Lake Ontario.

Binding of Hg by bacterial extracellular polysaccharide: a possible role in Hg tolerance.

Science.gov (United States)

Cruz, Kimberly; Guézennec, Jean; Barkay, Tamar

2017-07-01

Bacteria employ adaptive mechanisms of mercury (Hg) tolerance to survive in environments containing elevated Hg concentrations. The potential of extracellular polysaccharides (EPS) production by bacteria as a mechanism of Hg tolerance has not been previously investigated. The objectives of this study were to determine if bacterial EPS sorb Hg, and if so does sorption provide protection against Hg toxicity. Purified EPS with different chemical compositions produced by bacterial isolates from microbial mats in French Polynesian atolls and deep-sea hydrothermal vents were assessed for Hg sorption. The data showed that EPS sorbed up to 82% of Hg from solution, that this sorption was dependent on EPS composition, and that sorption was a saturable mechanism. Hg uptake capacities ranged from 0.005 to 0.454 mmol Hg/g for the different EPS. To determine if EPS production could alter bacterial Hg tolerance, Escherichia coli K-12 strains and their EPS defective mutants were tested by the disc inhibition assay. Mercury inhibited growth in a dose-dependent manner with wild-type strains having smaller (~1 mm), but statistically significant, zones of inhibition than various mutants and this difference was related to a 2-fold decline in the amount of EPS produced by the mutants relative to cell biomass. These experiments identified colanic acid and hexosamine as Hg-binding moieties in EPS. Together these data indicate that binding of Hg to EPS affords a low level of resistance to the producing bacteria.

Identification of contamination in a lake sediment core using Hg and Pb isotopic compositions, Lake Ballinger, Washington, USA

International Nuclear Information System (INIS)

Gray, John E.; Pribil, Michael J.; Van Metre, Peter C.; Borrok, David M.; Thapalia, Anita

2013-01-01

Highlights: ► Hg and Pb concentration and isotopic compositions traced anthropogenic sources. ► Concentrations and metal loadings of Hg and Pb increased during the smelting period. ► Hg isotopic compositions changed during smelting compared to the pre-smelting period. ► Data indicate mass independent fractionation of Hg isotopes. - Abstract: Concentrations and isotopic compositions of Hg and Pb were measured in a sediment core collected from Lake Ballinger, near Seattle, Washington, USA. Lake Ballinger has been affected by input of metal contaminants emitted from the Tacoma smelter, which operated from 1887 to 1986 and was located about 53 km south of the lake. Concentrations and loadings of Hg and Pb in Lake Ballinger increased by as much as three orders of magnitude during the period of smelting as compared to the pre-smelting period. Concentrations and loadings of Hg and Pb then decreased by about 55% and 75%, respectively, after smelting ended. Isotopic compositions of Hg changed considerably during the period of smelting (δ 202 Hg = −2.29‰ to −0.38‰, mean −1.23‰, n = 9) compared to the pre-smelting period (δ 202 Hg = −2.91‰ to −2.50‰, mean −2.75‰, n = 4). Variations were also observed in 206 Pb/ 207 Pb and 208 Pb/ 207 Pb isotopic compositions during these periods. Data for Δ 199 Hg and Δ 201 Hg indicate mass independent fractionation (MIF) of Hg isotopes in Lake Ballinger sediment during the smelting and post-smelting period and suggest MIF in the ore smelted, during the smelting process, or chemical modification at some point in the past. Negative values for Δ 199 Hg and Δ 201 Hg for the pre-smelting period are similar to those previously reported for soil, peat, and lichen, likely suggesting some component of atmospheric Hg. Variations in the concentrations and isotopic compositions of Hg and Pb were useful in tracing contaminant sources and the understanding of the depositional history of sedimentation in Lake Ballinger

Silver ion modulated CdS quantum dots for highly selective detection of trace Hg{sup 2+}

Energy Technology Data Exchange (ETDEWEB)

Uppa, Yuwapon; Kulchat, Sirinan; Ngamdee, Kessarin; Pradublai, Kaewklao [Materials Chemistry Research Unit, Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Tuntulani, Thawatchai [Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Ngeontae, Wittaya, E-mail: wittayange@kku.ac.th [Materials Chemistry Research Unit, Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Research Center for Environmental and Hazardous Substance Management, Khon Kaen University, Khon Kaen 40002 (Thailand); Center of Excellence for Environmental and Hazardous Waste Management (EHWM), Bangkok 10330 (Thailand)

2016-10-15

In the present work, water-soluble cysteamine capped-CdS quantum dots (Cys-CdS QDs) modulated with Ag{sup +} were employed as fluorescence sensors for the determination of Hg{sup 2+} ion. The synthesized Cys-CdS QDs exhibit relatively weak fluorescence emission, however, the emission was enhanced exclusively in the presence of Ag{sup +} compared to other metal ions. Moreover, the fluorescence intensity of the Ag{sup +} modulated Cys-CdS QDs (Ag{sup +}@Cys-CdS QDs) was significantly quenched in the presence of trace amounts of Hg{sup 2+} due to high-affinity metallophilic interactions between Hg{sup 2+} and Ag{sup +}. Based on this specific interaction, good selectivity towards the detection of Hg{sup 2+} over other metal ions was achieved. To gain the best sensing performance, parameters affecting the Hg{sup 2+} detection sensitivity were studied and optimized in detail. Under the optimized conditions, the fluorescence intensity of Ag{sup +}@Cys-CdS QDs decreased linearly with Hg{sup 2+} concentration in the range of 0.1–3.5 μM, with a limit of detection of around 0.09 μM. The applicability of this sensor was demonstrated by the determination of Hg{sup 2+} in drinking water samples, corresponding well with results of cold-vapor atomic absorption spectrometry.

Novel methodology for the study of mercury methylation and reduction in sediments and water using {sup 197}Hg radiotracer

Energy Technology Data Exchange (ETDEWEB)

Ribeiro Guevara, Sergio; Perez Catan, Soledad [Centro Atomico Bariloche, Laboratorio de Analisis por Activacion Neutronica, Bariloche (Argentina); Zizek, Suzana; Repinc, Urska; Jacimovic, Radojko; Horvat, Milena [Jozef Stefan Institute, Department of Environmental Sciences, Ljubljana (Slovenia)

2007-03-15

Mercury tracers are powerful tools that can be used to study mercury transformations in environmental systems, particularly mercury methylation, demethylation and reduction in sediments and water. However, mercury transformation studies using tracers can be subject to error, especially when used to assess methylation potential. The organic mercury extracted can be as low as 0.01% of the endogenous labeled mercury, and artefacts and contamination present during methylmercury (MeHg) extraction processes can cause interference. Solvent extraction methods based on the use of either KBr/H{sub 2}SO{sub 4} or HCl were evaluated in freshwater sediments using {sup 197}Hg radiotracer. Values obtained for the {sup 197}Hg tracer in the organic phase were up to 25-fold higher when HCl was used, which is due to the coextraction of {sup 197}Hg{sup 2+} into the organic phase during MeHg extraction. Evaluations of the production of MeHg gave similar results with both MeHg extraction procedures, but due to the higher Hg{sup 2+} contamination of the controls, the uncertainty in the determination was higher when HCl was used. The Hg{sup 2+} contamination of controls in the HCl extraction method showed a nonlinear correlation with the humic acid content of sediment pore water. Therefore, use of the KBr/H{sub 2}SO{sub 4} method is recommended, since it is free from these interferences. {sup 197}Hg radiotracer (T{sub 1/2} = 2.673 d) has a production rate that is about 50 times higher than that of {sup 203}Hg (T{sub 1/2} = 46.595 d), the most frequently used mercury radiotracer. Hence it is possible to obtain a similar level of performance to {sup 203}Hg when it is used it in short-term experiments and produced by the irradiation of {sup 196}Hg with thermal neutrons, using mercury targets with the natural isotopic composition. However, if the 0.15% natural abundance of the {sup 196}Hg isotope is increased, the specific activity of the {sup 197}Hg tracer can be significantly improved. In

First principles study of elemental mercury (Hg{sup 0}) adsorption on low index CoMnO{sub 3} surfaces

Energy Technology Data Exchange (ETDEWEB)

Ji, Wenchao; Su, Pingru; Tang, Qingli; Cheng, Zhiwen [School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240 (China); Shen, Zhemin, E-mail: zmshen@sjtu.edu.cn [School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240 (China); Fan, Maohong [Department of Chemical and Petroleum Engineering, University of Wyoming, Laramie, Wyoming, 82071 (United States); School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia, 30332 (United States)

2017-06-30

Highlights: • Hg{sup 0} adsorption on low index CoMnO{sub 3} surface was predicted by DFT method. • Hg{sup 0} is adsorbed on the CoMnO{sub 3} surface with chemisorption interaction. • Hg{sup 0} has highest adsorption energy on CoMnO{sub 3} (1 0 0) surface with Hg-Mn mechanism. • The electron transfer of Hg{sup 0} has positive relationship with adsorption energy. - Abstract: The density functional theory (DFT) is applied to predict elemental mercury (Hg{sup 0}) adsorption on CoMnO{sub 3} surface for the first time. GGA/PBE functional were selected to determine the potential Hg{sup 0} capture mechanisms. The results show that Hg{sup 0} has good affinity with CoMnO{sub 3} surfaces with chemical adsorption. The adsorption energy of Hg{sup 0}-CoMnO{sub 3} (1 0 0), Hg{sup 0}-CoMnO{sub 3} (1 0 1) and Hg{sup 0}-CoMnO{sub 3} (1 1 0) are −85.225, −72.305 and −70.729 kJ/mol, respectively. The Hg-Mn and Hg-Co mechanisms were revealed on low index surfaces. Hg{sup 0} was oxidized to its valence state of 0.236 on Mn site in CoMnO{sub 3} (1 0 0) surface. The Hg-Co interaction mechanism occurred on Hg{sup 0}-CoMnO{sub 3} (1 0 1) and Hg{sup 0}-CoMnO{sub 3} (1 1 0) with 0.209e{sup −} and 0.189e{sup −} transformation, respectively. The PDOS analysis shows that Hg-Mn interaction depends on the hybridization of Hg(s- and d-orbitals) and Mn (s-, p- and d- orbitals). However, Hg-Co interaction stems from s- and d- orbitals of Hg, which only overlapping with d- and p- orbital of Co. Both the adsorption energy and electronic structure analysis indicated that CoMnO{sub 3} catalyst performed excellent in Hg{sup 0} oxidation. Exposing CoMnO{sub 3} (1 0 0) is most favorable in Hg{sup 0} control, which provides theoretical instruction on certain crystal plane synthesis in experiment.

Off-on fluorescent sensor based on the bis(2,4,7,8,9-pentamethyldipyrrolylmethene-3-yl)methane for detection of Cd{sup 2+} and Hg{sup 2+} cations

Energy Technology Data Exchange (ETDEWEB)

Bumagina, Natalia A., E-mail: nad@isc-ras.ru [G.A. Krestov Institute of Solution Chemistry of Russian Academy of Sciences (ISC RAS), 1 Akademicheskaya St., 153045 Ivanovo (Russian Federation); Antina, Elena V., E-mail: eva@isc-ras.ru [G.A. Krestov Institute of Solution Chemistry of Russian Academy of Sciences (ISC RAS), 1 Akademicheskaya St., 153045 Ivanovo (Russian Federation); Sozonov, Dmitry I., E-mail: super_dk@mail.ru [Ivanovo State University of Chemistry and Technology (ISUCT), 7 Sheremetevskij Prosp., 153000 Ivanovo (Russian Federation)

2017-03-15

The off-on fluorescent chemosensor based on the bis(2,4,7,8,9-pentamethyldipyrrolylmethene-3-yl)methane for detection of Cd{sup 2+} and Hg{sup 2+} ions was obtained and its metal ion sensing properties were investigated. The bis(dipyrrin) exhibited remarkably fluorescence enhancement (150- and 40-fold) to Cd{sup 2+} and Hg{sup 2+} ions, respectively, with significant color change on the background of other metal ions in propanol-1/cyclohexane (1:30) binary mixture. Consequently, it can be used as a “naked eye” indicator with an obvious color change from yellow-orange to orange-green color upon the addition of Cd{sup 2+} and Hg{sup 2+}. The fluorescent response mechanism of bis(dipyrrin) to Cd{sup 2+} and Hg{sup 2+} was based on the fluorescence enhancement effect upon complexation (CHEF) due to formation of a metal–ligand (2:2) complex [M{sub 2}L{sub 2}]. The detection limit of Cd{sup 2+} and Hg{sup 2+} ions was 2 × 10{sup –9} and 1.7 × 10{sup –8} M ions, respectively.

Turn-on fluorescent chemosensor for Hg2+ based on multivalent rhodamine ligands

NARCIS (Netherlands)

Wang, X.; Iqbal, M.; Huskens, Jurriaan; Verboom, Willem

2012-01-01

Rhodamine-based fluorescent chemosensors 1 and 2 exhibit selective fluorescence enhancement to Fe3+ and Hg2+ over other metal ions at 580 nm in CH3CN/H2O (3/1, v/v) solution. Bis(rhodamine) chemosensor 1, under optimized conditions (CH3CN/HEPES buffer (0.02 M, pH = 7.0) (95/5, v/v)), shows a high

Electronic structure and optical properties of Cs2HgCl4: DFT calculations and X-ray photoelectron spectroscopy measurements

Science.gov (United States)

Lavrentyev, A. A.; Gabrelian, B. V.; Vu, V. T.; Parasyuk, O. V.; Fedorchuk, A. O.; Khyzhun, O. Y.

2016-10-01

A high-quality single crystal of cesium mercury tetrabromide, Cs2HgCl4, was synthesized by using the vertical Bridgman-Stockbarger method and its electronic structure was studied from both experimental and theoretical viewpoints. In particular, X-ray photoelectron spectra were measured for both pristine and Ar+ ion-bombarded Cs2HgCl4 single crystal surfaces. The present XPS measurements indicate that the Cs2HgCl4 single crystal surface is sensitive with respect to Ar+ ion-bombardment: such a treatment changes substantially its elemental stoichiometry. With the aim of exploring total and partial densities of states within the valence band and conduction band regions of the Cs2HgCl4 compound, band-structure calculations based on density functional theory (DFT) using the augmented plane wave + local orbitals (APW + lo) method as incorporated within the WIEN2k package are performed. The calculations indicate that the Cl 3p states are the principal contributors in the upper portion of the valence band, while the Hg 5d and Cs 5p states dominate in its lower portion. In addition, the calculations allow for concluding that the unoccupied Cl p and Hg s states are the main contributors to the bottom of the conduction band. Furthermore, main optical characteristics of Cs2HgCl4, namely dispersion of the absorption coefficient, real and imaginary parts of dielectric function, electron energy-loss spectrum, refractive index, extinction coefficient and optical reflectivity, are elucidated based on the DFT calculations.

Ab initio study of structural, electronic and optical properties of MnHg(SCN)4 and FeHg(SCN)4

International Nuclear Information System (INIS)

He, K.H.; Zheng, G.; Chen, G.; Lue, T.; Wan, M.; Ji, G.F.

2007-01-01

The structural, electronic and optical properties of MnHg(SCN) 4 and FeHg(SCN) 4 were studied by means of quantum-mechanical calculations based on the density-functional theory and pseudopotential method. The lattice constants can be compared with the experimental values when the effects of temperature are considered. The peaks of partial density of states of S, C, N and Hg of FeHg(SCN) 4 have a tendency of shifting to the higher energy levels relative to those of MnHg(SCN) 4 . The distributions of the 3d electronic states in the transition metal atoms show quite large difference and decide different optical properties. We found that absorptional peaks of FeHg(SCN) 4 lag behind those of MnHg(SCN) 4 and the peak in the infrared range has a higher absorptional intensity, which are in accord with the experimental results. By analyzing the distributions and transitions of the 3d electronic states, we explained the different absorption phenomena

Giant Tc shift in HgBa2CaCu2O6+δ and TlBa2CaCu2O7-δ superconductors due to Hg-Tl exchange

International Nuclear Information System (INIS)

Gapud, A.A.; Wu, J.Z.; Kang, B.W.; Yan, S.L.; Xie, Y.Y.; Siegal, M.P.

1999-01-01

The irreversibility lines of epitaxial thin films of HgBa 2 CaCu 2 O 6+δ and TlBa 2 CaCu 2 O 7-δ , whether deduced from field-induced magnetoresistive broadening or onset of nonhysteretic magnetization, were found to coincide when plotted against reduced temperature, showing the same exponential-decay temperature behavior for T/T c c >0.8 (where T c is zero-field, zero-resistivity critical temperature). These results indicate that replacing Tl with Hg has no noticeable effect on the anisotropy and suggests that T c is not determined by anisotropy. copyright 1999 The American Physical Society

Structural and Transition Temperature of HgPbxBa2Ca2Cu3O8+δ Superconductor

International Nuclear Information System (INIS)

Hermiz, G.Y.; Abbass, M.M.

2005-01-01

Solid state reaction technique (SSR) was used to prepare high-T c phase in HgPb x Ba 2 Ca 2 Cu 3 O 8+δ superconductors. The effect of additional Pb to HgBa 2 Ca 2 Cu 3 O 8+δ was investigated. It has been found that the maximum transition temperature T c =133K is at x=0.1.X-ray diffraction showed a tetragonal structure with an average value of e=15.816 A . The average value of the valence of copper (v) is equal to 2.025. There is an increasing of density with the enhancement of the concentration of Pb 2

Immobilization of aqueous Hg(II) by mackinawite (FeS)

International Nuclear Information System (INIS)

Liu Jianrong; Valsaraj, Kalliat T.; Devai, Istvan; DeLaune, R.D.

2008-01-01

As one of the major constituents of acid volatile sulfide (AVS) in anoxic sediments, mackinawite (FeS) is known for its ability to scavenge trace metals. The interaction between aqueous Hg(II) (added as HgCl 2 ) and synthetic FeS was studied via batch sorption experiments conducted under anaerobic conditions. Due to the release of H + during formation of hydrolyzed Hg(II) species which is more reactive than Hg 2+ in surface adsorption, the equilibrium pH decreased with the increase in Hg(II)/FeS molar ratio. Counteracting the loss of FeS solids at lower pH, the maximum capacity for FeS to remove aqueous Hg(II) was approximately 0.75 mol Hg(II) (mol FeS) -1 . The comparison of X-ray power diffraction (XRPD) patterns of synthetic FeS sorbent before and after sorption showed that the major products formed from the interaction between FeS and the aqueous Hg(II) were metacinnabar, cinnabar, and mercury iron sulfides. With the addition of FeS at 0.4 g L -1 to a 1 mM Hg(II) solution with an initial pH of 5.6, Fe 2+ release was approximately 0.77 mol Fe 2+ per mol Hg(II) removed, suggesting that 77% of Hg(II) was removed via precipitation reaction under these conditions, with 23% of Hg(II) removed by adsorption. Aeration does not cause significant release of Hg(II) into the water phase

Structural and elastic properties of defect chalcopyrite HgGa{sub 2}S{sub 4} under high pressure

Energy Technology Data Exchange (ETDEWEB)

Gomis, O., E-mail: osgohi@fis.upv.es [Centro de Tecnologías Físicas: Acústica, Materiales y Astrofísica, MALTA Consolider Team, Universitat Politècnica de València, 46022 València (Spain); Santamaría-Pérez, D. [Departamento de Física Aplicada-ICMUV, MALTA Consolider Team, Universitat de València, Edificio de Investigación, C/Dr. Moliner 50, Burjassot, 46100 València (Spain); Departamento de Química Física I, Universidad Complutense de Madrid, MALTA Consolider Team, Avenida Complutense s/n, 28040 Madrid (Spain); Vilaplana, R.; Luna, R. [Centro de Tecnologías Físicas: Acústica, Materiales y Astrofísica, MALTA Consolider Team, Universitat Politècnica de València, 46022 València (Spain); Sans, J.A.; Manjón, F.J. [Instituto de Diseño para la Fabricación y Producción Automatizada, MALTA Consolider Team, Universitat Politècnica de València, 46022 València (Spain); Errandonea, D. [Departamento de Física Aplicada-ICMUV, MALTA Consolider Team, Universitat de València, Edificio de Investigación, C/Dr. Moliner 50, Burjassot, 46100 València (Spain); and others

2014-01-15

Highlights: • Single crystals of HgGa{sub 2}S{sub 4} with defect-chalcopyrite (DC) structure were synthesized. • High-pressure X-ray diffraction in DC-HgGa{sub 2}S{sub 4} was performed. • Equation of state of DC-HgGa{sub 2}S{sub 4} determined (bulk modulus of 48.4 GPa). • Calculated elastic constants of DC-HgGa{sub 2}S{sub 4} reported at different pressures. • DC-HgGa{sub 2}S{sub 4} becomes mechanically unstable above 13.8 GPa. -- Abstract: In this work, we focus on the study of the structural and elastic properties of mercury digallium sulfide (HgGa{sub 2}S{sub 4}) at high pressures. This compound belongs to the family of AB{sub 2}X{sub 4} ordered-vacancy compounds and exhibits a tetragonal defect chalcopyrite structure. X-ray diffraction measurements at room temperature have been performed under compression up to 15.1 GPa in a diamond anvil cell. Our measurements have been complemented and compared with ab initio total energy calculations. The axial compressibility and the equation of state of the low-pressure phase of HgGa{sub 2}S{sub 4} have been experimentally and theoretically determined and compared to other related ordered-vacancy compounds. The pressure dependence of the theoretical cation–anion and vacancy-anion distances and compressibilities in HgGa{sub 2}S{sub 4} are reported and discussed in comparison to other related ordered-vacancy compounds. Finally, the pressure dependence of the theoretical elastic constants and elastic moduli of HgGa{sub 2}S{sub 4} has been studied. Our calculations indicate that the low-pressure phase of HgGa{sub 2}S{sub 4} becomes mechanically unstable above 13.8 GPa.

Binding Affinity of a Highly Sensitive Au/Ag/Au/Chitosan-Graphene Oxide Sensor Based on Direct Detection of Pb2+ and Hg2+ Ions

Directory of Open Access Journals (Sweden)

Nur Hasiba Kamaruddin

2017-10-01

Full Text Available The study of binding affinity is essential in surface plasmon resonance (SPR sensing because it allows researchers to quantify the affinity between the analyte and immobilised ligands of an SPR sensor. In this study, we demonstrate the derivation of the binding affinity constant, K, for Pb2+ and Hg2+ ions according to their SPR response using a gold/silver/gold/chitosan–graphene oxide (Au/Ag/Au/CS–GO sensor for the concentration range of 0.1–5 ppm. The higher affinity of Pb2+ to binding with the CS–GO sensor explains the outstanding sensitivity of 2.05 °ppm−1 against 1.66 °ppm−1 of Hg2+. The maximum signal-to-noise ratio (SNR upon detection of Pb2+ is 1.53, and exceeds the suggested logical criterion of an SNR. The Au/Ag/Au/CS–GO SPR sensor also exhibits excellent repeatability in Pb2+ due to the strong bond between its functional groups and this cation. The adsorption data of Pb2+ and Hg2+ on the CS–GO sensor fits well with the Langmuir isotherm model where the affinity constant, K, of Pb2+ and Hg2+ ions is computed. The affinity of Pb2+ ions to the Au/Ag/Au/CS–GO sensor is significantly higher than that of Hg2+ based on the value of K, 7 × 105 M−1 and 4 × 105 M−1, respectively. The higher shift in SPR angles due to Pb2+ and Hg2+ compared to Cr3+, Cu2+ and Zn2+ ions also reveals the greater affinity of the CS–GO SPR sensor to them, thus supporting the rationale for obtaining K for these two heavy metals. This study provides a better understanding on the sensing performance of such sensors in detecting heavy metal ions.

Folic acid functionalized silver nanoparticles with sensitivity and selectivity colorimetric and fluorescent detection for Hg2+ and efficient catalysis.

Science.gov (United States)

Su, Dongyue; Yang, Xin; Xia, Qingdong; Zhang, Qi; Chai, Fang; Wang, Chungang; Qu, Fengyu

2014-09-05

In this research, folic acid functionalized silver nanoparticles (FA-AgNPs) were selected as a colorimetric and a 'turn on' fluorescent sensor for detecting Hg(2+). After being added into Hg(2+), AgNPs can emit stable fluorescence at 440 nm when the excitation wavelength is selected at 275 nm. The absorbance and fluorescence of the FA-AgNPs could reflect the concentration of the Hg(2+) ions. Thus, we developed a simple, sensitive analytical method to detect Hg(2+) based on the colorimetric and fluorescence enhancement of FA-AgNPs. The sensor exhibits two linear response ranges between absorbance and fluorescence intensity with Hg(2+) concentration, respectively. Meanwhile, a detection limit of 1 nM is estimated based on the linear relationship between responses with a concentration of Hg(2+). The high specificity of Hg(2+) with FA-AgNPs interactions provided the excellent selectivity towards detecting Hg(2+) over other metal ions (Pb(2+), Mg(2+), Zn(2+), Ni(2+), Cu(2+), Co(2+), Ca(2+), Mn(2+), Fe(2+), Cd(2+), Ba(2+), Cr(6+) and Cr(3+)). This will provide a simple, effective and multifunctional colorimetric and fluorescent sensor for on-site and real-time Hg(2+) ion detection. The proposed method can be applied to the analysis of trace Hg(2+) in lake water. Additionally, the FA-AgNPs can be used as efficient catalyst for the reduction of 4-nitrophenol and potassium hexacyanoferrate (III).

3,9-Dithia-6-azaundecane-appended Iridium (III) Complex for the Selective Detection of Hg2+ in Aqueous Acetonitrile

International Nuclear Information System (INIS)

Ann, Jee Hye; Li, Yinan; Hyun, Myung Ho

2012-01-01

Detection of mercuric ion (Hg 2+ ) originated from natural or industrial sources is very important because it is extremely toxic even at low levels and causes serious environmental and health problems. Consequently, many efforts have been devoted to the development of sensitive chemosensors for the detection of Hg 2+ . For example, various fluorescent chemosensors based on rhodamine, nitrobenzoxadiazole, fluorescein, boradiazaindacene (BODIPY), dansyl, pyrene, or other fluorophores have been developed for the selective detection of Hg 2+ . While various fluorescent chemosensors for the selective detection of Hg 2+ have been developed, phosphorescent chemosensors for the selective detection of Hg 2+ are relatively rare. Among various phosphors, iridium (III) complexes with sulfur containing cyclometalated ligands have been used as phosphorescent chemosensors for the selective detection of Hg 2+ . Azacrown ether-appended iridium (III) complex developed in our laboratory has also been utilized as a phosphorescent chemosensor for the selective detection of Hg 2+ . As an another iridium (III) complex-based phosphorescent chemosensors for the selective detection of Hg 2+ , in this study, we wish to prepare iridium (III) complex containing two 3,9-dithia-6-azaundecane units as chelating ligands for metal ions. Some fluorophores containing 3,9-dithia-6-azaundecane unit have been successfully applied for the selective detection of Hg 2+ . In this instance, iridium (III) complex containing two 3,9-dithia-6-azaundecane units is expected to be useful as a phosphorescent chemosensor for the selective detection of Hg 2+ . Iridium (III) complex containing two 3,9-dithia-6-azaundecane units was prepared starting from 2-phenylpyridine according to the procedure shown in Scheme 1. 2-Phenylpyridine was transformed into chloride bridged dimeric iridium complex, [(ppy) 2 IrCl] 2 , via the reported procedure. By treating [(ppy) 2 IrCl] 2 with 4,4'-bis(bromomethyl)-2,2'-bipyridine, which

Use of HgI2 as gamma radiation detector

International Nuclear Information System (INIS)

Perez Morales, J.M.

1993-01-01

The Mercuric Iodide (HgI 2 ) has become one of the most promising room temperature semiconductors for the construction of X and gamma radiation detectors. The classical methods of spectroscopy have not demonstrated to achieve optimum results with HgI 2 detectors, mainly due to its particular carrier transport properties. Several alternative spectroscopic methods developed in the last ten years are presented and commented, selecting for a complete study one of them: 'The Partial Charge Collection Method'. The transport properties of the carriers generated by the radiation in the detector is specially important for understanding the spectroscopic behaviour of the HgI 2 detectors. For a rigorous characterization of this transport, it has been studied a digital technique for the analysis of the electric pulses produced by the radiation. Theoretically, it has been developed a Monte Carlo simulation of the radiation detection and the electronic signal treatment processes with these detectors in the energy range of 60-1300 KeV. These codes are applied to the study of the The Partial Charge Collection Method and its comparison with gaussian methods. Experimentally, this digital techniques is used for the study of the transport properties of thin HgI 2 detectors. Special interest is given to the contribution of the slower carriers, the holes, obtaining some consequent of spectroscopic interest. Finally, it is presented the results obtained with the first detectors grown and mounted in CIEMAT with own technology. (author). 129 ref

Selective sensing of two novel coordination polymers based on tris(4-carboxylphenyl)phosphine oxide for organic molecules and Fe3+ and Hg2+ ions

Science.gov (United States)

Huo, Liangqin; Zhang, Jie; Gao, Lingling; Wang, Xiaoqing; Fan, Liming; Fang, Kegong; Hu, Tuoping

2017-12-01

Two novel coordination polymers, formulated as {[Zn(HTPO)(bib)]·4H2O}n (1), {[Cu3(TPO)2 (bib)3]·2DMF·0.5EtOH·0.5H2O}n (2) (H3TPO = tris(4-carboxylphenyl)phosphine oxide; bib = 1,4-bis(1H-imidazol-4-yl) benzene), have been synthesized under solvothermal method and characterized by single-crystal X-ray diffraction, elemental analysis (EA), IR spectra, thermogravimetric (TG) analysis, powder X-ray diffraction (PXRD). Structural analysis reveals that complex 1 is a 2D 4-connected sheet with an intriguing 2D + 2D→2D network. Complex 2 displays a 3D 3,4-connected net with the point symbol of {103}2{106}3. Furthermore, the photoluminescence properties of 1 and 2 were investigated in the solid state and various solvent emulsions, the results show that 1 and 2 have better fluorescent recognition for organic molecules, Fe3+ and Hg2+ ions.

A New Trapped Ion Clock Based on Hg-201(+)

Science.gov (United States)

Taghavi-Larigani, S.; Burt, E. A.; Lea, S. N.; Prestage, J. D.; Tjoelker, R. L.

2009-01-01

There are two stable odd isotopes of mercury with singly ionized hyperfine structure suitable for a microwave clock: Hg-199(+) and Hg-201(+). Virtually all trapped mercury ion clocks to date have used the 199 isotope. We have begun to investigate the viability of a trapped ion clock based on Hg-201(+). We have measured the unperturbed frequency of the (S-2)(sub 1/2) F = 1, m(sub F) = 0 to (S-2)(sub 1/2) F = 2, m(sub F) = 0 clock transition to be 29.9543658211(2) GHz. In this paper we describe initial measurements with Hg-201(+) and new applications to clocks and fundamental physics.

Organ-specific accumulation, transportation, and elimination of methylmercury and inorganic mercury in a low Hg accumulating fish.

Science.gov (United States)

Peng, Xiaoyan; Liu, Fengjie; Wang, Wen-Xiong

2016-08-01

Low mercury (Hg) concentrations down to several nanograms Hg per gram of wet tissue are documented in certain fish species such as herbivorous fish, and the underlying mechanisms remain speculative. In the present study, bioaccumulation and depuration patterns of inorganic Hg(II) and methylmercury (MeHg) in a herbivorous rabbitfish Siganus canaliculatus were investigated at organ and subcellular levels following waterborne or dietary exposures. The results showed that the efflux rate constants of Hg(II) and MeHg were 0.104 d(-1) and 0.024 d(-1) , respectively, and are probably the highest rate constants recorded in fish thus far. The dietary MeHg assimilation efficiency (68%) was much lower than those in other fish species (∼90%). The predominant distribution of MeHg in fish muscle was attributable to negligible elimination of MeHg from muscle (Hg(II) was much more slowly distributed into muscle but was efficiently eliminated by the intestine (0.13 d(-1) ). Subcellular distribution indicated that some specific membrane proteins in muscle were the primary binding pools for MeHg, and both metallothionein-like proteins and Hg-rich granules were the important components in eliminating both MeHg and Hg(II). Overall, the present study's results suggest that the low tissue Hg concentration in the rabbitfish was partly explained by its unique biokinetics. Environ Toxicol Chem 2016;35:2074-2083. © 2016 SETAC. © 2016 SETAC.

Pathways of CH3Hg and Hg ingestion in benthic organisms: an enriched isotope approach.

Science.gov (United States)

Taylor, Vivien F; Bugge, Deenie; Jackson, Brian P; Chen, Celia Y

2014-05-06

Mercury is a widespread contaminant in marine food webs, and identifying uptake pathways of mercury species, CH3Hg(+) and Hg(2+), into low trophic level organisms is important to understanding its entry into marine food webs. Enriched stable isotope tracers were used to study benthic vs. pelagic pathways of CH3Hg(+) and Hg(2+) uptake via food to the infaunal estuarine amphipod, Leptocheirus plumulosus. Algal cells differentially labeled with isotopically enriched CH3Hg(+) or Hg(2+) were added simultaneously to the sediment and water column of microcosms, and Hg species were monitored in amphipods and in sediment and water compartments. Methylation of Hg(2+) occurred during the course of the experiment, enhancing the uptake of Hg(2+) spikes. Trophic transfer of Hg from algae added to the water column was determined to be the major uptake route for amphipods, suggesting inputs of contaminated organic matter from the pelagic zone are important to mercury bioaccumulation even in organisms living in sediments.

HgI2 nanostructures obtained hydrothermally for application in ionizing radiation detection

International Nuclear Information System (INIS)

Pérez Barthaburu, María; Bentos Pereira, Heinkel; Fornaro, Laura; Galain, Isabel; Aguiar, Ivana

2016-01-01

The compound semiconductor HgI 2 has been widely studied and employed as a material for ionizing radiation detection. Monocrystal growth is an intricate method for obtaining materials for this application. With the aim of finding a simpler and more effective way to develop ionizing radiation detectors, we employed HgI 2 nanostructures subjected to a hydrothermal treatment and then pressed for this purpose. In the synthesis procedure, aqueous solutions of Hg(NO 3 ) 2 and NaI were mixed until their reaction completed and the suspension obtained was then placed in a homemade autoclave and heated at 120 °C for 2, 10 or 24 h. We confirmed the HgI 2 tetragonal phase by powder XRD in all cases, independently of the synthesis conditions employed. Nanoparticles were characterized by their size and morphology by TEM. We used the HgI 2 nanostructures to obtain a pellet by applying 0.7 GPa of pressure at room temperature. The pellet was then used to construct the detector, and we studied the electrical properties of the detector and its response to 241 Am sources of different exposure rates. The resistivity and signal-to-noise ratio obtained are of the order of those reported for HgI 2 detectors assembled with monocrystals. The results obtained in this work encourage us to work further on this topic, improving the method, scaling the detector’s size and studying its spectrometric grade. (paper)

Crystal structure and transport properties of Pd5HgSe

Czech Academy of Sciences Publication Activity Database

Laufek, F.; Vymazalová, A.; Drábek, M.; Navrátil, Jiří; Plecháček, T.; Drahokoupil, Jan

2012-01-01

Roč. 14, č. 10 (2012), s. 1476-1479 ISSN 1293-2558 R&D Projects: GA ČR GAP108/10/1315 Institutional support: RVO:61389013 ; RVO:68378271 Keywords : Pd5HgSe * Pd-Hg-Se system * crystal structure Subject RIV: CA - Inorganic Chemistry Impact factor: 1.671, year: 2012

Dielectric properties of nanophase Ag2HgI4 and Ag2HgI4–Al2O3 ...

Indian Academy of Sciences (India)

Unknown

ions (Leute and Rusche 1981). Many authors (Neubert ... The particles of Ag2HgI4 were separated from the suspen- sion, washed ... Capacitance (C) and dielectric loss (tan δ) were measured using a .... the energy of formation of lattice defects. Since the ... in fast-ion conductors is interpreted in terms of random hopping of ...

Internal conversion of the (13/2+→5/2-) isomeric transition in 199Hg

International Nuclear Information System (INIS)

Radha Krishna, K.; Chandrasekhar Rao, M.V.S.; Sree Krishna Murty, G.; Venkateswara Rao, N.; Bhuloka Reddy, S.; Satyanarayana, G.; Sastry, D.L.; Iyer, M.R.; Sahasrabhude, S.G.

1990-01-01

The total conversion coefficient of the M4 transition (374 KeV) in the decay of the 13/2 + isomeric state to 5/2 - state in 199 Hg measured using the relative gamma intensity method α T is determined to be 6.34 ± 0.29 in agreement with the theory due to Rosel et al. (author). 1 tab., 3 figs., 11 refs

Neutron production in bombardments of thin and thick W, Hg, Pb targets by 0.4, 0.8, 1.2, 1.8 and 2.5 GeV protons

International Nuclear Information System (INIS)

Letrourneau, A.; Galin, J.; Goldenbaum, F.; Lott, B.; Peghaire, A.; Enke, M.; Hilscher, D.; Jahnke, U.; Nuenighoff, K.; Filges, D.; Neef, R.D.; Paul, N.; Schaal, H.; Sterzenbach, G.; Tietze, A.

2000-05-01

Neutron experimental data relevant to the design of the target of neutron spallation sources are presented and discussed. The data include the reaction cross sections for W, Hg and Pb investigated with 0.4, 0.8, 1.2, 1.8 and 2.5 GeV proton beams as well as the neutron production, neutron multiplicity distribution, as determined event per event using a high efficiency detector. The production as a function of target material is investigated for both thin (with a single reaction) and thick targets (multiple reactions). Comparisons are made with the predictions of a high energy transport code. (authors)

46 CFR 53.10-3 - Inspection and tests (modifies HG-500 through HG-540).

Science.gov (United States)

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Inspection and tests (modifies HG-500 through HG-540... tests (modifies HG-500 through HG-540). (a) The inspections required by HG-500 through HG-540 must be performed by the “Authorized Inspector” as defined in HG-515 of section IV of the ASME Boiler and Pressure...

Improved fabrication of HgI2 nuclear radiation detectors by machine-cleaving

International Nuclear Information System (INIS)

Levi, A.; Burger, A.; Schieber, M.; Vandenberg, L.; Yellon, W.B.; Alkire, R.W.

1982-01-01

The perfection of machine-cleaved sections from HgI 2 bulk crystals was examined. The perfection of the machine-cleaved sections as established by gamma diffraction rocking curves was found to be much better than the perfection of hand-cleaved sections or as grown thin platelets, reaching a perfection similar to that of the wire-sawn sections of HgI 2 . A correlation between the perfection and the thickness of the machine-cleaved section was also found, i.e., the thicker the cleaved-section the more perfect it is. The reproducibility of the fabrication was significantly improved by using machine cleaving in the process of fabrication. Large single crystals of HgI 2 weighing 20 to 200 g, can be grown from the vapor phase using the TOM Technique. In order to fabricate nuclear radiation detectors from these single crystals, thin sections of about 0.4 to 0.8 mm thickness have to be prepared. Up till now, the state-of-the-art of fabricating HgI 2 nuclear radiation detectors involved two methods to get thin sections from the large single crystals: (1) hand-cleaving using a razor-blade and (2) solution wire sawing. The chemical wire sawing method involves a loss of about 50% of the crystal volume and is usually followed by a chemical polishing process which involves a significant loss of volume of the original volume. This procedure is complicated and wasteful. The traditional fabrication method, i.e., hand-cleaving followed by rapid nonselective chemical etching, is simpler and less wasteful

Absolute cross sections for emission of 284.7-nm (Hg II) and 479.7-nm (Hg III) radiation in electron--mercury-ion collisions

International Nuclear Information System (INIS)

Phaneuf, R.A.; Taylor, P.O.; Dunn, G.H.

1976-01-01

Crossed beams of electrons and Hg + ions have been used to measure absolute cross sections for emission of 284.7-nm radiation, resulting from excitation of a predominantly ground-state Hg + target to the 7s 2 S 1 / 2 state. Values range from 3 x 10 -17 cm 2 near threshold, where the cross section is strongly peaked, to 1.3 x 10 -18 cm 2 at 280 eV. Also reported are some measurements of emission of 479.7-nm (Hg III) radiation, resulting from electron impact on both Hg + and Hg ++ targets. Cross sections range from approximately 5 x 10 -19 to 5 x 10 -20 cm 2 , and in the case of electron-Hg ++ collisions, are more than an order of magnitude smaller than predicted by an available semiclassical binary-encounter calculation

A Turn-On Fluorescent Sensor for Hg2+ Based on Graphene Oxide

Directory of Open Access Journals (Sweden)

Yong Wu He

2017-01-01

Full Text Available A graphene oxide- (GO- boradiazaindacenes (BODIPY charge-transfer complex (BGO has been easily synthesized, and the structure of BGO was confirmed by FT-IR and atomic force microscopy (AFM. Moreover, the BGO was found that could be used as a turn-on fluorescent sensor for Hg2+. Upon addition of Hg2+, the fluorescence of BGO would be enhanced since the energy transfer between BODIPY and GO was inhibited. The selectivity and the competition performance of BGO towards Hg2+ were good among other heavy metal ions.

Treatment with a Small Molecule Mutant IDH1 Inhibitor Suppresses Tumorigenic Activity and Decreases Production of the Oncometabolite 2-Hydroxyglutarate in Human Chondrosarcoma Cells

Science.gov (United States)

Li, Luyuan; Paz, Ana C.; Wilky, Breelyn A.; Johnson, Britt; Galoian, Karina; Rosenberg, Andrew; Hu, Guozhi; Tinoco, Gabriel; Bodamer, Olaf; Trent, Jonathan C.

2015-01-01

Chondrosarcomas are malignant bone tumors that produce cartilaginous matrix. Mutations in isocitrate dehydrogenase enzymes (IDH1/2) were recently described in several cancers including chondrosarcomas. The IDH1 inhibitor AGI-5198 abrogates the ability of mutant IDH1 to produce the oncometabolite D-2 hydroxyglutarate (D-2HG) in gliomas. We sought to determine if treatment with AGI-5198 would similarly inhibit tumorigenic activity and D-2HG production in IDH1-mutant human chondrosarcoma cells. Two human chondrosarcoma cell lines, JJ012 and HT1080 with endogenous IDH1 mutations and a human chondrocyte cell line C28 with wild type IDH1 were employed in our study. Mutation analysis of IDH was performed by PCR-based DNA sequencing, and D-2HG was detected using tandem mass spectrometry. We confirmed that JJ012 and HT1080 harbor IDH1 R132G and R132C mutation, respectively, while C28 has no mutation. D-2HG was detectable in cell pellets and media of JJ012 and HT1080 cells, as well as plasma and urine from an IDH-mutant chondrosarcoma patient, which decreased after tumor resection. AGI-5198 treatment decreased D-2HG levels in JJ012 and HT1080 cells in a dose-dependent manner, and dramatically inhibited colony formation and migration, interrupted cell cycling, and induced apoptosis. In conclusion, our study demonstrates anti-tumor activity of a mutant IDH1 inhibitor in human chondrosarcoma cell lines, and suggests that D-2HG is a potential biomarker for IDH mutations in chondrosarcoma cells. Thus, clinical trials of mutant IDH inhibitors are warranted for patients with IDH-mutant chondrosarcomas. PMID:26368816

Treatment with a Small Molecule Mutant IDH1 Inhibitor Suppresses Tumorigenic Activity and Decreases Production of the Oncometabolite 2-Hydroxyglutarate in Human Chondrosarcoma Cells.

Directory of Open Access Journals (Sweden)

Luyuan Li

Full Text Available Chondrosarcomas are malignant bone tumors that produce cartilaginous matrix. Mutations in isocitrate dehydrogenase enzymes (IDH1/2 were recently described in several cancers including chondrosarcomas. The IDH1 inhibitor AGI-5198 abrogates the ability of mutant IDH1 to produce the oncometabolite D-2 hydroxyglutarate (D-2HG in gliomas. We sought to determine if treatment with AGI-5198 would similarly inhibit tumorigenic activity and D-2HG production in IDH1-mutant human chondrosarcoma cells. Two human chondrosarcoma cell lines, JJ012 and HT1080 with endogenous IDH1 mutations and a human chondrocyte cell line C28 with wild type IDH1 were employed in our study. Mutation analysis of IDH was performed by PCR-based DNA sequencing, and D-2HG was detected using tandem mass spectrometry. We confirmed that JJ012 and HT1080 harbor IDH1 R132G and R132C mutation, respectively, while C28 has no mutation. D-2HG was detectable in cell pellets and media of JJ012 and HT1080 cells, as well as plasma and urine from an IDH-mutant chondrosarcoma patient, which decreased after tumor resection. AGI-5198 treatment decreased D-2HG levels in JJ012 and HT1080 cells in a dose-dependent manner, and dramatically inhibited colony formation and migration, interrupted cell cycling, and induced apoptosis. In conclusion, our study demonstrates anti-tumor activity of a mutant IDH1 inhibitor in human chondrosarcoma cell lines, and suggests that D-2HG is a potential biomarker for IDH mutations in chondrosarcoma cells. Thus, clinical trials of mutant IDH inhibitors are warranted for patients with IDH-mutant chondrosarcomas.

Type conversion by high-energy particles in Hg1-xCdxTe compounds

International Nuclear Information System (INIS)

Blanchard, C.; Favre, J.; Barbot, J.F.; Desoyer, J.C.; Toulemonde, M.; Konczykowski, M.; Le Scoul, D.; Dessus, J.L.

1990-01-01

p-type crystals of the ternary compounds Hg 1-x Cd x Te have been irradiated with high-energy ions and electrons. Electron-beam-induced current signals on xenon- and krypton-irradiated Hg 1-x Cd x Te show that n-type conversion, occurring all along the ion path, is related to the presence of mercury atoms. Resistivity and Hall measurements on carbon-, oxygen-, xenon- and electron-irradiated Hg 0.8 Cd 0.2 Te crystals allow us to determine the effective cross section for atomic displacement. We observe, for electron-irradiated samples, a saturation in carrier concentration interpreted as the pinning of the Fermi level at a resonant donor state 370 meV above the bottom of the conduction band. Comparison between ion and electron irradiations shows that electrically active produced defects are mainly due to atomic collisions. Additional reduction of defect production efficiency for xenon ions may be the onset of some energy transfer from electronic loss to target atoms

GHRSST Level 4 Australian Bureau of Meteorology GAMSSA_28km Global SST:1

Data.gov (United States)

National Aeronautics and Space Administration — The GAMSSA v1.0 system blends NAVOCEANO's GAC 9.9 km x 4.4 km resolution AVHRR L2P SST1m data (NOAA-17, NOAA-18 and METOP-A), European Space Agency's 0.17 AATSR skin...

Hg-II/Ag-I-mediated base pairs and their NMR spectroscopic studies

Czech Academy of Sciences Publication Activity Database

Dairaku, T.; Furuita, K.; Sato, H.; Šebera, Jakub; Nakashima, K.; Ono, A.; Sychrovský, Vladimír; Kojima, C.; Tanaka, Y.

2016-01-01

Roč. 452, Oct 1 (2016), s. 34-42 ISSN 0020-1693 R&D Projects: GA ČR GAP205/10/0228 Institutional support: RVO:61388963 Keywords : NMR * Hg * Ag * metal-DNA Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.002, year: 2016

Cocaine Inhibits Dopamine D2 Receptor Signaling via Sigma-1-D2 Receptor Heteromers

Science.gov (United States)

Navarro, Gemma; Moreno, Estefania; Bonaventura, Jordi; Brugarolas, Marc; Farré, Daniel; Aguinaga, David; Mallol, Josefa; Cortés, Antoni; Casadó, Vicent; Lluís, Carmen; Ferre, Sergi

2013-01-01

Under normal conditions the brain maintains a delicate balance between inputs of reward seeking controlled by neurons containing the D1-like family of dopamine receptors and inputs of aversion coming from neurons containing the D2-like family of dopamine receptors. Cocaine is able to subvert these balanced inputs by altering the cell signaling of these two pathways such that D1 reward seeking pathway dominates. Here, we provide an explanation at the cellular and biochemical level how cocaine may achieve this. Exploring the effect of cocaine on dopamine D2 receptors function, we present evidence of σ1 receptor molecular and functional interaction with dopamine D2 receptors. Using biophysical, biochemical, and cell biology approaches, we discovered that D2 receptors (the long isoform of the D2 receptor) can complex with σ1 receptors, a result that is specific to D2 receptors, as D3 and D4 receptors did not form heteromers. We demonstrate that the σ1-D2 receptor heteromers consist of higher order oligomers, are found in mouse striatum and that cocaine, by binding to σ1 -D2 receptor heteromers, inhibits downstream signaling in both cultured cells and in mouse striatum. In contrast, in striatum from σ1 knockout animals these complexes are not found and this inhibition is not seen. Taken together, these data illuminate the mechanism by which the initial exposure to cocaine can inhibit signaling via D2 receptor containing neurons, destabilizing the delicate signaling balance influencing drug seeking that emanates from the D1 and D2 receptor containing neurons in the brain. PMID:23637801

46 CFR 53.05-2 - Relief valve requirements for hot water boilers (modifies HG-400.2).

Science.gov (United States)

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Relief valve requirements for hot water boilers (modifies HG-400.2). 53.05-2 Section 53.05-2 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... requirements for hot water boilers (modifies HG-400.2). (a) The relief valve requirements for hot water boilers...

Pulmonary scintigraphy using 197HgCl2 and pulmonary perfusion scintigraphy in bronchopulmonary diseases

International Nuclear Information System (INIS)

Fujii, Tadashige; Kanai, Hisakata; Handa, Kenjiro; Kusama, Shozo

1981-01-01

75 patients with pulmonary tuberculosis and 106 patients with bronchopulmonary diseases whose chest x-rays showed diffuse shadows were studied. Pulmonary scintigraphy using 197 HgCl 2 was useful for the diagnosis of the localization and the activity of pulmonary tuberculosis, because 197 HgCl 2 readily accumulated in the foci, and its accumulation rate was related to the activity of the foci. 197 HgCl 2 also accumulated markedly in foci of pneumoconiosis, especially, in areas showing large shadows and foci suspected to be tuberculosis. 197 HgCl 2 also accumulated in areas of chronic bronchitis, diffuse interstitial pneumonia and bronchiectasis. Its accumulation was considered to have a relation to the activity of inflammation. In primary pulmonary carcinoma, 197 HgCl 2 accumulated most markedly, in the primary lesions. 197 HgCl 2 also accumulated in metastatic or invasion areas of the hilus and the mediastinum. It accumulated in intrapulmonary metastatic foci of pulmonary carcinoma and multiple metastatic pulmonary tumors, but it was difficult to differentiate these diseases from other pulmonary diseases. In selected cases, it was useful to use pulmonary scintigraphy using 197 HgCl 2 together with pulmonary perfusion scintigraphy for the diagnosis of diffuse bronchopulmonary diseases. (Tsunoda, M.)

Arene-mercury complexes stabilized by gallium chloride: relative rates of H/D and arene exchange.

Science.gov (United States)

Branch, Catherine S; Barron, Andrew R

2002-11-27

We have previously proposed that the Hg(arene)(2)(GaCl(4))(2) catalyzed H/D exchange reaction of C(6)D(6) with arenes occurs via an electrophilic aromatic substitution reaction in which the coordinated arene protonates the C(6)D(6). To investigate this mechanism, the kinetics of the Hg(C(6)H(5)Me)(2)(GaCl(4))(2) catalyzed H/D exchange reaction of C(6)D(6) with naphthalene has been studied. Separate second-order rate constants were determined for the 1- and 2-positions on naphthalene; that is, the initial rate of H/D exchange = k(1i)[Hg][C-H(1)] + k(2i)[Hg][C-H(2)]. The ratio of k(1i)/k(2i) ranges from 11 to 2.5 over the temperature range studied, commensurate with the proposed electrophilic aromatic substitution reaction. Observation of the reactions over an extended time period shows that the rates change with time, until they again reach a new and constant second-order kinetics regime. The overall form of the rate equation is unchanged: final rate = k(1f)[Hg][C-H(1)] + k(2f)[Hg][C-H(2)]. This change in the H/D exchange is accompanied by ligand exchange between Hg(C(6)D(6))(2)(GaCl(4))(2) and naphthalene to give Hg(C(10)H(8))(2)(GaCl(4))(2,) that has been characterized by (13)C CPMAS NMR and UV-visible spectroscopy. The activation parameters for the ligand exchange may be determined and are indicative of a dissociative reaction and are consistent with our previously calculated bond dissociation for Hg(C(6)H(6))(2)(AlCl(4))(2). The initial Hg(arene)(2)(GaCl(4))(2) catalyzed reaction of naphthalene with C(6)D(6) involves the deuteration of naphthalene by coordinated C(6)D(6); however, as ligand exchange progresses, the pathway for H/D exchange changes to where the protonation of C(6)D(6) by coordinated naphthalene dominates. The site selectivity for the H/D exchange is initially due to the electrophilic aromatic substitution of naphthalene. As ligand exchange occurs, this selectivity is controlled by the activation of the naphthalene C-H bonds by mercury.

Integrated MSM-FET photoreceiver fabricated on MOCVD grown Hg2-xCdxTe

International Nuclear Information System (INIS)

Leech, P.W.; Gwynn, P.J.; Pain, G.N.; Petkovic, N.R.; Thompson, J.; Jamieson, D.N.

1991-01-01

This paper reports on progress in the monolithic integration of a metal-semiconductor-metal (MSM) detector and transimpedance amplifier and of a photoconductive detector (PCD) with a metal-semiconductor field effect transistor (MESFET) in Hg 1-x Cd x Te. The layers of CdTe/n-type Hg 1-x Cd x Te were grown by MOCVD on semi-insulating GaAs substrates (2 0 misoriented 100). Fabrication of the devices was by an FET planar process; with a standard lift-off used to form Schottky metallization on both the interdigitated electrodes of the MSM detector (2 μm width, 2 μm spacing) and the gate of the MESFETs (5μm length, 100μm width). The MSM photodetectors exhibited breakdown voltages in the range 60 to 80V, a dark current of 10na at 5V bias, and responsivities of >1.0 A/W measured at 40V using CW 1.3 μm illumination

Picomolar selective detection of mercuric ion (Hg{sup 2+}) using a functionalized single plasmonic gold nanoparticle

Energy Technology Data Exchange (ETDEWEB)

Song, Hyeon Don; Choi, Inhee; Yang, Young In; Hong, Surin; Lee, Suseung; Yi, Jongheop [School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul 151-742 (Korea, Republic of); Kang, Taewook, E-mail: xinly601@snu.ac.kr, E-mail: iniini79@snu.ac.kr, E-mail: netmo00@snu.ac.kr, E-mail: pell2004@snu.ac.kr, E-mail: jazz1863@snu.ac.kr, E-mail: twkang@sogang.ac.kr, E-mail: jyi@snu.ac.kr [Department of Chemical and Biomolecular Engineering, Sogang University, Seoul 121-742 (Korea, Republic of)

2010-04-09

A highly sensitive method for the selective detection and quantification of mercuric ions (Hg{sup 2+}) using single plasmonic gold nanoparticle (GNP)-based dark-field microspectroscopy (DFMS) is demonstrated. The method is based on the scattering property of a single GNP that is functionalized with thiolated molecules, which is altered when analytes bind to the functionalized GNP. The spectral resolution of the system is 0.26 nm and a linear response to Hg{sup 2+} was found in the dynamic range of 100 pM-10 {mu}M. The method permits Hg{sup 2+} to be detected at the picomolar level, which is a remarkable reduction in the detection limit, considering the currently proscribed Environmental Protection Agency regulation level (10 nM, or 2 ppb) and the detection limits of other optical methods for detecting Hg{sup 2+} (recently approx. 1-10 nM). In addition, Hg{sup 2+} can be sensitively detected in the presence of Cd{sup 2+}, Pb{sup 2+}, Cu{sup 2+}, Zn{sup 2+} and Ni{sup 2+}, which do not interfere with the analysis. Based on the findings reported herein, it is likely that single-nanoparticle-based metal ion sensing can be extended to the development of other chemo- and biosensors for the direct detection of specific targets in an intracellular environment as well as in environmental monitoring.

Effects of metals doping on the removal of Hg and H{sub 2}S over ceria

Energy Technology Data Exchange (ETDEWEB)

Ling, Lixia, E-mail: linglixia@tyut.edu.cn [College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, Shanxi (China); Zhao, Zhongbei; Zhao, Senpeng [College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, Shanxi (China); Wang, Qiang [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, Shanxi (China); Wang, Baojun, E-mail: wangbaojun@tyut.edu.cn [Key Laboratory of Coal Science and Technology (Taiyuan University of Technology), Ministry of Education and Shanxi Province, Taiyuan 030024, Shanxi (China); Zhang, Riguang [Key Laboratory of Coal Science and Technology (Taiyuan University of Technology), Ministry of Education and Shanxi Province, Taiyuan 030024, Shanxi (China); Li, Debao [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, Shanxi (China)

2017-05-01

Highlights: • Mn and Fe doped CeO{sub 2}(111) surfaces favor Hg capture via strong interaction. • HgS adsorbs on Mn and Fe/CeO{sub 2}(111) surfaces with molecule mode. • Hg is easily oxidized by the active S on Mn and Fe/CeO{sub 2}(111) surfaces. • Mn and Fe doped ceria have the potential to simultaneous remove Hg and H{sub 2}S. - Abstract: The effects of Mn and Fe doping into the CeO{sub 2}(111) surface on the simultaneous removal of Hg and H{sub 2}S was investigated, a density functional theory calculation with the on-site Coulomb interaction taken into account was adopted. The adsorptions of Hg-containing species on perfect CeO{sub 2}(111), Mn/CeO{sub 2}(111) and Fe/CeO{sub 2}(111) surfaces were studied, the results showed that Mn and Fe dopants facilitated Hg adsorption, and more charge transferred from Hg atom to the metal doped surfaces; HgS preferred to adsorb on the perfect surface with the dissociated mode, while with the molecular mode on Mn/CeO{sub 2}(111) and Fe/CeO{sub 2}(111) surfaces. The reaction mechanism show that the dissociated S by H{sub 2}S can easily react with Hg leading to the formation of HgS on Mn/CeO{sub 2}(111) and Fe/CeO{sub 2}(111) surfaces, which is crucial to capture mercury.

OMI/Aura and MODIS/Aqua Merged Cloud Product 1-Orbit L2 Swath 13x24 km V003

Data.gov (United States)

National Aeronautics and Space Administration — The OMI/Aura and MODIS/Aqua Merged Cloud Product 1-Orbit L2 Swath 13x24 km (OMMYDCLD) is a Level-2 orbital product that combines cloud parameters retrieved by the...

Rapid Annealing of Iron Implanted Hg(1-x)Cd(x)Te

Science.gov (United States)

1990-03-01

Alnrroveii rFoi’ PubikI Release; distributin tilIntl ted DTICELECTEJUN 12 IMU’ BEest Available Cop, D i ..:6 (J,•, 4iL& , AD Rapid Annealing of Ion...Recently, we have received from Or.J. Dinan of the Night Vision and Electro-optic Army Labs at Fort Belvoir a few electrically uncharacterized Hg

An exonuclease-assisted amplification electrochemical aptasensor for Hg(2+) detection based on hybridization chain reaction.

Science.gov (United States)

Bao, Ting; Wen, Wei; Zhang, Xiuhua; Xia, Qinghua; Wang, Shengfu

2015-08-15

In this work, a novel electrochemical aptasensor was developed for Hg(2+) detection based on exonuclease-assisted target recycling and hybridization chain reaction (HCR) dual signal amplification strategy. The presence of Hg(2+) induced the T-rich DNA partly folded into duplex-like structure via the Hg(2+) mediated T-Hg(2+)-T base pairs, which triggered the activity of exonuclease III (Exo III). Exo III selectively digested the double-strand DNA containing multiple T-Hg(2+)-T base pairs from its 3'-end, the released Hg(2+) participated analyte recycle. With each digestion cycle, a digestion product named as help DNA was obtained, which acted as a linkage between the capture DNA and auxiliary DNA. The presence of help DNA and two auxiliary DNA collectively facilitated successful HCR process and formed long double-stranded DNA. [Ru(NH3)6](3+) was used as redox indicator, which electrostatically bound to the double strands and produced an electrochemical signal. Exo III-assisted target recycling and HCR dual amplification significantly improved the sensitivity for Hg(2+) with a detection limit of 0.12 pM (S/N=3). Furthermore, the proposed aptasensor had a promising potential for the application of Hg(2+) detection in real aquatic sample analysis. Copyright © 2015 Elsevier B.V. All rights reserved.

Excitation functions for 197Au (d, p)198Au, 197Au(d, 2n)197mHg, 197Au(d, 2n)197Hg and 197Au(d, p2n)196Au

International Nuclear Information System (INIS)

Long Xianguan; Peng Xiufeng; He Fuqing

1987-01-01

By using activation method and stack-foil technique, the excitation functions for d + 197 Au reaction in 6.6-13.1 MeV energy range are measured. The measured values are compared with previous results and theoretical calculations

Formation of stable and metastable phases in reciprocal systems PbSe + MI2 = MSe + PbI2 (M = Hg, Mn, Sn)

International Nuclear Information System (INIS)

Odin, I.N.; Grin'ko, V.V.; Kozlovskij, V.F.; Safronov, E.V.; Gapanovich, M.V.

2004-01-01

Using data of differential thermal, X-ray phase and microstructural analyses, phase diagrams of reciprocal systems PbSe + MI 2 = MSe + PbI 2 (M=Hg (1), Mn (2), Sn (3)) were constructed. It was ascertained that the HgSe-PbI 2 diagonal in system 1 is stable. Transformations leading to crystallization of metastable ternary compound formed in the system PbSe-PbI 2 and metastable polytypes of lead iodide in systems 1 and 2 in the range of temperatures from 620 to 685 K were studied. New intermediate metastable phases in systems 1, 2 and 3 were prepared by melt quenching. Crystal lattice parameters of the phases crystallizing in the CdCl 2 structural type were defined [ru

On QCD Q2-evolution of deuteron structure function F2D(xD, Q2) for xD>1

International Nuclear Information System (INIS)

Sidorov, A.V.; Tokarev, M.V.

1995-01-01

The deep-inelastic deuteron structure function (SF) F 2 D (x D ,Q 2 ) in the covariant approach in light-cone variables is considered. The x D and Q 2 -dependences of SF are calculated. The QCD analysis of generated data both for non-cumulative x D D >1 ranges was performed. It was shown that Q 2 -evolution of SF is valid for ranges 0.275 D D D -dependence of SF for the ranges is essentially different. 23 refs., 2 figs., 1 tab

Electrochemical DNA probe for Hg(2+) detection based on a triple-helix DNA and Multistage Signal Amplification Strategy.

Science.gov (United States)

Wang, Huan; Zhang, Yihe; Ma, Hongmin; Ren, Xiang; Wang, Yaoguang; Zhang, Yong; Wei, Qin

2016-12-15

In this work, an ultrasensitive electrochemical sensor was developed for detection of Hg(2+). Gold nanoparticles decorated bovine serum albumin reduction of graphene oxide (AuNP-BSA-rGO) were used as subsurface material for the immobilization of triple-helix DNA. The triple-helix DNA containing a thiol labelled single-stranded DNA (sDNA) and a thymine-rich DNA (T-rich DNA), which could be unwinded in the present of Hg(2+) to form more stable thymine-Hg(2+)-thymine (T-Hg(2+)-T) complex. T-Hg(2+)-T complex was then removed and the sDNA was left on the electrode. At this time, gold nanoparticle carrying thiol labelled cytosine-rich complementary DNA (cDNA-AuNP) could bind with the free sDNA. Meanwhile, the other free cDNA on AuNP could bind with each other in the present of Ag(+) to form the stable cytosine-Ag(+)-cytosine (C-Ag(+)-C) complex and circle amplification. Plenty of C-Ag(+)-C could form silver nanoclusters by electrochemical reduction and the striping signal of Ag could be measured for purpose of the final electrochemical detection of Hg(2+). This sensor could detect Hg(2+) over a wide concentration range from 0.1 to 130nM with a detection limit of 0.03nM. Copyright © 2016 Elsevier B.V. All rights reserved.

Using MOF-74 for Hg2+ removal from ultra-low concentration aqueous solution

International Nuclear Information System (INIS)

Xiong, Yang Yang; Li, Jian Qiang; Gong, Le Le; Feng, Xue Feng; Meng, Li Na; Zhang, Le; Meng, Pan Pan; Luo, Ming Biao; Luo, Feng

2017-01-01

Mercury (Hg 2+ ) ions have very high toxicity and widely spread as environmental pollutants. At present, many efforts have been taken to remove the hazardous materials of mercury(II) by adsorption, and it is highly desirable to develop a novel adsorbent with high adsorptive capacities. However it is still a big challenge to remove the ultra-low-concentration mercury ions from water. In this paper, MOF-74-Zn is explored for such function, showing high removal rate of Hg(II) from water without any pretreatment, especially for the ultra-trace Hg(II) ions in the ppb magnitude with the removal rate reaching to 54.48%, 69.71%, 72.26% when the initial concentration of Hg(II) is 20ppb, 40ppb, 50ppb, respectively. - Graphical abstract: The absorption of mercury ions on MOF-74-Zn is due to somewhat weak interactions between MOF skeleton that is composed of carboxylate and hydroxy group and Hg2+ ions. - Highlights: • MOF-74-Zn shows high removal rate of Hg(II) from water without any pretreatment. • The MOF-74-Zn has a notable performance at ultra-low concentration of Hg(II). • MOF-74-Zn shows the potential for Hg(II) removal from industrial waste water.

Vibrational spectroscopic investigation of some hofmann-T/sub d/ type complexes: Ni(I-phenyl piperazine)/sub 2/ M(CN)/sub 4/ (M = Cd or Hg)

International Nuclear Information System (INIS)

Parlak, C.; Senyel, M.

2009-01-01

New Hofmann-Td type complexes in the form of Ni(pp)/sub 2/M(CN)/sub 4/ (where pp = 1-Phenyl piperazine and M = Cd or Hg) have been prepared in powder form and their in/Tared (4000-100 cm-l) and Raman (2800-1650 cm/sup -1/) spectra have been reported. The results suggest that these compounds are similar in structure to the Hofmann- T d type complexes, in which the M atom is tetrahedrally coordinated to the carbon atoms of the four cyanide groups, while the Ni atom is octahedrally surrounded by six nitrogen atoms, two of which are from pp ligands which have been coordinated as a un identate ligand coordinating only through the NH nitrogen and the rest are from cyanide groups. In this host structure, the M(CN)/sub 4/ groups have been linked by the Ni(pp)z moieties to form a three-dimensional network. (author)

3,9-Dithia-6-azaundecane-appended Iridium (III) Complex for the Selective Detection of Hg{sup 2+} in Aqueous Acetonitrile