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Sample records for centre dot ccl4

  1. Zinc In CCl4 Toxicity

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Objective To investigate the protective effect of zinc in CCl4-induced hepatotoxicity. Methods Rats were treated with zinc acetate for four days. The zinc doses were 5 mg Zn/kg and 10 mg Zn/kg body weight respectively. Two groups of the zinc acetate-treated rats were later challenged with a single dose of CCl4 (1.5 mL/kg body weight). Results Compared to control animals, the plasma of rats treated with CCl4 showed hyperbilirubinaemia, hypoglycaemia, hypercreatinaemia and hypoproteinaemia. When the animals were however supplemented with zinc in form of zinc acetate before being dosed with CCl4, the 5 mg Zn/kg body weight of zinc acetate reversed the hypoproteinaemia induced by CCl4, whereas the 10mg Zn/kg body weight of zinc acetate reversed the hypoglycaemia, hyperbilimbinaemia and hypercreatinaemia induced by CCl4. Conclusion The 10mug Zn/kg body weight of zinc acetate is more consistent in protecting against CCl4 hepatotoxicity. The possible mechanisms of protection are highlighted.

  2. Analysis of the heat capacity for pure CH4 and CH4/CCl4 on graphite near the melting point and calculation of the T-X phase diagram for (CH3)CCl3 + CCl4

    Science.gov (United States)

    Yurtseven, Hamit; Yılmaz, Aygül

    2016-06-01

    We study the temperature dependence of the heat capacity Cp for the pure CH4 and the coadsorbed CH4/CCl4 on graphite near the melting point. The heat capacity peaks are analyzed using the experimental data from the literature by means of the power-law formula. The critical exponents for the heat capacity are deduced below and above the melting point for CH4 (Tm = 104.8 K) and CH4/CCl4 (Tm = 99.2 K). Our exponent values are larger as compared with the predicted values of some theoretical models exhibiting second order transition. Our analyses indicate that the pure methane shows a nearly second order (weak discontinuity in the heat capacity peak), whereas the transition in coadsorbed CH4/CCl4 is of first order (apparent discontinuity in Cp). We also study the T – X phase diagram of a two-component system of CH3CCl3+CCl4 using the Landau phenomenological model. Phase lines of the R+L (rhombohedral+liquid) and FCC+L (face-centred cubic + liquid) are calculated using the observed T – X phase diagram of this binary mixture. Our results show that the Landau mean field theory describes the observed behavior of CH3CCl3+CCl4 adequately. From the calculated T – X phase diagram, critical behavior of some thermodynamic quantities can be predicted at various temperatures and concentrations (CCl4) for a binary mixture of CH3CCl3+CCl4.

  3. The Carbon Tetrachloride (CCl4) Budget: Mystery or Not

    Science.gov (United States)

    Liang, Qing; Newman, Paul A.; Daniel, John S.; Reimann, Stefan; Hall, Bradley; Dutton, Geoff; Kuijpers, Lambert J. M.

    2014-01-01

    Carbon tetrachloride (CCl4) is a major anthropogenic ozone-depleting substance and greenhouse gas and has been regulated under the Montreal Protocol. However, atmospheric observations show a very slow decline in CCl4 concentrations, inconsistent with the nearly zero emissions estimate based on the UNEP reported production and feedstock usage in recent years. It is now apparent that there are either unidentified industrial leakages, an unknown production source of CCl4, or large legacy emissions from CCl4 contaminated sites. In this paper we use a global chemistry climate model to assess the budget mystery of atmospheric CCl4. We explore various factors that affect the global trend and the gradient between the Northern and Southern hemispheres or interhemispheric gradient (IHG): emissions, emission hemispheric partitioning, and lifetime variations. We find a present-day emission of 30-50 Gg per yr and a total lifetime 25 - 36 years are necessary to reconcile both the observed CCl4 global trend and IHG.

  4. Biological destruction of CCl4: I -- Experimental design and data

    International Nuclear Information System (INIS)

    A denitrifying consortium capable of transforming carbon tetrachloride (CCl4) was cultured from aquifer sediment from the US Department of Energy's Hanford Site in southeastern Washington State. To understand the kinetics of the biological destruction of CCl4 by these microbes, a set of experiments, the conditions of which were chosen according to a fractional factorial experimental design, were completed. This article reports on the experimental design along with the results for CCl4, biomass, acetate, nitrate, and nitrite concentrations. These data indicate that growth is inhibited by high nitrite concentrations, whereas CCl4 degradation is slowed by the presence of nitrate and/or nitrite

  5. Effect of CCl4 on positronium formation in isooctane

    International Nuclear Information System (INIS)

    The effect of CCl4 in positronium (Ps) formation is examined in isooctane through positron lifetime spectroscopy experiments, in the framework of a series of studies on AOT-based reverse micellar systems. This solute appears as a rather strong Ps formation inhibitor, as expected in view of its well-known electron scavenging properties. The reciprocal of the triplet Ps intensity (1/Ι3) varies linearly with CCl4 concentration (C), up to about 0.08M, allowing to derive a high inhibition constant, k=36.6M-1. Above 0.08M, however, the inhibition slackens out, which is attributed to an anti-inhibition effect. On the basis of previous reports on halocompounds, a general scheme of reactions is proposed to occur in the positron spur, including, besides the primary Ps formation through the e+/e- reaction and the recombination reactions, electron scavenging by CCl4 as the direct inhibiting reaction, followed by the reaction of the thus formed anion with the positron. The latter reaction may lead either to a [CCl4Ps] bound-state or, if the positron picks off the electron from the anion, to some additional Ps formation. By using a simple quantitative approach to this scheme, an equation descriptive of the variation of Ι3 with C is derived which agrees well with the experimental data. (author)

  6. Photocatalytic decomposition of CCl4 on Zr-MCM-41

    International Nuclear Information System (INIS)

    Photocatalytic decomposition of CCl4 (80 mg L-1 in H2O) effected by Zr-MCM-41 (Zr incorporated in the amorphous wall of MCM-41) has been studied in the present work. Experimentally, photocatalytic decomposition of CCl4 on Zr-MCM-41 was enhanced by about 1.96 times over that on ZrO2. Photocatalytic decomposition of CCl4 may proceed via a two-electron transfer process that yields mainly CHCl3, Cl- and H2. Since little C2Cl2, C2Cl6 or CH2Cl2 was found, it is unlikely that CHCl3 involved in the secondary photocatalytic degradation process. In addition, photocatalytic splitting of H2O on Zr-MCM-41 was also enhanced. The yield of H2 was 6.5 mmol (g ZrO2)-1. About 68% of this hydrogen (6.5 mmol (g ZrO2)-1) was consumed in the photocatalytic decomposition of CCl4

  7. Dynamic Heterogeneity In The Monoclinic Phase Of CCl$_4$

    CERN Document Server

    Caballero, Nirvana B; Carignano, Marcelo; Serra, Pablo

    2016-01-01

    Carbon tetrachloride (CCl$_4$) is one of the simplest compounds having a translationally stable monoclinic phase while exhibiting a rich rotational dynamics below 226 K. Recent nuclear quadrupolar resonance (NQR) experiments revealed that the dynamics of CCl$_4$ is similar to that of the other members of the isostructural series CBr$_{n}$Cl$_{4-n}$, suggesting that the universal relaxation features of canonical glasses such as $\\alpha$- and $\\beta$-relaxation are also present in non-glass formers. Using molecular dynamics (MD) simulations we studied the rotational dynamics in the monoclinic phase of CCl$_4$. The molecules undergo $C3$ type jump-like rotations around each one of the four C-Cl bonds. The rotational dynamics is very well described with a master equation using as the only input the rotational rates measured from the simulated trajectories. It is found that the heterogeneous dynamics emerges from faster and slower modes associated with different rotational axes, which have fixed orientations relat...

  8. Role of suppressed hepatocellular regeneration and Ca2+ in chlordecone-potentiated CCl4 hepatotoxicity

    International Nuclear Information System (INIS)

    The mechanism by which the chlorinated pesticide chlordecone (CD; Kepone) potentiates CCl4-induced hepatotoxicity and lethality was investigated. It was hypothesized that perturbations in Ca2+ homeostasis, greater than those observed with a low dose of CCl4 alone, in concert with a suppression of hepatocellular regeneration induced by CD alone or by CD + CCl4 are responsible, at least in part, for CD-potentiated CCl4 hepatotoxicity. Ca2+ homeostasis was evaluated by measuring total cell Ca2+ and 45Ca2+ uptake in viable isolated hepatocyte suspension obtained from normal and CD-pretreated rats receiving CCl4 in vivo. In the normal rats in vivo CCL challenge did not affect 45Ca2+ uptake by viable isolated hepatocytes. In contrast, 45Ca2+ uptake was inhibited in viable isolated hepatocytes obtained from rats exposed to CD + CCl4

  9. Decomposition of CCl4 and CHCl3 on gliding arc plasma

    Institute of Scientific and Technical Information of China (English)

    Antonius Indarto; CHOI Jae-wook; LEE Hwaung; SONG Hyung-keun

    2006-01-01

    Decomposition of chlorinated hydrocarbons, CCl4 and CHCl3, in gliding plasma was examined. The effects of initial concentrations, total gas flow rates, and power consumption have been investigated. The conversion result was relatively high. It reached 80% for CCl4 and 97% for CHCl3. Using atmospheric air as the carrier gas, the plasma reaction occurred at exothermic reaction and the main products were CO2, CO, and Cl2. Transformation into CCl4 was also detected for CHCl3 decomposition reaction.The conversion of CCl4 and CHCl3 were increased with the increasing applied frequency and decreasing total gas flow rate.

  10. Estudi immunogenètic de les quimiocines CCL4 i CCL4L exemple i model de la complexitat de la superfamília de les quimiocines /

    OpenAIRE

    Colobran i Oriol, Roger

    2008-01-01

    Els resultats d'aquesta tesi doctoral, presentada per compendi de publicacions, es divideixen en 2 grups:A) Basats en la variabilitat de CCL4 i CCL4L:Article: Multiple Products Derived from Two CCL4 Loci: High Incidence of a New Polymorphism in HIV+ Patients. Roger Colobran, Patricia Adreani, Yaqoub Ashhab, Anuska Llano, José A. Esté, Orlando Dominguez, Ricardo Pujol-Borrell, and Manel Juan. The Journal of Immunology, 2005, 174: 5655-5664. Els locus CCL4 i CCL4L originen les quimiocines CCL4 ...

  11. In vivo metabolism of CCl4 by rats pretreated with chlordecone, mirex, or phenobarbital

    International Nuclear Information System (INIS)

    The propensity of chlordecone (CD) to potentiate hepatotoxic and lethal effects of CCl4 is well established. Mirex (M), a close structural analogue of CD, or phenobarbital (PB), powerful inducers of hepatic microsomal drug metabolizing enzymes, are much weaker potentiators of CCl4 toxicity. The purpose of this study was to test the possibility that CD potentiates the toxicity of CCl4 by increasing the metabolism of CCl4 to a greater degree than either PB or M. We compared the in vivo metabolism of CCl4 in rats pretreated with CD, M, or PB, by measuring the hepatic content of 14CCl4, the expiration of 14CCl4, expiration of 14CCl4-derived 14CO2, and lipid peroxidation. Male Sprague-Dawley rats (250-270 g) were pretreated with a single oral dose of CD (10 mg/kg), M (10 mg/kg), or corn oil vehicle (1 ml/kg). PB pretreatment consisted of an ip injection of sodium PB (80 mg/kg) in saline (0.9%) for 2 successive days. Twenty-four hours later, 14CCl4 (0.1 ml/kg; sp act: 0.04 mCi/mmol) was administered ip in corn oil and the radioactivity present in the expired air was collected for 6 hr. Excretion of the parent compound as represented by the 14C label in the toluene trap was unchanged by any of the pretreatments. Expiration of 14CO2 measured during the 6 hr after CCl4 administration was increased in animals pretreated with PB or CD. In vivo lipid peroxidation measured as diene conjugation in lipids extracted from the livers was increased to a similar extent in animals pretreated with PB and CD, whereas the serum transaminases (ALT, AST) were significantly elevated only in animals pretreated with CD.M did not affect 14CO2 production and was without a significant effect on the lipid peroxidation

  12. In vivo metabolism of CCl4 by gerbils pretreated with chlordecone, phenobarbital, or mirex

    International Nuclear Information System (INIS)

    Gerbils are known to be much more sensitive to CCl4 lethality than rats as indicated by 48 hours LD50 (0.08 vs 2.8 ml/kg). On the other hand, gerbils are refractory to chlordecone (CD) potentiation of CCl4 toxicity. To investigate the possible mechanism underlying gerbil's high sensitivity to CCl4 lethality, the authors studied in vivo metabolism of CCl4 in gerbils pretreated with dietary CD (10 ppm), phenobarbital (PB, 225 ppm) or mirex (M, 10 ppm). The hepatic content of CCl4, the expiration of 14CCl4 and 14CCl4-derived Co2, and lipid peroxidation were measured and the results were compared with our previous data for rats. After 15-day dietary pretreatment, male gerbils (60-80 g) received 14CCl4 (80 ml/kg; sp act: 0.04 mCi/mmol) ip in corn oil and the expired air was collected for 6 hours. More than 80% of the dose administered was expired as parent compound in 6 hours regardless of pretreatments. Expiration of 14CCl4 derived 14CO2 in control gerbils was 3.5-fold more than in control rats and was increased significantly in pretreated gerbils (M>PB>CD). PB and M pretreatments resulted in significant increase of 14C label bound to non-lipid fraction of hepatic content as compared with CD or control gerbils. The radiolabel present in hepatic content of control gerbils was 5-fold higher than that of control rats. In vivo liquid peroxidation measured as diene conjugation in lipid extracts from the livers was lower in gerbils than in rats, and there were no significant differences among control and pretreated gerbils. These data indicate that the more extensive metabolism of CCl4 in gerbils may partially explain their high sensitivity to CCl4 toxicity. However, the significantly enhanced metabolism of CCl4 found in CD, PB, or M pretreated gerbils did not lead to amplification of CCl4 hepatotoxic and lethal effects

  13. Negative ion formation and motion in a mixture of CCl4 and Ar

    International Nuclear Information System (INIS)

    This paper deals with the measurement of the mobility of negative ions in the mixtures of CCl4 with Ar with the CCl4 ratio up to 33.3%. The pulsed Townsend technique was employed to produce an integrated ionic avalanche over a range of the density-reduced electric field E/N for which ionization is either negligible or absent, and attachment processes are dominant, leading to the formation of mostly CCl4-. The E/N range of measurement was 1-50 Td (1 Td=10-17 V cm2). Our measurements strongly suggest that attachment is the dominant process and only negative ions are formed

  14. A comprehensive estimate for loss of atmospheric carbon tetrachloride (CCl4) to the ocean

    OpenAIRE

    Butler, J. H.; S. A. Yvon-Lewis; Lobert, J. M.; King, D. B.; S. A. Montzka; Bullister, J. L.; Koropalov, V.; J. W. Elkins; B. D. Hall; Hu, L.; Liu, Y.

    2016-01-01

    Abstract. Extensive undersaturations of carbon tetrachloride (CCl4) in Pacific, Atlantic, and Southern Ocean surface waters indicate that atmospheric CCl4 is consumed in large amounts by the ocean. Observations made on 16 research cruises between 1987 and 2010, ranging in latitude from 60° N to 77° S, show that negative saturations extend over most of the surface ocean. Corrected for physical effects associated with radiative heat flux, mixing, and air injection, these anomalies were ...

  15. Vibrational spectroscopy of SnBr4 and CCl4 using Lie algebraic approach

    Indian Academy of Sciences (India)

    Joydeep Choudhury; Srinivasa Rao Karmuri; Nirmal Kumar Sarkar; Ramendu Bhattacharjee

    2008-09-01

    The stretching and bending vibrational energies of SnBr4 and CCl4 are calculated in the one-dimensional framework. The dynamical symmetry group of tetrahedral molecule was taken into consideration to construct the model Hamiltonian in this frame-work. Casimir and Majorana invariant operators were also determined accordingly. Using the model Hamiltonian so constructed, we reported the vibrational energy levels of SnBr4 and CCl4 molecules accurately.

  16. Phase Transition in CCl4 under Pressure: a Raman Spectroscopic Study

    Institute of Scientific and Technical Information of China (English)

    LIU Tie-Cheng; ZHOU Mi; GAO Shu-Qin; LI Zuo-Wei; LI Zhan-Long; ZHANG Peng; LI Liang; LV Tian-Quan; XU Da-Peng

    2009-01-01

    High-pressure Raman studies at room temperature are performed on CCla up to 13 GPa. The Raman bands of the internal modes (v2, v4 and v1) show entirely positive pressure dependence. The slopes dw/dP of the internal modes exhibit two sudden changes at 0.73 GPa and 7.13 GPa, respectively. A new lower frequency mode (225cm-1) appears at 3.03 GPa, and the splitting of v2, v3 and v4 occurs at about 7.13 GPa. Moreover, Raman spectra of Fermi resonance show that the relative position of the v1 + v4 combination and the v3 fundamental firstly interchanges corresponding to that at ambient pressure, then the v1 + va combination disappears in the gradual process of compression. It is indicated that the pressure-induced phase transition from CCl4 II to CCl4 III occurs at 0.73 GPa, and CCl4 III undergoes a transition to CCl4 IV below 3.03 GPa. Further CCl4 IV transforms in a new high-pressure phase at about 7.13 GPa, and the symmetry of the new high-pressure phase is lower than that of CCl4 IV. All the transitions are reversible during decompression.

  17. Solving the carbon tetrachloride (CCl4) budget mystery using surface observations

    Science.gov (United States)

    Liang, Q.; Newman, P. A.; Daniel, J. S.; Reimann, S.; Hall, B. D.; Dutton, G. S.; Kuijpers, L. J. M.

    2014-12-01

    Carbon tetrachloride (CCl4) is a major anthropogenic ozone-depleting substance, with an ozone depletion potential (with respect to CFC-11) of 0.82. CCl4 is also a greenhouse gas and the 100-yr global warming potential is 1,400. In 1987, the Montreal Protocol (MP) included CCl4, and production and consumption were phased out for developed countries in 1996. Developing countries were allowed a delayed reduction, but CCl4 was fully phased out from emissive uses in 2010. However, the near-zero 2007-2012 emissions estimate based on the UNEP reported production and feedstock usage cannot be reconciled with the observed slow decline of atmospheric concentrations, year-to-year variability, and the inter-hemispheric gradient (IHG). We use available source and sink data in the NASA 3-Dimensional (3-D) Chemistry Climate Model, GEOSCCM, to test existing emissions and lifetime estimates against CCl4 mixing ratio observations. Our model results show that the IHG and global trend provide useful information for quantitatively constraining CCl4 emissions and lifetime estimates. The observed IHG (1.5±0.2 ppt for 2000-2012) is primarily caused by ongoing current emissions, while ocean and soil losses and stratosphere-troposphere exchange together contribute a small negative gradient (~0 - -0.3 ppt). Using the observed CCl4 global trend and IHG from the National Oceanic and Atmospheric Administration - Global Monitoring Division (NOAA-GMD) and Advanced Global Atmospheric Gases Experiment (AGAGE) networks, we deduce the mean global emissions for the 2000-2012 period are 39 (34-45, lower-upper limit emission estimates) Gg/yr (~ 30% of the peak 1980s emissions) and a corresponding total lifetime of 35 (37-32, upper-lower limit lifetime estimates) years. These results point to the need for a more accurate bottom-up estimate of CCl4 emissions as well as re-evaluation of the CCl4 best estimate lifetime (currently 25 years).

  18. Herbal Supplement Ameliorates Cardiac Hypertrophy in Rats with CCl4-Induced Liver Cirrhosis

    Directory of Open Access Journals (Sweden)

    Ping-Chun Li

    2012-01-01

    Full Text Available We used the carbon tetrachloride (CCl4 induced liver cirrhosis model to test the molecular mechanism of action involved in cirrhosis-associated cardiac hypertrophy and the effectiveness of Ocimum gratissimum extract (OGE and silymarin against cardiac hypertrophy. We treated male wistar rats with CCl4 and either OGE (0.02 g/kg B.W. or 0.04 g/kg B.W. or silymarin (0.2 g/kg B.W.. Cardiac eccentric hypertrophy was induced by CCl4 along with cirrhosis and increased expression of cardiac hypertrophy related genes NFAT, TAGA4, and NBP, and the interleukin-6 (IL-6 signaling pathway related genes MEK5, ERK5, JAK, and STAT3. OGE or silymarin co-treatment attenuated CCl4-induced cardiac abnormalities, and lowered expression of genes which were elevated by this hepatotoxin. Our results suggest that the IL-6 signaling pathway may be related to CCl4-induced cardiac hypertrophy. OGE and silymarin were able to lower liver fibrosis, which reduces the chance of cardiac hypertrophy perhaps by lowering the expressions of IL-6 signaling pathway related genes. We conclude that treatment of cirrhosis using herbal supplements is a viable option for protecting cardiac tissues against cirrhosis-related cardiac hypertrophy.

  19. Effect of Platelet-Rich Plasma on CCl4-Induced Chronic Liver Injury in Male Rats.

    Science.gov (United States)

    Hesami, Zahra; Jamshidzadeh, Akram; Ayatollahi, Maryam; Geramizadeh, Bita; Farshad, Omid; Vahdati, Akbar

    2014-01-01

    Platelet-rich plasma (PRP) has been of great concern to the scientists and doctors who are involved in wound healing and regenerative medicine which focuses on repairing and replacing damaged cells and tissues. Growth factors of platelet-rich plasma are cost-effective, available, and is more stable than recombinant human growth factors. Given these valuable properties, we decided to assess the effect of PRP on CCl4-induced hepatotoxicity on rats. The rats received CCl4 (1 mL/kg, i.p. 1 : 1 in olive oil) twice per week for 8 weeks. Five weeks after CCl4 injection, the rats also received PRP (0.5 mL/kg, s.c.) two days a week for three weeks. Twenty-four hours after last CCl4 injection, the animals bled and their livers dissected for biochemical and histopathological studies. Blood analysis was performed to evaluate enzyme activity. The results showed that PRP itself was not toxic for liver and could protect the liver from CCl4-induced histological damages and attenuated oxidative stress by increase in glutathione content and decrease in lipid peroxidative marker of liver tissue. The results of the present study lend support to our beliefs in hepatoprotective effects of PRP. PMID:24707405

  20. [Protective effects of S-adenosylmethionine against CCl4 - and ethanol-induced experimental hepatic fibrosis].

    Science.gov (United States)

    Zhang, F; Gu, J-X; Zou, X-P; Zhuge, Y-Z

    2016-01-01

    In this study the effects of S-adenosylmethionine (SAM) on experimental hepatic fibrotic rats induced by carbon tetrachloride (CCl(4)) and ethanol and the relevant potential mechanisms were explored. Hepatic fibrotic rat models were established with CCl(4) diluted in olive oil being drunk with 10% ethanol in water. SAM was used both for prevention and treatment. Histological evaluation was carried out by hematoxylin-eosin (HE) and Masson staining of hepatic samples. Serum biochemical assays showed that alanine aminotransferase (ALT) was increased and albumin (ALB) was decreased by CCl(4) and ethanol, and both effects were suppressed by preventing and treating use of SAM. The model control rats got significantly higher scores in fatty degeneration, lobular inflammation, and hepatocyte ballooning. A significant improvement was observed in the SAM-prevented rats and SAM-treated rats, which was consistent with the change of fibrosis scoring in each group. Smad3 was induced by CCl(4) and ethanol in the model control group, which was significantly down regulated by SAM. SAM reduced both total Smad3 and phospho-Smad3 in vitro. SAM had a protective effect on hepatic fibrosis in rats induced by CCl(4) combined with ethanol and the down-regulation of activity and expression of Smad3 were involved in the potential mechanisms. PMID:27239849

  1. Ultrastructural changes in hepatocytes after taurine treatment in CCl4 induced liver injury

    Institute of Scientific and Technical Information of China (English)

    Ilker Tasci; Nuket Has; Mehmet Refik Has; Muwet Tuncer; Bilgin Comert

    2008-01-01

    AIM:To search the organelle based changes in hepatocytes after taurine treatment in experimental liver fibrosis induced by CCl4 administration.METHODS:Thirty rats were divided into two groups.Group 1(η=15)was injected with CCl4 plus taurine and Group 2(η=is)with Ccl4 plus saline for 12 wk.At the end of 12th wk,mitochondria,rough and smooth endoplasmic reticulum,and nuclei of hepatocytes were evaluated using a scoring system.The results were compared with histopathological findings,as well.RESULTS:Taurine treatment reduced fibrosis scores significantly as compared to placebo.Organelle injury scores decreased significantly with taurine treatment.Ultrastructural and hiStopathological scores in both groups were in strong correlation(r=0.931 for CCl4 plus taurine and r=0.899 fOr CCl4 plus saline group).CONCLUSION:Organelle based transmission electron microscopy findings can reflect successfully histological results as well as tissue healing in hepatocytes from hepatotoxin-induced liver fibrosis.

  2. The essential oil of Artemisia capillaris protects against CCl4-induced liver injury in vivo

    Directory of Open Access Journals (Sweden)

    Qinghan Gao

    2016-06-01

    Full Text Available Abstract To study the hepatoprotective effect of the essential oil of Artemisia capillaris Thunb., Asteraceae, on CCl4-induced liver injury in mice, the levels of serum aspartate aminotransferase and alanine aminotransferase, hepatic levels of reduced glutathione, activity of glutathione peroxidase, and the activities of superoxide dismutase and malondialdehyde were assayed. Administration of the essential oil of A. capillaris at 100 and 50 mg/kg to mice prior to CCl4 injection was shown to confer stronger in vivo protective effects and could observably antagonize the CCl4-induced increase in the serum alanine aminotransferase and aspartate aminotransferase activities and malondialdehyde levels as well as prevent CCl4-induced decrease in the antioxidant superoxide dismutase activity, glutathione level and glutathione peroxidase activity (p < 0.01. The oil mainly contained β-citronellol, 1,8-cineole, camphor, linalool, α-pinene, β-pinene, thymol and myrcene. This finding demonstrates that the essential oil of A. capillaris can protect hepatic function against CCl4-induced liver injury in mice.

  3. Antioxidant Bioactivity of Samsum Ant (Pachycondyla sennaarensis Venom Protects against CCL4-Induced Nephrotoxicity in Mice

    Directory of Open Access Journals (Sweden)

    Hossam Ebaid

    2014-01-01

    Full Text Available To assess whether SAV could influence the effects of carbon tetrachloride (CCL4 exposure, mice were treated with SAV in doses of 100, 200, 300 and 400 μg/kg body weight and the effects on oxidative status and kidney function were studied. Serum levels of creatinine, malondialdehyde (MDA, and blood urea, together with renal and hepatic levels of MDA, glutathione (GSH, superoxide dismutase (SOD, and catalase (CAT were quantified in order to evaluate antioxidant activity. Results showed that the group injected with CCL4 exhibited significantly higher levels of oxidative stress markers, MDA, and significantly lower concentrations of GSH, SOD and catalase. SAV was found to significantly improve these oxidative markers, occasionally, in a dose-dependent manner. Furthermore, treatment with SAV was associated with the same behaviour in respect to kidney functions which had previously been impaired by CCL4. Histopathological examination demonstrated that SAV, in different groups, improved the renal tissue damage induced by CCL4 and histological scores confirmed that significant improvements were obtained after treatment with SAV, particularly with the lowest dose (100 μg/kg body weight. In conclusion, SAV has the potential capability to restore oxidative stability and to improve kidney functions after CCL4 acute injury.

  4. Protective effects of L-carnosine on CCl4 -induced hepatic injury in rats.

    Science.gov (United States)

    Alsheblak, Mehyar Mohammad; Elsherbiny, Nehal M; El-Karef, Amro; El-Shishtawy, Mamdouh M

    2016-03-01

    The present study was undertaken to investigate the possible protective effect of L-carnosine (CAR), an endogenous dipeptide of alanine and histidine, on carbon tetrachloride (CCl4)-induced hepatic injury. Liver injury was induced in male Sprague-Dawley rats by intraperitoneal (i.p.) injections of CCl4, twice weekly for six weeks. CAR was administered to rats daily, at dose of 250 mg/kg, i.p. At the end of six weeks, blood and liver tissue specimens were collected. Results show that CAR treatment attenuated the hepatic morphological changes, necroinflammation and fibrosis induced by CCl4, as indicated by hepatic histopathology scoring. In addition, CAR treatment significantly reduced the CCl4-induced elevation of liver-injury parameters in serum. CAR treatment also combatted oxidative stress; possibly by restoring hepatic nuclear factor erythroid 2-related factor 2 (Nrf-2) levels. Moreover, CAR treatment prevented the activation of hepatic stellate cells (HSCs), as indicated by reduced α-smooth muscle actin (α-SMA) expression in the liver, and decreased hepatic inflammation as demonstrated by a reduction in hepatic tumor necrosis factor-α (TNF-α) and restoration of interleukin-10 (IL-10) levels. In conclusion, CCl4-induced hepatic injury was alleviated by CAR treatment. The results suggest that these beneficial, protective effects are due, at least in part, to its anti-oxidant, anti-inflammatory and anti-fibrotic activities. PMID:27094155

  5. PROTECTIVE EFFECT OF Solanum Pubescens LINN ON CCL4 INDUCED HEPATOTOXICITY IN ALBINO RATS

    Directory of Open Access Journals (Sweden)

    M.Pushpalatha

    2012-01-01

    Full Text Available Ethanol extract of Solanum pubescens Linn was evaluated for hepato protective and antioxidant activities in rats. The plant extract (500mg/kg/day showed a remarkable hepatoprotective and antioxidant activity against Carbon tetrachloride (CCl4-induced hepatotoxicity as judged from the serum marker enzymes and antioxidant levels in liver tissues. CCl4 induced a significant rise in aspartate amino transferase (AST, alanine amino transferase (ALT, alkaline phosphatase (ALP, total bilirubin, LPO with a reduction of total protein, superoxide dismutase (SOD, catalase, and reduced glutathione (GSH. Treatment of rats with plant extract (500 mg/kg significantly (P<0.01 altered serum marker enzymes and antioxidant levels to near normal against CCl4 - treated rats. The activity of the extract at dose of 500 mg/kg was comparable to the standard drug, Silymarin (50 mg/kg, p.o.. Histopathological examination of the liver tissues supported the hepatoprotective activity of plant.

  6. Constraining the carbon tetrachloride (CCl4) budget using its global trend and inter-hemispheric gradient

    Science.gov (United States)

    Liang, Qing; Newman, Paul A.; Daniel, John S.; Reimann, Stefan; Hall, Bradley D.; Dutton, Geoff; Kuijpers, Lambert J. M.

    2014-07-01

    Carbon tetrachloride (CCl4) is a major anthropogenic ozone-depleting substance and greenhouse gas and has been regulated under the Montreal Protocol. However, the near-zero 2007-2012 emissions estimate based on the UNEP reported production and feedstock usage cannot be reconciled with the observed slow decline of atmospheric concentrations and the inter-hemispheric gradient (IHG) for CCl4. Our 3-D model simulations suggest that the observed IHG (1.5 ± 0.2 ppt for 2000-2012) is primarily caused by ongoing current emissions, while ocean and soil losses and stratosphere-troposphere exchange together contribute a small negative gradient (~0 - -0.3 ppt). Using the observed CCl4 global trend and IHG, we deduce that the mean global emissions for the 2000-2012 period are 393445 Gg/yr (~30% of the peak 1980s emissions) and a corresponding total lifetime of 353732 years.

  7. Protective Effect of Procyanidin B2 against CCl4-Induced Acute Liver Injury in Mice

    Directory of Open Access Journals (Sweden)

    Bing-Ya Yang

    2015-07-01

    Full Text Available Procyanidin B2 has demonstrated several health benefits and medical properties. However, its protective effects against CCl4-induced hepatotoxicity have not been clarified. The present study aimed to investigate the hepatoprotective effects of procyanidin B2 in CCl4-treated mice. Our data showed that procyanidin B2 significantly decreased the CCl4-induced elevation of serum alanine aminotransferase activities, as well as improved hepatic histopathological abnormalities. Procyanidin B2 also significantly decreased the content of MDA but enhanced the activities of antioxidant enzymes SOD, CAT and GSH-Px. Further research demonstrated that procyanidin B2 decreased the expression of TNF-α, IL-1β, cyclooxygenase-2 (COX-2 and inducible nitric oxide synthase (iNOS, as well as inhibited the translocation of nuclear factor-kappa B (NF-κB p65 from the cytosol to the nuclear fraction in mouse liver. Moreover, CCl4-induced apoptosis in mouse liver was measured by (terminal-deoxynucleotidyl transferase mediated nick end labeling TUNEL assay and the cleaved caspase-3. Meanwhile, the expression of apoptosis-related proteins Bax and Bcl-xL was analyzed by Western blot. Results showed that procyanidin B2 significantly inhibited CCl4-induced hepatocyte apoptosis, markedly suppressed the upregulation of Bax expression and restored the downregulation of Bcl-xL expression. Overall, the findings indicated that procyanidin B2 exhibited a protective effect on CCl4-induced hepatic injury by elevating the antioxidative defense potential and consequently suppressing the inflammatory response and apoptosis of liver tissues.

  8. Hepatoprotective activity of cinnamon ethanolic extract against CCl4-induced liver injury in rats

    OpenAIRE

    Bazargan, Maryam; Eidi, Akram; MORTAZAVI, Pejman; Zaringalam, Jalal

    2012-01-01

    The inner bark of cinnamon (Cinnamomum zeylanicum L.) is commonly used as a spice and has also been widely employed in the treatment and prevention of disease. The aim of the present study is to evaluate the protective effect of cinnamon bark extract against carbon tetrachloride (CCl4)-induced liver damage in male Wistar rats. Administration with cinnamon extracts (0.01, 0.05 and 0.1 g/kg) for 28 days significantly reduced the impact of CCl4 toxicity on the serum markers of liver damage, ...

  9. L -Carnitine and Melatonin Reverse CCl4 Induced Liver Fibrosis In Rats (Histological and Histochemical Studies

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    Fatma, A. Morsy, Abdel Razik, H. Farrag and Sonya, L. El-Sharkawy

    2004-12-01

    Full Text Available Carbontetrachloride (CCl4 is closely related chemically to chloroform and likewise in hepatic poisons. This study was designed to evaluate the effects of carbon tetrachloride on liver of male rats and the reversing effects of L-carnitine and melatonin on established liver fibrosis. A total of 72 adult male albino rats were used in this study. The animals were divided into six groups. Group (1 animals of the first group were kept as control andtreated with paraffin oil twice weekly for eight weeks. Group (2 rats of the second group were injected with CCl4 intraperitoneally at 0.15 ml per rats (diluted 1:1 in liquid paraffin twice weekly for eight weeks to produced liver fibrosis. Group (3 following establishment with CCl4 which induced liver fibrosis, the rats were treated with L-carnitine at a dose level of 50 mg/kg for four weeks. Group (4 rats with liver fibrosis were injected intraperitoneally with melatonin at dose level of 10 mg/kg for four weeks. The fifth and sixth groups were given L-carnitine and/or melatonin at dose levels of 50 mg/kg and 10 mg/kg respectively for four weeks. Histological changes in the liver of rats treated with CCl4 including liver fibrosis, architecture distortion and appearance of many pseudolobule. The fibrous tissues run in septa between the nodules. The liver damage varied from one area to another and varied from moderate fibrosis to cirrhosis. Quantitative measurement of the severity of liver fibrosis (area damage was achieved by using computerized image analysis (Leica image showed that highly significant increase in area of fibrosis was recorded in the case of rats treated with CCl4 only. Quantitative DNA image analysis showed that 3% of aneuploid cells could be noticed in liver of rats treated with CCl4 only. Histochemical results of rats treated with CCl4 showed highly significant increase in grey level of mucopolysaccharides and protein levels. No histological and histochemical changes could be noticed in

  10. Inhibitory effect of Newcastle disease virus on hepatic fibrosis induced by CCl4

    OpenAIRE

    Ya-lin LI

    2013-01-01

    Objective To explore the inhibitory effect of Newcastle diseases virus (NDV) on CCl4-induced liver fibrosis in mice. Methods Liver fibrosis model was reproduced in 30 Kunming mice by intraperitoneal injection of CCl4/peanut oil solution for 2 times a week, and the total treatment lasted for 8 weeks. Three days after last injection, NDV was injected through tail vein for 1 or 3 times (24h intervals). Twenty-four hours after NDV infusion, mice were sacrificed and the livers were removed for gro...

  11. Effect of extracts from araticum (Annona crassiflora on CCl4-induced liver damage in rats

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    Roberta Roesler

    2011-03-01

    Full Text Available The influence of ethanolic extracts of Annona crassiflora on the activities of hepatic antioxidant enzymes was examined. Extracts of A. crassiflora seeds and peel were administered orally (50 mg of galic acid equivalents.kg-1 to Wistar rats for 14 consecutive days followed by a single oral dose of carbon tetrachloride (CCl4, 2 g.kg-1. Lipid peroxidation and the activities of hepatic catalase (CAT, cytochromes P450 (CP450 and b5, glutathione peroxidase (GPx, glutathione reductase (GRed, superoxide dismutase (SOD, and the content of glutathione equivalents (GSH were evaluated. The treatment with CCl4 increased lipid peroxidation, the level of GSH equivalents and the content of cytochrome b5 by 44, 140 and 32%, respectively, with concomitant reductions of 23, 34 and 39% in the activities of CAT, SOD, and CP450, respectively. The treatment with A. crassiflora seeds and peel extracts alone inhibited lipid peroxidation by 27 and 22%, respectively without affecting the CP450 content. The pretreatment with the A. crassiflora extracts prevented the lipid peroxidation, the increase in GSH equivalents and the decrease in CAT activity caused by CCl4, but it had no effect on the CCl4-mediated changes in CP450 and b5 and SOD. These results show that A. crassiflora seeds and peel contain antioxidant activity in vivo that could be of potential therapeutic use.

  12. Protective effect of wedelolactone against CCl4-induced acute liver injury in mice.

    Science.gov (United States)

    Lu, Yang; Hu, DongMei; Ma, ShanBo; Zhao, Xian; Wang, Shan; Wei, Guo; Wang, XiFang; Wen, AiDong; Wang, JingWen

    2016-05-01

    Eclipta, a traditional Chinese medicine, has been used to treat liver disease for centuries. However, the chemical basis and biological mechanisms of Eclipta remain elusive. The current study aims to investigate the hepatoprotective effect of wedelolactone (WEL), a major coumarin in Eclipta, using C57BL/6 mice with carbon tetrachloride CCl4-induced acute liver injury (ALI). Our data showed that WEL markedly decreased the CCl4-induced elevation of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities, and improved hepatic histopathology changes. WEL also significantly decreased the content of MDA in liver tissues, meanwhile increased the activities of antioxidant enzymes SOD and GSH-Px. In addition, WEL reduced the protein expression of TNF-α, IL-1β and IL-6, as well as mRNA expression. Western blot results revealed that WEL repressed phosphorylation of extracellular signal-regulated kinase (ERK) and translocation of NF-κB p65 from cytoplasm to nucleus and enhanced the phosphorylation of c-Jun. N-terminal kinase (JNK). Moreover, results showed that WEL significantly inhibited CCl4-induced hepatocytes apoptosis, markedly suppressed the down-regulation of Bax and active Caspase-3 expression and accelerated the expression of Bcl-2. Overall, the findings indicate that WEL exhibits a protective effect against CCl4-induced ALI in mice by enhancing the antioxidative defense system, suppressing the inflammatory response and cell apoptosis of liver. PMID:26921731

  13. Inhibitory effect of Newcastle disease virus on hepatic fibrosis induced by CCl4

    Directory of Open Access Journals (Sweden)

    Ya-lin LI

    2013-11-01

    Full Text Available Objective To explore the inhibitory effect of Newcastle diseases virus (NDV on CCl4-induced liver fibrosis in mice. Methods Liver fibrosis model was reproduced in 30 Kunming mice by intraperitoneal injection of CCl4/peanut oil solution for 2 times a week, and the total treatment lasted for 8 weeks. Three days after last injection, NDV was injected through tail vein for 1 or 3 times (24h intervals. Twenty-four hours after NDV infusion, mice were sacrificed and the livers were removed for gross morphology observation. The liver tissue sections were stained by HE and Sirius red dyeing. α-smooth muscle actin (α-SMA expression was detected by Western blotting. Results After CCl4 induction for 8 weeks, obvious fibrosis symptoms appeared in the liver of model mice, and the surface of liver tissue became hard with rough, with white patches on it. HE staining showed that there was loosening of tissue and enlarged perisinusoidal spaces in liver with fibrosis. Sirius red dyeing displayed abnormal collagen deposition in the fibrotic liver tissues. After NDV injection for 3 times, white spots on the surface of mouse liver were significantly reduced, and collagen deposition was lowered. Western blotting showed that α-SMA levels decreased with increasing frequency of NDV injection. Conclusion NDV may effectively suppress the development of CCl4-induced liver fibrosis in mice. DOI: 10.11855/j.issn.0577-7402.2013.11.003

  14. Carbon Tetrachloride (CCl4) in the Atmosphere: A Mystery Between Sources and Sinks

    Science.gov (United States)

    Reimann, S.; Newman, P. A.; Liang, Q.; Rigby, M. L.; Kuijpers, L.

    2013-12-01

    Carbon tetrachloride (CCl4) is an ozone depleting substance and therefore has been banned from usage under the Montreal Protocol. However, it is still allowed for contained use in industrial processes as so-called feedstock substance, where emissions should be negligible. The regulation of CCl4 in the Montreal Protocol suggests that, presently, emission should be zero, and that CCl4 ought to be declining exponentially depending on its atmospheric lifetime. Although atmospheric CCl4 concentrations are declining, the rate is slower than expected, suggesting that there is an unknown source of CCl4 or that the combined partial lifetimes in different environmental compartments (atmosphere, ocean, soil) are slower than our understood processes. In the last years there were increasing discrepancies between emissions reported under the Montreal Protocol ('bottom-up method') and those which are inferred from measurements at global background sites ('top-down method'). In 2012 the potential gap in global emissions between the two methods widened to several ten thousand tons per year. In order to close this gap several possibilities were tested with atmospheric models and results are verified against the global trends and the interhemispheric gradients. 1) Existing data from sources and sinks were fed into the models to test the incompatibility of the existing emission data with the observed atmospheric observation for CCl4. 2) A newly revised 44-year steady-state atmospheric lifetime was assessed. This new lifetime together with an improved uncertainty has been carefully evaluated within a lifetime assessment for ODSs and related substances under SPARC (Stratosphere-troposphere Processes And their Role in Climate). The new atmospheric lifetime is substantially longer than the 35-years which were used in WMO (2011) for the atmosphere alone. However, estimates of soil sinks (195 yr) and ocean sinks (81 yr) lead to a best-estimated global lifetime of only 25 years, comparable

  15. CCl4对左旋氧氟沙星超声降解的影响%Effect of CCl4 on Antibiotics Levofloxacin' s Ultrasonic Degradation

    Institute of Scientific and Technical Information of China (English)

    魏红; 李娟; 李克斌; 孙剑宇; 赵锋

    2012-01-01

    The ultrasonic degradation of quinolone antibiotics levofloxacin in water with CC14 enhancement was investigated. The effects of CC14.dosage, ultrasonic power, pH value and initial concentration of levofloxacin were discussed. The products were examined by HPLC and LC-MS/MS. The results.indicated that the ultrasonic degradation of levofloxacin was obviously enhanced by CC14 addition; the degradation efficiency increased from 1. 9% to 69. 2% with CC14 dosage changed from 0 to 0. 06% ( volume fraction). The enhancement effect was attributed to the increasing · OH radical concentration and formation of chlorine-containing radicals in the presence of CC14 during ultrasonic processes. Levofloxacin degradation efficiency by ultrasonic in the presence of CC14 increased with the increasing of ultrasonic power in 100-200 W. The pH values of solution had prominent effect on levofloxacin degradation, while the initial concentration of levofloxacin had a negative effect. The temperature between 33-49 ℃ was found to be favorable to levofloxacin degradation. Moreover, HPLC analysis showed that two main by-products were simultaneously produced in the course of the ultrasonic degradation of levofloxacin in addition of CC14, the two products were confirmed by LC-MS/MS analysis.%研究了CCl4对超声降解喹诺酮类抗生素左旋氧氟沙星(Levofloxacin)的影响,考察了CCl4添加量、超声功率、溶液初始pH值及左旋氧氟沙星初始浓度等影响因素,并采用HPLC和LC-MS/MS对超声降解产物进行了初步分析.结果表明,CCl4增强了左旋氧氟沙星的超声降解,当反应液体积为50 mL,超声35 min时,随着CCl4体积分数的增大(0~0.06%),左旋氧氟沙星的降解率由1.9%增至69.2%;超声功率为100 ~200 W时,降解率随着功率的升高而增大,功率为200~400 W时降解率有所降低;pH值对左旋氧氟沙星的超声降解影响很大,pH =7.14时容易超声降解,pH过低或过高均导致降解率显著减小;CCl

  16. Chicory (Cichorium intybus L.) root extract regulates the oxidative status and antioxidant gene transcripts in CCl4-induced hepatotoxicity.

    Science.gov (United States)

    El-Sayed, Yasser S; Lebda, Mohamed A; Hassinin, Mohammed; Neoman, Saad A

    2015-01-01

    The ability of Cichorium intybus root extract (chicory extract) to protect against carbon tetrachloride (CCl4)-induced oxidative stress and hepatotoxicity was evaluated in male rats. The rats were divided into four groups according to treatment: saline (control); chicory extract (100 mg/kg body weight daily, given orally for 2 weeks); CCl4 (1 ml/kg body weight by intraperitoneal injection for 2 consecutive days only); or chicory extract (100 mg/kg body weight daily for 2 weeks) + CCl4 injection on days 16 and 17. The levels of hepatic lipid peroxidation, antioxidants, and molecular biomarkers were estimated twenty-four hours after the last CCl4 injection. Pretreatment with chicory extract significantly reduced CCl4-induced elevation of malondialdehyde levels and nearly normalized levels of glutathione and activity of glutathione S-transferase, glutathione peroxidase (GPx), glutathione reductase, catalase (CAT), paraoxonase-1 (PON1), and arylesterase in the liver. Chicory extract also attenuated CCl4-induced downregulation of hepatic mRNA expression levels of GPx1, CAT and PON1 genes. Results of DNA fragmentation support the ability of chicory extract to ameliorate CCl4-induced liver toxicity. Taken together, our results demonstrate that chicory extract is rich in natural antioxidants and able to attenuate CCl4-induced hepatocellular injury, likely by scavenging reactive free radicals, boosting the endogenous antioxidant defense system, and overexpressing genes encoding antioxidant enzymes. PMID:25807561

  17. Chicory (Cichorium intybus L. root extract regulates the oxidative status and antioxidant gene transcripts in CCl4-induced hepatotoxicity.

    Directory of Open Access Journals (Sweden)

    Yasser S El-Sayed

    Full Text Available The ability of Cichorium intybus root extract (chicory extract to protect against carbon tetrachloride (CCl4-induced oxidative stress and hepatotoxicity was evaluated in male rats. The rats were divided into four groups according to treatment: saline (control; chicory extract (100 mg/kg body weight daily, given orally for 2 weeks; CCl4 (1 ml/kg body weight by intraperitoneal injection for 2 consecutive days only; or chicory extract (100 mg/kg body weight daily for 2 weeks + CCl4 injection on days 16 and 17. The levels of hepatic lipid peroxidation, antioxidants, and molecular biomarkers were estimated twenty-four hours after the last CCl4 injection. Pretreatment with chicory extract significantly reduced CCl4-induced elevation of malondialdehyde levels and nearly normalized levels of glutathione and activity of glutathione S-transferase, glutathione peroxidase (GPx, glutathione reductase, catalase (CAT, paraoxonase-1 (PON1, and arylesterase in the liver. Chicory extract also attenuated CCl4-induced downregulation of hepatic mRNA expression levels of GPx1, CAT and PON1 genes. Results of DNA fragmentation support the ability of chicory extract to ameliorate CCl4-induced liver toxicity. Taken together, our results demonstrate that chicory extract is rich in natural antioxidants and able to attenuate CCl4-induced hepatocellular injury, likely by scavenging reactive free radicals, boosting the endogenous antioxidant defense system, and overexpressing genes encoding antioxidant enzymes.

  18. Dynamic change of hepcidin in liver fibrosis induced by CCl4 among mice

    Directory of Open Access Journals (Sweden)

    PANG Guojin

    2015-03-01

    Full Text Available ObjectiveTo investigate the dynamic change of hepcidin in liver fibrosis induced by CCl4 among mice. MethodsC57BL/6 mice were given CCl4 by intragastric administration to establish a liver fibrosis model. The degree of liver injury and fibrosis was evaluated by HE and Masson staining. Prussian blue staining was used to detect liver iron deposition in the progression of liver fibrosis. Primary hepatocytes, hepatic stellate cells, and Kupffer cells were isolated from C57BL/6 mice by two-step in situ collagenase perfusion and density gradient centrifugation. The mRNA levels of tumor necrosis factor alpha (TNFα, interleukin-6 (IL-6, interleukin-1β (IL-1β, and hepcidin were measured by quantitative real-time PCR (qRT-PCR. Continuous data were expressed as mean±SD, and comparison of continuous data between the two groups was made by t test. ResultsThe HE and Masson staining of liver tissues showed that the degree of liver fibrosis gradually increased as CCl4 was given, and hepatic fibrosis was reversed after the administration of CCl4 was stopped. Prussian blue staining showed that liver iron deposition increased as CCl4 was given; the area of liver iron deposition was significantly increased compared with that of the normal control group at week 4 of administration (t=4.772, P<0.05, but no significant increase was seen from week 4 to week 6; the area of liver iron deposition at week 6 was still higher than that of the normal control group (t=10.32, P<0.05; liver iron deposition decreased in the spontaneous reversal after the administration was stopped. The mRNA levels of TNFα, IL-1β, and IL-6 assessed by qRT-PCR continuously increased in model mice, reaching the peak levels at week 6, and significant differences were observed between the model mice and normal controls (t=4.322, 9.707, and 5.678, P<0.05 for all. The expression of hepcidin in the liver increased in the early stage of model establishment and reached the peak level at week 4

  19. Antihepatotoxic effect of golden berry (Physalis peruviana Linn.) in carbon tetrachloride (CCl4) intoxicated rats.

    Science.gov (United States)

    Taj, Darakhshan; Khan, Hira; Sultana, Viqar; Ara, Jehan; Ehteshamul-Haque, Syed

    2014-05-01

    Liver is the main site in the body for intense metabolism and excretion. A number of chemicals and drugs which are used routinely cause liver damage. The present study investigates the antihepatotoxic effect of Physalis peruviana whole ripe fruit, water and ethanol extracts of fruit in normal as well as in carbon tetrachloride (CCl(4)) intoxicated rats. The CCl(4) treated rats showed marked elevation in liver enzymes: alanine transaminse, aspratate transaminase, alkaline phosphatase, lactate dehydrogenase and other biochemical parameters: bilirubin, creatinine and urea, thus indicating liver injury. Whereas animal treated/fed with various preparations of Physalis peruviana showed significant lowering effect (pPhysalis peruviana showed highest activity in both rat models while ripe fruit and ethanol extract showed moderate activity compared to standard drug. PMID:24811807

  20. HEPATOPROTECTIVE EFFECT OF METHANOLIC EXTRACT OF HEDYOTIS HERBACEA LINN IN CCl4 TREATED MALE RATS

    OpenAIRE

    Sharma Naveen; Jain AK; Sharma Vipin; Jain Suman; Saluja Gurdeep

    2012-01-01

    To evaluate the hepatoprotective effect of methanolic extract of Hedyotis herbacea Linn in rats treated with CCl4. In Hepatotoxic rats, liver damage was studied by assessing parameters such as aspartate amino transferase (AST), alanine amino transferase (ALT), alkaline phosphate transferase (ALP) and gamma glutamyl transpeptidase (GGT) in serum and concentration of total proteins, total lipids, phospholipids, triglycerides and cholesterol in both serum and liver. The effect of co-administrati...

  1. Pharmacological investigation of Polyherbal formulation on Carbon tetrachloride (CCl4-induced liver damage in wistar rats

    Directory of Open Access Journals (Sweden)

    Hardik Soni

    2014-09-01

    Full Text Available Objective: To investigate effect of Polyherbal formulation on Carbon tetrachloride (CCl4-induced liver damage in wistar rats. Methods: Wistar albino rats weighing 180-230 g either sex were used. The selected animals were divided in to four groups where each group consisted of six animals. Experimentally liver damage was produced by intra-peritoneal administration of CCl4 and olive oil mixture (1:1 v/v (1 mL/kg, once daily, i.p. for 7 days. Test Drug, Polyherbal formulation was administered orally for 7 consecutive days at 3 mL/kg, once daily. On 8th day, Blood samples were collected to evaluate different serum biochemical parameters like Aspartate aminotransferase (AST, Alanine aminotransferase (ALT, Alkaline phosphatase (ALP, Total bilirubin and Total protein. Liver from animals of each group was dissected out for histopathological examination. Statistical analysis: Statistical calculation were done by analysis of variance (ANOVA followed by post hoc Dunnett’s test, with significant level of p<0.05. Results and dDiscussion: Polyherbal formulation showed significant effect on activity levels of serum AST, ALT, ALP and total bilirubin level while comparing test group to disease control group. It also showed significant elevation in decreased level of serum total protein. Pre-treatment of Polyherbal formulation restored the hepatic architecture and protected the liver tissue from fatty degenerative changes by preventing the toxic chemical reaction induced by CCl4. Conclusion: Finding of this study concludes that Polyherbal formulation (Vasuliv Syrup has promising hepatoprotective activity against CCl4-induced liver damage. It can be employed as safe and effective treatment for hepato-toxicity or liver damage.

  2. PROTECTIVE ABILITY OF MOMORDICA CHARANTIA L AGAINST CCL4 INDUCED HEPATIC DAMAGE IN RATS

    OpenAIRE

    Pingale Shirish S

    2010-01-01

    The aim of this study is to evaluate the efficacy of Momordica charantia on the experimental hepatotoxicity induced by carbon tetrachloride (CCl4). Carbon tetrachloride was administered once and simultaneously suspension of dry fruit powder was prepared in aqueous medium and was daily administered at a dose level of 1mg/kg body weight for 4 days. Silymarin was used as a standard drug for this study. Administration of carbon tetrachloride showed significant changes in the levels of serum amino...

  3. Ginkgo biloba extract reverses CCl4-induced liver fibrosis in rats

    Institute of Scientific and Technical Information of China (English)

    Yan-Jun Luo; Jie-Ping Yu; Zhao-Hong Shi; Li Wang

    2004-01-01

    AIM: To study the reversing effect of Ginkgo biloba extract (GbE) on established liver fibrosis in rats.METHODS: Following confirmation of CCl4-induced liver fibrosis, GbE or saline was administrated to the rats for 4 weeks. The remaining rats received neither CCl4 nor GbE as normal control. The four groups were compared in terms of serum enzymes, tissue damage, expression of αSMA and tissue inhibitor-1 of metalloproteinase (TIMP-1) and metalloproteinase-1 (MMP-1).RESULTS: Compared with saline-treated group, liver fibrosis rats treated with GbE had decreased serum total bilirubin (P<0.01) and aminotransferase levels (P<0.01) and increased levels of serum albumin (P<0.01). Microscopic studies revealed that the livers of rats receiving GbE showed allieviation in fibrosis (P<0.05) as well as expression of αSMA (P<0.01). The liver collagen and reticulum contents were lower in rats treated with GbE than saline-treated group (P<0.01). RT-PCR revealed that the level of TIMP-1 decreased while the level of MMP-1 increased in GbE group.CONCLUSION: Administration of GbE improved CCl4-induced liver fibrosis. It is possibly attributed to its effect of inhibiting the expression of TIMP-1 and promoting the apoptosis of hepatic stellate cells.

  4. [Triterpenoids from Inonotus obliquus protect mice against oxidative damage induced by CCl4].

    Science.gov (United States)

    Zhao, Fen-Qin; Yan, Lin; Cui, Xian-Hong; Lin, Sheng; Wang, Cong; Zhang, Hui; Kang, Xiao-Yan; Ji, Bian-Sheng

    2012-05-01

    To investigate the effects of lanosterol (1), inotodiol (2) and trametenolic acid (3) from Inonotus obliquus against oxidative damage induced by CCl4 in mice, 1, 2 and 3 (20, 10 and 5 mg x kg(-1)) were respectively administered to mice, once a day for 3 days. Then the mice were induced to oxidative damage by CCl4 on the third day 30 min after the administration. The activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-PX) and the content of malondialdehyde (MDA) and reductive glutathione (GSH) in serum and liver homogenate were determined. And the levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and interleukin-6 (IL-6) concentration in serum were detected. The results showed that treatment with compound 1, 2 and 3 could significantly increase the activities of SOD, CAT and GSH-PX in serum and liver homogenate. Furthermore, the content of GSH in serum and liver homogenate increased and MDA content decreased markedly. In addition, compound 1, 2 and 3 could significantly inhibit the activities of ALT and AST in serum, and decrease the IL-6 concentration in serum remarkably. So, compound 1, 2 and 3 can protect mice against oxidative stress injury induced by CCl4. Furthermore, compound 1, 2 and 3 can protect cells from damage through inhibition on ALT, AST and the expression of IL-6. PMID:22812017

  5. Analysis of radiorespirometric pattern in rats bearing liver injury treated with CCl4

    International Nuclear Information System (INIS)

    Respirometric pattern in rats during the recovery from liver injury treated with 20% CCl4 for radioactivity from glucose (U-14C) was studied associating with the changes in transaminase and glycolytic enzyme activities. The results were as follows: (1) In radiorespirometry, peak time (PT) was delayed about 10 minutes over as compared with control, hastened markedly at 3rd day, and thereafter become to be normal level. On the other hand, peak height (PH) and yield value (YV) which decreased at 1st day were represented the values at 3rd day before the treatment of CCl4. (2) Transaminase, glutamic oxalacetic transaminase (GOT), and glutamic pyruvic transaminase (GPT) activities were both increased immediately after the treatment of CCl4 on the basis of liver cell destruction and reached at maximum between 1st and 2nd day. At 3rd day, these activities were become to decrease and shown normal levels at 4th day. (3) Glycolytic enzyme, pyruvate kinase (PK), hexokinase (HK), and glucose-6-phosphate dehydrogenase (G-6-PD) were markedly activated at 3rd day and thereafter shown normal level. (4) These radiorespirometric pattern reflected well the physiological or biochemical states in rats. As the results of this study, radiorespirometry can be useful method for clinical diagnosis of liver disease. (author)

  6. Attenuation of CCl4-Induced Oxidative Stress and Hepatonephrotoxicity by Saudi Sidr Honey in Rats

    Directory of Open Access Journals (Sweden)

    Mohammed Al-Yahya

    2013-01-01

    Full Text Available The present study was undertaken to investigate the possible protective effect of Saudi Sidr honey (SSH on carbon tetrachloride (CCl4 induced oxidative stress and liver and kidney damage in rat. Moreover, the antioxidant activity and the phenolic and flavonoidal contents were determined. The hepatorenal protective activity of the SSH was determined by assessing biochemical, hematological, and histological parameters. Serum transaminases, ALP, GGT, creatinine, bilirubin urea, uric acid, and MDA level in liver and kidney tissues were significantly elevated, and the antioxidant status of nonprotein sulfhydryls, albumin, and total protein levels in liver and kidney were declined significantly in CCl4 alone treated animals. Pretreatment with SSH and silymarin prior to the administration of CCl4 significantly prevented the increase of the serum levels of enzyme markers and reduced oxidative stress. SSH also exhibited a significant lipid-lowering effect and caused an HDL-C enhanced level in serum. The histopathological evaluation of the liver and kidney also revealed that honey protected incidence of both liver and kidney lesions. Moreover, SSH showed a strong antioxidant activity in DPPH and β-carotene-linoleic acid assays. SSH was found to contain phenolic compounds. Additionally, the SSH supplementation restored the hepatocytes viability against 2′,7′-dichlorofluorescein (DCF toxicity in ex vivo test.

  7. Prevention of carbon tetrachloride (CCl4)-induced toxicity in testes of rats treated with Physalis peruviana L. fruit.

    Science.gov (United States)

    Abdel Moneim, Ahmed E

    2016-06-01

    Treatment of rats with carbon tetrachloride (CCl4; 2 ml/kg body weight) once a week for 12 weeks caused a significant decrease in serum levels of testosterone, luteinizing hormone, and follicle-stimulating hormone. These decreases in sex hormones were reduced with Physalis peruviana L. (Cape gooseberry) juice supplementation. In addition, testicular activity of antioxidant enzymes such as superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, and glutathione-S-transferase suppressed with CCl4 were elevated after P. peruviana juice supplements. P. peruviana juice supplementation significantly increased the testicular glutathione and significantly decreased the level of lipid peroxidation and the nitric oxide production compared with the CCl4 group. In addition, the decline in the activity of antioxidant enzymes after CCl4 was ameliorated by P. peruviana Moreover, degeneration of germ and Leydig cells along with deformities in spermatogenesis induced after CCl4 injections were prevented with the supplementation of P. peruviana juice. Furthermore, P. peruviana juice attenuated CCl4-induced apoptosis in testes tissue by inhibition of caspase-3 activity. The results clearly demonstrate that P. peruviana juice augments the antioxidants defense mechanism against CCl4-induced reproductive toxicity and provides evidence that the juice may have a therapeutic role in free radical-mediated diseases and infertility. PMID:25147302

  8. Chicory (Cichorium intybus L.) Root Extract Regulates the Oxidative Status and Antioxidant Gene Transcripts in CCl4-Induced Hepatotoxicity

    OpenAIRE

    El-Sayed, Yasser S.; Lebda, Mohamed A.; Mohammed Hassinin; Neoman, Saad A.

    2015-01-01

    The ability of Cichorium intybus root extract (chicory extract) to protect against carbon tetrachloride (CCl4)-induced oxidative stress and hepatotoxicity was evaluated in male rats. The rats were divided into four groups according to treatment: saline (control); chicory extract (100 mg/kg body weight daily, given orally for 2 weeks); CCl4 (1 ml/kg body weight by intraperitoneal injection for 2 consecutive days only); or chicory extract (100 mg/kg body weight daily for 2 weeks) + CCl4 injecti...

  9. Protective effect of recombinant human IL-1Ra on CCl_4-induced acute liver injury in mice

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    AIM: To evaluate the effects of positive regulation of recombinant human interleukin 1 receptor antagonist (rhIL-1Ra) on hepatic tissue recovery in acute liver injury in mice induced by carbon tetrachloride (CCl 4 ). METHODS: Acute liver damage was induced by injecting 8-wk-old mice with CCl 4 1 mL/kg (1:3 dilution in corn oil) intraperitoneally (ip). Survival after liver failure was assessed by injecting 8-wk-old mice with a lethal dose of CCl 4 2.6 mL/kg (1:1 dilution in corn oil) ip. Mice were subcutaneo...

  10. Ferroelectric phase transition in hydrogen-bonded 2-aminopyridine phosphate (NC sub 4 H sub 4 NH sub 2)centre dot H sub 3 PO sub 4

    CERN Document Server

    Czapla, Z; Waskowska, A

    2003-01-01

    A new crystal of 2-aminopyridine phosphate (NC sub 4 H sub 4 NH sub 2)centre dot H sub 3 PO sub 4 has been grown and its x-ray structure and physical properties were studied. At room temperature the crystals are monoclinic, space group C2/c. The flat 2-aminopyridine cations are hydrogen bonded to the anionic [PO sub 4 ] groups. The interesting feature of the crystal structure is the three-dimensional network of hydrogen bonds including, among others, two strong, symmetrical O centre dot centre dot centre dot H, H centre dot centre dot centre dot O interactions with disordered proton locations. Symmetrically related PO sub 4 anions linked through these protons form infinite (PO sub 4) subinfinity chains along the crystal a-axis. The anomalies in the temperature dependence of the electric permittivity showed that the crystal undergoes ferroelectric phase transition at T sub c = 103.5 K. The spontaneous polarization takes place along the crystal a-axis, being parallel to the chains of the hydrogen-bonded PO sub ...

  11. Suppression of indium droplet formation by adding CCl4 during metalorganic chemical vapor deposition growth of InN films

    International Nuclear Information System (INIS)

    In this work, the influences of CCl4 on the metalorganic chemical vapor deposition (MOCVD) growth of InN were studied for the first time. It was found that the addition of CCl4 can effectively suppress the formation of metal indium (In) droplets during InN growth, which was ascribed to the etching effect of Cl to In. However, with increasing of CCl4 flow, the InN growth rate decreased but the lateral growth of InN islands was enhanced. This provides a possibility of promoting islands coalescence toward a smooth surface of the InN film by MOCVD. The influence of addition of CCl4 on the electrical properties was also investigated

  12. Protective effect of recombinant human IL-1Ra on CCl4-induced acute liver injury in mice

    OpenAIRE

    Zhu, Run-Zhi; Xiang, Di; Xie, Chao; Li, Jing-Jing; Hu, Jian-Jun; He, Hong-Lin; Yuan, Yun-Sheng; GAO, JIN; HAN, WEI; Yu, Yan

    2010-01-01

    AIM: To evaluate the effects of positive regulation of recombinant human interleukin 1 receptor antagonist (rhIL-1Ra) on hepatic tissue recovery in acute liver injury in mice induced by carbon tetrachloride (CCl4).

  13. The Protective Effect of Liquorice Plant Extract on CCl4-Induced Hepatotoxicity in Common Carp (Cyprinus carpio

    Directory of Open Access Journals (Sweden)

    Hassan Malekinejad

    2010-12-01

    Full Text Available The protective effect of liquorice plant extract (LPE on CCl4-induced hepatotoxicity in common carp was evaluated using fifty adult carps. The fish were cultured in a standard environment in terms of water flow rate, oxygen, pH, food and temperature. The fish were assigned into 5 groups (N = 10 as control, sham, and tests. The test groups were pre-treated for 3 h with various concentrations of LPE, 3 days before CCl4 exposure. The control and sham groups received normal saline before and after CCl4 exposure. To induce hepatotoxicity, animals in the sham and test groups were exposed against 100 l L-1 CCl4 for 45 min. The fish in all groups 1 h after CCl4 exposure were anesthetized and the blood samples were collected. Immediately the liver specimens were dissected out and were stored in 10 % formalin for further pathological studies. Determination of serum level of ALP and SGOT revealed that acute form of CCl4 exposure elevated significantly (P < 0.05 the serum level of either tested hepatic marker enzymes. While 3 days pretreatment with LPE prevented from ALP and SGOT enhancement. The pathological evaluation revealed that the CCl4 exposure resulted in a minor pathologic manifestation such as slight congestion, which the LPE pretreated groups showed the remarkable improvement. The anti-oxidant capacity of LPE was assayed by FRAP and DPPH methods. Both provided techniques showed that LPE exerts an excellent anti-oxidant effect. This data suggest that LPE exerts protective effect against CCl4-induced hepatotoxicity. Moreover, the hepatoprotective effect of LPE may attribute to its antioxidant capacity.

  14. Bone marrow cells ameliorate liver fibrosis and express albumin after transplantation in CCl 4 -induced fibrotic liver

    Directory of Open Access Journals (Sweden)

    Gibran Ali

    2012-01-01

    Full Text Available Background/Aim: We investigated the effect of bone marrow-derived stem cell (BMSC transplantation on carbon tetrachloride (CCl 4 -induced liver fibrosis. Patients and Methods: BMSCs of green fluorescent protein (GFP mice were transplanted into 4-week CCl 4 -treated C57BL/6 mice directly to the liver, and the mice were treated for 4 more weeks with CCl 4 (total, 8 weeks. After sacrificing the animals, quantitative data of percentage fibrosis area and the number of cells expressing albumin was obtained. One-way analysis of variance was applied to calculate the significance of the data. Results: GFP expressing cells clearly indicated migrated BMSCs with strong expression of albumin after 28 days post-transplantation shown by anti-albumin antibody. Double fluorescent immunohistochemistry showed reduced expression of αSMA on GFP-positive cells. Four weeks after BMSC transplantation, mice had significantly reduced liver fibrosis as compared with that of mice treated with CCl 4 assessed by Sirius red staining. Conclusion: Mice with BMSC transplantation with continuous CCl 4 injection had reduced liver fibrosis and a significantly improved expression of albumin compared with mice treated with CCl 4 alone. These findings strengthen the concept of cellular therapy in liver fibrosis.

  15. Protective effect of Tetracera scandens L.leaf extract against CCl4-induced acute liver injury in rats

    Institute of Scientific and Technical Information of China (English)

    Tung; Bui; Thanh; Hai; Nguyen; Thanh; Hue; Pham; Thi; Minh; Huong; Le-Thi-Thu; Huong; Duong; Thi; Ly; Loi; Vu; Duc

    2015-01-01

    Objective:To investigate the protective potential of ethanolic extracts of Tetracera scandens L.(T.scandens) against CCl4 induced oxidative stress in liver tissues.Methods:Dried leaf powder of T.scandens was extracted with ethanol and concentrated to yield a dry residue.Rats were administered with 100 mg/kg of ethanolic extracts orally once daily for one week.Animals were subsequently administered with a single dose of CCl4(I mL/kg body weight,intraperitoneal injection).Various assays,such as serum levels of alanine aminotransferase,aspartate aminotransferase,lipid peroxidation,protein oxidation(carbonyl protein group),tumor necrosis factor alpha,catalase,superoxide dismutase,and glutathione peroxidase,were used to assess damage caused by CCl4 and the protective effects of the ethanol extract on liver tissues.Results:Hepatotoxicity induced by CCl4 was evidenced by a significant increase in serum aspartate aminotransferase and alanine aminotransferase level,lipid peroxidation,protein carbonyl group,and tumor necrosis factor alpha,as well as decreased activity of the hepatic antioxidant enzymes(catalase.superoxide dismutase.and glutathione peroxidase).Treatment with ethanolic T.scandens extracts prevented all of these typically observed changes in CCl4-treated rats.Conclusions:Our findings indicate that T.scandens has a significant protective effect against CCl4 induced hepatotoxicity in rat.which may be due to its antioxidant properties.

  16. Deuteron and triton production in Pb+Pb collisions at 158 A centre dot GeV.

    CERN Document Server

    Hansen, A G; Bøggild, H; Boissevain, J G; Conin, L; Christiansen, P; Dodd, J; Erazmus, B; Esumi, S; Fabjan, Christian Wolfgang; Ferenc, D; Fields, D E; Franz, A; Gaardhøje, J J; Hansen, A G; Hansen, O; Hardtke, D; Hecke, H V; Holzer, E B; Humanic, T J; Hummel, P; Jacak, B V; Jayanti, R; Kaimi, K; Kaneta, M; Kohama, T; Kopytine, M; Leltchouk, M; Ljubicic, A; Lörstad, B; Martin, L; Maeda, N; Malina, R; Medvedev, A; Murray, M; Ohnishi, H; Paic, G; Pandey, S U; Piuz, François; Pluta, J; Polychronakos, V; Potekhin, M V; Poulard, G; Reichhold, D M; Sakaguchi, A; Simon-Gillo, J; Schmidt-Sørensen, J; Sondheim, W E; Sugitate, T; Sullivan, J P; Sumi, Y; Willis, W J; Wolf, K L; Xu, N; Zachary, D S

    1999-01-01

    NA44 has measured the invariant cross section of deuterons and tritons at non zero p sub t in 158 A centre dot GeV lead on lead collisions at CERN SPS. Normalized transverse mass spectra and coalescence parameters versus p sub t have been calculated showing a significant transverse flow. Radius parameters have been extracted using a simple thermal coalescence model. Results from RQMD+coalescence calculations are compared to the data.

  17. Intestinal permeability assessed by 51Cr-EDTA in rats with CCl4 - induced cirrhosis Permeabilidade intestinal ao 51-Cr-EDTA em ratos com cirrose induzida por CCl4

    Directory of Open Access Journals (Sweden)

    Ana Regina L. Ramos

    2010-06-01

    Full Text Available CONTEXT: The straight relationship between cirrhosis and impaired intestinal barrier has not been elucidated yet. OBJECTIVES: To verify 51Cr-EDTA-intestinal permeability in rats with CCl4-induced cirrhosis and controls. METHOD: Fifty male Wistar rats weighing 150-180 g were separated in three groups: 25 animals received CCl4 0.25 mL/kg with olive oil by gavage with 12 g/rat/day food restriction for 10 weeks (CCl4-induced cirrhosis; 12 received the same food restriction for 10 weeks (CCl4-non exposed. Other 13 rats received indomethacin 15 mg/kg by gavage as positive control of intestinal inflammation. RESULTS: The median (25-75 interquartile range 51Cr-EDTA-IP values of cirrhotic and CCl4-non exposed rats were 0.90% (0.63-1.79 and 0.90% (0.60-1.52 respectively, without significant difference (P = 0.65. Animals from indomethacin group showed 51Cr-EDTA-IP, median 7.3% (5.1-14.7, significantly higher than cirrhotic and CCl4-non exposed rats (PCONTEXTO: A relação direta entre cirrose e alterações na barreira intestinal ainda não foi devidamente esclarecida. OBJETIVO: Verificar a permeabilidade intestinal ao 51Cr-EDTA em ratos com cirrose induzida por tetracloreto de carbono (CCl4 e controles. MÉTODO: Cinquenta ratos Wistar machos pesando 150-180 g foram separados em três grupos: 25 animais receberam CCl4 0,25 mL/kg diluído em óleo de oliva por gavagem com restrição dietética de 12 g/rato/dia por 10 semanas (grupo cirrose induzida por CCl4; 12 receberam a mesma restrição dietética por 10 semanas (grupo não exposto ao CCl4. Outros 13 ratos receberam indometacina 15 mg/kg por gavagem como controle positivo de inflamação intestinal. RESULTADOS: A mediana (intervalo interquartil 25-75 dos valores de permeabilidade intestinal ao 51Cr-EDTA dos grupos cirrose induzida por CCl4 e não exposto ao CCl4 foram 0,90% (0,63-1,79 e 0,90% (0,60-1,52, respectivamente, sem significância estatística (P = 0,65. Os animais do grupo indometacina

  18. Hepatoprotective effects of solanum nigrum extracts on carbon tetrachloride (CCl4) induced hepatotoxicity in rats

    International Nuclear Information System (INIS)

    Effects of aqueous and alcoholic extracts of Solanum nigrum were investigated against CCl4 induced hepatic damage in male albino rats of Sprague Dowley Strain. Enzymatic activities i.e. Aspartate Transaminase, Alanine Transaminase and Alkaline Phosphatase, and gross microscopic appearance of liver were used as parameters and hepato protective studies were performed. In case of hepato protective study i.e. pre-treatment of rats with aqueous extracts of plant (500 mg orally, two doses with 24 hours interval) prevented (p <0.001) CCl4 induced rise in activity of serum Transaminases (ALT and AST) and ALP, whereas the alcoholic extract did not prevent the rise of same enzymes, compared to the sham control group in which liver was damaged by CCI4, no treatment given. Histological examination of the liver of animals treated with aqueous extract of plant showed that change in fatty acids was less in comparison to the sham control group. In the treated group, reduction in body-weight was minimal and liver enlargement was also less, as compared to the animals in sham control group. These results indicate that only aqueous extract of Solanum nigrum exhibits hepatoprotective effects, at least within the parameters of the present study. (author)

  19. Effects of Lawsonia inermis L. (Henna Leaves' Methanolic Extract on CCl4-induced Hepatotoxicity in Rats

    Directory of Open Access Journals (Sweden)

    Musab Awad Mohamed

    2016-03-01

    Background: Natural products with therapeutic properties such as plants, minerals and animal products, for many years, were the main sources of drugs for treatment of numerous diseases; hence selection of Lawsonia inermis L. (Henna in order to study its hepatoprotective activity was considered. Objectives: This was an attempt to evaluate the hepatoprotective effect of Lawsonia inermis leaves' methanolic extract on CCl4-induced hepatotoxicity in rats. Methods: The L. inermis leaves' methanolic extract, which obtained by maceration, was orally administered in doses of 100mg/kg and 200mg/kg to the tested animals in order to assess it's effects on serum levels of hepatotoxicity parameters, alanine aminotransferase (ALT, aspartate aminotransferase (AST, alkaline phosphatase (ALP, bilirubin and total proteins along with histopathological liver sections examination, while silymarin (25mg/kg, a potent hepatoprotective drug, was used as standard control. Results: The two doses of the plant extract showed dose-dependent hepatoprotective effect, as evident by the significant reduction (P < 0.05 in serum levels of AST, ALT, ALP and bilirubin along with the improvement in histopathological liver sections compared to CCl4-only treated animals. Conclusion: As experimentally evident, it could be concluded that, this plant material could provide a hepatoprotective effect which could be attributed to its antioxidant properties. [J Intercult Ethnopharmacol 2016; 5(1.000: 22-26

  20. Antioxidant Potential of Plumieride against CCl4-Induced Peroxidative Damage in Rats

    Directory of Open Access Journals (Sweden)

    Dharmendra Singh

    2014-11-01

    Full Text Available In search of a new potent as an antioxidant from natural sources, plumieride—an iridoid isolated from the methanol extract of the bark of Plumeria bicolor (family Apocynaceae was evaluated for its antioxidant potential against CCl4-induced peroxidative damage in liver of rats. The antioxidant potential was evaluated by using hepatic tissue for SOD (superoxide dismutase, CAT (catalase, GSH (reduced glutathione, GPx (glutathione peroxidase, GR (glutathione reductase and LPO (lipid peroxidation alongwith the concomitant blood serum for AST & ALT (aspartate and alanine transaminases, GGT (gamma glutamyl transpeptidase, ALP (alkaline phosphatase, total bilirubin and total protein contents. All the biochemical parameters were significantly (p ≤ 0.001 altered by CCl4 (0.3 mL/kg body weight/twice a week, intra-peritoneally for 30 days. Simultaneously, oral treatment with plumieride (5, 10 and 20 mg/kg body weight/day for 30 days, restored all the parameters towards a normal level, remarkably. The histological findings of liver sections further corroborated the antioxidant potential of plumieride compared with standard drug-silymarin. In conclusion, plumieride consists of sugar molecules, which have alcoholic groups. Therefore, the alcoholic groups of sugar increase its antioxidant potential through intermolecular hydrogen bonding along with the thiol(SH group of non-protein thiols and enzymes resulting in the restoration of the antioxidant system. Therefore, it might be considered a natural antioxidant against peroxidative damage in rats.

  1. Protective Effect of γ-Irradiated Dried Powder of Artichoke Leaves against CCl4 Oxidative Stress Induced in Rat Liver

    International Nuclear Information System (INIS)

    Liver injuries are one of the most degenerative worldwide diseases and can lead to different complications. Artichoke (Cynara scolymus L.) is full of natural antioxidants and has hepato protective effect against liver toxicity. Gamma irradiation has been widely used as a first choice sterilization method of raw medicinal plants to be used in the phytotherapic industry worldwide .This study was designed to investigate the effect of dietary supplementation with γ- irradiated artichoke against carbon tetrachloride (CCl4)-induced oxidative stress and hepatotoxicity. The results of high performance liquid chromatography (HPLC) analysis of artichoke leaves indicated that the value of some of the main phenolic constituents was elevated under the effect of γ-irradiation (10 KGy). CCl4 administration resulted in significant increase in the activity of serum alkaline phosphatase, gamma glutamyl transferase and transaminase in addition to an increase in the level of total bilirubine, malondialdehyde (MDA), glucose and the concentration of some lipid contents. Furthermore, CCl4 administration reduced glutathione content, superoxides dismutase (SOD) and catalase (CAT) activity as well as a remarkable decrease in the level of insulin and high density lipoprotein-cholesterol was observed. In CCl4-treated rats dietary supplemented with either raw or γ-irradiated artichoke, a significant amelioration was observed on the adverse effects of the above mentioned parameters induced by CCl4 administration. The present findings concluded that artichoke may be useful, as dietary supplement and possess phenolic compounds, for the prevention of oxidative stress-induced hepatotoxicity

  2. Comparative Study of Decomposition of CCl4 in Different Atmosphere Thermal Plasmas

    Institute of Scientific and Technical Information of China (English)

    HUANG Jianjun; GUO Wenkang; XU Ping

    2007-01-01

    Decomposition of carbon tetrachloride was studied theoretically in the most commonly used thermal plasma atmosphere such as H2, N2, O2 and water steam. A code developed by the National Aeronautics and Space Administration (NASA) was adopted to calculate the chemical equilibrium distribution and energy consumption of the decomposition of CCl4 in the H2, N2, O2 and water steam atmosphere thermal plasma respectively, with a temperature range of 500 K to 5000 K. In the neutral condition (H2, N2, atmosphere) formation of solid carbon was observed and in the oxygen-atmosphere (O2 and water steam) solid carbon formation disappeared through controlling the ratio of C/O. This indicates that the formation of polycyclic aromatic hydrocarbons (PAHs) is impossible theoretically. The energy consumption in the N2 atmosphere was much higher than that in the H2, O2 and water steam atmosphere at 1500 K.

  3. PROTECTIVE ABILITY OF MOMORDICA CHARANTIA L AGAINST CCL4 INDUCED HEPATIC DAMAGE IN RATS

    Directory of Open Access Journals (Sweden)

    Pingale Shirish S

    2010-12-01

    Full Text Available The aim of this study is to evaluate the efficacy of Momordica charantia on the experimental hepatotoxicity induced by carbon tetrachloride (CCl4. Carbon tetrachloride was administered once and simultaneously suspension of dry fruit powder was prepared in aqueous medium and was daily administered at a dose level of 1mg/kg body weight for 4 days. Silymarin was used as a standard drug for this study. Administration of carbon tetrachloride showed significant changes in the levels of serum aminotransferase, alkaline phosphatase, bilirubin and total proteins levels, however necrosis, collagen deposition and altered hepatic architecture were also observed. Markers of liver injury, altered aminotransferase, alkaline phosphatase, bilirubin etc. and morphological changes such as necrosis and collagen deposition were significantly decreased in the rats treated with Momordica charantia fruit powder. These results suggest that the Momordica charantia showed hepatoprotective effect on carbon tetrachloride induced hepatic damage and may be a potential clinical application for treatment of liver diseases.

  4. HEPATOPROTECTIVE EFFECT OF METHANOLIC EXTRACT OF HEDYOTIS HERBACEA LINN IN CCl4 TREATED MALE RATS

    Directory of Open Access Journals (Sweden)

    Sharma Naveen

    2012-10-01

    Full Text Available To evaluate the hepatoprotective effect of methanolic extract of Hedyotis herbacea Linn in rats treated with CCl4. In Hepatotoxic rats, liver damage was studied by assessing parameters such as aspartate amino transferase (AST, alanine amino transferase (ALT, alkaline phosphate transferase (ALP and gamma glutamyl transpeptidase (GGT in serum and concentration of total proteins, total lipids, phospholipids, triglycerides and cholesterol in both serum and liver. The effect of co-administration of Methanolic extract of Hedyotis herbacea on the above parameters was further investigated. Histopathological study of the liver was also undertaken. A rise in the level of AST, ALT, ALP & GGT in serum evidence as hepatic damage and also changes in other biochemical parameters observed in serum and liver showed a tendency to attain near normalcy in animals co-administration with Methanolic extract of Hedyotis herbacea. The normal value for AST – 25.25 IU/L, ALP – 73.02 IU/L, Protein - 6.62 IU/L, Total lipid – 133.45 gm/100 ml. Were found to alter towards value AST – 34.51 IU/L, ALP – 130.15 IU/L, Protein – 3.42 IU/L, Total lipid – 270.82 gm/100 ml in Hepatoprotective rats. These parameters attained near normal values. AST – 24.82 IU/L, ALP – 85.15 IU/L, Protein – 5.98 IU/L, Total lipid – 151.24 gm/100 ml in Methanolic extract of Hedyotis herbacea co-administrated rats. Profound steatosis- Ballooning degeneration and nodule formation observed in the hepatic architecture of CCl4 treated rats were found to acquire near normalcy in drug co-administration rats thus corroborating the biochemical observations. The study substantiates the Hepatoprotective potential of Methanolic extract of Hedyotis herbacea.

  5. Polyphenolic screening and protective properties of some vegetables against CCl4 liver damage

    International Nuclear Information System (INIS)

    In the present study, we screened for the polyphenolic compounds present in some selected tropical vegetables and the protective effect of the vegetable extract against CCl4-induced hepatotoxicity in rats as a way of evaluating their medicinal potential in addition to their nutritional values. The use of HPLC/DAD/MS revealed the presence of some phenolic compounds in the studied vegetables. Crassocephalum crepidioides; caffeoyl derivatives, Talinum triangulare; rutin and kaempferol derivatives, Amaranthus hybridus; caffeoyl derivative, rutin and kaempferol derivative, Hibiscus esculentus; caffeoyl derivative, quercetin derivative and an unidentified flavonoid, Xanthosoma mafaffa; six unidentified flavonoids with similar absorption maximum at different retention times) and Celocia argentia (luteolin derivative and four unidentified flavonoids. Carbon tetrachloride at a dose of 0.5ml/kg body weight (b.w) produced liver damage in rats as manifested by the rise in the levels of ALT (IU/l), AST (IU/l) and total protein (g/l) in the serum (40.60 ± 3.50, 80.60 ± 5.10, 73.20 ± 1.87), in the liver homogenate (1300.00 ± 7.38, 1660.00 ± 13.69, 250.00 ± 7.51) and MDA content (nmol TBARS/mg Liver Protein) in the liver homogenate (82.00 ± 0.02, 82.00 ± 0.07) compared to the control. The result revealed a reduction of the serum marker enzymes (ALT, AST and Total protein), compared with the CCl4 treated group after the administration of the various polyphenolic extract. In a similar manner, the extract brings about a reduction of the MDA content. It could be concluded that the protective properties exhibited by the vegetables could be amongst other factor due to the presence of some polyphenols. (author)

  6. Attenuation of CCl4-induced hepatic fibrosis in mice by vaccinating against TGF-β1.

    Directory of Open Access Journals (Sweden)

    Xiaobao Fan

    Full Text Available Transforming growth factor β1 (TGF-β1 is the pivotal pro-fibrogenic cytokine in hepatic fibrosis. Reducing the over-produced expression of TGF-β1 or blocking its signaling pathways is considered to be a promising therapeutic strategy for hepatic fibrosis. In this study, we evaluated the feasibility of attenuating hepatic fibrosis by vaccination against TGF-β1 with TGF-β1 kinoids. Two TGF-β1 kinoid vaccines were prepared by cross-linking TGF-β1-derived polypeptides (TGF-β1(25-[41-65] and TGF-β1(30-[83-112] to keyhole limpet hemocyanin (KLH. Immunization with the two TGF-β1 kinoids efficiently elicited the production of high-levels of TGF-β1-specific antibodies against in BALB/c mice as tested by enzyme-linked immunosorbent assay (ELISA and Western blotting. The antisera neutralized TGF-β1-induced growth-inhibition on mink lung epithelial cells (Mv1Lu and attenuated TGF-β1-induced Smad2/3 phosphorylation, α-SMA, collagen type 1 alpha 2 (COL1A2, plasminogen activator inhibitor-1 (PAI-1 and tissue inhibitor of metalloproteinase-1 (TIMP-1 expression in the rat hepatic stellate cell (HSC line, HSC-T6. Vaccination against TGF-β1 with the kinoids significantly suppressed CCl4-induced collagen deposition and the expression of α-SMA and desmin, attenuated hepatocyte apoptosis and accelerated hepatocyte proliferation in BALB/c mice. These results demonstrated that immunization with the TGF-β1 kinoids efficiently attenuated CCl4-induced hepatic fibrosis and liver injury. Our study suggests that vaccination against TGF-β1 might be developed into a feasible therapeutic approach for the treatment of chronic fibrotic liver diseases.

  7. Inhibitory effects of saikosaponin-d on CCl4-induced hepatic fibrogenesis in rats

    Institute of Scientific and Technical Information of China (English)

    Shuang-Suo Dang; Bao-Feng Wang; Yan-An Cheng; Ping Song; Zhen-Guo Liu; Zong-Fang Li

    2007-01-01

    AIM: To investigate the suppressive effect of saikosaponin-d (SSd) on hepatic fibrosis in rats induced by CCl4 injections in combination with alcohol and high fat, low protein feeding and its relationship with the expression of nuclear factor-κB (NF-κB), tumor necrosis factor-alpha (TNF-α) and interleukins-6 (IL-6).METHODS: Hepatic fibrosis models were induced by subcutaneous injection of CCl4 at a dosage of 3 mL/kg in rats. At the same time, rats in treatment groups were injected intraperitoneally with SSd at different doses (1.0,1.5 and 2.0 mg/kg) once daily for 6 wk in combination with CCl4, while the control group received olive oil instead of CCl4. At the end of the experiment, rats were anesthetized and killed (except for 8 rats which died during the experiment; 2 from the model group, 3 in high-dose group, 1 in medium-dose group and 2 in lowdose group). Hematoxylin and eosin (HE) staining and Van Gieson staining were used to examine the changes in liver pathology. The levels of alanine aminotransferase (ALT), triglyeride (TG), albumin (ALB), globulin (GLB),hyaluronic acid (HA) and laminin (LN) in serum and the content of hydroxyproline (HYP) in liver were measured by biochemical examinations and radioimmuneoassay,respectively. In addition, the expression of TNF-α and IL-6 in liver homogenate was evaluated by enzymelinked immunosorbent assay (ELISA) and the levels of NF-κBp65 and I-κBα in liver tissue were analyzed by Western blotting.RESULTS: Both histological examination and Van Gieson staining demonstrated that SSd could attenuate the area and extent of necrosis and reduce the scores of liver fibrosis. Similarly, the levels of ALT, TG, GLB, HA, and LN in serum, and the contents of HYP, TNF-α and IL-6 in liver were all significantly increased in model group in comparison with those in control group. Whereas,the treatment with SSd markedly reduced all the above parameters compared with the model group, especially in the medium group (ALT: 412 ± 94

  8. Effect of aqueous extract of Tinospora cordifolia on functions of peritoneal macrophages isolated from CCl4 intoxicated male albino mice

    Directory of Open Access Journals (Sweden)

    Sharma Gauri D

    2011-10-01

    Full Text Available Abstract Background The current practice of ingesting phytochemicals for supporting the immune system or fighting infections is based on centuries-old tradition. Macrophages are involved at all the stages of an immune response. The present study focuses on the immunostimulant properties of Tinospora cordifolia extract that are exerted on circulating macrophages isolated from CCl4 (0.5 ml/kg body weight intoxicated male albino mice. Methods Apart from damaging the liver system, carbon tetrachloride also inhibits macrophage functions thus, creating an immunocompromised state, as is evident from the present study. Such cell functions include cell morphology, adhesion property, phagocytosis, enzyme release (myeloperoxidase or MPO, nitric oxide (NO release, intracellular survival of ingested bacteria and DNA fragmentation in peritoneal macrophages isolated from these immunocompromised mice. T. cordifolia extract was tested for acute toxicity at the given dose (150 mg/kg body weight by lactate dehydrogenase (LDH assay. Results The number of morphologically altered macrophages was increased in mice exposed to CCl4. Administration of CCl4 (i.p. also reduced the phagocytosis, cell adhesion, MPO release, NO release properties of circulating macrophages of mice. The DNA fragmentation of peritoneal macrophages was observed to be higher in CCl4 intoxicated mice. The bacterial killing capacity of peritoneal macrophages was also adversely affected by CCl4. However oral administration of aqueous fraction of Tinospora cordifolia stem parts at a dose of 40 mg/kg body weight (in vivo in CCl4 exposed mice ameliorated the effect of CCl4, as the percentage of morphologically altered macrophages, phagocytosis activity, cell adhesion, MPO release, NO release, DNA fragmentation and intracellular killing capacity of CCl4 intoxicated peritoneal macrophages came closer to those of the control group. No acute toxicity was identified in oral administration of the aqueous

  9. A novel role of Yin-Yang-1 in pulmonary tuberculosis through the regulation of the chemokine CCL4.

    Science.gov (United States)

    Rangel-Santiago, Jesus F; Baay-Guzman, Guillermina J; Duran-Padilla, Marco A; Lopez-Bochm, Karla A; Garcia-Romero, Beatriz L; Hernandez-Cueto, Daniel D; Pantoja-Escobar, Gerardo; Vega, Mario I; Hernandez-Pando, Rogelio; Huerta-Yepez, Sara

    2016-01-01

    Mycobacterium tuberculosis (M. tb) is the etiological agent of pulmonary tuberculosis (TB); this disease remains a worldwide health problem. Yin-Yang-1 (YY1) plays a major role in the maintenance and progression of some pulmonary diseases, including pulmonary fibrosis. However, the role of YY1 in TB remains unknown. The aim of this study was to elucidate the role of YY1 in the regulation of CCL4 and its implication in TB. We determined whether YY1 regulates CCL4 using reporter plasmids, ChIP and siRNA assays. Immunohistochemistry and digital pathology were used to measure the expression of YY1 and CCL4 in a mouse model of TB. A retrospective comparison of patients with TB and control subjects was used to measure the expression of YY1 and CCL4 using tissue microarrays. Our results showed that YY1 regulates the transcription of CCL4; moreover, YY1, CCL4 and TGF-β were overexpressed in the lung tissues of mice with TB during the late stages of the disease and the tissues of TB patients. The expression of CCL4 and TGF-β correlated with YY1 expression. In conclusion, YY1 regulates CCL4 transcription; moreover, YY1 is overexpressed in experimental and human TB and is positively correlated with CCL4 and TGF-β expression. Therefore, treatments that decrease YY1 expression may be a new therapeutic strategy against TB. PMID:26786659

  10. Effect of Misgurnus anguillicaudatus Lyophilized Power on Liver Fibrosis Induced by CCl 4 in Mice%泥鳅冻干粉抗CCl4小鼠肝纤维化作用

    Institute of Scientific and Technical Information of China (English)

    张倩; 商萌萌; 凌去非; 刘春宇

    2014-01-01

    To study the effect of Misgurnus anguillicaudatus lyophilized power on liver fibrosis, the model in mice was established by using CCl4. Given different doses of Misgurnus anguillicaudatus lyophilized power, the serum ALT and AST activities and tissue Hyp content were detected. The pathological changes of liver were observed. Results showed that the AST and ALT activities and Hyp levels were significantly decreased (P<0.05) in three doses groups of Misgurnus Anguillicaudatus lyophilized power, compared with the model group. The pathological improvements were observed. The fibrogenesis in liver tissues were markedly reduced and the formation of liver pseudoluboli was alleviated. The Misgurnus anguillicaudatus lyophilized power can prevent the formation of liver fibrosis induced by CCl4 in mice.%采用CCl4小鼠肝纤维化模型,给予不同剂量泥鳅冻干粉,检测小鼠血清中ALT、AST活性及肝组织中羟脯氨酸(Hyp)含量,并观察肝组织病理变化,探讨泥鳅冻干粉抗CCl4小鼠肝纤维化作用。结果表明,与模型组相比,泥鳅粉冻干粉明显降低CCl4诱导的肝纤维化小鼠血清ALT、AST活性,显著降低肝组织Hyp含量(P<0.05)。病理学观察结果,泥鳅粉冻干粉给药组小鼠胶原纤维沉积明显减轻,假小叶结构明显减少。泥鳅冻干粉能预防小鼠肝纤维化的形成,具有抗肝纤维化作用。

  11. CCl4 induces tissue-type plasminogen activator in rat brain; protective effects of oregano, rosemary or vitamin E.

    Science.gov (United States)

    Lavrentiadou, Sophia N; Tsantarliotou, Maria P; Zervos, Ioannis A; Nikolaidis, Efstathios; Georgiadis, Marios P; Taitzoglou, Ioannis A

    2013-11-01

    The high metabolic rate and relatively low antioxidant defenses of the lipid-rich brain tissue render it highly susceptible to reactive oxygen species (ROS) and oxidative stress, whereas the implication of ROS in the pathogenesis of several diseases in the central nervous system is well-established. The plasminogen activator (PA) system is a key modulator of extracellular proteolysis, extracellular matrix remodeling and neuronal cell signaling and has been implicated in the pathogenesis of these diseases. This study evaluates the role of tissue-type PA (t-PA) in oxidative stress and the protective role of dietary antioxidants in the rat brain. We used the CCl4 experimental model of ROS-induced lipid peroxidation and evaluated the antioxidant effect of oregano, rosemary or vitamin E. CCl4-treated Wistar rats exhibited elevated brain t-PA activity, which was decreased upon long-term administration of oregano, rosemary or vitamin E. PA inhibitor-1 (PAI-1) activity was also slightly elevated by CCl4, but this increase was not affected by the antioxidants. We hypothesize that the CCl4-induced t-PA activity indicates extracellular proteolytic activity that may be linked to neuronal cell death and brain damage. Vitamin E or antioxidants present in oregano or rosemary are effective in inhibiting t-PA elevation and can be considered as a potential protection against neuronal damage. PMID:23831191

  12. Fast food diet with CCl4 micro-dose induced hepatic-fibrosis –a novel animal model

    Science.gov (United States)

    2014-01-01

    Background Non-alcoholic fatty liver disease (NAFLD) is defined as a spectrum of conditions ranging from hepatocellular steatosis to steatohepatitis and fibrosis, progressing to cirrhosis, which occur in the absence of excessive alcohol use. Several animal models capture aspects of NAFLD but are limited either in their representation of the disease stages or use for development of therapeutics due to the extended periods of time required to develop full histological features. Methods Here, we report the development of a novel rat model for NAFLD that addresses some of these limitations. We used a fast food diet (FFD) and a CCl4 micro dose (0.5 ml/kg B.wt) for 8 weeks in Wistar rats. Serological analyses, gene expression profiling and liver histology studies were conducted to investigate the development of steatosis, steatohepatitis and fibrosis in the FFD-CCl4 model when compared to the individual effects of a FFD or a micro dose of CCl4 in rats. Results The serum biochemical profile of the FFD-CCl4 model showed an increase in liver injury and fibrosis. This was also accompanied by a significant increase in liver triglycerides (TG), inflammation and oxidative stress. Importantly, we observed extensive fibrosis confirmed by: i) increased gene expression of fibrosis markers and, ii) moderate to severe collagen deposition seen as perisinusoidal and bridging fibrosis using H&E, Trichome and Sirius Red staining. Conclusions In summary, we find that the FFD-CCl4 rat model developed NAFLD histological features including, steatosis, inflammation and fibrosis in 8 weeks showing promise as a model that can be used to develop NAFLD therapeutics and liver anti-fibrotics. PMID:24884574

  13. The protective effect of silymarin on the carbon tetrachloride (CCl4)-induced liver injury in common carp (Cyprinus carpio).

    Science.gov (United States)

    Jia, Rui; Cao, Liping; Du, Jinliang; Xu, Pao; Jeney, Galina; Yin, Guojun

    2013-03-01

    Silymarin, a mixture of bioactive flavonolignans from the milk thistle (Silybum marianum), is traditionally used in herbal medicine to defend against various hepatotoxic agents. The aim of the present study was to evaluate the protective effect of silymarin against carbon tetrachloride (CCl4)-induced liver injury in fish. Common carp, with an average initial weight of 17.0 ± 1.1 g, were fed diet containing four doses of silymarin (0, 0.1, 0.5, and 1 g/kg diet) for 60 d. Fish were then given an intraperitoneal injection of CCl4 (30% in arachis oil) at a dose of 0.5 ml/kg body weight. At 72 h after CCl4 injection, blood and liver samples were collected for the analyses of serum biochemical parameters, liver index, peroxidation product, glutathione, and antioxidant enzyme activities. The results showed that administration of silymarin at 0.5 and 1 g/kg diet for 60 d prior to CCl4 intoxication significantly reduced the elevated activities of glutamate pyruvate transaminase, glutamate oxalate transaminase, lactate dehydrogenase (LDH), and increased the reduced levels of total protein and albumin in the serum. The reduced levels of liver index, superoxide dismutase, glutathione peroxidase, catalase, glutathione, and total antioxidant capacity were markedly increased, and malondialdehyde formation was significantly restrained in the liver. However, these parameters, except LDH, were not significantly changed in fish fed with silymarin at 0.1 g/kg diet. Based on the results, it can be concluded that silymarin has protective effect against CCl4-induced hepatotoxicity in fish. It is suggested that silymarin may be used as a hepatoprotective agent to prevent liver diseases in fish. PMID:23435858

  14. Nanodiamond-based nanostructures for coupling nitrogen-vacancy centres to metal nanoparticles and semiconductor quantum dots

    Science.gov (United States)

    Gong, Jianxiao; Steinsultz, Nat; Ouyang, Min

    2016-06-01

    The ability to control the interaction between nitrogen-vacancy centres in diamond and photonic and/or broadband plasmonic nanostructures is crucial for the development of solid-state quantum devices with optimum performance. However, existing methods typically employ top-down fabrication, which restrict scalable and feasible manipulation of nitrogen-vacancy centres. Here, we develop a general bottom-up approach to fabricate an emerging class of freestanding nanodiamond-based hybrid nanostructures with external functional units of either plasmonic nanoparticles or excitonic quantum dots. Precise control of the structural parameters (including size, composition, coverage and spacing of the external functional units) is achieved, representing a pre-requisite for exploring the underlying physics. Fine tuning of the emission characteristics through structural regulation is demonstrated by performing single-particle optical studies. This study opens a rich toolbox to tailor properties of quantum emitters, which can facilitate design guidelines for devices based on nitrogen-vacancy centres that use these freestanding hybrid nanostructures as building blocks.

  15. Volumetric Properties of the Mixture Tetrachloromethane CCl4 + C16H34 Hexadecane (VMSD1141, LB3350_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Tetrachloromethane CCl4 + C16H34 Hexadecane (VMSD1141, LB3350_V)' providing data from direct measurement of mass density at variable pressure and constant temperature and mole fraction.

  16. Volumetric Properties of the Mixture Tetrachloromethane CCl4 + C16H34 Hexadecane (VMSD1342, LB3352_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Tetrachloromethane CCl4 + C16H34 Hexadecane (VMSD1342, LB3352_V)' providing data by calculation of isothermal compressibility from direct measurements of mass densities at variable pressure and constant temperature and mole fraction.

  17. Volumetric Properties of the Mixture Tetrachloromethane CCl4 + C16H34 Hexadecane (VMSD1242, LB3379_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Tetrachloromethane CCl4 + C16H34 Hexadecane (VMSD1242, LB3379_V)' providing data by calculation of molar excess volume from density measurements at variable pressure and constant temperature and mole fraction.

  18. Oligonol Ameliorates CCl4-Induced Liver Injury in Rats via the NF-Kappa B and MAPK Signaling Pathways

    Directory of Open Access Journals (Sweden)

    Jeonghyeon Bak

    2016-01-01

    Full Text Available Oxidative stress is thought to be a key risk factor in the development of hepatic diseases. Blocking or retarding the reactions of oxidation and the inflammatory process by antioxidants could be a promising therapeutic intervention for prevention or treatment of liver injuries. Oligonol is a low molecular weight polyphenol containing catechin-type monomers and oligomers derived from lychee fruit. In this study, we investigated the anti-inflammatory effect of oligonol on carbon tetrachloride- (CCl4- induced acute hepatic injury in rats. Oral administration of oligonol (10 or 50 mg/kg reduced CCl4-induced abnormalities in liver histology and serum AST and serum ALT levels. Oligonol treatment attenuated the CCl4-induced production of inflammatory mediators, including TNF-α, IL-1β, cyclooxygenase-2 (COX-2, and inducible nitric oxide synthase (iNOS mRNA levels. Western blot analysis showed that oligonol suppressed proinflammatory nuclear factor-kappa B (NF-κB p65 activation, phosphorylation of extracellular signal-regulated kinase (ERK, c-Jun NH2-terminal kinase (JNK, and p38 mitogen-activated protein kinases (MAPKs as well as Akt. Oligonol exhibited strong antioxidative activity in vitro and in vivo, and hepatoprotective activity against t-butyl hydroperoxide-induced HepG2 cells. Taken together, oligonol showed antioxidative and anti-inflammatory effects in CCl4-intoxicated rats by inhibiting oxidative stress and NF-κB activation via blockade of the activation of upstream kinases including MAPKs and Akt.

  19. Effect of aqueous extract of Tinospora cordifolia on functions of peritoneal macrophages isolated from CCl4 intoxicated male albino mice

    OpenAIRE

    Sharma Gauri D; Sengupta Mahuya; Chakraborty Biswajit

    2011-01-01

    Abstract Background The current practice of ingesting phytochemicals for supporting the immune system or fighting infections is based on centuries-old tradition. Macrophages are involved at all the stages of an immune response. The present study focuses on the immunostimulant properties of Tinospora cordifolia extract that are exerted on circulating macrophages isolated from CCl4 (0.5 ml/kg body weight) intoxicated male albino mice. Methods Apart from damaging the liver system, carbon tetrach...

  20. Hepatoprotective and Antioxidant Effect of Hibiscus Polyphenol Rich Extract (HPE) Against Carbon Tetrachloride (CCL4) - Induced Damage in Rats

    OpenAIRE

    Adetutu, Adewale; Owoade, Abiodun O.

    2013-01-01

    Aims: Hibiscus sabdariffa is a medicinal plant that is consumed for its health benefits in Africa. The study was designed to investigate the hepatoprotective potentials of Hibiscus polyphenolic rich extract (HPE), (a group of phenolic compounds occurring in the dried calyx of Hibiscus sabdariffa) against CCl4-induced damaged in rats. Place and Duration of Study: Department of Biochemistry, Ladoke Akintola University of Technology, Ogbomosho, Nigeria, between January 2011 and June 2012. Method...

  1. Hepatoprotective effect of manual acupuncture at acupoint GB34 against CCl4-induced chronic liver damage in rats

    Institute of Scientific and Technical Information of China (English)

    Yun-Kyoung Yim; Hyun Lee; Kwon-Eui Hong; Young-Il Kim; Byung-Ryul Lee; Tae-Han Kim; Ji-Young Yi

    2006-01-01

    AIM: To investigate the hepatoprotective effect of manual acupuncture at Yanglingquan (GB34) on CCl4-induced chronic liver damage in rats.METHODS: Rats were injected intraperitoneally with CCl4 (1 mL/kg) and treated with manual acupuncture using reinforcing manipulation techniques at left GB34(Yanglingquan) 3 times a week for 10 wk. A nonacupoint in left gluteal area was selected as a sham point. To estimate the hepatoprotective effect of manual acupuncture at GB34, measurement of liver index,biochemical assays including serum ALT, AST, ALP and total cholesterol, histological analysis and blood cell counts were conducted.RESULTS: Manual acupuncture at GB34 reduced the liver index, serum ALT, AST, ALP and total cholesterol levels as compared with the control group and the sham acupuncture group. It also increased and normalized the populations of WBC and lymphocytes.CONCLUSION: Manual acupuncture with reinforcing manipulation techniques at left GB34 reduces liver toxicity, protects liver function and liver tissue, and normalizes immune activity in CCl4-intoxicated rats.

  2. Red Sea Suberea mollis Sponge Extract Protects against CCl4-Induced Acute Liver Injury in Rats via an Antioxidant Mechanism

    Directory of Open Access Journals (Sweden)

    Aymn T. Abbas

    2014-01-01

    Full Text Available Recent studies have demonstrated that marine sponges and their active constituents exhibited several potential medical applications. This study aimed to evaluate the possible hepatoprotective role as well as the antioxidant effect of the Red Sea Suberea mollis sponge extract (SMSE on carbon tetrachloride- (CCl4- induced acute liver injury in rats. In vitro antioxidant activity of SMSE was evaluated by 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH assay. Rats were orally administered three different concentrations (100, 200, and 400 mg/kg of SMSE and silymarin (100 mg/kg along with CCl4 (1 mL/kg, i.p., every 72 hr for 14 days. Plasma aspartate aminotransferase (AST, alanine aminotransferase (ALT, alkaline phosphatase (ALP, and total bilirubin were measured. Hepatic malondialdehyde (MDA, reduced glutathione (GSH, nitric oxide (NO, superoxide dismutase (SOD, glutathione peroxidase (GPx, and catalase (CAT were also measured. Liver specimens were histopathologically examined. SMSE showed strong scavenging activity against free radicals in DPPH assay. SMSE significantly reduced liver enzyme activities. Moreover, SMSE significantly reduced hepatic MDA formation. In addition, SMSE restored GSH, NO, SOD, GPx, and CAT. The histopathological results confirmed these findings. The results of this study suggested a potent protective effect of the SMSE against CCl4-induced hepatic injury. This may be due to its antioxidant and radical scavenging activity.

  3. In-Vivo Antioxidant activity of ethanolic extract of Mentha pulegium leaf against CCl4 induced toxicity in rats

    Institute of Scientific and Technical Information of China (English)

    Sachin Jain; Dinesh Kumar Jain; Neelam Balekar

    2012-01-01

    Objective: To evaluate the in-vivo antioxidant potential of ethanolic extract of Mentha Pulegium against CCl4 induced toxicity in rats. Methods: Animals were treated with plant extract for 7 days and then toxicity was induced with a single CCl4 intraperitoneal injection. Pre-treatment with 600 mg/kg (p.o.) of ethanolic extract of Mentha Pulegium improved the glutathione, SOD, catalase, and peroxidase levels significantly as compared to control group. Results: The present studies revealed that Mentha Pulegium has significant in-vivo antioxidant activity and can be used to protect tissue from oxidative stress. The result showed that the activities of glutathione, SOD, catalase and peroxidase in group treated with CCl4 declined significantly than that of normal group. Conclusion: Ethanolic extract of Mentha Pulegium in the dose of 600 mg/kg, p.o., has improved the glutathione, SOD, catalase, and peroxidase levels significantly, which were comparable with Liv 52. Based on this study we conclude that Ethanolic extract of MenthaPulegium possesses in vivo antioxidant activity and can be employed in protecting tissue from oxidative stress.

  4. Hepatoprotective and antioxidant properties of marine halophyte Luminetzera racemosa bark extract in CCL4 induced hepatotoxicity

    Institute of Scientific and Technical Information of China (English)

    MurugesanGnanadesigan; SundaramRavikumar; SamuelJacobInbaneson

    2011-01-01

    Objective:To identify the hepatoprotective and antioxidant activity of Luminetzera racemosa (L. racemosa )bark extract. Methods:Wistar albino rats were divided into 6 groups:Group 1 served as control;Group 2 served as hepatotoxin (CCL4 treated) group;Group 3 served as positive control (Silymarin) treated groups;Group 4, 5 and 6 served as (100, 200 and 300 mg/kg bw p.o.) L. racemosa bark extract treated groups. Moreover, in vitro antioxidant indexes, including DPPH, hydroxyl radical scavenging activity (HRSA), NO, ferric reducing antioxidant power (FRAP), lipid hydroperoxide (LPO) and super oxide dismutase (SOD) were also analyzed in the bark extract. Results:The results suggested that, the level of serum glutamate oxyloacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT), alkaline phosphatise (ALP), bilurubin, cholesterol, sugar and lactate dehydrogenase (LDH) were significantly (P<0.05) increased in hepatotoxin treated rats when compared with the control group. But, the maximum reduction of SGOT [(225.36±13.65) IU/L], SGPT [(96.85±17.36) IU/L], ALP [(315.37±17.16) IU/L], bilirubin [(2.97±0.46) mg/dL], cholesterol [(163.73±17.54) mg/dL], sugar [(127.35±27.35) mg/dL] and LDH [(1 784.00±268.36) IU/L] were observed with 300 mg/kg bw of bark extract treated rats. Histopathological scores showed that, no visible changes were observed with high dose (300 mg/kg bw) of bark extract treated rats except mild fatty changes. The in vitro antioxidant assays showed that, the IC50 values were observed as (44.17±6.87)μg/mL, (42.45±2.81)μg/mL, (62.37±3.98)μg/mL, (54.24±3.09)μg/mL, (87.25±5.90)μg/mL and (71.54±5.42)μg/mL for DPPH, HRSA, NO, FRAP, LPO and SOD radical scavenging activities, respectively. Conclusions:The hepatoprotective and antioxidant activities of the bark extract might be to the presence of unique chemical classes such as flavonoids, alkaloids and polyphenols.

  5. Suppressive effects of 17β-estradiol on hepatic fibrosis in CCl4-induced rat model

    Institute of Scientific and Technical Information of China (English)

    Qing-Hua Liu; Ding-Guo Li; Xin Huang; Chun-Hua Zong; Qin-Fang Xu; Han-Ming Lu

    2004-01-01

    AIM: To investigate the pathway via which 17β-estradiol (β-Est) exerts suppressive effects on rat hepatic fibrosis.METHODS: In vivo study was done in CCl4-induced female hepatofibrotic rats. Fibrosis-suppressive effect of β-Est rat models. Six weeks after the treatment, all the rats were sacrificed and specimens of serum or liver tissue were collected for the studies. Serum liver enzymes,fibrosis markers and estradiol levels were determined by standard enzymatic methods, ELISA and RIA, respectively.Degrees of fibrosis and areas of hepatic stellate cells (HSCs) positive for alpha-smooth muscle actin (α-SMA) in the liver were determined by van Gieson (VG) stain and immunohistochemistry.In vitro studies, HSCs were isolated by a combination of pronase-collagenase perfusion and density gradient centrifugation. First-passage HSCs were randomly divided into 10 groups, and different concentrations of β-Est, 2-hydroxyestradiol (2OHE) or 2-methoxyestradiol (2MeOE) were separately added to the cell groups. After incubation for 72 h, the degree of cell proliferation, collagen production, α-SMA or estrogen receptor (ER) expression was determined by MTT assay, ELISA and immunohistochemistry,respectively.RESULTS: β-Est treatment reduced aspartate aminotransferase (AST), alanine aminotransferase (ALT), hyaluronic acid (HA) and type Ⅳ collagen (C Ⅳ) in sera, suppressed hepatic collagen content, decreased the areas of HSCs positive for α-SMA significantly in both intact and ovariectomized female hepatofibrotic rats. There was a negative correlation between the percentage of fibrotic area of liver tissue and the serum estradiol level; the calculated correlation coefficient was -0.57 (P<0.01). β-Est and its metabolites concentration-dependently (10-9 mol/L-10-7 mol/L) inhibited HSC proliferation and collagen synthesis. At the concentration of 10-7 mol/L, they could inhibit α-SMA expression. The order of potency was 2MeOE>2OHE>β-Est.CONCLUSION: β-Est may suppress

  6. 核苷酸补偿对CCl_4致肝纤维化大鼠血清蛋白和尿酸水平的影响

    Institute of Scientific and Technical Information of China (English)

    朱善良

    2012-01-01

    本研究以添加核苷酸的日粮饲喂四氯化碳(CCl4)致肝纤维化大鼠,测定大鼠血清蛋白和尿酸等生化指标变化,以探讨外源核苷酸对CCl4致肝纤维化的干预作用.结果表明,CCl4组大鼠体重均低于或显著低于C组和CCl4+NTs组;CCl4组血清总蛋白含量显著低于CCl4+NTs组和C组,而CCl4+NTs组与C组之间差异不显著.C组、CCl4组和CCl4+NTs组之间的血清A含量存在显著差异,其中C组最高,CCl4+NTs组次之,CCl4组最低.CCl4组和CCl4+NTs组的血清G含量显著高于与C组,而CCl4+NTs组显著高于CCl4组.CCl4+NTs组和CCl4组的A/G比值显著低于C组,而CCl4组与CCl4+NTs组间无显著差异.CCl4组血清UA水平显著低于CCl4+NTs组和C组,而CCl4+NTs组与C组UA水平基本持平.结果提示,日粮补偿核苷酸引起CCl4致肝纤维化大鼠的血清白蛋白、球蛋白和尿酸等生化指标发生了明显变化,这可能是外源核苷酸干预肝纤维化损伤的重要机制之一.

  7. Hepatoprotective and cytoprotective properties of Hyptis suaveolens against oxidative stress-induced damage by CCl4 and H2O2

    Institute of Scientific and Technical Information of China (English)

    Hadi Ghaffari; Behrouz Jalali Ghassam; HS Prakash

    2012-01-01

    Objective:To investigate capacity of Hyptis suaveolens (H. suaveolens) methanol extract as an antioxidant to protect against carbon tetrachloride (CCl4)-induced oxidative stress, hepatotoxicity in Albino Wistar rats and cytoprotective effect of hydrogen peroxide (H2O2) induced cell death in HepG2 cell line. Methods: Two different doses of methanol extract of H. suaveolens were evaluated for the hepatoprotective activity against carbon tetrachloride (CCl4) induced hepatotoxicity in rats. Animals in Group I: served as control, group II:H. suaveolens (100 mL/kg b.w), group III:H. suaveolens (50 mL/kg b.w) + CCl4 (1 mg/kg), group IV:H. suaveolens (100 mL/kg b.w) + CCl4 (1 mL/kg) and group V: CCl4 (1 mL/kg). Histopathologic changes of liver were also evaluated. Cytotoxicity was also determined by 3, (4,5-dimethylthiazol-2-yl)2,5-diphenyl-tetrazolium bromide (MTT) assay. Results:Oral sigle dose treatment of CCl4 produced a marked elevation in the serum levels of aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP) and Lactate dehydrogenase (LDH). Histopathological analysis of the liver of CCl4-induced rats revealed marked liver cell necrosis with inflammatory collections that were conformed to increase in the levels of SOD, GSH, GST, GR and LPO. Treatment with H2O2 significantly induced death of HepG2 cell. Pretreatment with H. suaveolens methanol extract inhibited or attenuated H2O2 induced cytotoxicity. Conclusions: This study shows that H. suaveolens methanol extract can be proposed to protect the liver against CCl4-induced oxidative damage in rats and protect the cells against H2O2-induced oxidative damage in HepG2 cells. The hepatoprotective and cytoprotective effects might be correlated with its antioxidant and free radical scavenger effects.

  8. Antioksidan Ekstrak Air Biji Kopi Robusta Lampung dalam Menghambat Degenerasi Sel Hati Tikus Model Hepatitis yang Diinduksi CCL4

    Directory of Open Access Journals (Sweden)

    Asep Sukohar

    2012-09-01

    Full Text Available Liver plays an important role in maintaining homeostasis and is critical for physiological functions of other organs. Morphological changes of the liver will have an impact on changes in liver function and may appear as clinical manifestations. Hepatitis is a serious disorder that causes inflammation of the liver cells and is caused by viruses, chemicals and toxins. Reactions that occur in the form of oxidative stress, free radicals dominant condition of antioxidants. Traditionally coffee is used as an everyday beverage and known as antioxidants because it contains flavonoids (chlorogenic acid. This study aim was to determine the hepatoprotective/antioxidant effect of coffee growing in Pesawaran Lampung, on the description of hepatocyte cell damage in Wistar rats hepatitis model induced with carbon tetrachloride (CCl4. Laboratory experimental research has been conducted in Pharmacology >Department, Faculty Medicine Padjadjaran University Bandung and pathology examinations was performed at the Hospital Abdoel Moeloek Lampung in December 2008–July 2009, using 15 male Wistar rats divided in three groups, the negative control group, positive control as a model of hepatitis, and hepatitis model that received the water extract of robusta coffee beans 25 mg/kgBW/days for 7 days and then received CCl4 induction. The results were analyzed by analysis of variance and independent t test. Administration of water extract of robusta coffee beans can prevented damage to the liver cell degeneration picture from 58.4±7.09 to 34.4±5.85, these results differed significantly (p≤0.05 compared with positive and negative control. In conclusion, water extract of robusta coffee beans has the potential to prevent interference with the effects of liver function as antioxidants in the ra model of hepatitis which has been inducted with CCL4.

  9. Comparative Evaluation of Hepatoprotective Activities of Geniposide, Crocins and Crocetin by CCl4-Induced liver Injury in Mice

    OpenAIRE

    Chen, Ping; Chen, Yang; Wang, YaRong; Cai, Shining; Deng, Liang; Liu, Jia; Zhang, Hao

    2016-01-01

    Iridoid glycosides (mainly geniposide) and crocetin derivatives (crocins) are the two major active constituents in Gardenia jasminoides Ellis. In the present study, geniposide, crocins, crocin-1 and crocetin were separated from gardenia chromatographically. Then, mice were orally administrated with geniposide (400 mg/kg b.w.), crocins (400 mg/kg b.w.), crocin-1 (400 mg/kg b.w.) and crocetin (140 mg/kg b.w.) once daily for 7 days with CCl4. Hepatoprotective properties were evaluated by biochem...

  10. Linearization of calibration curves by aerosol carrier effect of CCl4 vapor in electrothermal vaporization inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Carbon tetrachloride vapor as gaseous phase modifier in a graphite furnace electrothermal vaporizer (GFETV) converts heavy volatile analyte forms to volatile and medium volatile chlorides and produces aerosol carrier effect, the latter being a less generally recognized benefit. However, the possible increase of polyatomic interferences in inductively coupled plasma mass spectrometry (GFETV-ICP-MS) by chlorine and carbon containing species due to CCl4 vapor introduction has been discouraging with the use of low resolution, quadrupole type MS equipment. Being aware of this possible handicap, it was aimed at to investigate the feasibility of the use of this halogenating agent in ICP-MS with regard of possible hazards to the instrument, and also to explore the advantages under these specific conditions. With sample gas flow (inner gas flow) rate not higher than 900 ml min-1 Ar in the torch and 3 ml min-1 CCl4 vapor flow rate in the furnace, the long-term stability of the instrument was ensured and the following benefits by the halocarbon were observed. The non-linearity error (defined in the text) of the calibration curves (signal versus mass functions) with matrix-free solution standards was 30-70% without, and 1-5% with CCl4 vapor introduction, respectively, at 1 ng mass of Cu, Fe, Mn and Pb analytes. The sensitivity for these elements increased by 2-4-fold with chlorination, while the relative standard deviation (RSD) was essentially the same (2-5%) for the two cases in comparison. A vaporization temperature of 2650 deg. C was required for Cr in Ar atmosphere, while 2200 deg. C was sufficient in Ar + CCl4 atmosphere to attain complete vaporization. Improvements in linear response and sensitivity were the highest for this least volatile element. The pyrolytic graphite layer inside the graphite tube was protected by the halocarbon, and tube life time was further increased by using traces of hydrocarbon vapor in the external sheath gas of the graphite furnace. Details

  11. Peptidyl arginine deiminase inhibitor effect on hepatic fibrogenesis in a CCl4 pre-clinical model of liver fibrosis

    DEFF Research Database (Denmark)

    Vassiliadis, E.; Veidal, Sanne Skovgård; Kristiansen, M. N.; Hansen, C.; Jorgensen, M.; Leeming, D. J.; Karsdal, M.

    2013-01-01

    Having previously shown that levels of the citrullinated vimentin peptide VICM are raised in liver fibrosis in rats, we aimed to investigate whether inhibition of citrullination as measured by VICM levels could affect fibrogenesis. METHODS: Fibrogenesis was evaluated by quantitative histology and...... same period, with N-a-benzoyl-N5-(2 Chloro-1-iminoethyl)-L-Ornithine amide, a known PAD inhibitor. RESULTS: All 40 CCl4 treated animals showed a statistically significant increase in total collagen (p0.05). In PAD-treated animals VICM levels were 51% (P...

  12. Rapamycin ameliorates CCl4-induced liver fibrosis in mice through reciprocal regulation of the Th17/Treg cell balance.

    Science.gov (United States)

    Gu, Lei; Deng, Wen-Sheng; Sun, Xiao-Fei; Zhou, Hong; Xu, Qing

    2016-08-01

    Previous investigations have suggested that the activation of Th17 cells and/or deficiency of regulatory T cells (Tregs) are involved in the pathogenesis of liver fibrosis. The aim of the present study was to investigate the effect of rapamycin on immune responses in a carbon tetrachloride (CCl4)-induced murine liver fibrosis model. Liver fibrosis was induced by intraperitoneal administration with CCl4. Following injection of CCl4, the mice were treated intraperitoneally with rapamycin (1.25 mg/kg/day) for 8 weeks. Hematoxylin and eosin staining and Masson's trichrome staining were used for histological examination. The protein levels of forkhead/winged helix transcription factor P3, retinoic-acid-related orphan receptor (ROR)‑γt in liver tissue were determined by western blotting, the frequency of Th17 and Treg cells in the liver was evaluated by flow cytometry, and a suppression assay was measured by incorporating [3H]‑thymidine. In addition, to explore the effect of Tregs expanded with rapamycin on hepatic stellate cells (HSC), HSCs were co‑cultured with Tregs from rapamycin or phosphate‑buffered saline‑treated mice. It was found that rapamycin treatment led to a significant reduction in the number of Th17 cells and in the expression levels of ROR‑γt in the liver tissues. Simultaneously, the results of the present study showed a significant increase in the frequency of Tregs and a marked enhancement in the expression of forkhead/winged helix transcription factor P3 in the rapamycin‑treated mice. Furthermore, the Tregs in rapamycin‑treated mice had significantly higher suppressive effects, compared with the cells from mice treated with phospphate‑buffered saline. Consequently, rapamycin treatment prevented the development of CCl4-induced hepatic fibrosis, which was shown by its histological appearances. These results suggested that the immunosuppressive effect of rapamycin on liver fibrosis was associated with the suppression of hepatic

  13. Targeting the environmental assessment of veterinary drugs with the multi-species-soil system (MS centred dot 3) agricultural soil microcosms: the ivermectin case study

    International Nuclear Information System (INIS)

    The environmental risk assessment of the veterinary pharmaceutical ivermectin is receiving significant attention. This paper assesses the capacity of the MS centred dot 3 soil microcosm as a tool for targeting the environmental impact assessment of veterinary drugs, using ivermectin as model. Two screening MS centred dot 3 were performed using different European soils; one with a soil collected in an agricultural station near to Madrid, Spain and a second with a soil collected in a farm area close to York, UK. Soils were fortified with ivermectin at the following ranges: 0.01-10 mg kg-1 and 0.1-100 mg kg-1 in the Madrid and York studies, respectively. The effects on earthworms, plants and soil microorganisms were assessed in the Madrid soil. Toxicity tests on aquatic organisms (algae, cladocerans and in vitro fish cell line RTLW1) were also conducted with the leachates. No effects were observed in earthworms and plants at any tested concentration; reduction in the respiration rate (-1 can be estimated. Comparisons based on toxicity data and equilibrium partitioning confirmed that the main risk is expected to be related to the high sensitivity of cladocerans. The results confirm that MS centred dot 3 systems are cost-effective tools for assessing the impact of veterinary pharmaceuticals when applied to agricultural land, as previously demonstrated for antimicrobials. (Author) 39 refs.

  14. Accelerated CCl4-induced liver fibrosis in Hjv-/- mice, associated with an oxidative burst and precocious profibrogenic gene expression.

    Directory of Open Access Journals (Sweden)

    Giada Sebastiani

    Full Text Available Hereditary hemochromatosis is commonly associated with liver fibrosis. Likewise, hepatic iron overload secondary to chronic liver diseases aggravates liver injury. To uncover underlying molecular mechanisms, hemochromatotic hemojuvelin knockout (Hjv-/- mice and wild type (wt controls were intoxicated with CCl(4. Hjv-/- mice developed earlier (by 2-4 weeks and more acute liver damage, reflected in dramatic levels of serum transaminases and ferritin and the development of severe coagulative necrosis and fibrosis. These responses were associated with an oxidative burst and early upregulation of mRNAs encoding α1-(I-collagen, the profibrogenic cytokines TGF-β1, endothelin-1 and PDGF and, notably, the iron-regulatory hormone hepcidin. Hence, CCl4-induced liver fibrogenesis was exacerbated and progressed precociously in Hjv-/- animals. Even though livers of naïve Hjv-/- mice were devoid of apparent pathology, they exhibited oxidative stress and immunoreactivity towards α-SMA antibodies, a marker of hepatic stellate cells activation. Furthermore, they expressed significantly higher (2-3 fold vs. wt, p<0.05 levels of α1-(I-collagen, TGF-β1, endothelin-1 and PDGF mRNAs, indicative of early fibrogenesis. Our data suggest that hepatic iron overload in parenchymal cells promotes oxidative stress and triggers premature profibrogenic gene expression, contributing to accelerated onset and precipitous progression of liver fibrogenesis.

  15. Protective effect of red-stemmed type of Ipomoea aquatica Forsk against CCl4-induced oxidative damage in mice.

    Science.gov (United States)

    Hirai, Shizuka; Ishibuchi, Toyohito; Watabe, Shinpei; Makita, Miki; Kishida, Chiaki; Takagaki, Michiko; Kurauchi, Nobuyuki; Egashira, Yukari

    2011-01-01

    Water spinach (Ipomoea aquatica Forsk; I. aquatica) of the green-stemmed type (green type) is widely consumed, but there also exists a red-stemmed variety (red type). In the present study, the antioxidant capacity of the red type was compared to that of the green type in carbon tetrachloride (CCl(4))-treated mice. CCl(4)-induced thiobarbituric acid reactive substrate (TBARS) formation in the liver was significantly suppressed in mice fed 5% red-type I. aquatica, while the green type showed no effect. Hydrophobic oxygen radical absorbance capacity (H-ORAC(FL)) in the red type showed a lower level than that in the green type; however, lipophilic ORAC (L-ORAC(FL)) and total-ORAC(FL) levels were significantly higher in the red type than in the green type. α-Tocopherol, anthocyanidin/proanthocyanidin, and β-carotene contents were all significantly higher in the red type than in the green type. These results suggest that the wild red-type I. aquatica contains certain lipophilic components that exert antioxidant capacities not only in vitro but also in vivo. Such effective components in the red type would be beneficial phytochemicals for suppressing several diseases related to oxidative stress. PMID:22041914

  16. Effect of 3 amino 1,2,4 triazole administration on the early CCl4-induced ultrastructural alterations in rat liver.

    Science.gov (United States)

    Bernacchi, A. S.; de Castro, C. R.; de Ferreyra, E. C.; de Fenos, O. M.; Castro, J. A.

    1982-01-01

    CCl4 administration to rats caused at 3 and 6 h intense effects on the liver-cell endoplasmic reticulum such as dilatation, disorganization, detachment of ribosomes, development of extensive areas of smooth component (SER) and formation of myelin figures. 3 Amino 1,2,4 triazole administration (AT) at 3 and 6 h led to the formation of round small vesicles from the rough endoplasmic reticulum (RER), detachment of ribosomes, appearance of extensive areas of SER, appearance of elongated and distorted mitochondria with an increase in the number of peroxisomes. The administration of CCl4 to AT-pretreated animals led to a mutual cancellation of the effects on the RER, particularly remarkable at 3 h but still evident at 6 h; also, the formation of myelin figures was prevented. The other effects on cell ultrastructure exerted either by CCl4 or by AT were also observed with the combination of both chemicals. These observations reinforce the hypothesis about the need of either covalent binding of CCl4 metabolites to cellular constituents or lipid peroxidation, or both, in the origin of CCl4-induced alterations. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 10 PMID:7066182

  17. Quantum yield of Cl∗ (21/2) production in the gas phase photolysis of CCl4 in the ultraviolet

    Indian Academy of Sciences (India)

    Manish Tak; Manabendra Chandra; Dulal Senapati; Puspendu K Das

    2006-07-01

    In this paper, we have probed the dynamics of chlorine atom production from the gas phase photodissociation of carbon tetrachloride at 222 and 235 nm. The quantum yield, * of Cl∗ (21/2) production has been determined by probing the nascent concentrations of both excited (21/2) and ground state (23/2) chlorine atoms by suitable resonance-enhanced multiphoton ionization (REMPI) detection schemes. Although at the photolysis wavelengths the absorption of carbon tetrachloride is weak, significant amounts of Cl∗ are produced. Surprisingly, the quantum yield of Cl∗ production does not follow the absorption spectrum closely, which gives rise to the possibility of an indirect dissociation mechanism present in CCl4 along with direct dissociation at these ultraviolet wavelengths.

  18. Dynamics of intermolecular interactions in CCl4via the isotope effect by femtosecond time-resolved spectroscopy.

    Science.gov (United States)

    Konarska, Jadwiga; Gadomski, Wojciech; Ratajska-Gadomska, Bożena; Polok, Kamil; Pudłowski, Grzegorz; Kardaś, Tomasz M

    2016-06-21

    We report our study on the ultrafast dynamics of intermolecular interactions in liquid CCl4. A transient transmission time domain signal, obtained in the 40 ps delay range, exhibits beating at the difference frequency of the totally symmetric stretching vibrations of the tetrachloride isotopologues. We show that the spectra obtained as the windowed Fourier transform of different parts of the time domain signal in the range of this totally symmetric vibration, split due to the isotope effect, carry the information about the dynamics of the coherently excited, coupled molecules. We use a simple theoretical model in order to prove that the intermolecular interaction influences the relative amplitudes of the isotopologue peaks in the spectrum. Moreover, we demonstrate that the pump induced coherence in the system leads to additional strengthening of the interaction, which can be observed in the spectra obtained from the experimental time domain signal. PMID:27244535

  19. Role of estrogen receptor β selective agonist in ameliorating portal hypertension in rats with CCl4-induced liver cirrhosis

    Science.gov (United States)

    Zhang, Cheng-Gang; Zhang, Bin; Deng, Wen-Sheng; Duan, Ming; Chen, Wei; Wu, Zhi-Yong

    2016-01-01

    AIM: To investigate the role of diarylpropionitrile (DPN), a selective agonist of estrogen receptor β (ERβ), in liver cirrhosis with portal hypertension (PHT) and isolated hepatic stellate cells (HSCs). METHODS: Female Sprague-Dawley rats were ovariectomized (OVX), and liver cirrhosis with PHT was induced by CCl4 injection. DPN and PHTPP, the selective ERβ agonist and antagonist, were used as drug interventions. Liver fibrosis was assessed by hematoxylin and eosin (HE) and Masson’s trichrome staining and by analyzing smooth muscle actin expression. Hemodynamic parameters were determined in vivo using colored microspheres technique. Protein expression and phosphorylation were determined by immunohistochemical staining and Western blot analysis. Messenger RNA levels were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR). Collagen gel contraction assay was performed using gel lattices containing HSCs treated with DPN, PHTPP, or Y-27632 prior to ET-1 addition. RESULTS: Treatment with DPN in vivo greatly lowered portal pressure and improved hemodynamic parameters without affecting mean arterial pressure, which was associated with the attenuation of liver fibrosis and intrahepatic vascular resistance (IHVR). In CCl4-treated rat livers, DPN significantly decreased the expression of RhoA and ROCK II, and even suppressed ROCK II activity. Moreover, DPN remarkedly increased the levels of endothelial nitric oxide synthase (eNOS) and phosphorylated eNOS, and promoted the activities of protein kinase G (PKG), which is an NO effector in the liver. Furthermore, DPN reduced the contractility of activated HSCs in the 3-dimensional stress-relaxed collagen lattices, and decreased the ROCK II activity in activated HSCs. Finally, in vivo/in vitro experiments demonstrated that MLC activity was inhibited by DPN. CONCLUSION: For OVX rats with liver cirrhosis, DPN suppressed liver RhoA/ROCK signal, facilitated NO/PKG pathways, and decreased IHVR, giving rise to

  20. [Pharmacokinetics of lidocaine and its metabolites in dog. Comparison between normal and CCl4-induced hepatic lesion].

    Science.gov (United States)

    Yamane, J

    1989-09-01

    Pharmacokinetic analysis of lidocaine (Lid) and its metabolites, monoethylglycinexylidide (MEGX) and glycinexylidide (GX), was performed in a dog bearing carbon tetrachloride (CCl4, 0.75 ml/kg ip)-induced acute hepatitis. Following pentobarbital sodium (25 mg/kg iv) anesthesia, lidocaine hydrochloride (2.5 mg/kg iv) was given and arterial blood was drawn 2, 5, 10, 15, 30, 45, 60, 90, and 120 min after administration. Lid and its metabolites in plasma were extracted with chloroform-hexane-isopropanol (60 : 30 : 10), and organic layer was dried down at 50 degrees C under N2. The residue was dissolved in 50mM phosphoric acid and subjected to HPLC analysis. 4-compartment model was introduced to analyze pharmacokinetic parameters, and which gave the most reasonable fit with actual results. Control experiment was carried out using identical dog with acute hepatitis. The following results were given: 1) Elimination of Lid was slightly depressed, but T1/2 was not altered. Plasma level of Lid was kept higher. 2) As for MEGX, the formation was depressed, and upto 23 min after Lid administration, MEGX concentration in the dog with acute hepatitis was lower than that of control, but after 23 min it was vice versa. 3) As for GX, the formation was depressed, but the elimination was not affected. In the dog with CCl4-induced hepatitis, metabolism of Lid was suppressed, and which resulted in maintaining a relatively higher levels of Lid and MEGX concentration in plasma. These results suggested that care should be taken to avoid acute poisoning with Lid especially in patients with acute hepatitis. PMID:2489793

  1. CH3Cl, CH2Cl2, CHCl3, and CCl4: Infrared spectra, radiative efficiencies, and global warming potentials

    Science.gov (United States)

    Wallington, Timothy J.; Pivesso, Bruno Pasquini; Lira, Alane Moura; Anderson, James E.; Nielsen, Claus Jørgen; Andersen, Niels Højmark; Hodnebrog, Øivind

    2016-05-01

    Infrared spectra for the title compounds were measured experimentally in 700 Torr of air at 295 K and systematically modeled in B3LYP, M06-2X and MP2 calculations employing various basis sets. Calibrated infrared spectra over the wavenumber range 600-3500 cm-1 are reported and combined with literature data to provide spectra for use in experimental studies and radiative transfer calculations. Integrated absorption cross sections are (units of cm-1 molecule-1): CH3Cl, 660-780 cm-1, (3.89±0.19)×10-18; CH2Cl2, 650-800 cm-1, (2.16±0.11)×10-17; CHCl3, 720-810 cm-1, (4.08±0.20)×10-17; and CCl4, 730-825 cm-1, (6.30±0.31)×10-17. CH3Cl, CH2Cl2, CHCl3, and CCl4 have radiative efficiencies of 0.004, 0.028, 0.070, and 0.174 W m-2 ppb-1 and global warming potentials (100 year horizon) of 5, 8, 15, and 1775, respectively. Quantum chemistry calculations generally predict larger band intensities than the experimental values. The best agreement with experiments is obtained in MP2(Full) calculations employing basis sets of at least triple-zeta quality augmented by diffuse functions. The B3LYP functional is found ill-suited for calculating vibrational frequencies and infrared intensities of halocarbons.

  2. Cultured Mycelium Cordyceps sinensis allevi¬ates CCl4-induced liver inflammation and fibrosis in mice by activating hepatic natural killer cells

    OpenAIRE

    Peng, Yuan; Huang, Kai; Shen, Li; Tao, Yan-Yan; Liu, Cheng-Hai

    2015-01-01

    Aim: Recent evidence shows that cultured mycelium Cordyceps sinensis (CMCS) effectively protects against liver fibrosis in mice. Here, we investigated whether the anti-fibrotic action of CMCS was related to its regulation of the activity of hepatic natural killer (NK) cells in CCl4-treated mice. Methods: C57BL/6 mice were injected with 10% CCl4 (2 mL/kg, ip) 3 times per week for 4 weeks, and received CMCS (120 mg·kg−1·d−1, ig) during this period. In another part of experiments, the mice were ...

  3. Ferroelectric TGS ((NH sub 2 CH sub 2 COOH) sub 3 centre dot H sub 2 SO sub 4) under high pressure

    CERN Document Server

    Kobayashi, Y; Furuta, H; Endo, S; Deguchi, K

    2002-01-01

    The ferroelectric transition temperature T sub c of (NH sub 2 CH sub 2 COOH) sub 3 centre dot H sub 2 SO sub 4 (TGS), which is a typical order-disorder-type ferroelectric, was determined by dielectric constant and Raman scattering measurements under high pressure. T sub c increased, passed through a maximum and then decreased slightly with increasing pressure, and then abruptly dropped at about 2.5 GPa, where a transition to a new high-pressure phase was confirmed to exist. A tentative p-T phase diagram was proposed for TGS.

  4. Activation of silicon quantum dots and coupling between the active centre and the defect state of the photonic crystal in a nanolaser

    International Nuclear Information System (INIS)

    A new nanolaser concept using silicon quantum dots (QDs) is proposed. The conduction band opened by the quantum confinement effect gives the pumping levels. Localized states in the gap due to some surface bonds on Si QDs can be formed for the activation of emission. An inversion of population can be generated between the localized states and the valence band in a QD fabricated by using a nanosecond pulse laser. Coupling between the active centres formed by localized states and the defect states of the two-dimensional (2D) photonic crystal can be used to select the model in the nanolaser. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  5. Effect of pumpkin seed (Cucurbita pepo) protein isolate on the activity levels of certain plasma enzymes in CCl4-induced liver injury in low-protein fed rats.

    Science.gov (United States)

    Nkosi, C Z; Opoku, A R; Terblanche, S E

    2005-04-01

    The effects of pumpkin seed (Cucurbita pepo) protein isolate on the activity levels of lactate dehydrogenase (LD), alanine transaminase (ALT), aspartate transaminase (AST) and alkaline phosphatase (ALP) against carbon tetrachloride (CCl4)-induced acute liver injury in low-protein fed rats were investigated. A group of male Sprague-Dawley rats maintained on a low-protein diet for 5 days were divided into three subgroups. Two subgroups were injected with carbon tetrachloride and the other group with an equivalent amount of olive oil. Two hours after CCl4 intoxication one of the two subgroups was administered with pumpkin seed protein isolate. All three subgroups of rats were maintained on the low-protein diet for the duration of the investigation. Groups of rats from the different subgroups were killed at 24, 48 and 72 h after their respective treatments. After 5 days on the low-protein diet the activity levels of all four enzymes were significantly higher than their counterparts on a normal balanced diet. CCl4 intoxication resulted in significant increases in the activity levels of all four enzymes investigated. The administration of pumpkin seed protein isolate after CCl4 intoxication resulted in significantly reduced activity levels of all four enzymes. It is concluded that pumpkin seed protein isolate administration was effective in alleviating the detrimental effects associated with protein malnutrition. PMID:16041732

  6. Glutamine inhibits CCl4 induced liver fibrosis in mice and TGF-β1 mediated epithelial-mesenchymal transition in mouse hepatocytes.

    Science.gov (United States)

    Shrestha, Nirajan; Chand, Lokendra; Han, Myung Kwan; Lee, Seung Ok; Kim, Chan Young; Jeong, Yeon Jun

    2016-07-01

    Glutamine, traditionally a non-essential amino acid, now has been considered as essential in serious illness and injury. It is a major precursor for glutathione synthesis. However, the anti-fibrotic effect of glutamine and its molecular mechanism in experimental liver fibrosis have not been explored. In the present study we aimed to examine the potential role of glutamine in carbon tetrachloride (CCl4) induced liver fibrosis and TGF-β1 mediated epithelial mesenchymal transition (EMT) and apoptosis in mouse hepatocytes. Liver fibrosis was induced by intraperitoneal injection of CCl4 three times a week for 10 weeks. Glutamine treatment effectively attenuated liver injury and oxidative stress. Collagen content was significantly decreased in liver sections of glutamine treated mice compared to CCl4 model mice. Furthermore, glutamine decreased expression level of α-SMA and TGF-β in liver tissue. Our in vitro study showed that TGF-β1 treatment in hepatocytes resulted in loss of E-cadherin and increased expression of mesenchymal markers and EMT related transcription factor. In addition, TGF-β1 increased the expression of apoptotic markers. However, glutamine interestingly suppressed TGF-β1 mediated EMT and apoptosis. In conclusion, our results suggest that glutamine ameliorates CCl4 induced liver fibrosis and suppresses TGF-β1 induced EMT progression and apoptosis. PMID:27137983

  7. In vivo antioxidant and hepatoprotective potential of Glycyrrhiza glabra extract on carbon tetra chloride (CCl4 induced oxidative-stress mediated hepatotoxicity

    Directory of Open Access Journals (Sweden)

    Varsha Sharma

    2014-02-01

    Results: The results suggest that, the crude extract of root of G. glabra at the doses of 300 and 600mg/kg body wt. expressed significant hepatoprotective potential against CCl4 induced oxidative stress mediated hepatotoxicity in student ‘t’ test (p [Int J Res Med Sci 2014; 2(1.000: 314-320

  8. Essential roles of the interaction between cancer cell-derived chemokine, CCL4, and intra-bone CCR5-expressing fibroblasts in breast cancer bone metastasis.

    Science.gov (United States)

    Sasaki, Soichiro; Baba, Tomohisa; Nishimura, Tatsunori; Hayakawa, Yoshihiro; Hashimoto, Shin-Ichi; Gotoh, Noriko; Mukaida, Naofumi

    2016-08-01

    From a murine breast cancer cell line, 4T1, we established a subclone, 4T1.3, which consistently metastasizes to bone upon its injection into the mammary fat pad. 4T1.3 clone exhibited similar proliferation rate and migration capacity as the parental clone. However, the intra-bone injection of 4T1.3 clone caused larger tumors than that of the parental cells, accompanied with increases in fibroblast, but not osteoclast or osteoblast numbers. 4T1.3 clone displayed an enhanced expression of a chemokine, CCL4, but not its specific receptor, CCR5. CCL4 shRNA-transfection of 4T1.3 clone had few effects on its in vitro properties, but reduced the tumorigenicity arising from the intra-bone injection. Moreover, intra-bone injection of 4T1.3 clone caused smaller tumors in mice deficient in CCR5 or those receiving CCR5 antagonist than in wild-type mice. The reduced tumor formation was associated with attenuated accumulation of CCR5-positive fibroblasts expressing connective tissue growth factor (CTGF)/CCN2. Tumor cell-derived CCL4 could induce fibroblasts to express CTGF/CCN2, which could support 4T1.3 clone proliferation under hypoxic culture conditions. Thus, the CCL4-CCR5 axis can contribute to breast cancer metastasis to bone by mediating the interaction between cancer cells and fibroblasts in bone cavity. PMID:27177471

  9. Effects of Biphenyldimethyl-dicarboxylate Administration Alone or Combined with Silymarin in the CCL4 Model of Liver Fibrosis in Rats

    Directory of Open Access Journals (Sweden)

    Omar M. E. Abdel-Salam

    2007-01-01

    Full Text Available The effect of biphenyldimethyldicarboxylate (DDB, a synthetic compound, in use for the treatment of chronic hepatitis was studied on hepatic injury caused in rats by administration of carbon tetrachloride (CCl4. Starting at time of administration of the first dose of CCl4, rats received DDB at four dose levels (3, 15, 75 or 375 mg/kg, silymarin (22 mg/kg, a combination of DDB (75 mg/kg and silymarin (22 mg/kg or saline (control once orally daily for 30 days. The administration of DDB in CCl4-treated rats at 75 or 375 mg/kg resulted in 61.2-76.2% decrease in alanine aminotransferase (ALT and 46.9-60.8% decrease in aspartate aminotransferase (AST, respectively compared with the CCl4 control group. Silymarin treatment resulted in 34.6 and 30% decrease in ALT and AST, while DDB (75 mg/kg combined with silymarin (22 mg/kg resulted in 58.2 and 31% decrease in ALT and AST, respectively. Serum creatinine increased by 50% by DDB at 375 mg/kg. After treatment with DDB at 75 or 375 mg/kg or DDB combined with silymarin, the development of liver necrosis and fibrosis caused by CCl4 was markedly reduced, while after DDB combined with silymarin no DNA aneuploid cells could be observed. The decrease in glycogen and protein contents in hepatocytes caused by CCl4 was markedly prevented by co-treatment with DDB at 75 or 375 mg/kg or DDB combined with silymarin. It is concluded that in the model of hepatic injury caused by chronic administration of CCl4 in rats, the synthetic compound DDB, limits hepatocellular injury and exerts antifibrotic effect. Better improvement in protein, DNA, mucopolysaccharide content was seen after both DDB and silymarin compared to DDB alone. It is suggested, therefore, that DDB alone or in combination with silymarin might prove of benefit in the therapy of chronic liver disease. Monitoring of kidney functions in patients taking DDB is warranted.

  10. Polymerization of MIP-1 chemokine (CCL3 and CCL4) and clearance of MIP-1 by insulin-degrading enzyme

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Min; Guo, Qing; Guo, Liang; Lenz, Martin; Qian, Feng; Koenen, Rory R.; Xu, Hua; Schilling, Alexander B.; Weber, Christian; Ye, Richard D.; Dinner, Aaron R.; Tang, Wei-Jen (IIT); (Aachen); (UC); (UIC)

    2010-12-07

    Macrophage inflammatory protein-1 (MIP-1), MIP-1{alpha} (CCL3) and MIP-1{beta} (CCL4) are chemokines crucial for immune responses towards infection and inflammation. Both MIP-1{alpha} and MIP-1{beta} form high-molecular-weight aggregates. Our crystal structures reveal that MIP-1 aggregation is a polymerization process and human MIP-1{alpha} and MIP-1{beta} form rod-shaped, double-helical polymers. Biophysical analyses and mathematical modelling show that MIP-1 reversibly forms a polydisperse distribution of rod-shaped polymers in solution. Polymerization buries receptor-binding sites of MIP-1{alpha}, thus depolymerization mutations enhance MIP-1{alpha} to arrest monocytes onto activated human endothelium. However, same depolymerization mutations render MIP-1{alpha} ineffective in mouse peritoneal cell recruitment. Mathematical modelling reveals that, for a long-range chemotaxis of MIP-1, polymerization could protect MIP-1 from proteases that selectively degrade monomeric MIP-1. Insulin-degrading enzyme (IDE) is identified as such a protease and decreased expression of IDE leads to elevated MIP-1 levels in microglial cells. Our structural and proteomic studies offer a molecular basis for selective degradation of MIP-1. The regulated MIP-1 polymerization and selective inactivation of MIP-1 monomers by IDE could aid in controlling the MIP-1 chemotactic gradient for immune surveillance.

  11. Hepatoprotective effect ofSolanum xanthocarpum fruit extract against CCl4 induced acute liver toxicity in experimental animals

    Institute of Scientific and Technical Information of China (English)

    Ramesh K Gupta; Talib Hussain; G Panigrahi; Avik Das; Gireesh Narayan Singh; K Sweety; Md Faiyazuddin; Chandana Venkateswara Rao

    2011-01-01

    Objective:To investigate the hepatoprotective potential ofSolanum xanthocarpum (Solanaceae) (S. xanthocarpum) in experimental rats to validate its traditional claim.Methods: 50%ethanolic fruit extract ofS. xanthocarpum (SXE, 100, 200or400 mg/kg body weight) was administered daily for14days in experimental animals. Liver injury was induced chemically, byCCl4administration (1 mL/kg i.p.).The hepatoprotective activity was assessed using various biochemical parameters like aspartate aminotransferase (AST), alanine aminotransferase(ALT), Serum alkaline phosphatise (SALP) and total bilirubin. Meanwhile, in vivo antioxidant activities as lipid peroxidation (LPO), reduced glutathione(GSH), superoxide dismutase(SOD) and catalase(CAT) were screened along with histopathological studies.Results: Obtained results demonstrated that the treatment with SXE significantly (P<0.05- <0.001) and dose-dependently prevented chemically induced increase in serum levels of hepatic enzymes. Furthermore,SXE significantly (up toP<0.001) reduced the lipid peroxidation in the liver tissue and restored activities of defence antioxidant enzymes GSH, SOD and catalase towards normal levels. Histopathology of the liver tissue showed thatSXE attenuated the hepatocellular necrosis and led to reduction of inflammatory cells inflltration. Conclusions: The results of this study strongly indicate the protective effect ofSXE against acute liver injury which may be attributed to its hepatoprotective activity, and there by scientifically support its traditional use.

  12. Complex permittivity of FeCl3/AOT/CCl4 microemulsions probed by AC impedance spectroscopy.

    Science.gov (United States)

    Calandra, Pietro; Ruggirello, Angela; Turco Liveri, Vincenzo

    2009-09-01

    The complex permittivity of FeCl(3)/AOT/CCl(4) microemulsions in the 1-10(5) Hz frequency range has been measured by the conventional AC complex impedance technique. Measurements as a function of the volume fraction of the dispersed phase (FeCl(3)+AOT) and temperature at fixed salt-to-AOT molar ratio (R, R = 0.5) show that the entrapment of FeCl(3) clusters significantly enhances the local permittivity of the AOT reverse micelles and the number density of charge carriers resulting from the peculiar state of the confined inorganic salt. An estimate of the apparent static permittivity of the FeCl(3) ionic clusters entrapped in the core of AOT reverse micelles gives the very high and quite surprisingly value of about 237. Moreover, a thorough analysis of conductivity data and of their temperature dependence strongly supports the hypothesis that the charge transport in these systems is mainly sustained by a mechanism of hopping consisting in the continuous jumping of charged species within supra-micellar aggregates of AOT reverse micelles whose aggregation is driven by fluctuating opposite charges on contacting micelles. PMID:19481764

  13. Anti-apoptotic effect of San Huang Shel Shin Tang cyclodextrin complex (SHSSTc) on CCl4 -induced hepatotoxicity in rats.

    Science.gov (United States)

    Yang, Cheng-Hsun; Ting, Wei-Jen; Shen, Chia-Yao; Hsu, Hsi-Hsien; Lin, Yueh-Min; Kuo, Chia-Hua; Tsai, Fuu-Jen; Tsai, Chang-Hai; Tsai, Yuhsin; Huang, Chih-Yang

    2016-06-01

    The metabolic loading is heavier in liver especially when injured or inflammation. San Huang Shel Shin Tang (SHSST) was an old traditional herbal decoction, which composed with Rheum officinale Baill, Scutellaria baicalnsis Geprgi and Coptis chinensis Franch (1:1:2 in weight), can provide a liver protection effects. We used a beta-cyclodextrin (β-CD) drug modification method in reduce of the necessary dose of the SHSST. As the results, the FAS-FADD expressions leaded apoptosis in CCl4 intraperitoneal (IP) injection induced acute liver injury in rats. Silymarin, baicalein, SHSST, and SHSST β-CD complex (SHSSTc) pretreatments protected liver through the decreasing of the expressions of FAS-FADD and downstream caspase-3 and caspase-8. Particularly, SHSSTc (30 mg/kg day) treatment enhanced cell survival pathway activation through the PI3K, Akt and Bad phosphorylation. Compared with SHSST as well as silymarin and baicalein, SHSSTc provided a magnificent liver protection effect, especially in survival pathway activation/TUNEL-apoptotic cell reduction/serum cholesterol level suppression. All these data suggested that β-CD complex modified the SHSST and promoted the bioavailability and liver protection effects. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 663-670, 2016. PMID:25447754

  14. Effectiveness of xenotransplantation of human fetal hepatocytes in spleen of rats with acute liver failure induced by CCL4

    Directory of Open Access Journals (Sweden)

    Abdukhakim Khadjibaev

    2013-04-01

    Full Text Available Human’s fetal hepatocytes (HFH were intrasplenic transplanted white non-pedigree rats with acute liver failure (ALF challenged by single per oral administration of hepatotropic toxin diluted in oil ССl4 at a dose 10 ml/kg (volumetric correlation 1:1 (10 mL/kg body weight as a 1:1 mixture of CCl4 and mineral oil. Transplantation had positive effect on all biochemical blood parameters of the studying animals. Morphologic study showed that reparative-restorative processes were arising in hepatic parenchyma after administration of HFH into splenic pulp of rats with model of ALF on days 14-21. Substantial and main factor in restoration of parenchyma was restoration of micro topographic interrelations in acinus as well as polyploidy of hepatic cells expressed in increase of hepatocytes’ nuclei sizes and hypertrophy of cells themselves. It is an indirect confirmation of engraftment of HFH in liver of rats with model of ALF.

  15. Role of Dehydroepiandrosterone on Oxidative Stress Bio markers in CCl4 Induced Acute Liver Injury in Rats

    International Nuclear Information System (INIS)

    Liver disease has become one of the serious health problems which threaten human as it is exposed to many kinds of xenobiotics and therapeutic agents. Moreover, the rapid growing morbidity and mortality from liver disease are attributed to the increasing number of chemical compounds and environmental pollution. Unfortunately, in the modern era of medicine, there is no specific treatment to counter the menacing impact of these dreaded diseases. Dehydroepiandrosterone (DHEA) is a widely studied steroid hormone with multi-functional properties. Reports suggested that some of the many activities of DHEA are due to its protective effect against lipid peroxidation. Nevertheless, the antioxidant properties of DHEA are still the subject of debate. In the current study, a significant decrease was occurred in liver glutathione (GSH), glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase (CAT) as a result of carbon tetrachloride (CCl4) administration. On the other hand, significant elevations in hepatic enzymes (ALT and AST), total lipids, cholesterol, MDA, tumor necrosis factor-γ, total oxidant capacity and poly (ADP-ribose) polymerase were recorded. These disturbances in all the studied parameters were ameliorated after the toxicated rats were treated with 100/ mg/100 g/day DEHA which depend on the time of treatment (1 and 2 weeks). These findings are consistent with the concept that DHEA is an antioxidant agent

  16. Optical excitation in doped quasi-one-dimensional antiferromagnet (CsMnCl3 centre dot 2H2O+Cu2+)

    International Nuclear Information System (INIS)

    In the wide range of wavelengths and temperatures, the spectra of light absorption and luminescence excitation as well as the emission decay kinetics of a quasi-one-dimensional dielectric crystal CsMnCl3 centre dot 2H2O doped with copper ions (molar concentration 0-3%) are studied. The conclusion is made of the exchange of electronic excitation energy being possible between the matrix and dopant subsystems only in the lowest excited state due to migration of excitation and their trapping by excitation traps of the copper origin. From the analysis of the shape of decay kinetics curves of the matrix luminescence of the crystal, the values of hopping (along the chains of manganese ions) and trapping rates of magnetic excitons are determined

  17. Solvent effects on infrared spectra of methyl 4-hydroxybenzoate in pure organic solvents and in ethanol/CCl 4 binary solvents

    Science.gov (United States)

    Liu, Qing; Fang, Danjun; Zheng, Jianping

    2004-06-01

    Infrared spectroscopy studies of methyl 4-hydroxybenzoate (MHB) in 17 different organic solvents and in ethanol/CCl 4 binary solvent were undertaken to investigate the solvent-solute interactions. The frequencies of carbonyl stretching vibration ν(CO) of MHB in single solvents were correlated with the solvent acceptor number (AN) and the linear solvation energy relationships (LSER). The assignments of the two bands of ν(CO) of MHB in alcohols and the single one of that in non-alcoholic solvents were discussed. The shifts of ν(CO) of MHB in ethanol/CCl 4 binary solvents showed that several kinds of solute-solvent hydrogen bonding interactions coexisted in the mixture solvents, with a change in the mole fraction of ethanol in the binary solvents.

  18. S-wave threshold in electron attachment - observations and cross sections in CCl4 and SF6 at ultralow electron energies

    International Nuclear Information System (INIS)

    The threshold photoionization method was used to study low-energy electron attachment phenomena in and cross sections of CCl4 and SF6 compounds, which have applications in the design of gaseous dielectrics and diffuse discharge opening switches. Measurements were made at electron energies from below threshold to 140 meV at resolutions of 6 and 8 meV. A narrow resolution-limited structure was observed in electron attachment to CCl4 and SF6 at electron energies below 10 meV, which is attributed to the divergence of the attachment cross section in the limit epsilon, l approaches zero. The results are compared with experimental collisional-ionization results, electron-swarm unfolded cross sections, and earlier threshold photoionization data. 34 refs

  19. s-wave threshold in electron attachment - Observations and cross sections in CCl4 and SF6 at ultralow electron energies

    Science.gov (United States)

    Chutjian, A.; Alajajian, S. H.

    1985-01-01

    The threshold photoionization method was used to study low-energy electron attachment phenomena in and cross sections of CCl4 and SF6 compounds, which have applications in the design of gaseous dielectrics and diffuse discharge opening switches. Measurements were made at electron energies from below threshold to 140 meV at resolutions of 6 and 8 meV. A narrow resolution-limited structure was observed in electron attachment to CCl4 and SF6 at electron energies below 10 meV, which is attributed to the divergence of the attachment cross section in the limit epsilon, l approaches zero. The results are compared with experimental collisional-ionization results, electron-swarm unfolded cross sections, and earlier threshold photoionization data.

  20. Pengaruh Ekstrak Metanol Daun Suren (Toona sureni Bl Merr) Terhadap Fungsi Hati dan Nilai Darah (Rattus norvegicus L.) Jantan yang Dipapari Karbon Tetraklorida (CCl4)

    OpenAIRE

    Simatupang, Sera Wida

    2016-01-01

    The effect of methanol extract of suren leaves (Toona sureni BL Merr) on the function of liver, erythrocyte count and haemoglobin level in male rat (Rattus norvegicus) induced by carbon tetracloride (CCl4) had been studied from April to November 2015. This research performed with completely randomized design and treatment was divided into 8 groups: 2 groups of positive control, 2 groups of solvent control, normal control, and 3 groups of extract concentration (100, 150 and 200 mg/kg/bw). The ...

  1. Oxymatrine attenuates CCl4-induced hepatic fibrosis via modulation of TLR4-dependent inflammatory and TGF-β1 signaling pathways.

    Science.gov (United States)

    Zhao, Hong-Wei; Zhang, Zhen-Fang; Chai, Xuan; Li, Guang-Quan; Cui, He-Rong; Wang, Hong-Bo; Meng, Ya-Kun; Liu, Hui-Min; Wang, Jia-Bo; Li, Rui-Sheng; Bai, Zhao-Fang; Xiao, Xiao-He

    2016-07-01

    Oxymatrine (OMT) is able to effectively protect against hepatic fibrosis because of its anti-inflammatory property, while the underlying mechanism remains incompletely understood. In this study, forty rats were randomly divided into five groups: control group, model group (carbon tetrachloride, CCl4) and three OMT treatment groups (30, 60, 120mg/kg). After CCl4 alone, the fibrosis score was 20.2±0.8, and the level of alanine aminotransferase (ALT), aspartate aminotransferase (AST), hydroxyproline content, and collagen I expression was elevated, but OMT blunted these parameters. Treatment with OMT prevented CCl4-induced increases in expression of pro-inflammatory and pro-fibrotic cytokines interleukin (IL)-6 and tumor necrosis factor (TNF)-α, meanwhile OMT promoted the expression of anti-inflammatory and anti-fibrotic factors such as interleukin (IL)-10 and bone morphogenetic protein and activin membrane-bound inhibitor (Bambi). Moreover, lipopolysaccharides (LPS) and high mobility group box-1 (HMGB1), which activates Toll-like receptor 4 (TLR4) and modulate hepatic fibrogenesis through hepatic stellate cells (HSCs) or Kupffer cells, were significantly decreased by OMT treatment. These results were further supported by in vitro data. First, OMT suppressed the expression of TLR4 and its downstream pro-inflammatory cytokines, lowered the level of HMGB1, TGF-β1 in macrophages. Then, OMT promoted Bambi expression and thereby inhibited activation of HSCs mediated by transforming growth factor (TGF)-β1. In conclusion, this study showed that OMT could effectively attenuate the CCl4-induced hepatic fibrosis, and this effect may be due to modulation of TLR4-dependent inflammatory and TGF-β1 signaling pathways. PMID:27179304

  2. Effect of 3 amino 1,2,4 triazole administration on the early CCl4-induced ultrastructural alterations in rat liver.

    OpenAIRE

    Bernacchi, A. S.; de Castro, C. R.; de Ferreyra, E. C.; de Fenos, O. M.; Castro, J.A.

    1982-01-01

    CCl4 administration to rats caused at 3 and 6 h intense effects on the liver-cell endoplasmic reticulum such as dilatation, disorganization, detachment of ribosomes, development of extensive areas of smooth component (SER) and formation of myelin figures. 3 Amino 1,2,4 triazole administration (AT) at 3 and 6 h led to the formation of round small vesicles from the rough endoplasmic reticulum (RER), detachment of ribosomes, appearance of extensive areas of SER, appearance of elongated and disto...

  3. Compositional characterisation of soluble apple polysaccharides, and their antioxidant and hepatoprotective effects on acute CCl4-caused liver damage in mice.

    Science.gov (United States)

    Yang, Xingbin; Yang, Su; Guo, Yurong; Jiao, Yadong; Zhao, Yan

    2013-06-01

    Water-soluble apple peel polysaccharides (APP) and apple flesh polysaccharides (AFP) were isolated from Pink Lady fruits, and their in vitro antioxidant capacities were characterised by DPPH(), HO(), and O(2)(-) systems, and ferric-reducing antioxidant power assay. Oral administration of APP at 250 and 500 mg/kg bw in mice was shown to be as effective as AFP in lowering the CCl(4)-caused increases of serum alanine aminotransferase, aspartate aminotransferase and lactic dehydrogenase activities, and hepatic malondialdehyde level, and antagonising the decreases in antioxidant superoxide dismutase and glutathione peroxidase activities caused by CCl(4) (p<0.05). Histopathological examinations further confirmed that both APP and AFP could protect the liver from CCl(4)-induced histological alteration. HPLC analysis also showed similar profiles of monosaccharide composition for APP and AFP with arabinose, galactose and galacturonic acid being main component monosaccharides. All of these findings demonstrate that the extracts of both APP and AFP possess antioxidant and hepatoprotective potential. PMID:23411241

  4. «Evaluation of the anti-icterus effect of crude powdered leaf of Argemone mexicana L. (Papaveraceae against CCl4-induced liver injury in rats».

    Directory of Open Access Journals (Sweden)

    T.S. SOURABIE

    2012-10-01

    Full Text Available Leaves of Argemone mexicana L. (Papaveraceae are used in the folk medicine of Burkina Faso (West Africa to treat a variety of illness. Aqueous decoction of the drug is indicated in the treatment of malaria fever, abdominal pains, and jaundice. A preliminary study led by the authors showed a good anti-icterus (hepatoprotective activity of leaves extracts on intoxicated Wistar rats. The aim of the present investigation was to evaluate the anti-icterus activity of crude leaf powder against CCl4 induced hepatotoxicity in rats. Liver functions were assessed by the activities of liver marker enzymes, ASAT/GOT, ALAT/GPT, ALP, Total Bilirubin (TBIL and Direct Bilirubin (DBIL.A crude powdered leaf suspended in acacia gum solution (2% p/w was administered orally to the animal at doses of 125, 250 and 500 mg/kg attenuated significantly (p<0,05 the elevation of serum enzymes level and bilirubin (total and direct if compared to the CCl4 treated groups. Silymarin (100 mg/kg, p.o., a known antihepatoprotective drug was used as reference. The results showed a dose-dependent anti-hepatotoxic effect against liver injury induced by CCl4 in rats. These findings give an opportunity for a future elaboration of galenic formulation as phytomedicament.

  5. Efficacy of a traditional unani formulation Jawarish-e-Amla Sada against CCl 4 induced liver toxicity in Albino Wistar rats: Comparison with silymarin treatment

    Directory of Open Access Journals (Sweden)

    Sunita Shailajan

    2015-01-01

    Full Text Available Background: Jawarish-e-Amla Sada (JAS; a polyherbal Unani formulation, is claimed as a potential hepatoprotective agent in traditional Unani medicine treatise. Aims and Objectives: Though, JAS has its composition recorded in ancient Unani texts, there have been minimal attempts to scientifically validate its hepatoprotective potential. The present work is an attempt to evaluate the hepatoprotective activity of JAS in vivo. Materials and Methods: CCl 4 intoxicated Albino Wistar rats were used to evaluate the hepatoprotective activity of JAS (0.7 g/kg and 1.0 g/kg, p.o. and the results were compared with, silymarin. The efficacy was established on the basis of altered levels of biochemical markers and histopathological analysis of the liver tissue. Results and Discussion: Treatment with the aqueous slurry of JAS significantly reduced the level of biochemical markers in CCl 4 intoxicated rats. These findings were well-supported by the histopathological analysis of liver tissue. The effect shown by JAS was found to be at par with silymarin treatment. Conclusion: This study suggests that CCl 4 induced liver damage can be ameliorated by traditional Unani formulation JAS. This justifies the traditional claim of JAS being a hepatoprotective agent.

  6. FT-IR study on interactions between medroxyprogesterone acetate and solvent in CHCl3/cyclo-C6H12 and CCl4/cyclo-C6H12 binary solvent systems

    Science.gov (United States)

    Shi, Jie-hua; Fan, Chun-hui

    2012-09-01

    The intermolecular interactions between medroxyprogesterone acetate (MPA) and CHCl3 and CCl4 solvent in CHCl3/cyclo-C6H12 and CCl4/cyclo-C6H12 binary solvent systems have been studied by Fourier transform infrared spectroscopy (FT-IR). The experimental results showed that there are hydrogen bonding interactions between oxygen atoms of all carbonyl groups in MPA and hydrogen atom of CHCl3 so as to form 1:3 complex of MPA with CHCl3 and produce three new absorption bands at 1728.9-1736.1, 1712.7-1717.4 and 1661.9-1673.8 cm-1, respectively. And, 1:1 complex of MPA with CCl4 is formed in CCl4/cyclo-C6H12 binary solvent as a result of hydrogen bonding interaction between C3 carbonyl group and empty d-orbital in chlorine atom of CCl4 leading to producing new absorption band at 1673.2-1674.2 cm-1. However, all free carbonyl and associated carbonyl stretching vibrations of MPA in CHCl3/cyclo-C6H12 and CCl4/cyclo-C6H12 binary solvent systems shift to lower wavenumbers with the increasing of volume fraction of CHCl3 and CCl4 in binary solvent systems owing to the dipole-dipole interaction and the dipole-induced dipole interaction between MPA and solvents.

  7. Antioxidative effects of pumpkin seed (Cucurbita pepo) protein isolate in CCl4-induced liver injury in low-protein fed rats.

    Science.gov (United States)

    Nkosi, C Z; Opoku, A R; Terblanche, S E

    2006-11-01

    The effects of pumpkin seed (Cucurbita pepo) protein isolate on the plasma activity levels of catalase (CA), superoxide dismutase (SOD), glutathione peroxidase (GSHpx) and total antioxidant capacity (TAC) as well as glucose-6-phosphatase (G6Pase) in liver homogenates and lipid peroxidation (LPO-malondialdehyde-MDA) levels in liver homogenates and liver microsomal fractions against carbon tetrachloride (CCl(4))-induced acute liver injury in low-protein fed Sprague-Dawley rats (Rattus norvegicus) were investigated. A group of male Sprague-Dawley rats maintained on a low-protein diet for 5 days were divided into three subgroups. Two subgroups were injected with carbon tetrachloride and the other group with an equivalent amount of olive oil. Two hours after CCl(4) intoxication one of the two subgroups was administered with pumpkin seed protein isolate and thereafter switched onto a 20% pumpkin seed protein isolate diet. The other two groups of rats were maintained on the low-protein diet for the duration of the investigation. Groups of rats from the different subgroups were killed at 24, 48 and 72 h after their respective treatments. After 5 days on the low-protein diet the activity levels of all the enzymes as well as antioxidant levels were significantly lower than their counterparts on a normal balanced diet. However, a low-protein diet resulted in significantly increased levels of lipid peroxidation. The CCl(4) intoxicated rats responded in a similar way, regarding all the variables investigated, to their counterparts on a low-protein diet. The administration of pumpkin seed protein isolate after CCl(4) intoxication resulted in significantly increased levels of all the variables investigated, with the exception of the lipid peroxidation levels which were significantly decreased. From the results of the present study it is concluded that pumpkin seed protein isolate administration was effective in alleviating the detrimental effects associated with protein

  8. Evaluation of chemopreventive effect ofFumaria indica against N-nitrosodiethylamine and CCl4-induced hepatocellular carcinoma in Wistar rats

    Institute of Scientific and Technical Information of China (English)

    Talib Hussain; Hefazat H Siddiqui; Sheeba Fareed; M Vijayakumar; Chandana V Rao

    2012-01-01

    Objective:To investigation the chemopreventive potential ofFumaria indica (F. indica) extract (FIE) on N-nitrosodiethylamine and CCl4-induced hepatocarcinogenesis in Wistar rats.Methods:The experimental animals were divided into six groups (n=6). Hepatocellular carcinoma was induced by single intraperitoneal injection ofN-nitrosodiethylamine (NDEA) in normal saline at a dose of 200 mg/kg body weight followed by weekly subcutaneous injections of CCl4 (3 mL/kg/week) for 6 weeks, as the promoter of carcinogenic effect. After administration of the carcinogen, 200 and 400 mg/kg of FIE were administered orally once a day throughout the study. At the end of 20 weeks, the body weight, liver weight and relative liver weight were measured. The percentage of nodule incidence and liver cancer markers such as aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP),γ-glutamyl transferase (γ-GT), total bilirubin level (TBL), α-feto protein (AFP) and carcinoembryonic antigen were estimated along with histopathological investigation in experimental groups of rats. Results: Obtained results demonstrated that the cotreatment with FIE significantly prevented the decrease of the body weight and also increased in relative liver weight caused by NDEA. The treatment with FIE significantly reduced the nodule incidence and nodule multiplicity in the rats after NDEA administration. The levels of liver cancer markers such as AST, ALT, ALP,γ-glutamyl transferase, TBL, AFP and carcinoembryonic antigen were substantially increased by NDEA treatment. However, FIE treatment significantly reduced the liver injury and restored the entire liver cancer markers. Histological observations of liver tissues too correlated with the biochemical observations.Conclusions: These finding powerfully supports thatF. indica exert chemopreventive effect by suppressing the tumor burden and restoring the activities of hepatic cancer marker enzymes on NDEA and CCl4-induced

  9. Hepatoprotective and antioxidant activity of methanolic extract of flowers ofNerium oleander against CCl4-induced liver injury in rats

    Institute of Scientific and Technical Information of China (English)

    Kumar Gaurav Singhal; Ghanshyam Das Gupta

    2012-01-01

    Objective:To investigate the antioxidant and hepatoprotective activity of methanolic flower extract ofNerium oleander againstCCl4-induced hepatotoxicity in rats.Methods:In vitro antioxidant activity of methanolic extract of flowers of Nerium oleander(MENO-F) was evaluated by various assays, including reducing power, lipid peroxidation,DPPH,ABTS, superoxide anion, hydroxyl radicals and metal chelation.The hepatoprotective andin vivo antioxidant activity ofMENO-F were evaluated againstCCl4-induced hepatic damage in rats.TheMENO-F at dose of100,200 and400 mg/kg were administered orally once daily for seven days.Serum enzymatic levels of serum glutamate oxaloacetate transaminase(AST), serum glutamate pyruvate transaminase(ALT), serum alkaline phosphatase(ALP) and total bilirubin were estimated along with estimation of superoxide dismutase(SOD) and malondialdehyde(MDA) levels in liver tissues.Further histopathological examination of the liver sections was carried out to support the induction of hepatotoxicity and hepatoprotective efficacy.Results:The extract showed potent activities on reducing power, lipid peroxide,DPPH,ABTS, superoxide anion, hydroxyl radical and metal chelation.The substantially elevated serum enzymatic levels ofAST,ALT,ALP and total bilirubin were found to be restored towards normalization significantly by theMENO-F in a dose dependent manner with maximum hepatoprotection at400 mg/kg dose level.The histopathological observations supported the biochemical evidences of hepatoprotection.Elevated level ofSOD and decreased level ofMDA further strengthen the hepatoprotective observations.Conclusions:The results of the present study strongly reveal thatMENO-F has potent antioxidant activity and hepatoprotective activity againstCCl4-induced hepatic damage in experimental animals.

  10. Adipose derived mesenchymal stem cells transplantation via portal vein improves microcirculation and ameliorates liver fibrosis induced by CCl4 in rats

    Directory of Open Access Journals (Sweden)

    Wang Yu

    2012-06-01

    Full Text Available Abstract Introduction Adipose derived mesenchymal stem cells (ADMSCs, carrying the similar characteristics to bone marrow mesenchymal stem cells, only much more abundant and easier to obtain, may be a promising treatment for liver fibrosis. We aim to investigate the therapeutic potential of ADMSCs transplantation in liver fibrosis caused by carbon tetrachloride (CCl4 in rats as well as its underlying mechanism, and to further explore the appropriate infusion pathway. Methods ADMSCs were isolated, cultured and identified. Placebo and ADMSCs were transplanted via portal vein and tail vein respectively into carbon tetrachloride (CCl4-induced liver fibrosis rats. Computed tomography (CT perfusion scan and microvessel counts were performed to measure the alteration of liver microcirculation after therapy. Liver function tests and histological findings were estimated. Results CT perfusion scan shown significant decrease of hepatic arterial perfusion index, significant increased portal vein perfusion, total liver perfusion in rats receiving ADMSCs from portal vein, and Factor VIII (FVIII immunohistochemical staining shown significant decrease of microvessels in rats receiving ADMSCs from portal vein, indicating microcirculation improvement in portal vein group. Vascular endothelial growth Factor (VEGF was significantly up-regulated in fibrosis models, and decreased after ADMSCs intraportal transplantation. A significant improvement of liver functional test and histological findings in portal vein group were observed. No significance was found in rats receiving ADMSCs from tail vein. Conclusions ADMSCs have a therapeutic effect against CCl4-mediated liver fibrosis. ADMSCs may benefit the fibrotic liver through alteration of microcirculation, evidenced by CT perfusion scan and down-regulation of VEGF. Intraportal transplantation is a better pathway than tail vein transplantation.

  11. NMR investigation on isotope effect of glycinium phosphite H sub 3 NCH sub 2 COOH centre dot H sub 2 PO sub 3

    CERN Document Server

    Ishibashi, T

    2003-01-01

    The motions of the phosphite anions and glycinium cations in H sub 3 NCH sub 2 COOH centre dot H sub 2 PO sub 3 (GPI) and its deuterated analogue (DGPI) were investigated by sup 1 H, sup 1 sup 3 C and sup 3 sup 1 P spin-lattice relaxation times T sub 1. For both GPI and DGPI, T sub 1 's of the sup 1 H, sup 1 sup 3 C and sup 3 sup 1 P nuclei reflect the amino rotation, methylene libration and motion of the phosphite anions, respectively. Activation energies obtained from T sub 1 's of sup 1 H, sup 1 sup 3 C and sup 3 sup 1 P nuclei are 28.6(2), 26.0(4) and 26.2(4) kJ/mol for GPI and are 34.9(6), 27(1), 47(2) kJ/mol for DGPI, respectively. The deuterium substitution increases E sub a for the motion influenced by the hydrogen bonding. In all the observed motions, correlation times of DGPI are larger than those of GPI. (author)

  12. A study of the x-irradiated Cs sub 5 H sub 3 (SO sub 4) sub 4 centre dot H sub 2 O crystal by EPR in the 80-415 K temperature range

    CERN Document Server

    Waplak, S; Baranov, A I; Shuvalov, L A

    1997-01-01

    The EPR spectra of the x-irradiated fast proton conductor Cs sub 5 H sub 3 (SO sub 4) sub 4 centre dot H sub 2 O were investigated in the temperature range of 80-415 K. Two kinds of paramagnetic SO sub 4 sup - centres with different proton configurations below about 370 K and freeze-out behaviour of one of them below about 200 K were observed. The role of acid proton dynamics with respect to the glassy-like transition is discussed. (author)

  13. Cannabinoid receptors are involved in the protective effect of a novel curcumin derivative C66 against CCl4-induced liver fibrosis.

    Science.gov (United States)

    Huang, Si-Si; Chen, Da-Zhi; Wu, He; Chen, Rui-Cong; Du, Shan-Jie; Dong, Jia-Jia; Liang, Guang; Xu, Lan-Man; Wang, Xiao-Dong; Yang, Yong-Ping; Yu, Zhen-Ping; Feng, Wen-Ke; Chen, Yong-Ping

    2016-05-15

    Liver fibrosis is one of the major causes of morbidity and mortality worldwide and lacks efficient therapy. Recent studies suggest the curcumin protects liver from fibrosis. However, curcumin itself is in low bioavailable concentration when administered orally, and the protective mechanism remains poorly understood. The current study aimed to investigate whether a more stable derivative of curcumin, C66, protects against CCl4-inudced liver fibrosis and examine the underlying mechanism involving cannabinoid receptor (CB receptor). At a dose lower than curcumin itself, C66 displayed a superior anti-fibrotic effect. C66 significantly reduced collagen deposition, pro-inflammatory cytokine expression, and liver enzyme activities. Mechanistic study revealed that C66 treatment decreased CCl4-induced cannabinoid receptor 1 (CB1 receptor) expression and increased cannabinoid receptor 2 (CB2 receptor) expression, along with an inhibition of JNK/NF-κB-mediated inflammatory signaling. In conclusion, this curcumin derivative attenuates liver fibrosis likely involving a CB/JNK/NF-κB-mediated pathway. PMID:26945822

  14. Ragweed-allergic subjects have decreased serum levels of chemokines CCL2, CCL3, CCL4 and CCL5 out of the pollen season.

    Science.gov (United States)

    Kostova, Zhivka; Batsalova, Tsvetelina; Moten, Dzhemal; Teneva, Ivanka; Dzhambazov, Balik

    2015-01-01

    CC-chemokines are important mediators of the allergic responses and regulate the cell trafficking. The aim of this study was to examine the serum levels of CCL2/MCP-1, CCL3/MIP-1α, CCL4/MIP-1β and CCL5/RANTES, and to determine whether there are differences between ragweed-allergic subjects and healthy individuals out of the pollen season. Peripheral blood samples were collected from 24 subjects allergic to ragweed pollen and 12 healthy controls. Serum concentrations of chemokines/cytokines were measured by an enzyme-linked immunosorbent assay. We observed significantly decreased concentrations of CCL2/MCP-1, CCL3/MIP-1α, CCL4/MIP-1β and CCL5/RANTES in the sera of ragweed-allergic patients compared to the healthy individuals (32.2 vs. 106.4 pg/ml, 89.5 vs. 135.7 pg/ml, 63.4 vs. 119.2 pg/ml and 11.2 vs. 18.1 ng/ml, respectively, p pollen allergy out of the season, to study the mechanisms for activation/inhibition of the subclinical allergic responses and for development of therapeutic strategies. PMID:26862308

  15. Evolution of the Copper Surface in the Course of Oxidation by CCl4-L (L=THF, Dmf, Dmso): Scanning Probe Microscope Study

    Science.gov (United States)

    Panteleev, S. V.; Maslennikov, S. V.; Ignatov, S. K.; Spirina, I. V.; Kruglova, M. V.; Gribkov, B. A.; Vdovichev, S. N.

    2013-08-01

    The evolution of compact surface of the 100 nm copper film deposited on the glass-ceramics doped with vanadium coating in the course of the oxidation by the CCl4-L (L = dimethylformamide (DMF), tetrahydrofuran (THF), dimethylsulfoxide (DMSO), CCl4 concentration ≈ 1 mol/L) was studied by atomic force microscopy (AFM) in contact mode. The dynamics of active centers formation and destruction was investigated in the course of the oxidation process. The metallic sample dissolution rate was estimated as a function of the coordinating solvent nature. The development of the metal surface oxidation was established to lead to a significant increase of surface roughness. This phenomenon can be explained by the fact that different parts of the surface react at different rates. Further course of the reaction leads to a significant decrease of the surface roughness of copper films. The amount of the metal reacted has an almost linear dependence on the reaction time. AFM scans indicate that there is the same mechanism of the reaction between copper and carbon tetrachloride for all solvents.

  16. Impact of a CXCL12/CXCR4 Antagonist in Bleomycin (BLM) Induced Pulmonary Fibrosis and Carbon Tetrachloride (CCl4) Induced Hepatic Fibrosis in Mice

    Science.gov (United States)

    Chow, Leola N.; Schreiner, Petra; Ng, Betina Y. Y.; Lo, Bernard; Hughes, Michael R.; Scott, R. Wilder; Gusti, Vionarica; Lecour, Samantha; Simonson, Eric; Manisali, Irina; Barta, Ingrid; McNagny, Kelly M.; Crawford, Jason; Webb, Murray; Underhill, T. Michael

    2016-01-01

    Modulation of chemokine CXCL12 and its receptor CXCR4 has been implicated in attenuation of bleomycin (BLM)-induced pulmonary fibrosis and carbon tetrachloride (CCl4)-induced hepatic injury. In pulmonary fibrosis, published reports suggest that collagen production in the injured lung is derived from fibrocytes recruited from the circulation in response to release of pulmonary CXCL12. Conversely, in hepatic fibrosis, resident hepatic stellate cells (HSC), the key cell type in progression of fibrosis, upregulate CXCR4 expression in response to activation. Further, CXCL12 induces HSC proliferation and subsequent production of collagen I. In the current study, we evaluated AMD070, an orally bioavailable inhibitor of CXCL12/CXCR4 in alleviating BLM-induced pulmonary and CCl4-induced hepatic fibrosis in mice. Similar to other CXCR4 antagonists, treatment with AMD070 significantly increased leukocyte mobilization. However, in these two models of fibrosis, AMD070 had a negligible impact on extracellular matrix deposition. Interestingly, our results indicated that CXCL12/CXCR4 signaling has a role in improving mortality associated with BLM induced pulmonary injury, likely through dampening an early inflammatory response and/or vascular leakage. Together, these findings indicate that the CXCL12-CXCR4 signaling axis is not an effective target for reducing fibrosis. PMID:26998906

  17. Evaluation of protective effect of Sapindus mukorossi saponin fraction on CCl4-induced acute hepatotoxicity in rats

    OpenAIRE

    Srinivasa Rao M; Syed Asad B; Fazil MA; Sudharshan RD; Rasheed SA; Pradeep HA; Aboobacker S; Thayyil AH; Riyaz AK; Mansoor M; Aleem MA; Zeeyauddin K; Lakshmi Narasu M; Anjum A.; Ibrahim M.

    2012-01-01

    M Srinivasa Rao,1 B Syed Asad,1 MA Fazil,1 RD Sudharshan,1 SA Rasheed,1 HA Pradeep,1 S Aboobacker,2 AH Thayyil,1 AK Riyaz,1 M Mansoor,1 MA Aleem,1 K Zeeyauddin,3 M Lakshmi Narasu,4 A Anjum,1,5 M Ibrahim1,51Nizam Institute of Pharmacy, Andhra Pradesh; 2Department of Pharmacology, Jamiya Salafiya College of Pharmacy, Kerala; 3Department of Pharmacology, Deccan School of Pharmacy, Andhra Pradesh; 4Centre for Biotechnology, Jawaharlal Nehru Technological University, Andhra Pradesh; 5Asian Institu...

  18. Dynamics of heavy-Rydberg ion-pair formation in K(14p,20p)-SF6, CCl4 collisions

    Science.gov (United States)

    Wang, C. H.; Kelley, M.; Buathong, S.; Dunning, F. B.

    2014-06-01

    The dynamics of formation of heavy-Rydberg ion-pair states through electron transfer in K(np)-SF6, CCl4 collisions is examined by measuring the velocity, angular, and binding energy distributions of the product ion pairs. The results are analyzed with the aid of a Monte Carlo collision code that models both the initial electron capture and the subsequent evolution of the ion pairs. The model simulations are in good agreement with the experimental data and highlight the factors such as Rydberg atom size, the kinetic energy of relative motion of the Rydberg atom and target particle, and (in the case of attaching targets that dissociate) the energetics of dissociation that can be used to control the properties of the product ion-pair states.

  19. Biosynthesis of silver nanoparticles from Premna serratifolia L. leaf and its anticancer activity in CCl4-induced hepato-cancerous Swiss albino mice

    Science.gov (United States)

    Arockia John Paul, J.; Karunai Selvi, B.; Karmegam, N.

    2015-11-01

    In this study, we report the biosynthesis of silver nanoparticles using the ethanolic leaf powder extract of Premna serratifolia L. and its anticancer activity in carbon tetra chloride (CCl4)-induced liver cancer in Swiss albino mice (Balb/c). The synthesized silver nanoparticles were characterized by SEM, FTIR and XRD analyses. The Debye-Scherrer equation was used to calculate particle size and the average size of silver nanoparticles synthesized from P. serratifolia leaf extract was 22.97 nm. The typical pattern revealed that the sample contained cubic structure of silver nanoparticles. FTIR analysis confirmed that the bioreduction of silver ions to silver nanoparticles is due to reduction by capping material of the plant extract. The silver nanoparticles of P. serratifolia leaf extract were effective in treating liver cancer in Swiss albino mice when compared with P. serratifolia leaf extract with isoleucine.

  20. Application of gas chromatography to the study of the chemical effects produced by the radiolysis and the 35Cl(n,p)35S reaction on the CCl4

    International Nuclear Information System (INIS)

    In this work the gas radiochromatography, which is essential in the hot atom chemistry is used. By means of this technique the chemical effects of the 35Cl(n,p)35S, and the radiolysis of liquid CCl4 were studied. The samples of liquid CCl4 were capsulated in cuarzo bulbs and were deaereated by several cycles of freeze and pumping in a vacuum line. The sample's irradiation was made in the Triga Mark III Salazar reactor with an approximated flux of 1012n-cm2-s-1 during ten hours. The sample's analysis was made using a gas radiochromatographer composed of a gas chromatographer, proportional flux detector and an adequate electronic system. In this form were obtained the radiochromatographics of the 35S labelled compounds possibly formed by hot atom chemistry and at the same time the hexachloroetane formed by the secondary radiolytic effect of the ionizing radiation on the CCl4 was identified. (author)

  1. EVALUATION OF HEPATOPROTECTIVE EFFECT OF CALOTROPIS PROCERA (AIT R.BR ROOT EXTRACT AGAINST CCL4 INDUCED HEPATO-OXIDATIVE STRESS IN ALBINO RATS

    Directory of Open Access Journals (Sweden)

    Patil Prakash

    2011-02-01

    Full Text Available In the present study, Calotropis procera (Asclepediaceae was evaluated for its possible hepatoprotective and antioxidant potential. Hepatoprotective activity of the methanol extract (MCP of the root bark was determined using carbon tetrachloride (CCl4 induced liver injury in rats. MCP extract evaluated, at an oral dose of 200 and 400 mg kg1. The animals were weighed each and divided in groups of six. Liver damage was achieved by injecting CCl4 in olive oil (1:1 0.8 mL kg-1. The treatment groups pretreated with above extracts. Silymarin was used as reference standard drug. At the end of 7 days, blood was collected, liver extracted, weighed, processed for histopathological assessments and for antioxidant activity. The MCP exhibited a significant (p<0.05 hepato-protective effect by lowering the elevated serum levels of serum transaminases (AST and ALT, Alkaline phosphatase (ALP, total and direct serum bilirubin, cholesterol and significantly increasing high density lipoprotein (HDL and moderately increasing total protein and albumin. These biochemical observations were supplemented by histopathological examination of liver sections. Further, the effects of the MCP extract on antioxidant enzymes also have been investigated to elucidate the possible mechanism of its hepatoprotective activity. The MCP extract exhibited a significant effect(p<0.05 in a dose dependent manner by modifying the levels of reduced glutathione, super oxide dimutase, catalase activity and malondialdehyde equivalent, an index of lipid peroxidation of the liver. These findings suggest that the MCP extract exhibited a dose dependent significant effect on hepatoprotective and antioxidant potential which revitalidates the use of this plant for the treatment of liver toxicity in oriental traditional medicine.

  2. Higher Expression of CCL2, CCL4, CCL5, CCL21, and CXCL8 Chemokines in the Skin Associated with Parasite Density in Canine Visceral Leishmaniasis

    Science.gov (United States)

    Menezes-Souza, Daniel; Guerra-Sá, Renata; Carneiro, Cláudia Martins; Vitoriano-Souza, Juliana; Giunchetti, Rodolfo Cordeiro; Teixeira-Carvalho, Andréa; Silveira-Lemos, Denise; Oliveira, Guilherme Corrêa; Corrêa-Oliveira, Rodrigo; Reis, Alexandre Barbosa

    2012-01-01

    Background The immune response in the skin of dogs infected with Leishmania infantum is poorly understood, and limited studies have described the immunopathological profile with regard to distinct levels of tissue parasitism and the clinical progression of canine visceral leishmaniasis (CVL). Methodology/Principal Findings A detailed analysis of inflammatory cells (neutrophils, eosinophils, mast cells, lymphocytes, and macrophages) as well as the expression of chemokines (CCL2, CCL4, CCL5, CCL13, CCL17, CCL21, CCL24, and CXCL8) was carried out in dermis skin samples from 35 dogs that were naturally infected with L. infantum. The analysis was based on real-time polymerase chain reaction (PCR) in the context of skin parasitism and the clinical status of CVL. We demonstrated increased inflammatory infiltrate composed mainly of mononuclear cells in the skin of animals with severe forms of CVL and high parasite density. Analysis of the inflammatory cell profile of the skin revealed an increase in the number of macrophages and reductions in lymphocytes, eosinophils, and mast cells that correlated with clinical progression of the disease. Additionally, enhanced parasite density was correlated with an increase in macrophages and decreases in eosinophils and mast cells. The chemokine mRNA expression demonstrated that enhanced parasite density was positively correlated with the expression of CCL2, CCL4, CCL5, CCL21, and CXCL8. In contrast, there was a negative correlation between parasite density and CCL24 expression. Conclusions/Significance These findings represent an advance in the knowledge about skin inflammatory infiltrates in CVL and the systemic consequences. Additionally, the findings may contribute to the design of new and more efficient prophylactic tools and immunological therapies against CVL. PMID:22506080

  3. Protective effect of Tanreqing injection on acute hepatic injury induced by CCl4 in rats%痰热清注射液对急性肝损伤大鼠的保护作用

    Institute of Scientific and Technical Information of China (English)

    雷扬; 周爱民; 郭涛; 谭烨; 陶艳艳; 刘成海

    2013-01-01

    目的:观察痰热清注射液对四氯化碳(CCl4)诱导大鼠急性肝损伤的保护作用.方法:首先复制CCl4单次染毒模型,100% CCl45mL·kg-1皮下注射,同时设正常对照组,观察染毒3,6h后大鼠肝损伤变化;继而复制CCl4多次染毒肝损伤模型,首次100% CCl45 mL·kg-1,第2次50% CCl4橄榄油溶液2 mL·kg-1,第3次20% CCl4橄榄油溶液2 mL·kg-1皮下注射诱导急性肝损伤模型,首次CCl4染毒6h后分为模型组、甘草酸二铵治疗组、痰热清高、中、低剂量治疗组,连续尾静脉给药7d,同时设正常对照组.观察大鼠体重、肝体比;HE染色观察肝组织炎症病理;试剂盒检测血清丙氨酸氨基转移酶(ALT)、天门冬氨酸氨基转移酶(AST)、总胆红素(T.Bil)、直接胆红素(D.Bil)、胆碱酯酶(CHE)、总胆汁酸(TBA)、γ-氨基酰转肽酶(γ-GT)、白蛋白(Alb).结果:单次染毒模型:CCl4单次皮下注射6h后,大鼠血清AST活性与T.Bil含量明显升高,肝组织小叶结构紊乱、肝细胞肿胀明显,呈现明显肝损伤.多次染毒药效实验结果发现:与正常组相比,模型组的ALT,AST与γ-GT活性明显升高(P<0.05),TBA,T.Bil含量明显增加(P<0.05),CHE含量明显降低(P<0.05);HE染色显示,模型组肝小叶结构排列紊乱,肝细胞气球样变明显.与模型组相比,痰热清高、中剂量组与甘草酸二铵组血清肝功能、肝组织炎症病理明显改善,其中痰热清高、中剂量组优于甘草酸二铵组.结论:痰热清注射液具有显著抗CCl4诱导的大鼠急性肝损伤作用.%Objective:To observe the protective effect of Tanreqing injection(TRQ) on carbon tetrachloride-induced acute hepatic injury in rats.Method:Rats were randomly divided into the normal group and the model group,and injected subcutaneously with 100% CCl4 5 mL · kg-1 to establish the single CCl4 infection model,in order to observe the changes in rat liver injury after 3 h and 6 h.Subsequently,the multiple CCl4

  4. Energies and wave functions of an off-centre donor in hemispherical quantum dot: Two-dimensional finite difference approach and ritz variational principle

    Science.gov (United States)

    Nakra Mohajer, Soukaina; El Harouny, El Hassan; Ibral, Asmaa; El Khamkhami, Jamal; Assaid, El Mahdi

    2016-09-01

    Eigenvalues equation solutions of a hydrogen-like donor impurity, confined in a hemispherical quantum dot deposited on a wetting layer and capped by an insulating matrix, are determined in the framework of the effective mass approximation. Conduction band alignments at interfaces between quantum dot and surrounding materials are described by infinite height barriers. Ground and excited states energies and wave functions are determined analytically and via one-dimensional finite difference approach in case of an on-center donor. Donor impurity is then moved from center to pole of hemispherical quantum dot and eigenvalues equation is solved via Ritz variational principle, using a trial wave function where Coulomb attraction between electron and ionized donor is taken into account, and by two-dimensional finite difference approach. Numerical codes developed enable access to variations of donor total energy, binding energy, Coulomb correlation parameter, spatial extension and radial probability density with respect to hemisphere radius and impurity position inside the quantum dot.

  5. Nitrosyl bromo complexes of rhenium: Re(NO)2Br3 and [Re(NO)2Br4]-; crystal structure of PPh4[Re(NO)2Br4] . 2 CCl4

    International Nuclear Information System (INIS)

    PPh4[Re(NO)2Br4] is prepared in the form of dark red-brown powder by the reaction of PPh4[Re(NO)2Cl4] with excess boron tribromide. From a solution of CH2Br2 and CCl4 it crystallizes with two moles CCl4, one of which splits off easily in vacuo. The reaction of aluminium tribromide in CH2Br2 solution leads to a slightly soluble red-brown Re(NO)2Br3 powder. The i.r. spectra indicate cis positions of the covalently bound NO ligands in both complexes. Re(NO)2Br3 is dimeric via bromo bridges. The crystal structure determination of PPh4[Re(NO)2Br4] . 2 CCl4 was solved by X-ray diffraction methods at -115 0C. The complex crystallizes in the monoclinic space group P21/c with four formula units per unit cell (4434 independent reflexions, R = 0.085). The unit cell dimensions are a = 1092.3 pm, b = 2088.0 pm, c = 1657.6 pm, β = 96.100. The structure consists of P(C6H5)4+ cations, [Re(NO)2Br4]- anions and intercalated CCl4 molecules. In the anion the NO groups are covalently bound to the Re atom like Re-=N+=O and they are arranged in cis position to one another. (author)

  6. Pd(OAc)2与PPh3在氯代甲烷中的反应研究%STUDY OF THE REACTION OF Pd(OAc)2 WITH PPh3 IN CCl4

    Institute of Scientific and Technical Information of China (English)

    韦凤萍; 黄永仁; 冯良波; 汪汉卿

    2001-01-01

    The complex Pd(PPh3)2Cl2*CCl4 has been prepared by treatment of Pd(OAc)2 with PPh3 in CCl4. 1H NMR, 31P NMR, data are given. The molecular structure of Pd(PPh3)2Cl2 has been determined by single crystal X-rays diffraction. The reaction mechanism is tentatively proposed and discussed. Radicals were trapped by PBN. This reaction was proved to be a free radical reaction by EPR-ST method. The solvent CCl4 participated in the reaction.%用Pd(OAc)2与PPh3在四氯甲烷中反应,合成了配合物PdCl2(PPh3)2*CCl4,得到单晶,用X-ray衍射确定了单晶结构.应用电子顺磁共振-自旋捕获(EPR-ST)技术研究了其反应的机理.捕获了含碳自由基中间体,提出了反应机理.

  7. Therapeutic efficacy of ethanolic extract of Aerva javanica aerial parts in the amelioration of CCl4-induced hepatotoxicity and oxidative damage in rats

    Science.gov (United States)

    Arbab, Ahmed H.; Parvez, Mohammad K.; Al-Dosari, Mohammed S.; Al-Rehaily, Adnan J.; Ibrahim, Khalid E.; Alam, Perwez; Alsaid, Mansour S.; Rafatullah, Syed

    2016-01-01

    Background Liver diseases, the fifth most common cause of global death, can be metabolic, toxin-induced, or infective. Though approximately 35 Saudi medicinal plants are traditionally used to treat liver disorders, the hepatoprotective potential of Aerva javanica has not been explored. Objective To investigate the antioxidative and hepatoprotective effect of Aerva javanica. Design Total ethanol extract of A. javanica aerial parts was prepared and tested on DCFH-toxicated HepG2 cells ex vivo, and in CCl4-injured Wistar rats in vivo. MTT assay was used to determine cell viability and the serum biochemical markers of liver injury as well as histopathology was performed. In vitro 1,1-diphenyl-2-picrylhydrazyl and β-carotene free-radical scavenging assay and phytochemical screening of the extract were done. Furthermore, A. javanica total extract was standardized and validated by high-performance thin layer chromatographic method. Results MTT assay showed that, while DCFH-injured cells were recovered to ~56.7% by 100 µg/ml of the extract, a 200 µg/ml dose resulted in hepatocytes recovery by ~90.2%. Oral administration of the extract (100 and 200 mg/kg.bw/day) significantly normalized the serum glutamate oxaloacetate transaminase, serum glutamate pyruvate transaminase, gamma-glutamyl transferase, alkaline phosphatase, bilirubin, cholesterol, high-density lipoprotein, low-density lipoprotein, very-low-density lipoprotein, triglyceride, and malondialdehyde levels, including tissue nonprotein sulfhydryl and total protein in CCl4-injured rats. In addition, the histopathology of dissected liver also revealed that A. javanica cured the tissue lesion compared to silymarin treatment. In vitro assays revealed strong free-radical scavenging ability of the extract and presence of alkaloids, flavonoids, tannins, sterols, and saponins where rutin, a well-known antioxidant flavonoid, was identified. Conclusions Our findings demonstrate the potential of A. javanica in the attenuation

  8. Mutant MMP-9 and HGF gene transfer enhance resolution of CCl4-induced liver fibrosis in rats: role of ASH1 and EZH2 methyltransferases repression.

    Directory of Open Access Journals (Sweden)

    Hussein Atta

    Full Text Available Hepatocyte growth factor (HGF gene transfer inhibits liver fibrosis by regulating aberrant cellular functions, while mutant matrix metalloproteinase-9 (mMMP-9 enhances matrix degradation by neutralizing the elevated tissue inhibitor of metalloproteinase-1 (TIMP-1. It was shown that ASH1 and EZH2 methyltransferases are involved in development of liver fibrosis; however, their role in the resolution phase of liver fibrosis has not been investigated. This study evaluated the role of ASH1 and EZH2 in two mechanistically different therapeutic modalities, HGF and mMMP-9 gene transfer in CCl4 induced rat liver fibrosis. Liver fibrosis was induced in rats with twice a week intraperitoneal injection of CCl4 for 8 weeks. Adenovirus vectors encoding mMMP-9 or HGF genes were injected through tail vein at weeks six and seven and were sacrificed one week after the second injection. A healthy animal group was likewise injected with saline to serve as a negative control. Rats treated with mMMP-9 showed significantly lower fibrosis score, less Sirius red stained collagen area, reduced hydroxyproline and ALT concentration, decreased transforming growth factor beta 1 (TGF-β1 mRNA and lower labeling indices of α smooth muscle actin (α-SMA and proliferating cell nuclear antigen (PCNA stained cells compared with HGF- or saline-treated rats. Furthermore, TIMP-1 protein expression in mMMP-9 group was markedly reduced compared with all fibrotic groups. ASH1 and EZH2 protein expression was significantly elevated in fibrotic liver and significantly decreased in mMMP-9- and HGF-treated compared to saline-treated fibrotic livers with further reduction in the mMMP-9 group.Gene transfer of mMMP-9 and HGF reduced liver fibrosis in rats. ASH1 and EZH2 methyltransferases are significantly reduced in mMMP-9 and HGF treated rats which underlines the central role of these enzymes during fibrogenesis. Future studies should evaluate the role of selective pharmacologic inhibitors

  9. SHSST Cyclodextrin Complex Prevents the Fibrosis Effect on CCl4-Induced Cirrhotic Cardiomyopathy in Rats through TGF-β Pathway Inhibition Effects

    Directory of Open Access Journals (Sweden)

    Cheng-Hsun Yang

    2014-05-01

    Full Text Available Patients with liver cirrhosis also have subtle cardiac structure or function abnormalities. This cardiac dysfunction commonly occurs in 56% of waiting orthotopic liver transplantation (OLT patients and is defined as cirrhotic cardiomyopathy (CCM. Up to now, there is no standard treatment because CCM does not have a solidly established diagnosis and is based on high clinical suspicion. The liver function of CCM is particularly limited, making patients vulnerable to more drug treatments. Here, we use silymarin (100 mg/kg/day, baicalein (30 mg/kg/day, San Huang Shel Shin Tang (SHSST, 30 mg/kg/day and β-cyclodextrin modified SHSST (SHSSTc, 30 and 300 mg/kg/day treatments for a CCl4-induced CCM rat model. The results show that silymarin, baicalein and SHSST treatments can only slightly reduce the collagen accumulation in CCM rat hearts. However, SHSSTc treatment protects the heart in CCM and significantly inhibits collagen acumination and the fibrosis regulating transforming growth factor-β (TGF-β pathway expression. SHSSTc treatments further reduced the heart weight and the ratio between left ventricular weight (LVW and tibia length (TL. This experimental data show that water solubility improved β-cyclodextrin modified Chinese herbal medicine formula (SHSSTc can provide an excellent heart protection effect through TGF-β pathway inhibition.

  10. Application of a new statistical mechanical model for calculating Kirkwood factors in self associating liquid systems to alkanol + CCl4 mixtures.

    Science.gov (United States)

    Vasiltsova, Tatiana; Heintz, Andreas; Nadolny, Holger; Weingärtner, Hermann

    2009-04-14

    A recently developed statistical-mechanical model for calculating Kirkwood correlation factors g(K) in self associating liquids and liquid mixtures has been applied for the simultaneous description of g(K) derived from dielectric constant data, the molar enthalpy of mixing H, and the infrared absorbtion of monomeric alcoholic species as function of the composition in alkanol + CCl(4) mixtures. The alkanols are methanol, ethanol, propanol, butan-1-ol, pentan-1-ol, hexan-1-ol, octan-1-ol, sec-butanol, tert-butanol and pentan-3-ol. The majority of parameters involved in the theory are obtained by independent quantum mechanical ab initio calculations of molecular clusters consisting of up to four alcohol molecules. As a consequence only two parameters have to be adjusted freely to each binary system, a third parameter responsible for the non-specific intermolecular dispersion interaction has been adjusted within a limited range of possible values given by physical arguments. Excellent agreement between theory and experimental data for g(K), H and IR absorbance is obtained covering the whole range of concentration. The theory also rationalizes the temperature dependence of these properties without adjusting further parameters. The Kirkwood correlation factor g(K) turns out to be a sensitive response to peculiarities of the molecular structure of hydrogen-bonded systems in the condensed liquid state. PMID:19325973

  11. The Effects of Taoren-Honghua Herb Pair on Pathological Microvessel and Angiogenesis-Associated Signaling Pathway in Mice Model of CCl4-Induced Chronic Liver Disease

    Directory of Open Access Journals (Sweden)

    Shengyan Xi

    2016-01-01

    Full Text Available Chronic liver disease is one of the most common diseases that threaten human health. Effective treatment is still lacking in western medicine. Semen Persicae (Taoren and Flos Carthami (Honghua are known to relieve acute hepatic injury and inflammation, improve microcirculation, and reduce tissue fiber. The aim of our study is to investigate the potential mechanisms of Taoren-Honghua Herb Pair (THHP in murine model of chronic liver disease caused by Carbon Tetrachloride (CCl4. Mice were randomly divided into seven groups: (1 blank, (2 model, (3 control (colchicine, 0.1 mg/kg, (4 THHP (5.53, 2.67, and 1.33 g/kg, and (5 Tao Hong Siwu Decoction (THSWD (8.50 g/kg. Histological change and microvessels density were examined by microscopy. Hepatic function, serum fibrosis related factors, and hepatic vascular endothelial growth factor (VEGF were measured with ELISA. VEGF, kinase insert domain-containing receptor (KDR, Flt-1, and Akt mRNA expression in hepatic tissue were determined with PCR. Tissues of Akt, pAkt, KDR, and Flt-1 were measured with western blotting. Data from this study showed that THHP improved hepatic function and restrained the hepatic inflammation and fibrosis. Its role in inhibiting pathological angiogenesis and hepatic fibrogenesis may be through affecting the angiogenesis-associated VEGF and its upstream and downstream signaling pathways.

  12. Preparation of ThO2-UO3 sols with uranium contents of 0 approx 35 % for gelation into microspheres in CCl4-ammonia media

    International Nuclear Information System (INIS)

    The conditions for producing mixed ThO2-UO3 sols with 0 ∼ 40 % U by neutralizing nitrate solutions with ammonia solution under pH control are studied. With 0 ∼ 35 % U, good source sols for gelation in CCl4-ammonia media are obtained. Colloid fraction of U in producible stable sols is lower than that of Th. The former, moreover, decreases considerably with increase in U content while the latter does only a little; this results abrupt decrease in their colloid fraction of (Th + U) with increase in U content. Whether gelation behavior of such sols is good or not depends on fraction of 4.1 nm or larger colloids, and on U content. The minimum value of the colloid fractions resulting no gel-sphere failure also decreases with increase in U content. The gel-sphere failure is a crack for lower U content and a hole like a dimple or a navel for higher one. The difference is also discussed. (author)

  13. Profile of circulating levels of IL-1Ra, CXCL10/IP-10, CCL4/MIP-1β and CCL2/MCP-1 in dengue fever and parvovirosis

    Directory of Open Access Journals (Sweden)

    Luzia Maria de-Oliveira-Pinto

    2012-02-01

    Full Text Available Dengue virus (DENV and parvovirus B19 (B19V infections are acute exanthematic febrile illnesses that are not easily differentiated on clinical grounds and affect the paediatric population. Patients with these acute exanthematic diseases were studied. Fever was more frequent in DENV than in B19V-infected patients. Arthritis/arthralgias with DENV infection were shown to be significantly more frequent in adults than in children. The circulating levels of interleukin (IL-1 receptor antagonist (Ra, CXCL10/inducible protein-10 (IP-10, CCL4/macrophage inflammatory protein-1 beta and CCL2/monocyte chemotactic protein-1 (MCP-1 were determined by multiplex immunoassay in serum samples obtained from B19V (37 and DENV-infected (36 patients and from healthy individuals (7. Forward stepwise logistic regression analysis revealed that circulating CXCL10/IP-10 tends to be associated with DENV infection and that IL-1Ra was significantly associated with DENV infection. Similar analysis showed that circulating CCL2/MCP-1 tends to be associated with B19V infection. In dengue fever, increased circulating IL-1Ra may exert antipyretic actions in an effort to counteract the already increased concentrations of IL-1β, while CXCL10/IP-10 was confirmed as a strong pro-inflammatory marker. Recruitment of monocytes/macrophages and upregulation of the humoral immune response by CCL2/MCP-1 by B19V may be involved in the persistence of the infection. Children with B19V or DENV infections had levels of these cytokines similar to those of adult patients.

  14. Inversion of spin levels in Ni sup 2 sup + : Zn(BF sub 4) sub 2 centre dot 6H sub 2 O at all -round compression and effect of transition coincidence

    CERN Document Server

    Krygin, I M; Nejlo, G N; Prokhorov, A D

    2001-01-01

    The study of the EPR spectrum of the Ni sup 2 sup + ion, replacing Zn sup 2 sup + in the Zn(BF sub 4) centre dot 6H sub 2 O crystals in the wide temperature range by the all-round compression in the X- and Q-ranges is carried out. The basic changes by varying temperature and pressure occur with the D parameter, characterizing the initial splitting by practically unchanged g-factor. The increase in the temperature is accompanied by the D nonlinear growth. The all-round compression linearly changes the initial splitting and leads to the change in the D-sign, signifying the spin levels inversion by 3.5 kbar. Coincidence of EPR lines, relative to different transitions, leads to the crevasse appearance in the outline of this one, that is connected with cross-relaxation inside the spin system

  15. Effect of Jianpihuoxue Formua on Rat's Heptatic Steatosis Induced by CCl4 with High Fat and Low Protein Diet%健脾活血方对CCl4高脂低蛋白诱导大鼠肝脂肪变性的影响

    Institute of Scientific and Technical Information of China (English)

    何东仪; 胡义扬; 刘平; 刘成; 薛惠明; 熊卫国; 李风华

    2001-01-01

    采用四氯化碳(CCl4)高脂低蛋白诱导大鼠肝脂肪变性模型,以东宝肝泰做对照,通过肝组织病理学、组织化学和电镜观察,肝组织甘油三酯、胆固醇、超氧化物歧化酶(SOD)及血清肝功能部分指标的检测,探讨健脾活血方治疗脂肪肝的效果及部分作用机理.结果显示:健脾活血方可显著减轻肝组织损伤和脂肪变性程度,同时显著降低肝组织甘油三酯,提高SOD含量,提示健脾活血方有显著的抗肝脂肪变性作用,其作用机理可能与调节肝脏脂肪代谢和三羧酸循环,促进肝细胞线粒体内的脂肪酸β氧化和抗脂质过氧化损伤有关.

  16. IFNα-2a对CCl4诱导肝纤维化的作用及影响因素%Interferon α-2a reduces carbon tetrachloride-induced hepatic fibrosis in rats

    Institute of Scientific and Technical Information of China (English)

    张伟; 易珍; 叶长根; 刘翠芸; 孙水林; 李金明; 席文娜

    2011-01-01

    目的:观察干扰素α-2a(interferon alfa-2a,IFNα-2a)对CCl4诱导肝纤维化的作用及影响因素.方法:建立CCl4诱导大鼠肝纤维化模型,SD雌性大鼠50只,分成5组,每组10只,即生理盐水对照组(A组)、纤维化模型组(B组)、6×104 U/kg IFNα-2a干预组(C组)、12×104 U/kgIFNα-2a干预组(D组)及6×104 U/kg IFNα-2a对照组(E组).造模8 wk时采集血标本及肝组织标本,分别进行肝功能指标ALT、AST、TBIL、TP,肝纤维化指标HA、LN、PCIII检测,及组织病理形态学观察包括HE染色、Masson染色和网状纤维染色.结果:CCl4腹腔注射成功诱导大鼠肝纤维化模型,表现为汇管区周围纤维化明显,有芒状纤维和纤维间隔形成.血清学检测:B、C、D组ALT、AST、TBiL、HA、LN均明显高于A组(F值分别为14.8,4.4,7.8,51.3,68.9;均P<0.05);C、D组ALT、AST、TBiL均明显低于B组;D组的上述指标又明显低于C组.组织病理:HE染色、Masson染色和网状纤维染色均显示,C、D组肝组织炎症及肝纤维化程度较B组显著减轻,D组较C组肝纤维化程度更轻,A、E组肝组织未见炎症及纤维化.结论:IFNα-2a能够阻断CC14诱导肝纤维化,其作用效果随IFNα-2a剂量增加而增强.%AIM: To observe the effect of IFNα-2a on liver fibrosis induced with carbon tetrachloride (CCL,) in rats.METHODS: Fifty female Sprague-Dawley rats were equally and randomly into five groups: groups A, B, C, D and E. Liver fibrosis was induced in rats of groups B, C and D with CCl4. Group A was treated with normal saline, while groups C, D and E were treated with 60 000, 120 000 and 60 000 U/kg IFNα-2a, respectively. At week 8, blood and liver tissue samples were collected to measure liver function (ALT, AST, TBIL, TP), evaluate liver fibrosis (HA, LN, PCIII) and pathological changes (HE staining, masson staining and reticular fiber staining).RESULTS: Hepatic fibrosis was successfully induced by CCl4 injection, and significant fibrosis around the

  17. Incommensurate phases in the improper ferroelastic MgGeF sub 6 centre dot 6H sub 2 O:Mn sup 2 sup + studied by means of EPR

    CERN Document Server

    Skrylnik, P G

    2002-01-01

    The results of an EPR study of the inhomogeneous phases existing in the temperature interval T sub C = 311.0 +- 0.3 K < T < T sub i sub 1 = 403 +- 0.3 K in improper ferroelastic crystals of MgGeF sub 6 centre dot 6H sub 2 O:Mn sup 2 sup + are presented. On the basis of the analysis of the temperature and angle dependences of the experimental parameters and numerical calculations, the conclusion has been drawn that at T sub i sub 1 the crystals considered undergo a transition to a structurally modulated phase and the order parameter of this transition may be the angle of the Mg[H sub 2 O] sub 6 sup 2 sup + octahedra rotation around the crystal C sub 3 -axis. From T sub i sub 1 to T sub C the modes of the modulated phase follow according to a completely classical scenario for incommensurate crystals: the origin of the incommensurate structure with plane-wave modulation at T sub i sub 1 , the appearance of structural phase solitons below T sub i sub 2 = 380 +- 0.3 K and decrease of the soliton density to v...

  18. p62 Is Required for Stem Cell/Progenitor Retention through Inhibition of IKK/NF-κB/Ccl4 Signaling at the Bone Marrow Macrophage-Osteoblast Niche

    Directory of Open Access Journals (Sweden)

    Kyung Hee Chang

    2014-12-01

    Full Text Available In the bone marrow (BM, hematopoietic progenitors (HPs reside in specific anatomical niches near osteoblasts (Obs, macrophages (MΦs, and other cells forming the BM microenvironment. A connection between immunosurveillance and traffic of HP has been demonstrated, but the regulatory signals that instruct the immune regulation of HP circulation are unknown. We discovered that the BM microenvironment deficiency of p62, an autophagy regulator and signal organizer, results in loss of autophagic repression of macrophage contact-dependent activation of Ob NF-κB signaling. Consequently, Ob p62-deficient mice lose bone, Ob Ccl4 expression, and HP chemotaxis toward Cxcl12, resulting in egress of short-term hematopoietic stem cells and myeloid progenitors. Finally, Ccl4 expression and myeloid progenitor egress are reversed by deficiency of the p62 PB1-binding partner Nbr1. A functional “MΦ-Ob niche” is required for myeloid progenitor/short-term stem cell retention, in which Ob p62 is required to maintain NF-κB signaling repression, osteogenesis, and BM progenitor retention.

  19. Quantum dots

    CERN Document Server

    Borovitskaya, Elena

    2002-01-01

    In this book, leading experts on quantum dot theory and technology provide comprehensive reviews of all aspects of quantum dot systems. The following topics are covered: (1) energy states in quantum dots, including the effects of strain and many-body effects; (2) self-assembly and self-ordering of quantum dots in semiconductor systems; (3) growth, structures, and optical properties of III-nitride quantum dots; (4) quantum dot lasers. Contents: Low-Dimensional Systems (E Borovitskaya & M S Shur); Energy States in Quantum Dots (A J Williamson); Self-Organized Quantum Dots (A R Woll et al.); Grow

  20. ACEI attenuates the progression of CCl4-induced rat hepatic fibrogenesis by inhibiting TGF-β1, PDGF-BB, NF-κB and MMP-2,9

    Institute of Scientific and Technical Information of China (English)

    Xu Li; Ying Meng; Xi-Shan Yang; Ling-Fei Mi; Shao-Xi Cai

    2005-01-01

    AIM: Angiotensin Ⅱ has pro-fibrotic function in the liver.Blockade of the renin-angiotensin-aldosterone-system (RAAS) attenuates hepatic fibrosis. The aim of the present study was to determine the mechanism of angiotensinconverting enzyme inhibitor (ACEI) on the progression of rat hepatic fibrosis.METHODS: Forty male Wistar rats were divided into three groups. Model group (Mo): The rats were injected subcutaneously with 40% of CCl4 0.25 mL/100 g. Perindopril group (Pe): The rats were injected subcutaneously with administrated. Control group (Nc): the rats were treated with olive oil only. After 4 and 6 wk, the rats were killed.The liver sections were stained with Masson. The protein expressions of AT1R, TGF-β1 and PDGF-BB were examined by Western blot. Nuclear factor κB (NF-κB) DNA binding activity was examined by EMSA (Electrophoretic gel mobility shift assay). Matrix metalloproteinase-2,9(MMP-2,9) activity was assessed by zymography. Serum laminin (LN) and hyaluronic acid (HA) were measured using radioimmunoassays.RESULTS: Using Western blot, we clearly provided direct evidence for the expression of AT1R in liver. The expression was up-regulated when fibrogenesis occurred. Perindopril treatment significantly reduced mean fibrosis score,protein levels of AT1R, TGF-β1 and PDGF-BB, serum levels of HA and LN, and the activity of MMP-2,9. NF-κB DNA binding activity markedly increased in model group, perindopril treatment considerably reduced NF-κB DNA binding activity.CONCLUSION: Perindopril attenuates CCl4-induced hepatic fibrogenesis of rat by inhibiting TGF-β1, PDGF-BB,NF-κB and MMP-2,9.

  1. The Influence of Methyl Ferulic Acid of Securidaca inappendiculata on Acute Liver Injury Induced by CCl4 in Mice%蝉翼藤中甲基阿魏酸对CCl4致急性肝损伤小鼠模型的影响

    Institute of Scientific and Technical Information of China (English)

    庞文箫; 李勇军; 李勇文; 容明智; 唐春燕; 杨桂君; 程钰; 李丽

    2015-01-01

    目的:研究蝉翼藤中甲基阿魏酸对急性肝损伤模型小鼠的保护作用.方法:60只KM小鼠随机均分为正常对照(等体积淀粉浆)组、模型(等体积淀粉浆)组、联苯双酯(100mg/kg)组与甲基阿魏酸高、中、低剂量(200、100、50 mg/kg)组,灌胃给药,每天1次,连续7d.末次给药1h后,一次性腹腔注射0.5%CC14-花生油(10ml/kg)以复制小鼠急性肝损伤模型.复制模型24 h后,测定小鼠肝脏、脾脏指数,测定小鼠血清中丙氨酸氨基转移酶(ALT)、天冬氨酸氨基转移酶(AST)活性,测定小鼠肝组织超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性与丙二醛(MDA)含量,光镜观察小鼠肝脏病理组织学并统计肝组织病变分级.结果:与正常对照组比较,模型组小鼠肝脏、脾脏指数升高;小鼠血清ALT、AST活性增强;小鼠肝组织SOD、GSH-Px活性减弱,MDA含量增加;小鼠肝组织全部出现病变,多集中于Ⅲ级,差异均具有统计学意义(P<0.01).与模型组比较,甲基阿魏酸高、中、低剂量组小鼠肝脏、脾脏指数降低;小鼠血清ALT、AST活性减弱;小鼠肝组织SOD、GSH-Px活性增强,MDA含量减少;甲基阿魏酸高、中剂量组小鼠肝组织病变程度减轻,多集中于0、Ⅰ、Ⅱ级,差异均具有统计学意义(P<0.01或P<0.05).结论:甲基阿魏酸对CCl4所致小鼠急性肝损伤有一定的保护作用.

  2. Quadra-Quantum Dots and Related Patterns of Quantum Dot Molecules: Basic Nanostructures for Quantum Dot Cellular Automata Application

    Directory of Open Access Journals (Sweden)

    Somsak Panyakeow

    2010-10-01

    Full Text Available Laterally close-packed quantum dots (QDs called quantum dot molecules (QDMs are grown by modified molecular beam epitaxy (MBE. Quantum dots could be aligned and cross hatched. Quantum rings (QRs created from quantum dot transformation during thin or partial capping are used as templates for the formations of bi-quantum dot molecules (Bi-QDMs and quantum dot rings (QDRs. Preferable quantum dot nanostructure for quantum computation based on quantum dot cellular automata (QCA is laterally close-packed quantum dot molecules having four quantum dots at the corners of square configuration. These four quantum dot sets are called quadra-quantum dots (QQDs. Aligned quadra-quantum dots with two electron confinements work like a wire for digital information transmission by Coulomb repulsion force, which is fast and consumes little power. Combination of quadra-quantum dots in line and their cross-over works as logic gates and memory bits. Molecular Beam Epitaxial growth technique called 'Droplet Epitaxy' has been developed for several quantum nanostructures such as quantum rings and quantum dot rings. Quantum rings are prepared by using 20 ML In-Ga (15:85 droplets deposited on a GaAs substrate at 390'C with a droplet growth rate of 1ML/s. Arsenic flux (7'8'10-6Torr is then exposed for InGaAs crystallization at 200'C for 5 min. During droplet epitaxy at a high droplet thickness and high temperature, out-diffusion from the centre of droplets occurs under anisotropic strain. This leads to quantum ring structures having non-uniform ring stripes and deep square-shaped nanoholes. Using these peculiar quantum rings as templates, four quantum dots situated at the corners of a square shape are regrown. Two of these four quantum dots are aligned either or, which are preferable crystallographic directions of quantum dot alignment in general.

  3. Quadra-quantum Dots and Related Patterns of Quantum Dot Molecules:

    Directory of Open Access Journals (Sweden)

    Somsak Panyakeow

    2010-10-01

    Full Text Available Abstract Laterally close-packed quantum dots (QDs called quantum dot molecules (QDMs are grown by modified molecular beam epitaxy (MBE. Quantum dots could be aligned and cross hatched. Quantum rings (QRs created from quantum dot transformation during thin or partial capping are used as templates for the formations of bi-quantum dot molecules (Bi-QDMs and quantum dot rings (QDRs. Preferable quantum dot nanostructure for quantum computation based on quantum dot cellular automata (QCA is laterally close-packed quantum dot molecules having four quantum dots at the corners of square configuration. These four quantum dot sets are called quadra-quantum dots (QQDs. Aligned quadra-quantum dots with two electron confinements work like a wire for digital information transmission by Coulomb repulsion force, which is fast and consumes little power. Combination of quadra-quantum dots in line and their cross-over works as logic gates and memory bits. Molecular Beam Epitaxial growth technique called ‘‘Droplet Epitaxy” has been developed for several quantum nanostructures such as quantum rings and quantum dot rings. Quantum rings are prepared by using 20 ML In-Ga (15:85 droplets deposited on a GaAs substrate at 390°C with a droplet growth rate of 1ML/s. Arsenic flux (7–8×10-6Torr is then exposed for InGaAs crystallization at 200°C for 5 min. During droplet epitaxy at a high droplet thickness and high temperature, out-diffusion from the centre of droplets occurs under anisotropic strain. This leads to quantum ring structures having non-uniform ring stripes and deep square-shaped nanoholes. Using these peculiar quantum rings as templates, four quantum dots situated at the corners of a square shape are regrown. Two of these four quantum dots are aligned either or , which are preferable crystallographic directions of quantum dot alignment in general.

  4. The fate of atmospheric phosgene and the stratospheric chlorine loadings of its parent compounds: CCl4, C2Cl4, C2HCL3, CH3CCl3, and CHCl3

    Science.gov (United States)

    Kindler, T. P.; Chameides, W. L.; Wine, P. H.; Cunnold, D. M.; Alyea, F. N.; Franklin, J. A.

    1995-01-01

    A study of the tropospheric and stratospheric cycles of phosgene is carried out to determine its fate and ultimate role in controlling the ozone depletion potentials of its parent compounds. Tropospheric phosgene is produced from the OH-initiated oxidation of C2Cl4, CH3CCl3, CHCl3, and C2HCl3. Simulations using a two-dimensional model indicate that these processes produce about 90 pptv/yr of tropospheric phosgene with an average concentration of about 18 pptv, in reasonable agreement with observations. We estimate a residence time of about 70 days for tropospheric phosgene, with the vast majority being removed by hydrolysis in cloudwater. Only about 0.4% of the phosgene produced in the troposphere avoids wet removal and is transported to the stratosphere, where its chlorine can be released to participate in the catalytic destruction of ozone. Stratospheric phosgene is produced from the photochemical degradation of CCl4, C2Cl4, CHCl3, and CH3CCl3 and is removed by photolysis and downward transport to the troposphere. Model calculations, in good agreement with observations, indicate that these processes produce a peak stratospheric concentration of about 25-30 pptv at an altitude of about 25 km. In contrast to tropospheric phosgene, stratospheric phosgene is found to have a lifetime against photochemical removal of the order of years. As a result, a significant portion of the phosgene that is produced in the stratosphere is ultimately returned to the troposphere, where it is rapidly removed by clouds. This phenomenon effectively decreases the amount of reactive chlorine injected into the stratosphere and available for ozone depletion from phosgene's parent compounds. A similar phenomenon due to the downward transport of stratospheric COFCl produced from CFC-11 is estimated to cause a 7% decrease in the amount of reactive chlorine injected into the stratosphere from this compound. Our results are potentially sensitive to a variety of parameters, most notably the rate

  5. 培哚普利抗实验性大鼠肝纤维化的实验研究%Perindopril attenuates the progression of CCl4-inducing rat hepatic fibrosis

    Institute of Scientific and Technical Information of China (English)

    李旭; 孟莹; 杨希山; 张振书; 吴平生; 邹峻岭

    2004-01-01

    目的研究血管紧张素转化酶抑制剂-培哚普利对实验性肝纤维化的影响,并探讨其作用机制. 方法取雄性大鼠40只,随机分为3组.模型组:40% CCl4油0.25g/L皮下注射,每周2次;培哚普利治疗组:培哚普利2mg/kg灌胃,1次/d.对照组:橄榄油皮下注射.于第4、6周取材.光镜下动态观察组织学改变,检测血管紧张素Ⅱ1型受体(AT1R)、转化生长因子β1(TGF-β1)、血小板衍生性生长因子-BB(PDGF-BB)蛋白的表达、金属蛋白酶-2(MMP-2)的活性和血清透明质酸(HA)、层黏连蛋白(LN)的含量. 结果培哚普利治疗组肝组织炎症程度明显减轻,纤维间隔较为细小,血清HA、LN(μg/L)含量分别为82.07±13.66和94.84±3.54,模型组分别为147.86±18.92和113.72±2.14,t=2.27~2.87,P<0.05;培哚普利治疗组AT1R mRNA和蛋白质表达水平、TGF-β1和PDGF-BB蛋质白的表达低于模型组,;模型组MMP-2活性高于培哚普利组. 结论培哚普利对实验性大鼠肝纤维化具有抑制作用.

  6. Quantum dot spectroscopy

    DEFF Research Database (Denmark)

    Leosson, Kristjan

    Semiconductor quantum dots ("solid-state atoms") are promising candidates for quantum computers and future electronic and optoelectronic devices. Quantum dots are zero-dimensional electronic systems and therefore have discrete energy levels, similar to atoms or molecules. The size distribution...... of quantum dots, however, results in a large inhomogeneous broadening of quantum dot spectra. Work on self-assembled InGaAs/GaAs quantum dots will be presented. Properties of atom-like single-dot states are investigated optically using high spatial and spectral resolution. Single-dot spectra can be used...

  7. Quantum dot spectroscopy

    DEFF Research Database (Denmark)

    Leosson, Kristjan

    1999-01-01

    Semiconductor quantum dots ("solid state atoms") are promising candidates for quantum computers and future electronic and optoelectronic devices. Quantum dots are zero-dimensional electronic systems and therefore have discrete energy levels, similar to atoms or molecules. The size distribution...... of quantum dots, however, results in a large inhomogeneous broadening of quantum dot spectra.Work on self-assembled InGaAs/GaAs quantum dots will be presented. Properties of atom-like single-dots states are investigated optically using high spatial and spectral resolution. Single-dot spectra can be used...

  8. Formation and ordering of epitaxial quantum dots

    Science.gov (United States)

    Atkinson, Paola; Schmidt, Oliver G.; Bremner, Stephen P.; Ritchie, David A.

    2008-10-01

    Single quantum dots (QDs) have great potential as building blocks for quantum information processing devices. However, one of the major difficulties in the fabrication of such devices is the placement of a single dot at a pre-determined position in the device structure, for example, in the centre of a photonic cavity. In this article we review some recent investigations in the site-controlled growth of InAs QDs on GaAs by molecular beam epitaxy. The method we use is ex-situ patterning of the GaAs substrate by electron beam lithography and conventional wet or dry etching techniques to form shallow pits in the surface which then determine the nucleation site of an InAs dot. This method is easily scalable and can be incorporated with marker structures to enable simple post-growth lithographic alignment of devices to each site-controlled dot. We demonstrate good site-control for arrays with up to 10 micron spacing between patterned sites, with no dots nucleating between the sites. We discuss the mechanism and the effect of pattern size, InAs deposition amount and growth conditions on this site-control method. Finally we discuss the photoluminescence from these dots and highlight the remaining challenges for this technique. To cite this article: P. Atkinson et al., C. R. Physique 9 (2008).

  9. CMS Centre at CERN

    CERN Multimedia

    2007-01-01

    A new "CMS Centre" is being established on the CERN Meyrin site by the CMS collaboration. It will be a focal point for communications, where physicists will work together on data quality monitoring, detector calibration, offline analysis of physics events, and CMS computing operations. Construction of the CMS Centre begins in the historic Proton Synchrotron (PS) control room. The historic Proton Synchrotron (PS) control room, Opened by Niels Bohr in 1960, will be reused by CMS to built its control centre. TThe LHC@FNAL Centre, in operation at Fermilab in the US, will work very closely with the CMS Centre, as well as the CERN Control Centre. (Photo Fermilab)The historic Proton Synchrotron (PS) control room is about to start a new life. Opened by Niels Bohr in 1960, the room will be reused by CMS to built its control centre. When finished, it will resemble the CERN Contro...

  10. The Anti-oxidation Effect of Herba Artemisiae Annuae on Acute Hepatic Injury Induced By Carbon Tetrachloride In Dogs%青蒿素对CCl4致犬急性肝损伤模型抗氧化指标的时效影响

    Institute of Scientific and Technical Information of China (English)

    徐伟; 宋倩倩; 苗双; 刘宁宁; 马健; 王振勇

    2009-01-01

    以50%CCl4花生油溶液1 mL/kg体重多点皮下注射制造犬急性肝损伤模型,试验组犬自造模后每天以青蒿素溶液(1 g生药/mL药液)1 mL/kg体重灌胃,对照组不做任何处理.前肢正中静脉采血分离血清,检测血清中MDA、T-AOC含量和AKP、GSH-PX活性.观察青蒿素对模型犬机体抗氧化水平的影响及保护、修复受损肝细胞的作用.

  11. Client Centred Desing

    DEFF Research Database (Denmark)

    Ørngreen, Rikke; Nielsen, Janni; Levinsen, Karin

    2008-01-01

    In this paper we argue for the use of Client Centred preparation phases when designing complex systems. Through Client Centred Design human computer interaction can extend the focus on end-users to alse encompass the client's needs, context and resources.......In this paper we argue for the use of Client Centred preparation phases when designing complex systems. Through Client Centred Design human computer interaction can extend the focus on end-users to alse encompass the client's needs, context and resources....

  12. SAP Nuclear Competence Centre

    International Nuclear Information System (INIS)

    In this issue we continue and introduce the SAP Nuclear Competence Centre and its head Mr. Igor Dzama. SAP Nuclear Competence Centrum is one of the fi rst competence centres outside ENEL headquarters. It should operate in Slovakia and should have competencies within the whole Enel group. We are currently dealing with the issues of organisation and funding. We are trying to balance the accountability to the NPP directors and to the management of the competence centres at Enel headquarters; we are looking at the relations between the competence centres within the group and defining the services that we will provide for the NPPs. author)

  13. Canadian Irradiation Centre

    International Nuclear Information System (INIS)

    The Canadian Irradiation Centre is a non-profit cooperative project between Atomic Energy of Canada Limited, Radiochemical Company and Universite du Quebec, Institut Armand-Frappier, Centre for Applied Research in Food Science. The Centre's objectives are to develop, demonstrate and promote Canada's radiation processing technology and its applications by conducting applied research; training technical, professional and scientific personnel; educating industry and government; demonstrating operational and scientific procedures; developing processing procedures and standards, and performing product and market acceptance trials. This pamphlet outlines the history of radoation technology and the services offered by the Canadian Irradiation Centre

  14. Improved operability of the CANDU 9 control centre

    Energy Technology Data Exchange (ETDEWEB)

    Macbeth, M. J.; Webster, A. [Atomic Energy of Canada Limited, Saskatoon (Canada)

    1996-04-15

    The next generation CANDU nuclear power plant being designed by AECL is the 900 MWe class CANDU 9 station. It is based upon the Darlington CANDU station design which is among the world leaders in capacity factor with low Operation, Maintenance and Administration (OM and A) costs. This Control Centre design includes the proven functionality of existing CANDU control centres (including the Wolsong 2,3, and 4 control centre improvements, such as the Emergency Core Cooling panels), the characteristics identified by systematic design with human factors analysis of operations requirements and the advanced features needed to improve station operability which is made possible by the application of new technology. The CANDU 9 Control Centre provides plant staff with an improved operability capability due to the combination of proveness, systematic design with human factors engineering and enhanced operating features. Significant features which contribute to this improved operability include: {center_dot} Standard NSP, BOP and F/H panels with controls and indicators integrated by a standard display/presentation philosophy. {center_dot} Common plant parameter signal database for extensive monitoring, checking, display and annunciation. {center_dot} Powerful annunciation system allowing alarm filtering, prioritizing and interrogation to enhance staff recognition of events, plant state and required corrective procedural actions. {center_dot} The use of an overview display to present immediate and uncomplicated plant status information to facilitate operator awareness of unit status in a highly readable and recognizable format. {center_dot} Extensive cross checking of similar process parameters amongst themselves, with the counterpart safety system parameters and as well as with 'signature' values obtained from known steady state conditions. {center_dot} Powerful calculation capabilities, using the plant wide database, providing immediate recognizable and readable and

  15. The IGU Knowledge Centre

    NARCIS (Netherlands)

    Huizing, Bernardus

    2005-01-01

    This article describes an innovative service for members of the International Gas Union - IGU. The IGU Knowledge Centre provides members with relevant information and data. In this article is described why, how and where.

  16. Virtual particle therapy centre

    CERN Multimedia

    2015-01-01

    Particle therapy is an advanced technique of cancer radiation therapy, using protons or other ions to target the cancerous mass. This advanced technique requires a multi-disciplinary team working in a specialised centre. 3D animation: Nymus3D

  17. The Bruce Energy Centre

    International Nuclear Information System (INIS)

    The Bruce Energy Centre Development Corporation is a joint venture of the Ontario Energy Corporation and 6 private companies formed to market surplus steam from the Bruce Nuclear Power Development. The corporation will also sell or lease land near Bruce NPD. The Bruce Energy Centre has an energy output of 900 BTU per day per dollar invested. Potential customers include greenhouse operators, aquaculturalists, food and beverage manufacturers, and traditional manufacturers

  18. CENTRE FOR GEOMETRICAL METROLOGY

    DEFF Research Database (Denmark)

    De Chiffre, Leonardo

    The objective of this Annual Report is to give a general introduction to CGM as well as to give an account of the tasks carried out using the facilities of CGM's Instrument Centre during 1998 and 1999.......The objective of this Annual Report is to give a general introduction to CGM as well as to give an account of the tasks carried out using the facilities of CGM's Instrument Centre during 1998 and 1999....

  19. The Aube centre

    International Nuclear Information System (INIS)

    This educational booklet is devoted to a general presentation of the Aube radioactive wastes storage centre. After a short presentation of the Andra, the French national agency for the management of radioactive wastes, it gives some general information about radioactive wastes (origin, classification), containers (quality assurance and different types), wastes transportation (planning, safety), and about the Aube centre itself: description, treatment and conditioning of drums (compacting and injection), storage facilities, geological situation of the site, and environmental controls. (J.S.)

  20. 丹参磷脂浸膏对急性四氯化碳肝损伤小鼠肝组织的保护作用%Protective effect of DSLZ on acute liver injury induced by CCl4 in mice

    Institute of Scientific and Technical Information of China (English)

    付丹阳; 刘雨哲; 曲极冰; 李红; 纪影实

    2014-01-01

    目的:探讨丹参磷脂浸膏(DSLZ)对实验小鼠肝损伤的保护作用。方法 ICR小鼠60只,随机分为空白对照组、模型组及丹参磷脂浸膏高、中、低剂量组和阳性对照丹参酮 IIA(SalviolⅡA IIA)组,采用四氯化碳(CCl4)法建立急性肝损伤实验动物模型,观察丹参磷脂浸膏对实验小鼠血清丙氨酸氨基转移酶(ALT)、天门冬氨酸氨基转移酶(AST)、丙二醛(MDA)、还原型谷胱甘肽(GSH)以及肝组织病理改变的影响。结果与空白对照组比较,模型组小鼠血清ALT、AST及MDA均显著增高(P<0.01),GSH明显降低(P<0.01)。丹参磷脂浸膏高、中剂量组ALT、AST及 MDA明显降低(P<0.05或P<0.01),GSH明显升高(P<0.05或P<0.01)。HE染色显示丹参磷脂浸膏组小鼠肝组织病理损伤减轻。结论丹参磷脂浸膏对小鼠急性四氯化碳性肝损伤具有明显的抑制作用,其机制可能与抗氧化有关。%Objective To explore the protective effect of DSLZ on acute chemical liver injury induced by 1% carbon Tetrachloride (CCl4 )in mice and to reveal its mechanism.Methods 60 mice were randomly divided into normal control group,model group,SalviolⅡA group,high dose DSLZ group (2.6 mg/kg),middle dose group (1.56 mg/kg)and low dose group (0.52 mg/kg).All the mice were intragastrically administered the corresponding agents respectively for 30 days.After the last administration 1% CCl4 2.0 ml/kg was given to mice in all groups except control group in a single administration of vegetable oil intragastrically to establish the acute liver inj ury mouse model.1 6 h later,the mice were sacrificed,alanine aminotransferase (ALT),aspartate aminotrsferase (AST),malondialdehyde (MDA),reduced gluta-thione hormone (GSH)level in serum were detected.HE staining was performed for observing the pathological changes of the liver.Results Compared with the control group,the level of ALT

  1. The ideal Atomic Centre

    International Nuclear Information System (INIS)

    The author presents considerations which should prove to be of interest to all those who have to design, to construct and to operate a nuclear research centre. A large number of the ideas presented can also be applied to non-nuclear scientific research centres. In his report the author reviews: various problems with which the constructor is faced: ground-plan, infrastructure, buildings and the large units of scientific equipment in the centre, and those problems facing the director: maintenance, production, supplies, security. The author stresses the relationship which ought to exist between the research workers and the management. With this aim in view he proposes the creation of National School for Administration in Research which would train administrative executives for public or private organisations; they would be specialised in the fields of fundamental or applied research. (author)

  2. Lidar Calibration Centre

    Science.gov (United States)

    Pappalardo, Gelsomina; Freudenthaler, Volker; Nicolae, Doina; Mona, Lucia; Belegante, Livio; D'Amico, Giuseppe

    2016-06-01

    This paper presents the newly established Lidar Calibration Centre, a distributed infrastructure in Europe, whose goal is to offer services for complete characterization and calibration of lidars and ceilometers. Mobile reference lidars, laboratories for testing and characterization of optics and electronics, facilities for inspection and debugging of instruments, as well as for training in good practices are open to users from the scientific community, operational services and private sector. The Lidar Calibration Centre offers support for trans-national access through the EC HORIZON2020 project ACTRIS-2.

  3. International research centre launched

    International Nuclear Information System (INIS)

    Full text: The first scientific research and educational institution to be set up on a completely international basis was officially inaugurated in Trieste on 5 October 1964 by the Director General of IAEA, Dr. Sigvard Eklund, when he opened the first seminar of the International Centre for Theoretical Physics. As evidence of the international nature of the institution he noted that the scientists who would work and teach there during the first year represented sixteen different countries. By the end of 1964, the Centre building was nearing completion and three of the five floors were occupied. A successful symposium had been held on the subject of plasma physics, and a score of professors and fellows were at work, from Bulgaria, Czechoslovakia, Greece, India, Japan, Jordan, the Netherlands, Norway, Pakistan, Poland, the United Kingdom, and the United States. A dozen scientific papers had been issued as preprints. The main purpose of the Centre is to foster the advancement of theoretical physics through training and research; at first the chief subject will be high-energy and elementary particle physics. Plasma physics, low energy physics and solid-state physics will also be dealt with. Special attention is paid to the needs of the developing countries. Of the 25 fellows selected for the academic year 1964-65, more than half are from South America, Africa and Asia. In conjunction with the Research Centre, there is an Advanced School for theoretical Physics to provide graduate training for fellows who need such preparation before they embark upon research. The Centre works under the guidance of a Scientific Council comprising the president, Prof. M. Sandoval-Vallarta (Nuclear Energy Commission of Mexico); Prof. A. Abragam (Saclay, France); Prof. R. Oppenheimer (Institute for Advanced Study, Princeton, USA); Dr. V. Soloviev (Dubna, USSR); Prof V.F. Weiskopf (Director General, CERN) ; Prof Abdus Salam (Imperial College, London) ; Prof. P. Budini (University of Trieste

  4. Quantum Dots: Theory

    Energy Technology Data Exchange (ETDEWEB)

    Vukmirovic, Nenad; Wang, Lin-Wang

    2009-11-10

    This review covers the description of the methodologies typically used for the calculation of the electronic structure of self-assembled and colloidal quantum dots. These are illustrated by the results of their application to a selected set of physical effects in quantum dots.

  5. Ultrasmall silicon quantum dots

    NARCIS (Netherlands)

    Zwanenburg, F.A.; Van Loon, A.A.; Steele, G.A.; Rijmenam, C.E.W.M.; Balder, T.; Fang, Y.; Lieber, C.M.; Kouwenhoven, L.P.

    2009-01-01

    We report the realization of extremely small single quantum dots in p-type silicon nanowires, defined by Schottky tunnel barriers with Ni and NiSi contacts. Despite their ultrasmall size the NiSi–Si–NiSi nanowire quantum dots readily allow spectroscopy of at least ten consecutive holes, and addition

  6. Quantum Dots: Theory

    OpenAIRE

    Vukmirovic, Nenad

    2010-01-01

    This review covers the description of the methodologies typically used for the calculation of the electronic structure of self-assembled and colloidal quantum dots. These are illustrated by the results of their application to a selected set of physical effects in quantum dots.

  7. Advanced CANDU control centre

    International Nuclear Information System (INIS)

    The CANDU 9 design is based upon the 900 MWe class Darlington station in Canada, which is among the world leading nuclear power stations for capacity factor with low operation, maintenance and administration costs. The CANDU 9 design provides an advanced control centre with enhanced operations features. The advanced AECL control centre design includes the proven functionality of existing CANDU control centres, those implementable characteristics identified by systematic design combined with a human factors analysis of operations requirements and features needed to improve station operability which are made possible by the application of current technology. The design strategy is to preserve the general main control room operations staff work area as unchanged as possible to facilitate the inclusion of past features and operational experience while incorporating operability improvements. The author will present those features of the advanced CANDU control centre which facilitates improved operability capabilities. As well, aspects of the design process utilized, application of simulation technology and conclusions regarding this design approach will be reviewed

  8. Desacralization of Sokol Centres

    Czech Academy of Sciences Publication Activity Database

    Švácha, Rostislav

    Ljubljana : Založba ZRC, 2015 - (Lavrič, A.; Lazarini, F.; Murovec, B.), s. 277-290 ISBN 978-961-254-873-5. - ( Opera Instituti Artis Historiae) Institutional support: RVO:68378033 Keywords : architecture * Sokol centres Subject RIV: AL - Art, Architecture, Cultural Heritage

  9. ATLAS Visitors Centre

    CERN Multimedia

    claudia Marcelloni

    2009-01-01

    ATLAS Visitors Centre has opened its shiny new doors to the public. Officially launched on Monday February 23rd, 2009, the permanent exhibition at Point 1 was conceived as a tour resource for ATLAS guides, and as a way to preserve the public’s opportunity to get a close-up look at the experiment in action when the cavern is sealed.

  10. The GSO Data Centre

    CERN Document Server

    Paletou, F; Génot, V; Rouillard, A; Petit, P; Palacios, A; Caux, E; Wakelam, V

    2015-01-01

    Hereafter we describe the activities of the $Grand \\, Sud-Ouest$ Data Centre operated for INSU/CNRS by the OMP-IRAP and the Universit\\'e Paul Sabatier (Toulouse), in a collaboration with the OASU-LAB (Bordeaux) and OREME-LUPM (Montpellier).

  11. Academic Drug Discovery Centres

    DEFF Research Database (Denmark)

    Kirkegaard, Henriette Schultz; Valentin, Finn

    2014-01-01

    Academic drug discovery centres (ADDCs) are seen as one of the solutions to fill the innovation gap in early drug discovery, which has proven challenging for previous organisational models. Prior studies of ADDCs have identified the need to analyse them from the angle of their economic...

  12. Protective Effects of Different Dosing Position of Misgurnus Anguillicaudatus Lyophilized Power on Chemical Liver Injury in Mice Induced by CCl4%泥鳅不同部位冻干粉对小鼠四氯化碳化学性肝损伤保护作用

    Institute of Scientific and Technical Information of China (English)

    商萌萌; 凌去非; 汪务诚; 刘春宇

    2013-01-01

    Objective: To investigate different dosing position of Misgurnus Anguiliicaudatus lyophilized power on chemical liver injury in mice induced by CCl4, screening of the best effective part. Methods: A mouse model of acute liver injury was induced by carbon tetraohloride, determining of serum ALT and AST activities so as to observe different parts of Misgurnus Anguiliicaudatus lyophilized power protective effect. Results: Misgurnus Anguiliicaudatus whole lyophilized power and muscle lyophilized power can significantly reduce the mice serum ALT and AST activities ( P0.05 ) . Conclusion: The Misgurnus Anguiliicaudatus lyophilized power had significant effect on mice liver injury induced by carbon tetrachloride. The effect of Misgurnus Anguiliicaudatus whole lyophilized power is most obvious, which is the main effective part of liver protection.%目的:本文研究不同部位泥鳅冻干粉对小鼠四氯化碳肝损伤的保护作用,筛选有效部位.方法:采用小鼠四氯化碳急性肝损伤模型,测定小鼠血清ALT、AST活性,观察泥鳅不同部位冻干粉的保护作用.结果:泥鳅全冻干粉和泥鳅肌肉冻干粉显著降低小鼠血清中ALT、AST活性(P<0.05),而泥鳅皮冻干粉的作用不明显(P>0.05).结论:泥鳅冻干粉对小鼠四氯化碳肝损伤具有显著的保护作用,其中泥鳅全冻干粉的作用最明显,是泥鳅保肝的主要有效部位.

  13. Effects of Xiaochaihu Decoction on Damage of Gut-liver-brain in CCl4/Ethanol Induced Mouse Hepatocellular Carcinoma%小柴胡汤对四氯化碳/乙醇诱发小鼠肝癌肠-肝-脑损伤的影响

    Institute of Scientific and Technical Information of China (English)

    胡小剑; 刘晓秋

    2012-01-01

    Objective; To investigate the effects of Xiaochaihu Decoction on damage of gut-liver-brain in CCl4/ethanol-induced mouse hepatocellular carcinoma. Method; Hepatocellular carcinoma group ( HCC ) were induced by subcutaneous injection with 25% CC14 olive oil solution (5 mL 'kg twice per week) and allowed free access to a 8% ethanol solution as drinking fluid for 4 weeks, and allowed free access to 0. 5% CQ4-8% ethanol solution as drinking fluid for 20 weeks; in HCC combined with liver depression and spleen deficiency ( LDSD) group (HCC-LDSD group) , on the basis of HCC modelling, the mice were stimulated with the factor of LDSD, squeezing tails (30 min -d-1 ) , solitary breeding and intermittent fasting for 4 weeks, solitary breeding and intermittent fasting for 20 weeks; Xiaochaihu decoction (XCHD) treated group was administered by gavage for 8 weeks after 4 weeks of the HCC-LDSD modelling. The mortality rates and HCC incidence rates were calculated, weight and clinical signs were monitored daily. The degree of tissue injuries in the gut and liver were studied using a scoring system, and brain weights were measured. Result: The mortality rate in HCC-LDSD group was higher than that in the HCC group, after treatment with XCHD, the mortality rate decreased significantly. In death mouse of HCC group, significantly more injuries in small intestine, cecum, liver and fecal loading in the cecum, with the increased in brain weights, the most in HCC-LDSD group, after treatment with XCHD, all of which were improved. HCC incidence rate in the HCC-LDSD group was higher than that in the HCC group, after treatment with XCHD, the HCC incidence rate decreased significantly. In survival mouse of HCC group, significantly more injuries in small intestine, cecum, liver ( mainly hyperplasia) , with slight decreased in brain weights, the most in HCC-LDSD group, after treatment with XCHD, all of which were improved. Correlative analysis showed that there was a positive or negative

  14. DGNB certified Healthcare Centres

    DEFF Research Database (Denmark)

    Brunsgaard, Camilla; Larsen, Tine Steen

    2015-01-01

    sustainability and wants a certification. This research investigates the decision‐making and design process (DMaDP) behind four DGNB certified Healthcare Centres (HCC) in Northern Jutland in Denmark. In general, knowledge about the DMaDP is important. However it is important to know what part DGNB plays in an...... the architect, the construction engineer, the plumbing engineer etc. which overlap professional field just like other disciplines. Secondly, the general conception is that DGNB brings in limited new things into the project, but it gives a common notion of sustainability which usually can be discussed...... Healthcare Centres, which was certified as office buildings, however more traditional office buildings might differ en experience with DGNB....

  15. Elderly Care Centre

    Science.gov (United States)

    Wagiman, Aliani; Haja Bava Mohidin, Hazrina; Ismail, Alice Sabrina

    2016-02-01

    The demand for elderly centre has increased tremendously abreast with the world demographic change as the number of senior citizens rose in the 21st century. This has become one of the most crucial problems of today's era. As the world progress into modernity, more and more people are occupied with daily work causing the senior citizens to lose the care that they actually need. This paper seeks to elucidate the best possible design of an elderly care centre with new approach in order to provide the best service for them by analysing their needs and suitable activities that could elevate their quality of life. All these findings will then be incorporated into design solutions so as to enhance the living environment for the elderly especially in Malaysian context.

  16. International Data Centre (IDC)

    International Nuclear Information System (INIS)

    The presentation outlines the International Data Centre (Indc) mission, objective and historical background. The Indc progressive commissioning and organizational plans are presented on charts. The IMS stations providing data to Indc operations and the global communication infrastructure are plotted on world maps. The various types of IMS data are thus listed as seismic, hydroacoustic, infrasound and radionuclide. Finally Indc products and services together with its main achievements are listed

  17. Quantum Dots for Biophotonics

    OpenAIRE

    Ken-Tye Yong

    2012-01-01

    This theme issue provides an excellent collection of reviews and original research articles on the study of various bioconjugated quantum dot formulations for diagnostics and therapy applications using biophotonic imaging and sensing approaches.

  18. Graphene quantum dots

    CERN Document Server

    Güçlü, Alev Devrim; Korkusinski, Marek; Hawrylak, Pawel

    2014-01-01

    This book reflects the current status of theoretical and experimental research of graphene based nanostructures, in particular quantum dots, at a level accessible to young researchers, graduate students, experimentalists and theorists. It presents the current state of research of graphene quantum dots, a single or few monolayer thick islands of graphene. It introduces the reader to the electronic and optical properties of graphite, intercalated graphite and graphene, including Dirac fermions, Berry's phase associated with sublattices and valley degeneracy, covers single particle properties of

  19. Treatment Outcomes of Patients Placed on Treatment Under Directly Observed Therapy Short-Course (Dots)

    OpenAIRE

    Kaur Gurpreet; Goel N; Kumar Dinesh; Janmeja A; Swami H; Kalia Meenu

    2008-01-01

    Background : Tuberculosis continues to be a pressing health problem in India. The Revised National Tuberculosis Programme (RNTCP), an application of Directly Observed Treatment Short-course (DOTS) in India, launched in 1997 needs contin-uous evaluation. Objective : To study the outcomes of treatment among the patients put on DOTS under RNTCP in Chandigarh, UT. Material & Methods : A Longitudi-nal study was conducted during 2004-2005 in 13 Microscopic centres (MC′s) spread over...

  20. The DESY Grid Centre

    International Nuclear Information System (INIS)

    DESY is one of the world-wide leading centers for research with particle accelerators, synchrotron light and astroparticles. DESY participates in LHC as a Tier-2 center, supports on-going analyzes of HERA data, is a leading partner for ILC, and runs the National Analysis Facility (NAF) for LHC and ILC in the framework of the Helmholtz Alliance, Physics at the Terascale. For the research with synchrotron light major new facilities are operated and built (FLASH, PETRA-III, and XFEL). DESY furthermore acts as Data-Tier1 centre for the Neutrino detector IceCube. Established within the EGI-project DESY operates a grid infrastructure which supports a number of virtual Organizations (VO), incl. ATLAS, CMS, and LHCb. Furthermore, DESY hosts some of HEP and non-HEP VOs, such as the HERA experiments and ILC as well as photon science communities. The support of the new astroparticle physics VOs IceCube and CTA is currently set up. As the global structure of the grid offers huge resources which are perfect for batch-like computing, DESY has set up the National Analysis Facility (NAF) which complements the grid to allow German HEP users for efficient data analysis. The grid infrastructure and the NAF use the same physics data which is distributed via the grid. We call the conjunction of grid and NAF the DESY Grid Centre. In the contribution to CHEP2012 we will in depth discuss the conceptional and operational aspects of our multi-VO and multi-community Grid Centre and present the system setup. We will in particular focus on the interplay of Grid and NAF and present experiences of the operations.

  1. The DESY Grid Centre

    Science.gov (United States)

    Haupt, A.; Gellrich, A.; Kemp, Y.; Leffhalm, K.; Ozerov, D.; Wegner, P.

    2012-12-01

    DESY is one of the world-wide leading centers for research with particle accelerators, synchrotron light and astroparticles. DESY participates in LHC as a Tier-2 center, supports on-going analyzes of HERA data, is a leading partner for ILC, and runs the National Analysis Facility (NAF) for LHC and ILC in the framework of the Helmholtz Alliance, Physics at the Terascale. For the research with synchrotron light major new facilities are operated and built (FLASH, PETRA-III, and XFEL). DESY furthermore acts as Data-Tier1 centre for the Neutrino detector IceCube. Established within the EGI-project DESY operates a grid infrastructure which supports a number of virtual Organizations (VO), incl. ATLAS, CMS, and LHCb. Furthermore, DESY hosts some of HEP and non-HEP VOs, such as the HERA experiments and ILC as well as photon science communities. The support of the new astroparticle physics VOs IceCube and CTA is currently set up. As the global structure of the grid offers huge resources which are perfect for batch-like computing, DESY has set up the National Analysis Facility (NAF) which complements the grid to allow German HEP users for efficient data analysis. The grid infrastructure and the NAF use the same physics data which is distributed via the grid. We call the conjunction of grid and NAF the DESY Grid Centre. In the contribution to CHEP2012 we will in depth discuss the conceptional and operational aspects of our multi-VO and multi-community Grid Centre and present the system setup. We will in particular focus on the interplay of Grid and NAF and present experiences of the operations.

  2. Town Centre Redevelopment Strategies

    DEFF Research Database (Denmark)

    Vagnby, Bo Hellisen

    After many years of urban growth Danish downtowns are facing some important choices. Shall the stake one-sidedly be on the town centres as driving forces for growth and 'city marketing', or do they still have a role to play in a broader socio-economic context? In the paper we look back on eight...... slum clearence and urban renewal. To a certain extent parallels are drawn to international experiences, especially where these are of such a nature that they can be assumed transferred to Danish connctions. Conclusively, the strategies are discussed in the light of the turn of Danish urban planning...

  3. Centre liikekeskuksen digital signage

    OpenAIRE

    Bincl, Suzana

    2015-01-01

    Opinnäytetyöni tarkastelee digital signagen suunnittelussa huomioitavia tekijöitä ja sen arvoa markkinointikanavana. Työ on toteutettu tilaustyönä Lappeenrantalaiselle mainostoimisto Mediakolmiolle. Työ sisältää teoriaosuuden lisäksi sisältösuunnitelman rakenteilla olevalle Centre liikekeskukselle. Tavoitteena oli luoda liikekeskukselle sen brändiä tukeva digital signage konsepti. Työ ei sisällä valmista tuotetta, vaan se toimii ehdotelmana myöhemmin alkavalle tuotanno...

  4. Quadra-Quantum Dots and Related Patterns of Quantum Dot Molecules: Basic Nanostructures for Quantum Dot Cellular Automata Application

    OpenAIRE

    Somsak Panyakeow

    2010-01-01

    Laterally close-packed quantum dots (QDs) called quantum dot molecules (QDMs) are grown by modified molecular beam epitaxy (MBE). Quantum dots could be aligned and cross hatched. Quantum rings (QRs) created from quantum dot transformation during thin or partial capping are used as templates for the formations of bi-quantum dot molecules (Bi-QDMs) and quantum dot rings (QDRs). Preferable quantum dot nanostructure for quantum computation based on quantum dot cellular automata (QCA) is late...

  5. A novel POSS-coated quantum dot for biological application

    OpenAIRE

    Rizvi SB; Yildirimer L; Ghaderi S; Ramesh B; Seifalian AM; Keshtgar M

    2012-01-01

    Sarwat B Rizvi,1 Lara Yildirimer,1 Shirin Ghaderi,1 Bala Ramesh,1 Alexander M Seifalian,1,2 Mo Keshtgar1,21UCL Centre for Nanotechnology and Regenerative Medicine, Division of Surgery and Interventional Science, University College London, United Kingdom; 2Royal Free Hampstead NHS Trust Hospital, London, United KingdomAbstract: Quantum dots (QDs) are fluorescent semiconductor nanocrystals that have the potential for major advancements in the field of nanomedicine through their unique photophys...

  6. [The primary healthcare centres].

    Science.gov (United States)

    Brambilla, Antonio; Maciocco, Gavino

    2014-04-01

    The central attributes of primary care are: first contact (accessibility), longitudinality (person- focused preventive and curative care overtime), patient-oriented comprehensiveness and coordination (including navigation towards secondary and tertiary care). Besides taking care of the needs of the individuals, primary health care teams are also looking at the community, especially when addressing social determinants of health. The rationale for the benefits for primary care for health has been found in: 1) greater access to needed services; 2) better quality of care; 3) a greater focus on prevention; 4) early management of health problems; 5) organizing and delivering high quality care for chronic non-communicable diseases. This paper describes the role of primary healthcare centres in strengthening community primary services and in reducing health inequalities. Furthemore, the experiences of Regional Health Services from Tuscany and Emilia-Romagna are discussed, with a brief overview of the literature. PMID:24770539

  7. Update on System Coordination Centre

    International Nuclear Information System (INIS)

    The new System Coordination Centre at the Power Pool of Alberta was designed to meet the unique requirements of Alberta's electric industry under the new regulatory regime. Development of the Centre, key provisions of the energy management system (EMS) are highlighted. The centre will provide an energy management system for the Pool's system controller function and interface with the Power Pool Administrator's market functions and the operations of the Transmission Administrator. System controllers are expected to be operating from the new location by the end of 1998. Unique EMS features of the centre include: (1) real-time management of energy market and network operations using diverse SCADA/EMS, (2) inter-control centre protocol used to accommodate the unique participant information requirements, and (3) special custom applications. The Centre is expected to be fully functioning by July 1999. 1 fig

  8. Experiences of Telebased Information Centres

    DEFF Research Database (Denmark)

    Falch, Morten

    1999-01-01

    Tele-based information community centres or just tele-centres have been seen as the killer application to empower local communities in developed and developing countries to meet the challenges of the information society. This paper will present a number of models for introducing such centres and ...... and discuss the different models and national strategies used for setting up tele-based information in relation to the Ghana experience.......Tele-based information community centres or just tele-centres have been seen as the killer application to empower local communities in developed and developing countries to meet the challenges of the information society. This paper will present a number of models for introducing such centres...

  9. Update on System Coordination Centre

    Energy Technology Data Exchange (ETDEWEB)

    Stangl, W. [Power Pool of Alberta, Calgary, AB (Canada)

    1998-07-01

    The new System Coordination Centre at the Power Pool of Alberta was designed to meet the unique requirements of Alberta`s electric industry under the new regulatory regime. Development of the Centre, key provisions of the energy management system (EMS) are highlighted. The centre will provide an energy management system for the Pool`s system controller function and interface with the Power Pool Administrator`s market functions and the operations of the Transmission Administrator. System controllers are expected to be operating from the new location by the end of 1998. Unique EMS features of the centre include: (1) real-time management of energy market and network operations using diverse SCADA/EMS, (2) inter-control centre protocol used to accommodate the unique participant information requirements, and (3) special custom applications. The Centre is expected to be fully functioning by July 1999. 1 fig.

  10. Quantum dot cascade laser

    OpenAIRE

    Zhuo, Ning; Liu, Feng Qi; Zhang, Jin Chuan; Wang, Li Jun; Liu, Jun Qi; Zhai, Shen Qiang; Wang, Zhan Guo

    2014-01-01

    We demonstrated an unambiguous quantum dot cascade laser based on InGaAs/GaAs/InAs/InAlAs heterostructure by making use of self-assembled quantum dots in the Stranski-Krastanow growth mode and two-step strain compensation active region design. The prototype generates stimulated emission at λ ~ 6.15 μm and a broad electroluminescence band with full width at half maximum over 3 μm. The characteristic temperature for the threshold current density within the temperature range of 82 to 162 K is up...

  11. Quantum dot solar cells

    CERN Document Server

    Wu, Jiang

    2013-01-01

    The third generation of solar cells includes those based on semiconductor quantum dots. This sophisticated technology applies nanotechnology and quantum mechanics theory to enhance the performance of ordinary solar cells. Although a practical application of quantum dot solar cells has yet to be achieved, a large number of theoretical calculations and experimental studies have confirmed the potential for meeting the requirement for ultra-high conversion efficiency. In this book, high-profile scientists have contributed tutorial chapters that outline the methods used in and the results of variou

  12. From Human-Centred to Human-Context centred Approach

    DEFF Research Database (Denmark)

    Rasmussen, Lauge Baungaard

    The article presents and discusses various human centred design approaches . In addtion it suggests a way to use narrative and numeric simulation methods in a combined approach to meet the challenges of sustainable development with a human-context centred approach....

  13. Analysis of Cl center dot center dot center dot Cl and C-H center dot center dot center dot Cl intermolecular interactions involving chlorine in substituted 2-chloroquinoline derivatives

    OpenAIRE

    Hathwar, Venkatesha R.; Roopan, Mohana S; R. Subashini; Khan, Nawaz F; Row, Guru TN

    2010-01-01

    Six crystal structures of substituted 2-chloroquinoline derivatives have been analysed to evaluate the role of Cl atom as a self recognizing unit resulting in the formation of Cl center dot center dot center dot Cl and C-H center dot center dot center dot Cl interactions to generate supramolecular assembly in the solid state. The features of Type I and Type II geometries associated with Cl center dot center dot center dot Cl interactions have been analysed to show directional preferences lead...

  14. Energy Centre Bratislava

    International Nuclear Information System (INIS)

    Energy Centre Bratislava (ECB) is a non-governmental, not-for-profit organization initiating and promoting development and exploitation of energy efficient processes and technologies, use of alternative and renewable energy sources and reduction of energy use impact on environment. ECB was founded in 1993 by European Commission and Upper Austrian Energy Saving Association in the frame of THERMIE program. or the eleven years of the ECB existence, it maintains a rapid growth rate through expansion of its client base and development of its activities. It is one of the few independent institutions working in energy sector of Slovakia. Due in part to these facts and the number of its activities, the ECB has become a generally recognized partner and has achieved an outstanding reputation. It has given advice to governments, institutions, organizations and the European Commission on the formulation of energy policies and the development and implementation of energy plans at a regional, national and European Union level. The principal goal of ECB activities is the promotion and support measures and activities aimed at increasing energy efficiency and improving environmental protection in Slovakia. The objective of the ECB is likewise to contribute to increasing of public energy awareness. ECB plays an active part in transferring innovative technologies and supporting the implementation of concrete projects,activities and legislative changes. The methods used to fulfill this goal include activities in some fields are reviewed. Main previous and current projects of ECB are presented

  15. Thailand's nuclear research centre

    International Nuclear Information System (INIS)

    The Office of Atomic Energy for Peace, Thailand, is charged with three main tasks, namely, Nuclear Energy development Plan, Utilization of Nuclear Based technology Plan and Science and Technology Plan. Its activities are centred around the research reactor TRR-1/M1. The main areas of contribution include improvement in agricultural production, nuclear medicine and nuclear oncology, health care and nutrition, increasing industrial productivity and efficiency and, development of cadre competent in nuclear science and technology. The office also has the responsibility of ensuring nuclear safety, radiation safety and nuclear waste management. The office has started a new project in 1997 under which a 10 MWt research reactor, an isotope production facility and a waste processing and storage facility would be set up by General Atomic of USA. OAEP has a strong linkage with the IAEA and has been an active participant in RCA programmes. In the future OAEP will enhance its present capabilities in the use of radioisotopes and radiation and look into the possibility of using nuclear energy as an alternative energy resource. (author)

  16. Fuzzy Dot Structure of BG-algebras

    OpenAIRE

    Tapan Senapati; Monoranjan Bhowmik; Madhumangal Pal

    2014-01-01

    In this paper, the notions of fuzzy dot subalgebras is introduced together with fuzzy normal dot subalgebras and fuzzy dot ideals of BG-algebras. The homomorphic image and inverse image are investigated in fuzzy dot subalgebras and fuzzy dot ideals of BG-algebras. Also, the notion of fuzzy relations on the family of fuzzy dot subalgebras and fuzzy dot ideals of BG-algebras are introduced with some related properties.

  17. Electron correlations in quantum dots

    CERN Document Server

    Tipton, D L J

    2001-01-01

    Quantum dot structures confine electrons in a small region of space. Some properties of semiconductor quantum dots, such as the discrete energy levels and shell filling effects visible in addition spectra, have analogies to those of atoms and indeed dots are sometimes referred to as 'artificial atoms'. However, atoms and dots show some fundamental differences due to electron correlations. For real atoms, the kinetic energy of electrons dominates over their mutual Coulomb repulsion energy and for this reason the independent electron approximation works well. For quantum dots the confining potential may be shallower than that of real atoms leading to lower electron densities and a dominance of mutual Coulomb repulsion over kinetic energy. In this strongly correlated regime the independent electron picture leads to qualitatively incorrect results. This thesis concentrates on few-electron quantum dots in the strongly correlated regime both for quasi-one-dimensional and two-dimensional dots in a square confining p...

  18. Colloidal Double Quantum Dots

    Science.gov (United States)

    2016-01-01

    Conspectus Pairs of coupled quantum dots with controlled coupling between the two potential wells serve as an extremely rich system, exhibiting a plethora of optical phenomena that do not exist in each of the isolated constituent dots. Over the past decade, coupled quantum systems have been under extensive study in the context of epitaxially grown quantum dots (QDs), but only a handful of examples have been reported with colloidal QDs. This is mostly due to the difficulties in controllably growing nanoparticles that encapsulate within them two dots separated by an energetic barrier via colloidal synthesis methods. Recent advances in colloidal synthesis methods have enabled the first clear demonstrations of colloidal double quantum dots and allowed for the first exploratory studies into their optical properties. Nevertheless, colloidal double QDs can offer an extended level of structural manipulation that allows not only for a broader range of materials to be used as compared with epitaxially grown counterparts but also for more complex control over the coupling mechanisms and coupling strength between two spatially separated quantum dots. The photophysics of these nanostructures is governed by the balance between two coupling mechanisms. The first is via dipole–dipole interactions between the two constituent components, leading to energy transfer between them. The second is associated with overlap of excited carrier wave functions, leading to charge transfer and multicarrier interactions between the two components. The magnitude of the coupling between the two subcomponents is determined by the detailed potential landscape within the nanocrystals (NCs). One of the hallmarks of double QDs is the observation of dual-color emission from a single nanoparticle, which allows for detailed spectroscopy of their properties down to the single particle level. Furthermore, rational design of the two coupled subsystems enables one to tune the emission statistics from single

  19. Colloidal Double Quantum Dots.

    Science.gov (United States)

    Teitelboim, Ayelet; Meir, Noga; Kazes, Miri; Oron, Dan

    2016-05-17

    Pairs of coupled quantum dots with controlled coupling between the two potential wells serve as an extremely rich system, exhibiting a plethora of optical phenomena that do not exist in each of the isolated constituent dots. Over the past decade, coupled quantum systems have been under extensive study in the context of epitaxially grown quantum dots (QDs), but only a handful of examples have been reported with colloidal QDs. This is mostly due to the difficulties in controllably growing nanoparticles that encapsulate within them two dots separated by an energetic barrier via colloidal synthesis methods. Recent advances in colloidal synthesis methods have enabled the first clear demonstrations of colloidal double quantum dots and allowed for the first exploratory studies into their optical properties. Nevertheless, colloidal double QDs can offer an extended level of structural manipulation that allows not only for a broader range of materials to be used as compared with epitaxially grown counterparts but also for more complex control over the coupling mechanisms and coupling strength between two spatially separated quantum dots. The photophysics of these nanostructures is governed by the balance between two coupling mechanisms. The first is via dipole-dipole interactions between the two constituent components, leading to energy transfer between them. The second is associated with overlap of excited carrier wave functions, leading to charge transfer and multicarrier interactions between the two components. The magnitude of the coupling between the two subcomponents is determined by the detailed potential landscape within the nanocrystals (NCs). One of the hallmarks of double QDs is the observation of dual-color emission from a single nanoparticle, which allows for detailed spectroscopy of their properties down to the single particle level. Furthermore, rational design of the two coupled subsystems enables one to tune the emission statistics from single photon

  20. CANDU 9 Control Centre Mockup

    International Nuclear Information System (INIS)

    This paper provides a summary of the design process being followed, the benefits of applying a systematic design using human factors engineering, presents an overview of the CANDU 9 control centre mockup facility, illustrates the control centre mockup with photographs of the 3D CADD model and the full scale mockup, and provides an update on the current status of the project. (author)

  1. Council celebrates CERN Control Centre

    CERN Multimedia

    2006-01-01

    With the unveiling of its new sign, the CERN Control Centre was officially inaugurated on Thursday 16 March. To celebrate its startup, CERN Council members visited the sleek centre, a futuristic-looking room filled with a multitude of monitoring screens.

  2. The Aube centre. 1997 statement

    International Nuclear Information System (INIS)

    Since January 1992 the Aube centre ensures the storage of 90% of the short life radioactive wastes produced in France. This educational booklet describes the organization of the activities in the centre from the storage of wastes to the radioactivity surveillance of the environment (air, surface and ground waters, river sediments, plants and milk). (J.S.)

  3. Hole centres in magnesium oxide

    International Nuclear Information System (INIS)

    When magnesium oxide crystals are exposed to ionizing radiation the electron-loss (hole) centres are normally identified as O·- ions. In this paper, I examine the EPR evidence for this, and compare the data with those for the hole centres in alkali- halides (VK centres). The latter are clearly σ* radical anions, such as F.-F-.The analogous centre in MgO is O.-O3-, which does not seem to have been considered. The results compare well, suggesting that the O·- centres are really O.-O3- radicals. In particular, the 17O data for the oxygen centre and the 19F data for F2·- give similar estimates of the 2s and 2p character of the orbitals on oxygen and fluorine, suggesting that the spin-density on oxygen is ca. 50%. The exception is the direction of the principal axes of these centres, which are quite different from each other. It is suggested that the primary hole-centres in MgO migrate by electron transfer to neighbouring cation vacancies where they are stable, and that at these sites the (1, 0, 0) directions are most favourable for σ- bonding

  4. 乙肝扶正排毒胶囊联合医用三氧对犬四氯化碳肝损伤的保护作用%Protective effect of Yigan Fuzheng Paidu capsules combined with ozone on CCl4-induced acute hepatic injury in dogs

    Institute of Scientific and Technical Information of China (English)

    李莉洁; 杨运高; 王程; 张志凌; 霍荻; 华何与; 陈佩禅; 张红栓; 郭亚兵

    2007-01-01

    目的 研究乙肝扶正排毒胶囊联合医用三氧对犬药物中毒性肝损伤的保护作用,为其临床应用提供实验依据.方法 用四氯化碳建立犬急性肝损伤模型:一次性腹腔注射50.0%(W/W)CCl4花生油溶液,0.9ml/kg体重.选择24只健康犬,随机分4个组(n=6),即模型组、齐墩果酸组、乙肝扶正排毒胶囊组和联合用药组.造模前,齐墩果酸组(齐墩果酸片,10mg/d·kg体重,口服)、乙肝扶正排毒胶囊组(乙肝扶正排毒胶囊,0.2 g/d·kg体重,口服)、联合用药组(乙肝扶正排毒胶囊用法同前;三氧与纯氧混合气体,三氧浓度20μg/ml,150ml/次·只,直肠吹注,隔天一次)均给药30 d.分别观察各犬的全身情况、记录生存时间、测定血液生化指标[丙氨酸氨基转移酶(ALT)、丙氨酸氨基转移酶与天门冬氨酸氨基转移酶比值(AST/ALT)、血清总胆红素(TBIL)、凝血酶原时间(PT)、血氨(AMMO)、尿素氮(BUN)]、犬死亡时或存活15 d时取肝脏组织病理检查.结果 联合用药组能控制犬的全身情况变化(活动性、精神、饮食、大小便等),提高生存率(P<0.05vs模型组),降低ALT、TBIL、PT值(P<0.05vs模型组或齐墩果酸组)和AMMO值(P<0.05vs模型组),使AST/ALT值维持在较为正常的水平.肝脏病理检查显示联合用药组的肝损伤程度较其他3组轻.结论 乙肝扶正排毒胶囊联合医用三氧能降低肝损伤实验犬的转氨酶、黄疸、血氨,延长生存时间,具有保护肝脏、减轻肝损伤的作用.

  5. CMCC Data Distribution Centre

    Science.gov (United States)

    Aloisio, Giovanni; Fiore, Sandro; Negro, A.

    2010-05-01

    The CMCC Data Distribution Centre (DDC) is the primary entry point (web gateway) to the CMCC. It is a Data Grid Portal providing a ubiquitous and pervasive way to ease data publishing, climate metadata search, datasets discovery, metadata annotation, data access, data aggregation, sub-setting, etc. The grid portal security model includes the use of HTTPS protocol for secure communication with the client (based on X509v3 certificates that must be loaded into the browser) and secure cookies to establish and maintain user sessions. The CMCC DDC is now in a pre-production phase and it is currently used only by internal users (CMCC researchers and climate scientists). The most important component already available in the CMCC DDC is the Search Engine which allows users to perform, through web interfaces, distributed search and discovery activities by introducing one or more of the following search criteria: horizontal extent (which can be specified by interacting with a geographic map), vertical extent, temporal extent, keywords, topics, creation date, etc. By means of this page the user submits the first step of the query process on the metadata DB, then, she can choose one or more datasets retrieving and displaying the complete XML metadata description (from the browser). This way, the second step of the query process is carried out by accessing to a specific XML document of the metadata DB. Finally, through the web interface, the user can access to and download (partially or totally) the data stored on the storage device accessing to OPeNDAP servers and to other available grid storage interfaces. Requests concerning datasets stored in deep storage will be served asynchronously.

  6. The Aube centre; Le Centre de l`Aube

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-07-01

    This educational booklet is devoted to a general presentation of the Aube radioactive wastes storage centre. After a short presentation of the Andra, the French national agency for the management of radioactive wastes, it gives some general information about radioactive wastes (origin, classification), containers (quality assurance and different types), wastes transportation (planning, safety), and about the Aube centre itself: description, treatment and conditioning of drums (compacting and injection), storage facilities, geological situation of the site, and environmental controls. (J.S.)

  7. Minister unveils new nanotech centres

    Science.gov (United States)

    Dumé, Belle

    2009-06-01

    Three new nanotechnology research centres are to be set up in France as part of a €70m government plan to help French companies in the sector. Researchers at the new centres, which will be located in Grenoble, Saclay (near Paris) and Toulouse, will be encouraged to collaborate with industry to develop new nanotech-based products. Dubbed NANO-INNOV, the new plan includes €46m for two new buildings at Saclay, with the rest being used to buy new equipment at the three centres and to fund grant proposals from staff to the French National Research Agency (ANR).

  8. Quantum Dot Sensitized Photoelectrodes

    OpenAIRE

    Thomas Nann; Thomas J. Macdonald

    2011-01-01

    Quantum Dots (QDs) are promising alternatives to organic dyes as sensitisers for photocatalytic electrodes. This review article provides an overview of the current state of the art in this area. More specifically, different types of QDs with a special focus on heavy-metal free QDs and the methods for preparation and adsorption onto metal oxide electrodes (especially titania and zinc oxide) are discussed. Eventually, the key areas of necessary improvements are identified and assessed.

  9. Quantum Dot Sensitized Photoelectrodes

    Directory of Open Access Journals (Sweden)

    Thomas Nann

    2011-11-01

    Full Text Available Quantum Dots (QDs are promising alternatives to organic dyes as sensitisers for photocatalytic electrodes. This review article provides an overview of the current state of the art in this area. More specifically, different types of QDs with a special focus on heavy-metal free QDs and the methods for preparation and adsorption onto metal oxide electrodes (especially titania and zinc oxide are discussed. Eventually, the key areas of necessary improvements are identified and assessed.

  10. Plasmonic fluorescent quantum dots

    OpenAIRE

    Jin, Yongdong; Gao, Xiaohu

    2009-01-01

    Combining multiple discrete components into a single multifunctional nanoparticle could be useful in a variety of applications. Retaining the unique optical and electrical properties of each component after nanoscale integration is, however, a long-standing problem1,2. It is particularly difficult when trying to combine fluorophores such as semiconductor quantum dots with plasmonic materials such as gold, because gold and other metals can quench the fluorescence3,4. So far, the combination of...

  11. Quantum dots in graphene

    OpenAIRE

    Silvestrov, P.G.; Efetov, K. B.

    2006-01-01

    We suggest a way of confining quasiparticles by an external potential in a small region of a graphene strip. Transversal electron motion plays a crucial role in this confinement. Properties of thus obtained graphene quantum dots are investigated theoretically for different types of the boundary conditions at the edges of the strip. The (quasi)bound states exist in all systems considered. At the same time, the dependence of the conductance on the gate voltage carries an information about the s...

  12. Quantum dot nanostructures

    Directory of Open Access Journals (Sweden)

    Mohamed Henini

    2002-06-01

    These sophisticated technologies for the growth of high quality epitaxial layers of compound semiconductor materials on single crystal semiconductor substrates are becoming increasingly important for the development of the semiconductor electronics industry. This article is intended to convey the flavor of the subject by focusing on the technology and applications of self-assembled quantum dots (QDs and to give an introduction to some of the essential characteristics.

  13. Quantum dot solar cell

    International Nuclear Information System (INIS)

    Full text: The much awaited desire of replacing fossil fuel with photovoltaic will remain a fairy tale if the myriad of issues facing solar cell development are marginalized. Foremost in the list is the issue of cost. Silicon has reached a stage where its use on large scale can no longer be lavishly depended upon. The demand for high grade silicon from the microelectronics and solar industries has soared leading to scarcity. New approach has to be sought. Notable is the increased attention on thin films such as cadmium telluride, copper indium gallium diselenide, amorphous silicon, and the not so thin non-crystalline family of silicon. While efforts to address the issues of stability, toxicity and efficiency of these systems are ongoing, another novel approach is quietly making its appearance - quantum dots. Quantum dots seem to be promising candidates for solar cells because of the opportunity to manipulate their energy levels allowing absorption of a wider solar spectrum. Utilization of minute quantity of these nano structures is enough to bring the cost of solar cell down and to ascertain sustainable supply of useful material. The paper outlines the progress that has been made on quantum dot solar cells. (author)

  14. Radiation sterilization centres worldwide

    International Nuclear Information System (INIS)

    Commercial radiation sterilization has been used for more than 50 years. The Ethicon Division of Johnson and Johnson inaugurated medical device sterilization in 1954 for use with sutures. Over the decades, there has been enormous growth in the disposable medical products market. With this, there has been significant growth in the use of ionizing radiation as a method for sterilization. At present, 40-50% of all disposable medical products manufactured in North America are radiation sterilized. There are now some 160 commercial 60Co irradiators for radiation sterilization operating in 47 countries worldwide, containing approximately 240-260 MCi (8.9-9.6 x 1018 Bq) of gamma emitting 60Co. Included in this are service type facilities operated in research and development centres. Because of the ability to downscale 60Co units, there are many R and D and pilot scale small facilities as well, almost equal in number (approximately 150). When other uses are taken into account, there are in total over 200 gamma irradiators being operated for a variety of purposes in 55 different countries: 100-120 gamma irradiators are located in Europe and in the United States of America. Syringes, surgical gloves, gowns, masks, sticking plasters, dressings, medical 'tetrapacks', bottle teats for premature babies, artificial joints, food packaging, raw materials for pharmaceuticals and cosmetics, and even wine corks, are gamma sterilized. An increasing number of e-beam accelerators are also being operated, but at present e-beam is used for only a minority of radiation sterilized product. The use of e-beam as a radiation source has many attractive features, such as near instantaneous dose delivery, scalability for different throughput, and the capability to integrate in an on-line process. E-beam processing is, however, limited by the penetration of electrons, which is proportional to the accelerator voltage. The highest electron energy used in commercial applications, 10 MeV, penetrates

  15. CERI: Ionizing Radiation Calibration Centre

    International Nuclear Information System (INIS)

    The CERI has been granted by the National Bureau of Metrology (BNM) as an Ionizing Radiation Calibration Centre and as an Estimation and Qualification Centre for the ionizing radiation measurement devices. This article gives some information on the scope covered by the BNM's grant and on the various equipment on which the laboratory relies. It describes the calibration and estimation activities and mentions many kinds of services which are offered to the users mainly in the medical and industrial fields

  16. The centre of the action

    CERN Multimedia

    2008-01-01

    The CERN Control Centre (CCC) has all the ingredients of an action movie control room: hundreds of screens, technicians buzzing in and out, huge floor-to-ceiling windows revealing the looming vista of a mountain range, flashing lights, microphones… This is the place where not just the LHC, but the whole of CERN’s accelerator complex and technical support is based - truly the centre of the action at CERN.

  17. Contemporary design for 'landmark' centre.

    Science.gov (United States)

    2009-08-01

    As one of the UK's largest builders of healthcare facilities, construction company Morgan Ashurst is accustomed to delivering complex, challenging hospital projects. The construction of a new oncology centre at Musgrove Park Hospital, Taunton for Taunton and Somerset NHS Foundation Trust-- said to be the first new stand-alone radiotherapy centre to be built in the UK for almost 20 years--was no exception. Health Estate Journal reports. PMID:19711668

  18. Training centres - organization and management

    International Nuclear Information System (INIS)

    In the lecture 'Training centres - organization and management' some principles and requirements which influence the organization, management and activity pattern of nuclear training centres, are briefly introduced. It is demonstrated, step by step, how these general principles are implemented in the development of the Czechoslovak nuclear power programme, it means, how the training of the NPP personnel proceeds in Czechoslovak nuclear training centres. General principles which are selected: a connection between the capacity of the training centre and the scope and needs of the nuclear power programme, a position of the training center within the institutional set-up, a structure and organization of the training system which complies with the system of NPP construction, reflect the pattern and the activity of the nuclear training centre and nuclear power technical level, a research group of workers in the nuclear training centre, main tasks and technical facilities, management of the training process and a transfer of knowledge and research results into the training process. The lecture is supplemented by pictures and slides. (orig.)

  19. RTEMS Centre - Support and Maintenance Centre to RTEMS Operating System

    Science.gov (United States)

    Silva, H.; Constantino, A.; Freitas, D.; Coutinho, M.; Faustino, S.; Mota, M.; Colaço, P.; Sousa, J.; Dias, L.; Damjanovic, B.; Zulianello, M.; Rufino, J.

    2009-05-01

    RTEMS CENTRE - Support and Maintenance Centre to RTEMS Operating System is a joint ESA/Portuguese Task Force initiative to develop a support and maintenance centre to the Real-Time Executive for Multiprocessor Systems (RTEMS). This paper gives a high level visibility of the progress, the results obtained and the future work in the RTEMS CENTRE [6] and in the RTEMS Improvement [7] projects. RTEMS CENTRE started officially in November 2006, with the RTEMS 4.6.99.2 version. A full analysis of RTEMS operating system was produced. The architecture was analysed in terms of conceptual, organizational and operational concepts. The original objectives [1] of the centre were primarily to create and maintain technical expertise and competences in this RTOS, to develop a website to provide the European Space Community an entry point for obtaining support (http://rtemscentre.edisoft.pt), to design, develop, maintain and integrate some RTEMS support tools (Timeline Tool, Configuration and Management Tools), to maintain flight libraries and Board Support Packages, to develop a strong relationship with the World RTEMS Community and finally to produce some considerations in ARINC-653, DO-178B and ECSS E-40 standards. RTEMS Improvement is the continuation of the RTEMS CENTRE. Currently the RTEMS, version 4.8.0, is being facilitated for a future qualification. In this work, the validation material is being produced following the Galileo Software Standards Development Assurance Level B [5]. RTEMS is being completely tested, errors analysed, dead and deactivated code removed and tests produced to achieve 100% statement and decision coverage of source code [2]. The SW to exploit the LEON Memory Management Unit (MMU) hardware will be also added. A brief description of the expected implementations will be given.

  20. Inter-dot coupling effects on transport through correlated parallel coupled quantum dots

    Indian Academy of Sciences (India)

    Shyam Chand; G Rajput; K C Sharma; P K Ahluwalia

    2009-05-01

    Transport through symmetric parallel coupled quantum dot system has been studied, using non-equilibrium Green function formalism. The inter-dot tunnelling with on-dot and inter-dot Coulomb repulsion is included. The transmission coefficient and Landaur–Buttiker like current formula are shown in terms of internal states of quantum dots. The effect of inter-dot tunnelling on transport properties has been explored. Results, in intermediate inter-dot coupling regime show signatures of merger of two dots to form a single composite dot and in strong coupling regime the behaviour of the system resembles the two decoupled dots.

  1. From single dots to interacting arrays

    OpenAIRE

    Gudmundsson, Vidar; Manolescu, Andrei; Krahne, Roman; Heitmann, Detlef

    2001-01-01

    We explore the structural changes in charge the density and the electron configuration of quantum dots caused by the presence of other dots in an array, and the interaction of neighboring dots. We discuss what recent measurements and calculation of the far-infrared absorption reveal about almost isolated quantum dots and investigate some aspects of the complex transition from isolated dots to dots with strongly overlapping electron density. We also address the the effects on the magnetization...

  2. GRUNCLE, 1. Collision Source Calculation for Program DOT. DOT-3.5, 2-D Neutron Transport, Gamma Transport Program DOT with New Space-Scaling

    International Nuclear Information System (INIS)

    mesh. Anisotropic scattering is treated using a Legendre expansion of arbitrary order. Convergence can be accelerated by several optional schemes, including a pointwise rescaling technique. DOT-3.5/E: Differs from DOT-3.5 in that exponential supplementary equations, as well as the usual diamond and weighted schemes, may be used to find the mesh-centre flux from the fluxes at the faces of the mesh. The model: 1. always gives positive solutions and does not require any fix-up techniques provided that the source is non-negative; 2. improves convergence rate in most neutron deep-penetration problems and, for any practical spatial discretization, always requires CPU times not only smaller than those required by DOT-3 mixed (linear + step fix-up) model, but also shorter (generally 10-20%) than the times required by DOT-3.5 weighted difference model; 3. increasing spatial mesh size supplies solutions which are always reasonable overestimates of the exact solution and its numerical behaviour is more stable and coherent than the mixed mode. Experience up to now from several deep penetration problems in (r,z) and (x,y) geometry shows that, while for neutrons the exponential model almost always works very well, for gamma rays its behaviour may be critical and in some cases there is lack of convergence. C - Restrictions on the complexity of the problem: The total storage requirement is determined by a formula given in the input description. No other restrictions to problem size are applicable

  3. Perceptual strategies of pigeons to detect a rotational centre--a hint for star compass learning?

    Directory of Open Access Journals (Sweden)

    Bianca Alert

    Full Text Available Birds can rely on a variety of cues for orientation during migration and homing. Celestial rotation provides the key information for the development of a functioning star and/or sun compass. This celestial compass seems to be the primary reference for calibrating the other orientation systems including the magnetic compass. Thus, detection of the celestial rotational axis is crucial for bird orientation. Here, we use operant conditioning to demonstrate that homing pigeons can principally learn to detect a rotational centre in a rotating dot pattern and we examine their behavioural response strategies in a series of experiments. Initially, most pigeons applied a strategy based on local stimulus information such as movement characteristics of single dots. One pigeon seemed to immediately ignore eccentric stationary dots. After special training, all pigeons could shift their attention to more global cues, which implies that pigeons can learn the concept of a rotational axis. In our experiments, the ability to precisely locate the rotational centre was strongly dependent on the rotational velocity of the dot pattern and it crashed at velocities that were still much faster than natural celestial rotation. We therefore suggest that the axis of the very slow, natural, celestial rotation could be perceived by birds through the movement itself, but that a time-delayed pattern comparison should also be considered as a very likely alternative strategy.

  4. Nuclear Information Centre is building branch reference centre

    International Nuclear Information System (INIS)

    Reference services are being prepared by the Nuclear Information Centre (NIC) in order to improve information services for nuclear science and technology. The objective is to analyse the user's request, to determine suitable information sources and to provide the end user with a reference to the appropriate information centre, specialized organization or a specialist, or to directly provide the requested information using own information sources. The reference services will use a number of the Centre's own information data files, the data bank of relevant information sources, a personal and corporate file, the record of Czechoslovak nonconventional materials, the data bank of NIC publishing operations, the auxiliary NIC services record, a catalogue of books and journals, and the data bases at NIC. Most information files will be automated and stored on IBM-compatible personal computers. (J.B.). 1 fig., 3 refs

  5. The ideal Atomic Centre; Le Centre Atomique ideal

    Energy Technology Data Exchange (ETDEWEB)

    Mas, R. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    The author presents considerations which should prove to be of interest to all those who have to design, to construct and to operate a nuclear research centre. A large number of the ideas presented can also be applied to non-nuclear scientific research centres. In his report the author reviews: various problems with which the constructor is faced: ground-plan, infrastructure, buildings and the large units of scientific equipment in the centre, and those problems facing the director: maintenance, production, supplies, security. The author stresses the relationship which ought to exist between the research workers and the management. With this aim in view he proposes the creation of National School for Administration in Research which would train administrative executives for public or private organisations; they would be specialised in the fields of fundamental or applied research. (author) [French] L'auteur propose une base de reflexions a tous ceux qui doivent concevoir, realiser et faire vivre un Centre d'Etudes Nucleaires. Un grand nombre des idees exprimees peut d'ailleurs s'appliquer a un Centre d'Etudes Scientifiques non nucleaires. Dans son ouvrage, l'auteur passe en revue les differents problemes qui se posent au constructeur: plan, masse, infrastructure, batiments et grands appareils du Centre, et ceux qu'a a resoudre le directeur: entretien, fabrication, approvisionnements, securite. L'auteur insiste sur l'aspect des rapports qui doivent exister entre les chercheurs et ceux qui les administrent. Il propose a cette fin la creation d'une Ecole Nationale d'Administration de la Recherche qui formerait des cadres administratifs pour les organismes publics ou prives, specialises dans la Recherche fondamentale ou appliquee. (auteur)

  6. Electrochromic nanocrystal quantum dots.

    Science.gov (United States)

    Wang, C; Shim, M; Guyot-Sionnest, P

    2001-03-23

    Incorporating nanocrystals into future electronic or optoelectronic devices will require a means of controlling charge-injection processes and an understanding of how the injected charges affect the properties of nanocrystals. We show that the optical properties of colloidal semiconductor nanocrystal quantum dots can be tuned by an electrochemical potential. The injection of electrons into the quantum-confined states of the nanocrystal leads to an electrochromic response, including a strong, size-tunable, midinfrared absorption corresponding to an intraband transition, a bleach of the visible interband exciton transitions, and a quench of the narrow band-edge photoluminescence. PMID:11264530

  7. The Galactic centre pulsar population

    CERN Document Server

    Chennamangalam, Jayanth

    2013-01-01

    The recent discovery of a magnetar in the Galactic centre region has allowed Spitler et al. to characterize the interstellar scattering in that direction. They find that the temporal broadening of the pulse profile of the magnetar is substantially less than that predicted by models of the electron density of that region. This raises the question of what the plausible limits for the number of potentially observable pulsars - i.e., the number of pulsars beaming towards the Earth - in the Galactic centre region are. In this paper, using realistic assumptions, we show that the potentially observable population of pulsars in the inner parsec has a conservative upper limit of $\\sim$950, and that it is premature to conclude that the number of pulsars in this region is small. We also show that the observational results so far are consistent with this number and make predictions for future radio pulsar surveys of the Galactic centre.

  8. The Belgian nuclear research centre

    International Nuclear Information System (INIS)

    The Belgian Nuclear Research Centre is almost exclusively devoted to nuclear R and D and services and is able to generate 50% of its resources (out of 75 million Euro) by contract work and services. The main areas of research include nuclear reactor safety, radioactive waste management, radiation protection and safeguards. The high flux reactor BR2 is extensively used to test fuel and structural materials. PWR-plant BR3 is devoted to the scientific analysis of decommissioning problems. The Centre has a strong programme on the applications of radioisotopes and radiation in medicine and industry. The centre has plans to develop an accelerator driven spallation neutron source for various applications. It has initiated programmes to disseminate correct information on issues of nuclear energy production and non-energy nuclear applications to different target groups. It has strong linkages with the IAEA, OECD-NEA and the Euratom. (author)

  9. Construction of the Wigner Data Centre

    CERN Multimedia

    2013-01-01

    A remote extension of the CERN data centre has recently been inaugurated. Hosted at the Wigner Research Centre for Physics in Hungary, it provides extra computing power required to cover CERN’s needs. This video presents the construction of the Wigner Data Centre from initial demolishing work through to its completion and details the major technical characteristics of the Data Centre.

  10. Printer model for dot-on-dot halftone screens

    Science.gov (United States)

    Balasubramanian, Raja

    1995-04-01

    A printer model is described for dot-on-dot halftone screens. For a given input CMYK signal, the model predicts the resulting spectral reflectance of the printed patch. The model is derived in two steps. First, the C, M, Y, K dot growth functions are determined which relate the input digital value to the actual dot area coverages of the colorants. Next, the reflectance of a patch is predicted as a weighted combination of the reflectances of the four solid C, M, Y, K patches and their various overlays. This approach is analogous to the Neugebauer model, with the random mixing equations being replaced by dot-on-dot mixing equations. A Yule-Neilsen correction factor is incorporated to account for light scattering within the paper. The dot area functions and Yule-Neilsen parameter are chosen to optimize the fit to a set of training data. The model is also extended to a cellular framework, requiring additional measurements. The model is tested with a four color xerographic printer employing a line-on-line halftone screen. CIE L*a*b* errors are obtained between measurements and model predictions. The Yule-Neilsen factor significantly decreases the model error. Accuracy is also increased with the use of a cellular framework.

  11. Training centres in Latin America

    International Nuclear Information System (INIS)

    Early 1958 the Brazilian representative on the Board of Governors of the International Atomic Energy Agency - supported by the Governors from Argentina and Guatemala -proposed that a study should be made of the possibility of setting up one or more atomic energy training centres in Latin America. On the Board's recommendation, the Director General of the Agency appointed a fact-finding team to make anon-the-spot study. In drafting this report the team was invited to consider the following points: (a) The need for establishing one or more regional training centres; (b) Existing facilities that are being or could be used for training, together with technical data concerning them; (c) The general scientific technological and industrial conditions of the countries visited insofar as they have a bearing on their training needs and capabilities. The authors of the report conclude that 'a training centre in radio-botany should provide vitally needed knowledge and vitally needed specialists to all the agricultural installations in Latin America. A training centre like this might provide an excellent model upon which to base training centres in other areas'. The report recommends that: 1. The Agency should meet the requests of Latin American universities by, for example, supplying equipment and sending experts; 2. At least one specialized training centre should be established as soon as possible. Taking as an example the field of radio-botany, such a centre would provide trained specialists in radio-botany to agricultural institutions throughout Latin America and also provide basic research results vital to agriculture. The cost of new facilities might be of the order of $7 500 000, with an annual budget of approximately $650 000. Staff required: 40 scientists and 175 employees; 3. Whenever it appears feasible to gather necessary staff of high creative ability and established productivity and when funds can be made available for facilities, equipment and operating costs, at

  12. Quantum dot cascade laser

    Science.gov (United States)

    2014-01-01

    We demonstrated an unambiguous quantum dot cascade laser based on InGaAs/GaAs/InAs/InAlAs heterostructure by making use of self-assembled quantum dots in the Stranski-Krastanow growth mode and two-step strain compensation active region design. The prototype generates stimulated emission at λ ~ 6.15 μm and a broad electroluminescence band with full width at half maximum over 3 μm. The characteristic temperature for the threshold current density within the temperature range of 82 to 162 K is up to 400 K. Moreover, our materials show the strong perpendicular mid-infrared response at about 1,900 cm-1. These results are very promising for extending the present laser concept to terahertz quantum cascade laser, which would lead to room temperature operation. PACS 42.55.Px; 78.55.Cr; 78.67.Hc PMID:24666965

  13. Complex dynamics in planar two-electron quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Schroeter, Sebastian Josef Arthur

    2013-06-25

    Quantum dots play an important role in a wide range of recent experimental and technological developments. In particular they are promising candidates for realisations of quantum bits and further applications in quantum information theory. The harmonically confined Hooke's atom model is experimentally verified and separates in centre-of-mass and relative coordinates. Findings that are contradictory to this separability call for an extension of the model, in particular changing the confinement potential. In order to study effects of an anharmonic confinement potential on spectral properties of planar two-electron quantum dots a sophisticated numerical approach is developed. Comparison between the Helium atom, Hooke's atom and an anharmonic potential model are undertaken in order to improve the description of quantum dots. Classical and quantum features of complexity and chaos are investigated and used to characterise the dynamics of the system to be mixed regular-chaotic. Influence of decoherence can be described by quantum fidelity, which measures the effect of a perturbation on the time evolution. The quantum fidelity of eigenstates of the system depends strongly on the properties of the perturbation. Several methods for solving the time-dependent Schrödinger equation are implemented and a high level of accuracy for long time evolutions is achieved. The concept of offset entanglement, the entanglement of harmonic models in the noninteracting limit, is introduced. This concept explains different questions raised in the literature for harmonic quantum dot models, recently. It shows that only in the groundstate the electrons are not entangled in the fermionic sense. The applicability, validity, and origin of Hund's first rule in general quantum dot models is further addressed. In fact Hund's first rule is only applicable, and in this case also valid, for one pair of singlet and triplet states in Hooke's atom. For more realistic models of two

  14. Complex dynamics in planar two-electron quantum dots

    International Nuclear Information System (INIS)

    Quantum dots play an important role in a wide range of recent experimental and technological developments. In particular they are promising candidates for realisations of quantum bits and further applications in quantum information theory. The harmonically confined Hooke's atom model is experimentally verified and separates in centre-of-mass and relative coordinates. Findings that are contradictory to this separability call for an extension of the model, in particular changing the confinement potential. In order to study effects of an anharmonic confinement potential on spectral properties of planar two-electron quantum dots a sophisticated numerical approach is developed. Comparison between the Helium atom, Hooke's atom and an anharmonic potential model are undertaken in order to improve the description of quantum dots. Classical and quantum features of complexity and chaos are investigated and used to characterise the dynamics of the system to be mixed regular-chaotic. Influence of decoherence can be described by quantum fidelity, which measures the effect of a perturbation on the time evolution. The quantum fidelity of eigenstates of the system depends strongly on the properties of the perturbation. Several methods for solving the time-dependent Schrödinger equation are implemented and a high level of accuracy for long time evolutions is achieved. The concept of offset entanglement, the entanglement of harmonic models in the noninteracting limit, is introduced. This concept explains different questions raised in the literature for harmonic quantum dot models, recently. It shows that only in the groundstate the electrons are not entangled in the fermionic sense. The applicability, validity, and origin of Hund's first rule in general quantum dot models is further addressed. In fact Hund's first rule is only applicable, and in this case also valid, for one pair of singlet and triplet states in Hooke's atom. For more realistic models of two-electron quantum dots an

  15. The DEMETER Science Mission Centre

    Czech Academy of Sciences Publication Activity Database

    Lagoutte, D.; Brochot, J.; Y.; de Carvalho, D.; Elie, F.; Harivelo, F.; Hobara, Y.; Madrias, L.; Parrot, M.; Pincon, J. L.; Berthelier, J. J.; Peschard, D.; Seran, E.; Gangloff, M.; Sauvaud, J. A.; Lebreton, J. P.; Štverák, Štěpán; Trávníček, Pavel M.; Grygorczuk, J.; Slominski, J.; Wronowski, R.; Barbier, S.; Bernard, P.; Gaboriaud, A.; Wallut, J. M.

    2006-01-01

    Roč. 54, č. 5 (2006), s. 428-440. ISSN 0032-0633 Institutional research plan: CEZ:AV0Z30420517 Keywords : Mission Centre * Data processing Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 1.509, year: 2006

  16. Vinohrady Sokol centre in Prague

    Czech Academy of Sciences Publication Activity Database

    Svobodová, Markéta

    Prague: Prostor - architektura, interiér, design, 2012 - (Švácha, R.), s. 178-181 ISBN 978-80-87064-09-2 Institutional support: RVO:68378033 Keywords : Sokol centre * functionalism * František Marek * Václav Vejrych * Zbyšek Jirsák Subject RIV: AL - Art, Architecture, Cultural Heritage

  17. ANALYTICAL REVIEW FOR DIFFERENT ASPECTS OF DOT GAIN

    OpenAIRE

    Parag Dnyandeo Nathe

    2013-01-01

    This document gives information about Dot reproduction, Dot gain, factors affecting dot gain, calculation of dot gain measurement and control over dot gain in different controlling parameters. Dot generation in print reproduction and different aspects which causes dot gain during image generation with photochemical process, during printing with mechanical process and during visual inspection of print dot gain is occurred. This document gives information about all causes of dot gain and contr...

  18. The CCCB is a cultural centre, not a tourist centre

    Directory of Open Access Journals (Sweden)

    Elena Xirau

    2004-04-01

    Full Text Available Last February, Barcelona's Centre of Contemporary Culture (CCCB celebrated its first ten years in existence. During this time, this institution has looked to be a showcase to the most modern and innovative cultural expressions focused on reflecting on the concept of the city. In this interview, Josep Ramoneda offers his personal view, as the CCCB's director. He talks of how this cultural project was born, of how the concept of the institution took shape in the CCCB, of its relations with Barcelona's Strategic Plan, of how the project has evolved, of the architectural remodelling of the Casa de la Caritat building for its conversion into a cultural centre, of the relations with other institutions and its future.

  19. The CCCB is a cultural centre, not a tourist centre

    OpenAIRE

    Elena Xirau

    2004-01-01

    Last February, Barcelona's Centre of Contemporary Culture (CCCB) celebrated its first ten years in existence. During this time, this institution has looked to be a showcase to the most modern and innovative cultural expressions focused on reflecting on the concept of the city. In this interview, Josep Ramoneda offers his personal view, as the CCCB's director. He talks of how this cultural project was born, of how the concept of the institution took shape in the CCCB, of its relations with Bar...

  20. Semiconductor nanocrystals inside spherical microcavities: A case of quantum dots in photonic dots

    OpenAIRE

    Artemyev, M. V.

    2003-01-01

    Quantum dots in photonic dots, a new type of microstructures involving highly luminescent II-VI semiconductor nanocrystals has been proposed and realized by incorporating nanocrystals (quantum dots) into glass and polymeric microspheres. The high quality micron-size microspheres represent simplest fully three-dimensional microcavities (photonic dots). Coupling of discrete electron states of quantum dots and photon states inside photonic dots strongly affects onto both stationary and dynamic p...

  1. Quantum dots: Rethinking the electronics

    Science.gov (United States)

    Bishnoi, Dimple

    2016-05-01

    In this paper, we demonstrate theoretically that the Quantum dots are quite interesting for the electronics industry. Semiconductor quantum dots (QDs) are nanometer-scale crystals, which have unique photo physical, quantum electrical properties, size-dependent optical properties, There small size means that electrons do not have to travel as far as with larger particles, thus electronic devices can operate faster. Cheaper than modern commercial solar cells while making use of a wider variety of photon energies, including "waste heat" from the sun's energy. Quantum dots can be used in tandem cells, which are multi junction photovoltaic cells or in the intermediate band setup. PbSe (lead selenide) is commonly used in quantum dot solar cells.

  2. DOT Official County Highway Map

    Data.gov (United States)

    Minnesota Department of Natural Resources — The County Highway Map theme is a scanned and rectified version of the original MnDOT County Highway Map Series. The cultural features on some of these maps may be...

  3. Electroluminescent hybrid organic/inorganic quantum dot devices

    International Nuclear Information System (INIS)

    The synthesis of PbS crystallites in aqueous solution in the presence of ethylenediaminetetraacetic acid (EDTA) has been investigated. Nanocrystalline material exhibiting charge confinement effects have been observed. The factors affecting crystallite growth, and hence the optical properties of the ultimately synthesised sample have been studied. A simple analytical model of the linear optical properties of quantum dots of finite size distribution has been developed. The model has been used in conjunction with the effective mass approximation (EMA) in order to model the optical properties of the synthesised PbS with a great deal of success. The EMA is found to limit the applicability of the optical model to samples of quantum dots consisting of larger crystallites as one would expect. Size-quantised CdSe particles have also been synthesised in aqueous solution. The same optical model successfully models the absorption spectra of these quantum dots, subject to the constraints of the EMA. Excessive scattering of light in solutions containing flocculated and/or bulk material is also found to limit the applicability of the model. The incorporation of colloidally suspended quantum dots into optoelectronic device structures has been considered. Energy level offsets between the quantum dots and host matrices have been studied and have been found to be unfavourable to the injection of electronic charge from the matrix into the dots. Alternative electroluminescent device structures in which the quantum dots are incorporated into electroluminescent host matrices which optically pump the quantum dots have therefore been proposed. Such devices have proved difficult to fabricate, eventual luminescence from quantum dot surface states having been obtained, but luminescence from the quantum dot effective bandgap not having been obtained. The scope of the project has extended to the investigation of charge injection into the quantum dot matrix materials themselves from the device

  4. Spin pumping through quantum dots

    OpenAIRE

    Rojek, Stephan; Governale, Michele; König, Jürgen

    2013-01-01

    We propose schemes for generating spin currents into a semiconductor by adiabatic or non-adiabatic pumping of electrons through interacting quantum dots. The appeal of such schemes lies in the possibility to tune the pumping characteristics via gate voltages that control the properties of the quantum dot. The calculations are based on a systematic perturbation expansion in the tunnel-coupling strength and the pumping frequency, expressed within a diagrammatic real-time technique. Special focu...

  5. Photonics of shungite quantum dots

    OpenAIRE

    Razbirin, Boris S.; Rozhkova, Natalia N.; Sheka, Elena F.

    2014-01-01

    Shungite quantum dots are associated with nanosize fragments of reduced graphene oxide similarly to synthetic graphene quantum dots thus forming a common class of GQDs. Colloidal dispersions of powdered shungite in water, carbon tetrachloride, and toluene form the ground for the GQD photonic peculiarities manifestation. Morphological study shows a steady trend of GQDs to form fractals and a drastic change in the colloids fractal structure caused by solvent was reliably established. Spectral s...

  6. The INTEGRAL Science Data Centre

    OpenAIRE

    Beckmann, V.

    2002-01-01

    The INTEGRAL Science Data Centre (ISDC) processes, archives and distributes data from the INTEGRAL mission. At the ISDC incoming data from the satellite are processed and searched for transient sources and Gamma-Ray bursts. The data are archived and distributed to the guest observers. As soon as the data are public, any astronomer can access the data via the internet. ISDC also provides the tools which are necessary for the data analysis and offers user support concerning questions related to...

  7. Radwaste Treatment Centre Jaslovske Bohunice

    International Nuclear Information System (INIS)

    In this leaflet the Bohunice Radwaste Treatment Centre (BSC RAO) is presented. BSC RAO is designed to process and treat liquid and solid radwaste, arising from the NPP A-1 decommissioning, from NPPs V-1, V-2, and Mochovce operations, as well as institutional radwaste of diverse institutional (hospitals, research institutes) in the Slovak Republic. Transport, sorting, incineration, compacting, concentration and cementation of radwaste as well as monitoring of emission are described

  8. Scalable Quantum Computing with "Enhancement" Quantum Dots

    CERN Document Server

    Lyanda-Geller, Y B; Yang, M J

    2005-01-01

    We propose a novel scheme of solid state realization of a quantum computer based on single spin "enhancement mode" quantum dots as building blocks. In the enhancement quantum dots, just one electron can be brought into initially empty dot, in contrast to depletion mode dots based on expelling of electrons from multi-electron dots by gates. The quantum computer architectures based on depletion dots are confronted by several challenges making scalability difficult. These challenges can be successfully met by the approach based on ehnancement mode, capable of producing square array of dots with versatile functionalities. These functionalities allow transportation of qubits, including teleportation, and error correction based on straightforward one- and two-qubit operations. We describe physical properties and demonstrate experimental characteristics of enhancement quantum dots and single-electron transistors based on InAs/GaSb composite quantum wells. We discuss the materials aspects of quantum dot quantum compu...

  9. The Notting Dale Urban Studies Centre

    Science.gov (United States)

    Webb, Chris; Lynas, Sue

    1976-01-01

    Founded in 1974, the Centre is one of the most intensively used resource centres in the United Kingdom. Adults and students from elementary to college level use its facilities to learn about the urban environment. (BD)

  10. Fuzzy dot ideals and fuzzy dot H-ideals of BCH-algebras

    Institute of Scientific and Technical Information of China (English)

    PENG Jia-yin

    2008-01-01

    The notions of fuzzy dot ideals and fuzzy dot H-ideals in BCH-algebras are intro duced,several appropriate examples are provided,and their some properties are investigated.The relations among fuzzy ideal,fuzzy H-ideal,fuzzy dot ideal and fuzzy dot H-ideals in BCH algebras are discussed,several equivalent depictions of fuzzy dot ideal are obtained. How to deal with the homomorphic image and inverse image of fuzzy dot ideals (fuzzy dot H-ideals) are studied. The relations between a fuzzy dot ideal (fuzzy dot H-ideal) in BCH-algebras and a fuzzy dot ideal (fuzzy dot H-ideal) in the product algebra of BCH-algebras are given.

  11. Communicating astronomy by the Unizul Science Centre

    Science.gov (United States)

    Beesham, A.; Beesham, N.

    2015-03-01

    The University of Zululand, situated along the east coast of KwaZulu-Natal, has a thriving Science Centre (USC) situated in the developing port city of Richards Bay. Over 30 000 learners visit the centre annually, and it consists of an exhibition area, an auditorium, lecture areas and offices. The shows consist of interactive games, science shows, competitions, quizzes and matriculation workshops. Outreach activities take place through a mobile science centre for schools and communities that cannot visit the centre.

  12. Teaching and Learning Centres: Towards Maturation

    Science.gov (United States)

    Challis, Di; Holt, Dale; Palmer, Stuart

    2009-01-01

    Approximately 70% of Australian Teaching and Learning Centres have been restructured and/or have undergone leadership changes in the last three years. The volatility of this environment reflects the number of significant challenges faced by Teaching and Learning Centres. In determining what makes Centres successful, the issues that are likely to…

  13. Fossil Dot Com

    DEFF Research Database (Denmark)

    2011-01-01

    technological examples from his background as director of the innovation centre at DONG Energy, Charles Nielsen will discuss the impact of upcoming changes to the backbone of industry: the energy supply. DONG Energy has an ambitious strategy of changing the energy supply from 15% to 85% renewable energy before...... 2040. Embodiment of the corporate strategy into designs including urban design, bio refineries, offshore wind, sun and electric vehicles will serve as a platform for describing design challenges of the future - A future where society at large becomes the most important stakeholder demanding sustenance....... Management gurus have taught us for the last 20 years that in the end we all are delivering products and services to end users. This may still hold true; however, we now need to learn that we all are nothing but subsidiary companies of the nature....

  14. InAs/GaAs submonolayer quantum dot superluminescent diode emitting around 970 nm

    Institute of Scientific and Technical Information of China (English)

    Li Xin-Kun; Liang De-Chun; Jin Peng; An Qi; Wei Heng; Wu Jian; Wang Zhan-Guo

    2012-01-01

    According to the InAs/GaAs submonolayer quantum dot active region,we demonstrate a bent-waveguide superlnminescent diode emitting at a wavelength of around 970 nm.At a pulsed injection current of 0.5 A,the device exhibits an output power of 24 mW and an emission spectrum centred at 971 nm with a full width at half maximum of 16 nm.

  15. The nonlinear optical rectification coefficient of quantum dots and rings with a repulsive scattering center

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Wenfang, E-mail: xiewf@gzhu.edu.cn

    2013-11-15

    By using the matrix diagonalization method within the effective-mass approximation, we have investigated the second-order nonlinear optical rectification coefficient associated with intersubband transitions in quantum dots and rings which include a repulsive scattering centre and are subjected to a perpendicular magnetic field. Based on the computed energies and wave functions, we have studied the effects of impurity and magnetic field in quantum dots and rings on this coefficient. The results show that the nonlinear optical properties of quantum dots and rings are strongly affected by the external magnetic field, the quantum size and the impurity. Also we find that the second-order nonlinear optical rectification coefficient of quantum rings shows the Aharonov–Bohm oscillation as the external magnetic field is increased. -- Highlights: • The nonlinear ORC in quantum dots and rings which include a repulsive scattering centre is investigated. • The nonlinear ORC in quantum rings shows the Aharonov–Bohm oscillation as the magnetic field is increased. • The nonlinear ORC shifts to higher energy and increases when the impurity effect is considered.

  16. Engineering colloidal quantum dot solids within and beyond the mobility-invariant regime

    KAUST Repository

    Zhitomirsky, David

    2014-05-06

    © 2014 Macmillan Publishers Limited. Colloidal quantum dots are attractive materials for efficient, low-cost and facile implementation of solution-processed optoelectronic devices. Despite impressive mobilities (1-30 cm2V-1 s-1) reported for new classes of quantum dot solids, it is-surprisingly-the much lower-mobility (10-3-10-2 cm2V-1 s-1) solids that have produced the best photovoltaic performance. Here we show that it is not mobility, but instead the average spacing among recombination centres that governs the diffusion length of charges in today\\'s quantum dot solids. In this regime, colloidal quantum dot films do not benefit from further improvements in charge carrier mobility. We develop a device model that accurately predicts the thickness dependence and diffusion length dependence of devices. Direct diffusion length measurements suggest the solid-state ligand exchange procedure as a potential origin of the detrimental recombination centres. We then present a novel avenue for in-solution passivation with tightly bound chlorothiols that retain passivation from solution to film, achieving an 8.5% power conversion efficiency.

  17. Colour centres in barium hexaaluminate (phase I)

    International Nuclear Information System (INIS)

    Colour centres produced by X-ray irradiation of barium hexaaluminate (phase I) with β-alumina structure are studied by electron paramagnetic resonance, optical absorption, and thermally stimulated luminescence. It is shown that in addition to the F+ centres characteristic of β-alumina phases, this compound presents other colour centres such as F, O-, and possibly V-type centres. The stability of these defects is investigated by means of thermal bleaching experiments and thermally stimulated luminescence. An alternative model to the generally accepted one is proposed, for the F+ centres, together with a mechanism of defect formation. (author)

  18. Sensing data centres for energy efficiency.

    Science.gov (United States)

    Liu, Jie; Terzis, Andreas

    2012-01-13

    Data centres are large energy consumers today, and their consumption is expected to increase further, driven by the growth in cloud services. The large monetary cost and the environmental impact of this consumption have motivated operators to optimize data centre management. We argue that one of the underlying reasons for the low-energy utilization is the lack of visibility into a data centre's highly dynamic operating conditions. Wireless sensor networks promise to remove this veil of uncertainty by delivering large volumes of data collected at high spatial and temporal fidelities. The paper summarizes data centre operations in order to describe the parameters that a data centre sensing network should collect and motivate the challenges that such a network faces. We present technical approaches for the problems of data collection and management and close with an overview of a data centre genome, an end-to-end data centre sensing system. PMID:22124086

  19. Discussion on 'Centres of excellence' in Africa

    International Nuclear Information System (INIS)

    In Africa, Centres of Excellence should be oriented to build up scientific and technological capacity in the four topics of international Monitoring System related technologies, namely, seismic monitoring, hydro acoustic monitoring, infrasound monitoring and radionuclides monitoring. Training programs on these topics should be a major objective. A network of such centres should be established in a number of African countries. Centres should be equipped with means and materials for on-line course dispatch to interested training centres or research institutions. African centres should develop strong relationship among themselves through information and data exchange and sharing, harmonization of training programs. National data centres may be established as a component of the African Centre of Excellence. States Signatories may authorize the establishment of a specific fund to support the activities of the African center

  20. Optical Fiber Sensing Using Quantum Dots

    OpenAIRE

    Faramarz Farahi; José Luís Santos; Tito Trindade; Manuel António Martins; Pedro Jorge

    2007-01-01

    Recent advances in the application of semiconductor nanocrystals, or quantum dots, as biochemical sensors are reviewed. Quantum dots have unique optical properties that make them promising alternatives to traditional dyes in many luminescence based bioanalytical techniques. An overview of the more relevant progresses in the application of quantum dots as biochemical probes is addressed. Special focus will be given to configurations where the sensing dots are incorporated in sol...

  1. Core Competencies Of A Call Centre AgentCore Competencies Of A Call Centre Agent

    OpenAIRE

    Christine White; Vera Roos

    2005-01-01

    Call centre agents are becoming increasingly important in the call centre context. They act as a contact point between the customer and the company. Call centre agents should have certain competencies to perform their duties sufficiently. Identifying competencies, required to be effective agents, will ease the task of training and recruitment. Due to the interrelatedness of the call centre agent, the management of a call centre and customers, all relevant role players’ perceptions were taken ...

  2. The new AMS control centre

    CERN Multimedia

    Anaïs Schaeffer

    2011-01-01

    Construction work for the future AMS control room began in November 2010 and should be finished this June. The new building, which will have been completed in record time thanks to the professionalism of the project team, will soon be ready to receive the initial data from the AMS experiment.     Luigi Scibile and Michael Poehler, from the GS department, at the AMS control centre construction site.   The Alpha Magnetic Spectrometer (AMS) is due to wing its way towards the International Space Station (ISS) on board the shuttle Discovery in April. Mainly intended for research on antimatter and dark matter, the data collected by AMS will be sent to Houston in the United States and then directly to CERN’s new Building 946. Construction work for the AMS control centre building on the Route Gentner at CERN’s Prévessin site started in November 2010 and must be completed in time to receive the first data from the spectrometer in June. “It normall...

  3. Perceptual centres in speech - an acoustic analysis

    Science.gov (United States)

    Scott, Sophie Kerttu

    Perceptual centres, or P-centres, represent the perceptual moments of occurrence of acoustic signals - the 'beat' of a sound. P-centres underlie the perception and production of rhythm in perceptually regular speech sequences. P-centres have been modelled both in speech and non speech (music) domains. The three aims of this thesis were toatest out current P-centre models to determine which best accounted for the experimental data bto identify a candidate parameter to map P-centres onto (a local approach) as opposed to the previous global models which rely upon the whole signal to determine the P-centre the final aim was to develop a model of P-centre location which could be applied to speech and non speech signals. The first aim was investigated by a series of experiments in which a) speech from different speakers was investigated to determine whether different models could account for variation between speakers b) whether rendering the amplitude time plot of a speech signal affects the P-centre of the signal c) whether increasing the amplitude at the offset of a speech signal alters P-centres in the production and perception of speech. The second aim was carried out by a) manipulating the rise time of different speech signals to determine whether the P-centre was affected, and whether the type of speech sound ramped affected the P-centre shift b) manipulating the rise time and decay time of a synthetic vowel to determine whether the onset alteration was had more affect on P-centre than the offset manipulation c) and whether the duration of a vowel affected the P-centre, if other attributes (amplitude, spectral contents) were held constant. The third aim - modelling P-centres - was based on these results. The Frequency dependent Amplitude Increase Model of P-centre location (FAIM) was developed using a modelling protocol, the APU GammaTone Filterbank and the speech from different speakers. The P-centres of the stimuli corpus were highly predicted by attributes of

  4. Quantum dot field effect transistors

    Directory of Open Access Journals (Sweden)

    Frederik Hetsch

    2013-09-01

    Full Text Available Solution processed colloidal semiconductor quantum dots offer a high potential for decreasing costs and expanding versatility of many electronic and optoelectronic devices. Initially used as a research tool to study charge carrier mobilities in closely packed quantum dot thin films, field effect transistors with quantum dots as the active layer have recently experienced a breakthrough in performance (achievement of mobilities higher than 30 cm2 V−1 s−1 as a result of a proper choice of surface ligands and/or improved chemical treatment of the nanoparticle films during device processing. Here we review these innovative developments and the continuing work that may soon lead to commercial grade electronic components.

  5. Beer's law in semiconductor quantum dots

    CERN Document Server

    Adamashvili, G T

    2010-01-01

    The propagation of a coherent optical linear wave in an ensemble of semiconductor quantum dots is considered. It is shown that a distribution of transition dipole moments of the quantum dots changes significantly the polarization and Beer's absorption length of the ensemble of quantum dots. Explicit analytical expressions for these quantities are presented.

  6. Quantum-dot emitters in photonic nanostructures

    DEFF Research Database (Denmark)

    Hvam, Jørn Märcher; Stobbe, Søren; Lodahl, Peter

    2010-01-01

    The spontaneous emission from self-assembled semiconductor quantum dots is strongly influenced by the environment in which they are placed. This can be used to determine fundamental optical properties of the quantum dots as well as to manipulate and control the quantum-dot emission itself....

  7. Chaos and Interactions in Quantum Dots

    OpenAIRE

    Alhassid, Y.

    2001-01-01

    Quantum dots are small conducting devices containing up to several thousand electrons. We focus here on closed dots whose single-electron dynamics are mostly chaotic. The mesoscopic fluctuations of the conduction properties of such dots reveal the effects of one-body chaos, quantum coherence and electron-electron interactions.

  8. A colloidal quantum dot spectrometer

    Science.gov (United States)

    Bao, Jie; Bawendi, Moungi G.

    2015-07-01

    Spectroscopy is carried out in almost every field of science, whenever light interacts with matter. Although sophisticated instruments with impressive performance characteristics are available, much effort continues to be invested in the development of miniaturized, cheap and easy-to-use systems. Current microspectrometer designs mostly use interference filters and interferometric optics that limit their photon efficiency, resolution and spectral range. Here we show that many of these limitations can be overcome by replacing interferometric optics with a two-dimensional absorptive filter array composed of colloidal quantum dots. Instead of measuring different bands of a spectrum individually after introducing temporal or spatial separations with gratings or interference-based narrowband filters, a colloidal quantum dot spectrometer measures a light spectrum based on the wavelength multiplexing principle: multiple spectral bands are encoded and detected simultaneously with one filter and one detector, respectively, with the array format allowing the process to be efficiently repeated many times using different filters with different encoding so that sufficient information is obtained to enable computational reconstruction of the target spectrum. We illustrate the performance of such a quantum dot microspectrometer, made from 195 different types of quantum dots with absorption features that cover a spectral range of 300 nanometres, by measuring shifts in spectral peak positions as small as one nanometre. Given this performance, demonstrable avenues for further improvement, the ease with which quantum dots can be processed and integrated, and their numerous finely tuneable bandgaps that cover a broad spectral range, we expect that quantum dot microspectrometers will be useful in applications where minimizing size, weight, cost and complexity of the spectrometer are critical.

  9. Centre for nuclear engineering University of Toronto annual report 1984

    International Nuclear Information System (INIS)

    The annual report of the Centre for Nuclear Engineering, University of Toronto covers the following subjects: message from the Dean; Chairman's message; origins of the centre; formation of the centre; new nuclear appointments; and activities of the centre, 1984

  10. Spin storage in quantum dot ensembles and single quantum dots

    International Nuclear Information System (INIS)

    This thesis deals with the investigation of spin relaxation of electrons and holes in small ensembles of self-assembled quantum dots using optical techniques. Furthermore, a method to detect the spin orientation in a single quantum dot was developed in the framework of this thesis. A spin storage device was used to optically generate oriented electron spins in small frequency selected quantum dot ensembles using circularly polarized optical excitation. The spin orientation can be determined by the polarization of the time delayed electroluminescence signal generated by the device after a continuously variable storage time. The degree of spin polarized initialization was found to be limited to 0.6 at high magnetic fields, where anisotropic effects are compensated. The spin relaxation was directly measured as a function of magnetic field, lattice temperature and s-shell transition energy of the quantum dot by varying the spin storage time up to 30 ms. Very long spin lifetimes are obtained with a lower limit of T1=20 ms at B=4 T and T=1 K. A strong magnetic field dependence T1∝B-5 has been observed for low temperatures of T=1 K which weakens as the temperature is increased. In addition, the temperature dependence has been determined with T1∝T-1. The characteristic dependencies on magnetic field and temperature lead to the identification of the spin relaxation mechanism, which is governed by spin-orbit coupling and mediated by single phonon scattering. This finding is qualitatively supported by the energy dependent measurements. The investigations were extended to a modified device design that enabled studying the spin relaxation dynamics of heavy holes in self-assembled quantum dots. The measurements show a polarization memory effect for holes with up to 0.1 degree of polarization. Furthermore, investigations of the time dynamics of the hole spin relaxation reveal surprisingly long lifetimes T1h in the microsecond range, therefore, comparable with electron spin

  11. Spin storage in quantum dot ensembles and single quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Heiss, Dominik

    2009-10-15

    This thesis deals with the investigation of spin relaxation of electrons and holes in small ensembles of self-assembled quantum dots using optical techniques. Furthermore, a method to detect the spin orientation in a single quantum dot was developed in the framework of this thesis. A spin storage device was used to optically generate oriented electron spins in small frequency selected quantum dot ensembles using circularly polarized optical excitation. The spin orientation can be determined by the polarization of the time delayed electroluminescence signal generated by the device after a continuously variable storage time. The degree of spin polarized initialization was found to be limited to 0.6 at high magnetic fields, where anisotropic effects are compensated. The spin relaxation was directly measured as a function of magnetic field, lattice temperature and s-shell transition energy of the quantum dot by varying the spin storage time up to 30 ms. Very long spin lifetimes are obtained with a lower limit of T{sub 1}=20 ms at B=4 T and T=1 K. A strong magnetic field dependence T{sub 1}{proportional_to}B{sup -5} has been observed for low temperatures of T=1 K which weakens as the temperature is increased. In addition, the temperature dependence has been determined with T{sub 1}{proportional_to}T{sup -1}. The characteristic dependencies on magnetic field and temperature lead to the identification of the spin relaxation mechanism, which is governed by spin-orbit coupling and mediated by single phonon scattering. This finding is qualitatively supported by the energy dependent measurements. The investigations were extended to a modified device design that enabled studying the spin relaxation dynamics of heavy holes in self-assembled quantum dots. The measurements show a polarization memory effect for holes with up to 0.1 degree of polarization. Furthermore, investigations of the time dynamics of the hole spin relaxation reveal surprisingly long lifetimes T{sub 1}{sup h

  12. Powering the Future Data Centre

    DEFF Research Database (Denmark)

    Zhang, Zhe

    2010-01-01

    . Duty cycle control reduces the circulating current due to the wide input voltage range. With particular transformer windings connection strategy, the proposed boost-type dual input bidirectional converter can draw power from two different dc sources with lower voltage and deliver it to the higher......The extended run Uninterruptible Power Supply system (UPSs) which powered by fuel cells and supercapcitors, is a promising solution for future data centre to obtain environmentfriendly energy efficient and cost effective. There are many challenges in power electronic interface circuits, because of...... the characteristics of these two power sources: long warm-up stage and low dynamics for fuel cell, and variable terminal voltage for supercapacitors. The motivation for this project was to find ways which can overcome those limitations to integrate fuel cells and supercapcitors to the system with high...

  13. Development and Functions of Retail Centres in Zadar

    OpenAIRE

    Martina Jakovčić; Ivica Rendulić

    2008-01-01

    The paper deals with the development of retail centres in Zadar. Types of retail centres are classified on the basis of the type of business outlets and functions. Four main types of retail centres are: shopping centres, hypermarkets, specialized hypermarkets and shopping centres – hypermarkets. Typology based on the location of centres is also developed. Functions of retail centres are analyzed based on the results gathered by a survey conducted in two retail centres, namely City Galleria – ...

  14. Luminescent Surface Quaternized Carbon Dots

    KAUST Repository

    Bourlinos, Athanasios B.

    2012-01-10

    Thermal oxidation of a salt precursor made from the acid base combination of tris(hydroxymethyl)aminomethane and betaine hydrochloride results in light-emitting surface quaternized carbon dots that are water-dispersible, display anion exchange properties, and exhibit uniform size/surface charge. © 2011 American Chemical Society.

  15. On triaxial ellipsoidal quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Voon, L C Lew Yan; Willatzen, M [Mads Clausen Institute, University of Southern Denmark, Grundtvigs Alle 150, DK-6400 Soenderborg (Denmark)

    2004-02-25

    The bound-state problem for triaxial ellipsoidal infinite-barrier quantum dots has been solved. It is exactly solvable in terms of ellipsoidal coordinates and the eigenmodes are written in terms of Lame wavefunctions. The need for all eight types of functions is shown. This presents a generalization over previous work on spheres and spheroids. Splitting of degeneracy and level crossing are obtained.

  16. DOT strategies versus orbiter strategies

    NARCIS (Netherlands)

    Rutten, R.J.

    2001-01-01

    The Dutch Open Telescope is a high-resolution solar imager coming on-line at La Palma. The definition of the DOT science niche, strategies, and requirements resemble Solar Orbiter considerations and deliberations. I discuss the latter in the light of the former, and claim that multi-line observation

  17. Quantum dot photonic crystal lasers

    OpenAIRE

    Yoshie, T.; Shchekin, O. B.; Chen, H.; Deppe, D. G.; Scherer, A.

    2002-01-01

    Coupled cavity designs on two-dimensional square lattice photonic crystal slabs were used to demonstrate optically pumped indium arsenide quantum dot photonic crystal lasers at room temperature. Threshold pump powers of 120 and 370 μW were observed for coupled cavities including two and four defect cavities defined in optimised photonic crystals.

  18. Hyperdense dots mimicking microcalcifications : Mammographic findings

    International Nuclear Information System (INIS)

    To differentiate fine hyperdense dots mimicking microcalcifications from true microcalcifications on mammography. Mammograms showing hyperdense dots in ten patients (mean age, 59 years) were evaluated. Two radiologists were asked to differentiate with the naked eye the hyperdense dots seen on ten mammograms and proven microcalcifications seen on ten mammograms. Densitometry was also performed for all lesions and the contrast index was calculated. The shape and distribution of the hyperdense dots were evaluated and enquires were made regarding any history of breast disease and corresponding treatment. Biopsies were performed for two patients with hyperdense dots. Two radiologists made correct diagnoses in 19/20 cases(95%). The contrast index was 0.10-0.88 (mean 0.58) for hyperdense dots and 0.02-0.45 (mean 0.17) for true microcalcifications. The hyperdense dots were finer and homogeneously rounder than the microcalcifications. Distribution of the hyperdense dots was more superficial in subcutaneous fat (seven cases) and subareolar area (six cases). All ten patients with hyperdense dots had history of mastitis and abscesses and had been treated by open drainage (six cases) and/or folk remedy (four cases). In eight patients, herb patches had been attached. Biopsies of hyperdense dots did not show any microcalcification or evidence of malignancy. These hyperdense dots were seen mainly in older patients. Their characteristic density, shape, distribution and clinical history makes differential diagnosis from true microcalcifications easy and could reduce unnecessary diagnostic procedures such as surgical biopsy

  19. Hyperdense dots mimicking microcalcifications : Mammographic findings

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Nam Hyeon; Park, Jeong Mi; Goo, Hyun Woo; Bang, Sun Woo [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

    1996-12-01

    To differentiate fine hyperdense dots mimicking microcalcifications from true microcalcifications on mammography. Mammograms showing hyperdense dots in ten patients (mean age, 59 years) were evaluated. Two radiologists were asked to differentiate with the naked eye the hyperdense dots seen on ten mammograms and proven microcalcifications seen on ten mammograms. Densitometry was also performed for all lesions and the contrast index was calculated. The shape and distribution of the hyperdense dots were evaluated and enquires were made regarding any history of breast disease and corresponding treatment. Biopsies were performed for two patients with hyperdense dots. Two radiologists made correct diagnoses in 19/20 cases(95%). The contrast index was 0.10-0.88 (mean 0.58) for hyperdense dots and 0.02-0.45 (mean 0.17) for true microcalcifications. The hyperdense dots were finer and homogeneously rounder than the microcalcifications. Distribution of the hyperdense dots was more superficial in subcutaneous fat (seven cases) and subareolar area (six cases). All ten patients with hyperdense dots had history of mastitis and abscesses and had been treated by open drainage (six cases) and/or folk remedy (four cases). In eight patients, herb patches had been attached. Biopsies of hyperdense dots did not show any microcalcification or evidence of malignancy. These hyperdense dots were seen mainly in older patients. Their characteristic density, shape, distribution and clinical history makes differential diagnosis from true microcalcifications easy and could reduce unnecessary diagnostic procedures such as surgical biopsy.

  20. Systematic safety evaluation on photoluminescent carbon dots

    Science.gov (United States)

    Wang, Kan; Gao, Zhongcai; Gao, Guo; Wo, Yan; Wang, Yuxia; Shen, Guangxia; Cui, Daxiang

    2013-03-01

    Photoluminescent carbon dots (C-dots) were prepared using the improved nitric acid oxidation method. The C-dots were characterized by tapping-mode atomic force microscopy, and UV-vis absorption spectroscopy. The C-dots were subjected to systematic safety evaluation via acute toxicity, subacute toxicity, and genotoxicity experiments (including mouse bone marrow micronuclear test and Salmonella typhimurium mutagenicity test). The results showed that the C-dots were successfully prepared with good stability, high dispersibility, and water solubility. At all studied C-dot dosages, no significant toxic effect, i.e., no abnormality or lesion, was observed in the organs of the animals. Therefore, the C-dots are non-toxic to mice under any dose and have potential use in fluorescence imaging in vivo, tumor cell tracking, and others.

  1. Smart work centres in rural areas

    DEFF Research Database (Denmark)

    Lorentzen, Anne Birte

    This paper discusses the establishment of telework centres as an element in local development strategies in rural areas, with a particular view to two new telework centres in region North Denmark. The paper argues that telework centres do not represent an easy solution to problems of local develo...... development and environmental sustainability, and further, that technology may not even be the most important feature needed to make them function as such....

  2. Elm Farm Organic Research Centre December 2006

    OpenAIRE

    Sanders, Richard; Whiltley, Andrew; Haigh, Zoe; Clarke, Sarah; Hitchings, Roger; O'Brien, Josie

    2006-01-01

    The Organic Research Centre. Elm Farm Research Centre Bulletin with Technical Updates from The Organic Advisory Service is a regular publication from The Organic Research Centre. The current issue covers: Report from 2006 Cirencester Conference; Quest for more home produced organic food; in a world where bread matters; Improving wheat with plenty of parents; Unlocking the secrets of the ancient (cereal varieties); Brain food- a good read; Not to late to protect the future: The organic...

  3. Introducing the Centre for Applied Archaeology

    OpenAIRE

    Dominic Perring

    2008-01-01

    The Centre for Applied Archaeology (CAA) is a new research centre within the Institute of Archaeology, established in 2006 to develop the work of the Institute’s Field Archaeology Unit, Archaeology South-East (ASE), through the creation of a productive research environment and the building of links with academic staff members of the Institute. In this article the Director of CAA defines “applied archaeology” and describes the aims and work of the Centre.

  4. Business plan – Tennis centre modernization

    OpenAIRE

    Moravec, Martin

    2012-01-01

    The goal of this master's thesis "Business plan -- Tennis centre modernization" - is creating and writing the business plan for the reconstruction of the existing tennis centre. The theoretical part describes characteristics of small and medium sized enterprises, their meaning. Describes the necessary parts of the business plan, its possible structure. The paper involves the knowledge gained into the concrete case of the tennis centre. Describes its nowadays conditions and possible solutions....

  5. Bangalore looks to new interdisciplinary science centre

    Science.gov (United States)

    Ramachandran, Ramaseshan

    2008-09-01

    A new centre to boost interdisciplinary research in India is being established in Bangalore - India's IT and software capital. The International Centre for Theoretical Sciences (ICTS) will be led by Spenta Wadia, a theoretical physicist from the Tata Institute of Fundamental Research (TIFR) in Mumbai, which is setting up the new centre. He expects construction of the ICTS, the first of its kind in India, to start by November 2009.

  6. ENERGY EFFICIENT REFURBISHMENT IN AUSTRALIAN SHOPPING CENTRES

    OpenAIRE

    Reed, R. G.; S.J. Wilkinson

    2006-01-01

    Retail shopping centres are a dynamic business in Australia, annually generating $51 billion in sales, employing nearly half a million employees and having an asset value of AUD$69 billion. There are 1,338 retail shopping centres in Australia ranging from large regional centres of more than 100,000 square metres of retail space down to smaller, supermarket based centres of around 5,000 square metres. Importantly they account for 28% of the retail space and generate 41% of retail sales (PCA, 2...

  7. Laparoscopic adrenalectomy: Single centre experience.

    LENUS (Irish Health Repository)

    O'Farrell, N J

    2012-02-01

    BACKGROUND: Laparoscopic adrenalectomy is an attractive alternative to the traditional open approach in the surgical excision of an adrenal gland. It has replaced open adrenalectomy in our institution and we review our experience to date. METHODS: All cases of laparoscopic adrenalectomies in our hospital over eight years (from 2001 to May 2009) were retrospectively reviewed. Patient demographics, diagnosis, length of hospital stay, histology and all operative and post-operative details were evaluated. RESULTS: Fifty-five laparoscopic adrenalectomies (LA) were performed on 51 patients over eight years. The mean age was 48 years (Range 16-86 years) with the male: female ratio 1:2. Twenty-three cases had a right adrenalectomy, 24 had a left adrenalectomy and the remaining four patients had bilateral adrenalectomies. 91% were successfully completed laparoscopically with five converted to an open approach. Adenomas (functional and non functional) were the leading indication for LA, followed by phaeochromocytomas. Other indications for LA included Cushing\\'s disease, adrenal malignancies and rarer pathologies. There was one mortality from necrotising pancreatitis following a left adrenalectomy for severe Cushing\\'s disease, with subsequent death 10 days later. CONCLUSION: Laparoscopic adrenalectomy is effective for the treatment of adrenal tumours, fulfilling the criteria for the ideal minimally invasive procedure. It has replaced the traditional open approach in our centre and is a safe and effective alternative. However, in the case of severe Cushing\\'s disease, laparoscopic adrenalectomy has the potential for significant adverse outcomes and mortality.

  8. Oil Trading Centre to Reopen in Shanghai

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ Chinese oil companies will likely resume activities at the oil trading centre in Shanghai this year, a move to further liberalize the once tightly controlled oil market. The centre will trade forward contracts for refined oil products,including gasoline, diesel oil, kerosene and fuel oil, industrial sources said.

  9. Neighbourhood Centres – Organisation, Management and Finance

    DEFF Research Database (Denmark)

    Larsen, Jacob Norvig

    From the late 1990s neighbourhood centres were brought to the fore of public urban regen-eration policy, because they were seen as a means to accelerate the formation of social capital in deprived urban neighbourhoods. A number of such local community centres were established with substantial pub...

  10. Safety strategy at the RACSO nuclear centre

    International Nuclear Information System (INIS)

    The paper describes in general terms the physical security situation at the RACSO nuclear centre and the principal measures adopted to deal with the risk of subversive activities. Since 1980, Peru had to face terrorist problems; therefore, measures were adopted at RACSO to deal with this risk. As a result, it has been possible to keep the nuclear centre free from terrorist attacks. (author)

  11. Modern Equipment at VATESI Emergency Response Centre

    International Nuclear Information System (INIS)

    The Emergency Response Centre of the State Nuclear Power Safety Inspectorate equipped with state-of-the-art instruments started operating. The Centre is fulfilling the functions prescribed by the Lithuanian legislation in case of an accident at the Ignalina NPP, as well as nuclear or radiation accidents in the neighboring countries in accordance with the Convention on Early Notification

  12. Communications strategy for the Chernobyl Centre

    International Nuclear Information System (INIS)

    This Communications Strategy was developed for the International Chernobyl Centre (ICC) as part of a joint UK/Ukraine project, sponsored by the Department of Trade and Industry and NNC Limited. The Plan was developed during four weeks of workshop discussions in the UK between staff from the centre and experienced PR Professionals from NNC Limited. The requirements for a sustained communications activity at the ICC go much further than simply enhancing or promoting the Centre's scientific and technical activities. Raising sufficient awareness of the Centre among potential funding agents and commercial partners is critical to its future development as a major centre for international co-operation and research. It is only through establishing and developing effective communications that the Centre will become well enough known and understood both within the Ukraine, and internationally, to secure its long term future. However, as the workshop programme unfolded, it also became clear that communications was in itself a legitimate and necessary function of the Centre, and part of the foundations of its existence. The Centre has a fundamental role as an 'information exchange', collecting and communicating information from within the Ukraine to the rest of the world, and interpreting world interest and attitudes to the Ukraine Government and nuclear industry. As such compliments the efforts of individual power plant and corporate PR functions within the Ukraine nuclear energy sector

  13. Next steps towards a Climate Innovation Centre in Ghana. Discussion Paper

    International Nuclear Information System (INIS)

    A climate innovation centre is an institution aimed at enabling development through catalysing climate technology research, development, market creation and policy. This discussion paper discusses the possibilities, considerations and next steps for a Climate Innovation Centre (CIC) in Ghana based on new insights within the government of Ghana, a mapping of climate innovation in Ghana, new developments in the international climate negotiations and other multilateral processes, and analysis conducted by ECN. The conclusion is that a Climate Innovation Centre can fill significant gaps in climate resilient development in Ghana. It seems important that a Ghana CIC does not become yet another institution that focuses on basic research in the area of climate change. Rather, it should connect the dots of the Ghanaian climate innovation system and act as a knowledge facilitator, also for the private sector. Various models of climate innovation centres exist. Before choices are made for a model or a combination of models for Ghana, it is recommended to allow for a broad stakeholder process. The World Bank's infoDev programme could be a model for such a process. Such stakeholder engagement should be aligned with other policymaking processes on adaptation and low-carbon development, as well as related policy arenas, such as agriculture, transport, waste and energy.

  14. CMS Centres Worldwide a New Collaborative Infrastructure

    CERN Document Server

    Taylor, Lucas

    2009-01-01

    The CMS Experiment at the LHC is establishing a global network of inter-connected "CMS Centres" for controls, operations and monitoring. These support: (1) CMS data quality monitoring, detector calibrations, and analysis; and (2) computing operations for the processing, storage and distribution of CMS data. We describe the infrastructure, computing, software, and communications systems required to create an effective and affordable CMS Centre. We present our highly successful operations experiences with the major CMS Centres at CERN, Fermilab, and DESY during the LHC first beam data-taking and cosmic ray commissioning work. The status of the various centres already operating or under construction in Asia, Europe, Russia, South America, and the USA is also described. We emphasise the collaborative communications aspects. For example, virtual co-location of experts in CMS Centres Worldwide is achieved using high-quality permanently-running "telepresence" video links. Generic Web-based tools have been developed ...

  15. The role of the sexual assault centre.

    LENUS (Irish Health Repository)

    Eogan, Maeve

    2013-02-01

    Sexual Assault Centres provide multidisciplinary care for men and women who have experienced sexual crime. These centres enable provision of medical, forensic, psychological support and follow-up care, even if patients chose not to report the incident to the police service. Sexual Support Centres need to provide a ring-fenced, forensically clean environment. They need to be appropriately staffed and available 24 hours a day, 7 days a week to allow prompt provision of medical and supportive care and collection of forensic evidence. Sexual Assault Centres work best within the context of a core agreed model of care, which includes defined multi-agency guidelines and care pathways, close links with forensic science and police services, and designated and sustainable funding arrangements. Additionally, Sexual Assault Centres also participate in patient, staff and community education and risk reduction. Furthermore, they contribute to the development, evaluation and implementation of national strategies on domestic, sexual and gender-based violence.

  16. Dot-in-Well Quantum-Dot Infrared Photodetectors

    Science.gov (United States)

    Gunapala, Sarath; Bandara, Sumith; Ting, David; Hill, cory; Liu, John; Mumolo, Jason; Chang, Yia Chung

    2008-01-01

    Dot-in-well (DWELL) quantum-dot infrared photodetectors (QDIPs) [DWELL-QDIPs] are subjects of research as potentially superior alternatives to prior QDIPs. Heretofore, there has not existed a reliable method for fabricating quantum dots (QDs) having precise, repeatable dimensions. This lack has constituted an obstacle to the development of uniform, high-performance, wavelength-tailorable QDIPs and of focal-plane arrays (FPAs) of such QDIPs. However, techniques for fabricating quantum-well infrared photodetectors (QWIPs) having multiple-quantum- well (MQW) structures are now well established. In the present research on DWELL-QDIPs, the arts of fabrication of QDs and QWIPs are combined with a view toward overcoming the deficiencies of prior QDIPs. The longer-term goal is to develop focal-plane arrays of radiationhard, highly uniform arrays of QDIPs that would exhibit high performance at wavelengths from 8 to 15 m when operated at temperatures between 150 and 200 K. Increasing quantum efficiency is the key to the development of competitive QDIP-based FPAs. Quantum efficiency can be increased by increasing the density of QDs and by enhancing infrared absorption in QD-containing material. QDIPs demonstrated thus far have consisted, variously, of InAs islands on GaAs or InAs islands in InGaAs/GaAs wells. These QDIPs have exhibited low quantum efficiencies because the numbers of QD layers (and, hence, the areal densities of QDs) have been small typically five layers in each QDIP. The number of QD layers in such a device must be thus limited to prevent the aggregation of strain in the InAs/InGaAs/GaAs non-lattice- matched material system. The approach being followed in the DWELL-QDIP research is to embed In- GaAs QDs in GaAs/AlGaAs multi-quantum- well (MQW) structures (see figure). This material system can accommodate a large number of QD layers without excessive lattice-mismatch strain and the associated degradation of photodetection properties. Hence, this material

  17. Adiabatic pumping through quantum dots

    International Nuclear Information System (INIS)

    A finite charge can be pumped through a mesoscopic system in the absence of an applied bias voltage by changing periodically in time some parameters of the system. If these parameters change slowly with respect to all internal time scales of the system, pumping is adiabatic. The scope of this work is to investigate adiabatic pumping through a quantum dot, in particular the influence of Coulomb interaction between electrons in the dot on the pumped charge. On one hand we develop a formalism based on Green's functions, in order to calculate the pumped charge from the weak-tunnel-coupling regime down to the Kondo regime. We extend our calculations to a system with a superconducting contact. On the other hand we use a systematic perturbation expansion for the calculation of the pumped charge, giving us the possibility to analyze processes which contribute to charge pumping and to highlight the important role of interaction-induced level renormalization. (orig.)

  18. Quantum dots: promises and accomplishments

    Directory of Open Access Journals (Sweden)

    Dieter Bimberg

    2011-09-01

    Full Text Available Exploration of the Stranski-Krastanow growth of strained semiconductor heterostructures marked the major breakthrough for easy fabrication of defect-free quantum dots (QDs. For the first time, single QDs are facilitating the development of electrically operated emitters of single polarized or entangled photons on demand: an essential component for quantum communication systems. QDs inserted in quantum wells, stacked in planes upon each other, have led to semiconductor lasers that can operate at wavelengths that were previously impossible, or at least difficult to reach, for a given semiconductor family. These lasers show excellent temperature stability, large radiation resistance, and excellent temporal and spatial stability. In this review we discuss recent progress in the field of quantum dot devices.

  19. The Canadian Astronomy Data Centre

    Science.gov (United States)

    Ball, Nicholas M.; Schade, D.; Astronomy Data Centre, Canadian

    2011-01-01

    The Canadian Astronomy Data Centre (CADC) is the world's largest astronomical data center, holding over 0.5 Petabytes of information, and serving nearly 3000 astronomers worldwide. Its current data collections include BLAST, CFHT, CGPS, FUSE, Gemini, HST, JCMT, MACHO, MOST, and numerous other archives and services. It provides extensive data archiving, curation, and processing expertise, via projects such as MegaPipe, and enables substantial day-to-day collaboration between resident astronomers and computer specialists. It is a stable, powerful, persistent, and properly supported environment for the storage and processing of large volumes of data, a condition that is now absolutely vital for their science potential to be exploited by the community. Through initiatives such as the Common Archive Observation Model (CAOM), the Canadian Virtual Observatory (CVO), and the Canadian Advanced Network for Astronomical Research (CANFAR), the CADC is at the global forefront of advancing astronomical research through improved data services. The CAOM aims to provide homogeneous data access, and hence viable interoperability between a potentially unlimited number of different data collections, at many wavelengths. It is active in the definition of numerous emerging standards within the International Virtual Observatory, and several datasets are already available. The CANFAR project is an initiative to make cloud computing for storage and data-intensive processing available to the community. It does this via a Virtual Machine environment that is equivalent to managing a local desktop. Several groups are already processing science data. CADC is also at the forefront of advanced astronomical data analysis, driven by the science requirements of astronomers both locally and further afield. The emergence of 'Astroinformatics' promises to provide not only utility items like object classifications, but to directly enable new science by accessing previously undiscovered or intractable

  20. IDRANAP - European Centre of Excellence

    International Nuclear Information System (INIS)

    Selected by the European Commission (EC) experts out of 185 proposals from 11 countries, IDRANAP (Inter-Disciplinary Research and Applications based on Nuclear and Atomic Physics) is the only EC Centre of Excellence in nuclear physics. The project, initiated and developed by a remarkable team from our institute, researchers with a recognized international scientific level, has as main objectives: - promotion in Romania and in the region of modern applications derived from basic and applied research in nuclear and atomic physics; - disciplinary research in ecology, health, biology, science of materials; - specific nuclear and atomic physics research aimed to open new possibilities for applications; - to ensure stimulative conditions for PhD students from Romania and other EC candidate countries to improve their knowledge and experience by joining scientific activities in the region, a fact that might counteract their tendency to migrate to Western countries. The high scientific level of researchers, their access to national and international facilities as well as the link with prestigious laboratories abroad and the socio-economic demand motivated the development of the project. Among expected results, we mention: improving and spreading the scientific knowledge by publications; producing new facilities, devices and instruments; application of nuclear methods in industry, health-care and environment protection, and training of young researchers. The project consists of 18 workpackages structured in 5 distinct areas: - Determining environmental pollution; - Nuclear methods in biology and medicine; - Radionuclide metrology; - Analysis and characterization of materials; - Nuclei far from stability, decay modes, cosmic rays, and facilities.We make an up-to-date presentation of obtained results and activities performed within IDRANAP project, as well as a short overview of our institute. (author)

  1. Big Surveys, Big Data Centres

    Science.gov (United States)

    Schade, D.

    2016-06-01

    Well-designed astronomical surveys are powerful and have consistently been keystones of scientific progress. The Byurakan Surveys using a Schmidt telescope with an objective prism produced a list of about 3000 UV-excess Markarian galaxies but these objects have stimulated an enormous amount of further study and appear in over 16,000 publications. The CFHT Legacy Surveys used a wide-field imager to cover thousands of square degrees and those surveys are mentioned in over 1100 publications since 2002. Both ground and space-based astronomy have been increasing their investments in survey work. Survey instrumentation strives toward fair samples and large sky coverage and therefore strives to produce massive datasets. Thus we are faced with the "big data" problem in astronomy. Survey datasets require specialized approaches to data management. Big data places additional challenging requirements for data management. If the term "big data" is defined as data collections that are too large to move then there are profound implications for the infrastructure that supports big data science. The current model of data centres is obsolete. In the era of big data the central problem is how to create architectures that effectively manage the relationship between data collections, networks, processing capabilities, and software, given the science requirements of the projects that need to be executed. A stand alone data silo cannot support big data science. I'll describe the current efforts of the Canadian community to deal with this situation and our successes and failures. I'll talk about how we are planning in the next decade to try to create a workable and adaptable solution to support big data science.

  2. Charging graphene nanoribbon quantum dots

    OpenAIRE

    Żebrowski, D. P.; B. Szafran

    2015-01-01

    We describe charging a quantum dot induced electrostatically within a semiconducting graphene nanoribbon by electrons or holes. The applied model is based on a tight-binding approach with the electron-electron interaction introduced by a mean field local spin density approximation. The numerical approach accounts for the charge of all the $p_z$ electrons and screening of external potentials by states near the charge neutrality point. Both a homogenous ribbon and a graphene flake embedded with...

  3. FRET sensor with quantum dot

    Czech Academy of Sciences Publication Activity Database

    Datinská, Vladimíra; Klepárník, Karel; Belšánová, Barbora; Minárik, M.; Foret, František

    Veszprém: PANNON Egyetem, 2015 - (Mizsey, P.), s. 20-23 ISBN 978-963-396-072-1. [Műszaki Kémiai Napok 2015. Veszprém (HU), 21.04.2015-23.04.2015] R&D Projects: GA ČR(CZ) GA14-28254S; GA TA ČR(CZ) TA02010672 Institutional support: RVO:68081715 Keywords : FRET * quantum dot * sensor Subject RIV: CB - Analytical Chemistry, Separation

  4. FRET sensor with quantum dot

    Czech Academy of Sciences Publication Activity Database

    Datinská, Vladimíra; Klepárník, Karel; Belšánová, Barbora; Minárik, M.; Foret, František

    Veszprém : PANNON Egyetem, 2015 - (Mizsey, P.), s. 20-23 ISBN 978-963-396-072-1. [Műszaki Kémiai Napok 2015. Veszprém (HU), 21.04.2015-23.04.2015] R&D Projects: GA ČR(CZ) GA14-28254S; GA TA ČR(CZ) TA02010672 Institutional support: RVO:68081715 Keywords : FRET * quantum dot * sensor Subject RIV: CB - Analytical Chemistry, Separation

  5. Semiconductor quantum-dot lasers and amplifiers

    DEFF Research Database (Denmark)

    Hvam, Jørn Märcher; Borri, Paola; Ledentsov, N. N.;

    2002-01-01

    We have produced GaAs-based quantum-dot edge-emitting lasers operating at 1.16 mu m with record-low transparency current, high output power, and high internal quantum efficiencies. We have also realized GaAs-based quantum-dot lasers emitting at 1.3 mu m, both high-power edge emitters and low-power...... biased to positive net gain. We have further measured gain recovery times in quantum dot amplifiers that are significantly lower than in bulk and quantum-well semiconductor optical amplifiers. This is promising for future demonstration of quantum dot devices with high modulation bandwidth...... surface emitting VCSELs. We investigated the ultrafast dynamics of quantum-dot semiconductor optical amplifiers. The dephasing time at room temperature of the ground-state transition in semiconductor quantum dots is around 250 fs in an unbiased amplifier, decreasing to below 50 fs when the amplifier is...

  6. Ultrasmall colloidal PbS quantum dots

    International Nuclear Information System (INIS)

    Ultrasmall colloidal lead sulfide quantum dots can increase the open circuit voltages of quantum-dot-based solar cells because of their large energy gap. Their small size and visible or near infrared light-emitting property make them attractive to the applications of biological fluorescence labeling. Through a modified organometallic route, we can synthesize lead sulfide quantum dots as small as 1.6 nm in diameter. The low reaction temperature and the addition of a chloroalkane cosolvent decrease the reaction rate, making it possible to obtain the ultrasmall quantum dots. - Highlights: • Ultrasmall colloidal PbS quantum dots as small as 1.6 nm in diameter are synthesized. • The quantum dots emit red light with photoluminescence peak at 760 nm. • The growth temperature is as low as 50 °C. • Addition of cosolvent 1,2-dichloroethane in the reaction decreases the reaction rate

  7. Few-electron quantum dots

    International Nuclear Information System (INIS)

    We review some electron transport experiments on few-electron, vertical quantum dot devices. The measurement of current versus source-drain voltage and gate voltage is used as a spectroscopic tool to investigate the energy characteristics of interacting electrons confined to a small region in a semiconducting material. Three energy scales are distinguished: the single-particle states, which are discrete due to the confinement involved; the direct Coulomb interaction between electron charges on the dot; and the exchange interaction between electrons with parallel spins. To disentangle these energies, a magnetic field is used to reorganize the occupation of electrons over the single-particle states and to induce changes in the spin states. We discuss the interactions between small numbers of electrons (between 1 and 20) using the simplest possible models. Nevertheless, these models consistently describe a large set of experiments. Some of the observations resemble similar phenomena in atomic physics, such as shell structure and periodic table characteristics, Hund's rule, and spin singlet and triplet states. The experimental control, however, is much larger than for atoms: with one device all the artificial elements can be studied by adding electrons to the quantum dot when changing the gate voltage. (author)

  8. Photoactivation of silicon quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Lockwood, R., E-mail: rossl@ualberta.c [Department of Physics, University of Alberta, Edmonton, Alberta, T6G 2G7 (Canada); McFarlane, S. [Department of Physics, University of Alberta, Edmonton, Alberta, T6G 2G7 (Canada); Rodriguez Nunez, J.R. [Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2 (Canada); Wang, X.Y. [Department of Physics, University of Alberta, Edmonton, Alberta, T6G 2G7 (Canada); Veinot, J.G.C. [Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2 (Canada); Meldrum, A. [Department of Physics, University of Alberta, Edmonton, Alberta, T6G 2G7 (Canada)

    2011-07-15

    We show that free-standing silicon quantum dots (QDs) can be photoactivated by blue or UV optical irradiation. The luminescence intensity increases by an order of magnitude for irradiation times of several minutes under moderate optical power. The cut-off energy for photoactivation is between 2.1 and 2.4 eV, not very different from the activation energy for hydrogen dissociation from bulk silicon surfaces. We propose the mechanism for this effect is associated with silicon-hydride bond breaking and the subsequent oxidation of dangling bonds. This phenomenon could be used to 'write' luminescent quantum dots into pre-determined arrays. - Research highlights: {yields}Laser light causes increased photoluminescence intensity in silicon quantum dots. {yields} The photoactivation process is effective for wavelengths of 514 nm and shorter. {yields} Hydrogen bound to the Si-QDs is replaced by oxygen in a two-step process. {yields} Patterning is possible but limited by physical dispersion of Si-QDs.

  9. Charge State Hysteresis in Semiconductor Quantum Dots

    OpenAIRE

    Yang, C. H.; Rossi, A; Lai, N. S.; Leon, R.; Lim, W. H.; Dzurak, A.S.

    2014-01-01

    Semiconductor quantum dots provide a two-dimensional analogy for real atoms and show promise for the implementation of scalable quantum computers. Here, we investigate the charge configurations in a silicon metal-oxide-semiconductor double quantum dot tunnel coupled to a single reservoir of electrons. By operating the system in the few-electron regime, the stability diagram shows hysteretic tunnelling events that depend on the history of the dots charge occupancy. We present a model which acc...

  10. Optical Fiber Sensing Using Quantum Dots

    Directory of Open Access Journals (Sweden)

    Faramarz Farahi

    2007-12-01

    Full Text Available Recent advances in the application of semiconductor nanocrystals, or quantumdots, as biochemical sensors are reviewed. Quantum dots have unique optical properties thatmake them promising alternatives to traditional dyes in many luminescence basedbioanalytical techniques. An overview of the more relevant progresses in the application ofquantum dots as biochemical probes is addressed. Special focus will be given toconfigurations where the sensing dots are incorporated in solid membranes and immobilizedin optical fibers or planar waveguide platforms.

  11. Spintronics and Quantum Computing with Quantum Dots

    OpenAIRE

    Recher, P.; Loss, D.; Levy, J

    2000-01-01

    The creation, coherent manipulation, and measurement of spins in nanostructures open up completely new possibilities for electronics and information processing, among them quantum computing and quantum communication. We review our theoretical proposal for using electron spins in quantum dots as quantum bits. We present single- and two qubit gate mechanisms in laterally as well as vertically coupled quantum dots and discuss the possibility to couple spins in quantum dots via superexchange. We ...

  12. Resonant electron transfer between quantum dots

    OpenAIRE

    Openov, Leonid A.

    1999-01-01

    An interaction of electromagnetic field with a nanostructure composed of two quantum dots is studied theoretically. An effect of a resonant electron transfer between the localized low-lying states of quantum dots is predicted. A necessary condition for such an effect is the existence of an excited bound state whose energy lies close to the top of the barrier separating the quantum dots. This effect may be used to realize the reversible quantum logic gate NOT if the superposition of electron s...

  13. Random Feature Maps for Dot Product Kernels

    CERN Document Server

    Kar, Purushottam

    2012-01-01

    Approximating non-linear kernels using feature maps has gained a lot of interest in recent years due to applications in reducing training and testing times of SVM classifiers and other kernel based learning algorithms. We extend this line of work and present low distortion embeddings for dot product kernels into linear Euclidean spaces. We base our results on a classical result in harmonic analysis characterizing all dot product kernels and use it to define randomized feature maps into explicit low dimensional Euclidean spaces in which the native dot product provides an approximation to the dot product kernel with high confidence.

  14. Activation of silicon quantum dots for emission

    Institute of Scientific and Technical Information of China (English)

    Huang Wei-Qi; Miao Xin-Jian; Huang Zhong-Mei; Liu Shi-Rong; Qin Chao-Jian

    2012-01-01

    The emission of silicon quantum dots is weak when their surface is passivated well. Oxygen or nitrogen on the surface of silicon quantum dots can break the passivation to form localized electronic states in the band gap to generate active centers where stronger emission occurs.From this point of view,we can build up radiative matter for emission.Emissions of various wavelengths can be obtained by controlling the surface bonds of silicon quantum dots.Our experimental results demonstrate that annealing is important in the treatment of the activation,and stimulated emissions at about 600 and 700 nm take place on active silicon quantum dots.

  15. Thermoelectric energy harvesting with quantum dots

    International Nuclear Information System (INIS)

    We review recent theoretical work on thermoelectric energy harvesting in multi-terminal quantum-dot setups. We first discuss several examples of nanoscale heat engines based on Coulomb-coupled conductors. In particular, we focus on quantum dots in the Coulomb-blockade regime, chaotic cavities and resonant tunneling through quantum dots and wells. We then turn toward quantum-dot heat engines that are driven by bosonic degrees of freedom such as phonons, magnons and microwave photons. These systems provide interesting connections to spin caloritronics and circuit quantum electrodynamics. (topical review)

  16. Sensitisation of visible and NIR lanthanide emission by InPZnS quantum dots in bi-luminescent hybrids.

    Science.gov (United States)

    Molloy, Jennifer K; Lincheneau, Christophe; Karimdjy, Maria Moula; Agnese, Fabio; Mattera, Lucia; Gateau, Christelle; Reiss, Peter; Imbert, Daniel; Mazzanti, Marinella

    2016-03-25

    The synthesis of stable hybrid nanoparticles combining InPZnS@ZnSe/ZnS quantum dots (QDs) and grafted lanthanide complexes has been performed using two different approaches in organic and aqueous media. The final bi-luminescent hybrids exhibit Ln(III) (Ln = Eu and Yb) centred luminescence upon QD excitation, suggesting that an energy transfer occurs from the QD to the lanthanide. PMID:26941180

  17. Synthesis and application of luminescent single CdS quantum dot encapsulated silica nanoparticles directed for precision optical bioimaging

    OpenAIRE

    Veeranarayanan S; Poulose AC; Mohamed MS; Nagaoka Y; Iwai S.; Nakagame Y; Kashiwada S; Yoshida Y; Maekawa T; Kumar DS

    2012-01-01

    Srivani Veeranarayanan, Aby Cheruvathoor Poulose, M Sheikh Mohamed, Yutaka Nagaoka, Seiki Iwai, Yuya Nakagame, Shosaku Kashiwada, Yasuhiko Yoshida, Toru Maekawa, D Sakthi KumarBio Nano Electronics Research Centre, Graduate School of Interdisciplinary New Science, Toyo University, Kawagoe, JapanAbstract: This paper presents the synthesis of aqueous cadmium sulfide (CdS) quantum dots (QDs) and silica-encapsulated CdS QDs by reverse microemulsion method and utilized as targeted bio-optical probe...

  18. Nuclear Power Plant Temelin Technical Support Centre

    International Nuclear Information System (INIS)

    The erection of the Technical Support Centre for the Nuclear Power Plant Temelin has been a relatively sophisticated and costly issue. It was by proper use of the existing systems, as e.g. I and C, ISE and other systems, that a robust system has been created that is able to meet any requirements laid on the performance of the Technical Support Centre. The decision of the utility CEZ, a.s. that made it possible to establish the Technical Support Centre at the Nuclear Power Plant Temelin has been a right step which shows the level of safety culture within the utility. (author)

  19. Review of CERN Data Centre Infrastructure

    Science.gov (United States)

    Andrade, P.; Bell, T.; van Eldik, J.; McCance, G.; Panzer-Steindel, B.; Coelho dos Santos, M.; Traylen and, S.; Schwickerath, U.

    2012-12-01

    The CERN Data Centre is reviewing strategies for optimizing the use of the existing infrastructure and expanding to a new data centre by studying how other large sites are being operated. Over the past six months, CERN has been investigating modern and widely-used tools and procedures used for virtualisation, clouds and fabric management in order to reduce operational effort, increase agility and support unattended remote data centres. This paper gives the details on the project's motivations, current status and areas for future investigation.

  20. Red luminescence of color centres in sapphire

    International Nuclear Information System (INIS)

    Spectral and polarization studies of the IR photoluminescence of neutron-irradiated sapphire crystals are presented aimed at the clarification of the luminescence centres and the involved electronic transitions. From the temperature dependence of the photoluminescence bands the existence of a potential barrier for the transition from the highest to the lowest excited state of the axial centre was deduced and the height of the barrier was estimated. For a luminescence centre involving a pair of oxygen vacancies with three located electrons a semiquantitative configuration - coordinate diagram is constructed and discussed

  1. Review of CERN Data Centre Infrastructure

    CERN Document Server

    Andrade, P; van Eldik, J; McCance, G; Panzer-Steindel, B; Coelho dos Santos, M; Traylen, S; Schwickerath, U

    2012-01-01

    The CERN Data Centre is reviewing strategies for optimizing the use of the existing infrastructure and expanding to a new data centre by studying how other large sites are being operated. Over the past six months, CERN has been investigating modern and widely-used tools and procedures used for virtualisation, clouds and fabric management in order to reduce operational effort, increase agility and support unattended remote data centres. This paper gives the details on the project’s motivations, current status and areas for future investigation.

  2. Towards Human-Centred Design

    Science.gov (United States)

    Bannon, Liam J.

    The field of HCI has evolved and expanded dramatically since its origin in the early 1980’s. The HCI community embraces a large community of researchers and practitioners around the world, from a variety of disciplinary backgrounds in the human and social sciences, engineering and informatics, and more recently, the arts and design disciplines. This kaleidoscope of cultures and disciplines as seen at INTERACT Conferences provides a rich pool of resources for examining our field. Applications are increasingly exploring our full range of sensory modalities, and merging the digital and physical worlds. WiFi has opened up a huge design space for mobile applications. A focus on usability of products and services has been complemented by an emphasis on engagement, enjoyment and experience. With the advent of ubiquitous computing, and the emergence of “The Internet of Things”, new kinds of more open infrastructures make possible radically new kinds of applications. The sources of innovation have also broadened, to include human and social actors outside of the computing and design organizations. The question is to what extent is our mainstream thinking in the HCI field ready for the challenges of this Brave New World? Do the technological and social innovations that we see emerging require us to re-shape, or even, re-create, our field, or is it a case of a more gradual evolution and development of that which we already know? In this closing Keynote, I will provide a perspective on the evolution and development of the HCI field, looking backwards as well as forwards, in order to determine what are some of the changes of significance in the field. This “broad-brush” approach to what I term “ human-centred design” will be complemented by the examination of specific projects and applications, to help anchor some of the discussion. Areas such as user-centred design, participatory design, computer-supported cooperative work and learning, and interaction design, in

  3. Quantum Dot Spectrum Converters for Enhanced High Efficiency Photovoltaics Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This research proposes to enhance solar cell efficiency, radiation resistance and affordability. The Quantum Dot Spectrum Converter (QDSC) disperses quantum dots...

  4. Symmetric centres of braided monoidal categories

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This paper introduces the concept of‘symmetric centres' of braided monoidal categories. Let H be a Hopf algebra with bijective antipode over a field k. We address the symmetric centre of the Yetter-Drinfel'd module category HH(yD) and show that a left Yetter-Drinfel'd module M belongs to the symmetric centre of HH(yD) if and only if M is trivial. We also study the symmetric centres of categories of representations of quasitriangular Hopf algebras and give a sufficient and necessary condition for the braid of H(M) to induce the braid of (H(H)(A),(○)A,A,φ,l,r), or equivalently, the braid of (A#H(H),(○)A,A,φ,l,r), where A is a quantum commutative H-module algebra.

  5. The Manche storage centre: Annual report 2010

    International Nuclear Information System (INIS)

    This report presents the installations of the CSM (Centre de Stockage de la Manche), the first French centre for the surface storage of low and intermediate level radioactive wastes. It briefly describes the site and its buildings, the multi-layer principle which is used to cover the wastes, how surface and drainage waters are managed, which controls are performed. It presents the different nuclear safety measures: principles, prevention measures, technical measures to meet the requirements, the legal plan for the control of the Centre and its environment, the quality management organization. It presents the measures regarding radioprotection and safety, indicates incidents and accidents which occurred in 2010, gives information and data on release management (effluents, controls, obtained data on surface and underground waters in different points). It briefly comments how the Centre's wastes are managed, evokes the case of other pollutions, and indicates actions performed in terms of public information

  6. The nuclear research centre at Bariloche, Argentina

    International Nuclear Information System (INIS)

    The nuclear research centre at Bariloche (CAB) is one of the four centres under the Atomic Energy Commission of Argentina (CNEA). The research programme of CAB addresses various issues like nuclear reactor development, nuclear fuel and fuel cycle, applications of radioisotopes and radiation, and waste management. There is also a basic nuclear science component. The human resource development in the areas of physics and nuclear engineering is done in an associated Balseiro Institute which has undergraduate and graduate programmes as well as doctoral and postdoctoral research. The Centre interacts well with the society and provides services in the nuclear area. It has a close interaction with the nuclear sector of Argentina as also with many international organisations. Regulatory control over the Centre is carried out by the Nuclear Regulatory Authority of Argentina. (author)

  7. Deloitte Global Immigration Service Centre -- Business Plan

    OpenAIRE

    Mejtský, Miroslav

    2013-01-01

    The thesis "Deloitte Global Immigration Service Centre -- Business Plan" is in the theoretical part focused on the aspects of the business plan as a document, the ways of its evaluation and financing business in general. The practical part is focused on creation of a business plan for a project of Global Immigration Service Centre with all the essentials in order to verify the feasibility of the project. The project seems feasible for implementation based on the results of the thesis.

  8. Nuclear research centres - The Egyptian experiment

    International Nuclear Information System (INIS)

    The Atomic Energy Authority of Egypt has four research centres located at two sites. Its research reactors are devoted to the production of isotopes, neutron beam experiments, activation analysis and materials research. The accelerators are devoted to the production of short lived isotopes for medical applications and materials R and D. Irradiation technology is used for sterilization of medical supplies and food preservation. High level of expertise in those centres is also useful for other developmental activities in Egypt. (author)

  9. Karlsruhe Nuclear Research Centre. Programme budget 1988

    International Nuclear Information System (INIS)

    Following a general survey of tasks, planned activities and developmental trends of the nuclear research centre, the report gives an account of the activities to be performed in the subject fields of main interest, showing the budgeting figures for annual expenditure (for personnel, investments, operating costs) up to the year 1991. Further information explains the infrastructure of the centre and the distribution of overall expenditure as well as the budgetary planning. (UA)

  10. The relativistic two-centre continuum

    International Nuclear Information System (INIS)

    A method is presented to define unique continuum states for the two-centre Dirac Hamiltonian. In the spherical limit these states become the familiar angular momentum eigenstates of the radial Coulomb potential. The different states for a fixed total energy vertical strokeEvertical stroke > m may be distinguished by considering the asymptotic spin-angular distribution of states with unique scattering-phases. First numerical solutions of the two-centre Dirac equation for continuum states are presented. (orig.)

  11. INFOTERM – Information Disseminating Centre for Terminology

    OpenAIRE

    Albina Auksoriūtė

    2014-01-01

    International Information Centre for Terminology (INFOTERM) was founded in 1971 by contract with the United Nations Educational, Scientific and Cultural Organization (UNESCO) and the Austrian Standards Institute (ASI). In 1996, INFOTERM was reorganized and established as an independent non-profit organization. INFOTERM promotes and supports the cooperation of existing and the establishment of new terminology centres and networks with the general aim to improve domain communication, knowledge ...

  12. Joint Research Centre. Ispra establishment-Italy

    International Nuclear Information System (INIS)

    A comprehensive review of the work carried out during 1974 and 1975 in the Ispra establishment of the Joint Research Centre is presented. A description of the activity carried out within the context of the running programmes is given. Some of the most relevant scientific and technical achievement are described from the viewpoints of the Scientific Departments of the Centre. The technical and administrative support activities are also presented. A list of publications issued by the Ispra Scientific staff is given

  13. Two centre problems in relativistic atomic physics

    OpenAIRE

    McConnell, Sean R.

    2012-01-01

    The work contained within this thesis is concerned with the explanation and usage of a set of theoretical procedures for the study of static and dynamic two–centre problems in the relativistic framework of Dirac’s equation. Two distinctly different theories for handling time–dependent atomic interactions are reviewed, namely semi–classical perturbation theory and a non–perturbative numerical technique based on the coupled channel equation to directly solve the time–dependent, two–centre Dirac...

  14. Social innovation for People-Centred Development

    DEFF Research Database (Denmark)

    Hulgård, Lars; P.K., Shajahan

    2013-01-01

    Social innovation is closely related to the people-centred development (PCD) framework of knowledge production. The discussion of PCD in this chapter particularly expands on the feature of empowerment and socio-political mobilization of people in social innovation......Social innovation is closely related to the people-centred development (PCD) framework of knowledge production. The discussion of PCD in this chapter particularly expands on the feature of empowerment and socio-political mobilization of people in social innovation...

  15. Nitrogen-Doped Carbon Dots for "green" Quantum Dot Solar Cells.

    Science.gov (United States)

    Wang, Hao; Sun, Pengfei; Cong, Shan; Wu, Jiang; Gao, Lijun; Wang, Yun; Dai, Xiao; Yi, Qinghua; Zou, Guifu

    2016-12-01

    Considering the environment protection, "green" materials are increasingly explored for photovoltaics. Here, we developed a kind of quantum dots solar cell based on nitrogen-doped carbon dots. The nitrogen-doped carbon dots were prepared by direct pyrolysis of citric acid and ammonia. The nitrogen-doped carbon dots' excitonic absorption depends on the N-doping content in the carbon dots. The N-doping can be readily modified by the mass ratio of reactants. The constructed "green" nitrogen-doped carbon dots solar cell achieves the best power conversion efficiency of 0.79 % under AM 1.5 G one full sun illumination, which is the highest efficiency for carbon dot-based solar cells. PMID:26781285

  16. Quantum Gates Between Two Spins in a Triple Dot System with an Empty Dot

    CERN Document Server

    Coello, Jose Garcia

    2011-01-01

    We propose a scheme for implementing quantum gates and entanglement between spin qubits in the outer dots of a triple-dot system with an empty central dot. The voltage applied to the central dot can be tuned to realize the gate. Our scheme exemplifies the possibility of quantum gates outside the regime where each dot has an electron, so that spin-spin exchange interaction is not the only relevant mechanism. Analytic treatment is possible by mapping the problem to a t-J model. The fidelity of the entangling quantum gate between the spins is analyzed in the presence of decoherence stemming from a bath of nuclear spins, as well as from charge fluctuations. Our scheme provides an avenue for extending the scope of two qubit gate experiments to triple-dots, while requiring minimal control, namely that of the potential of a single dot, and may enhance the qubit separation to ease differential addressability.

  17. The Imperial College Thermophysical Properties Data Centre

    Science.gov (United States)

    Angus, S.; Cole, W. A.; Craven, R.; de Reuck, K. M.; Trengove, R. D.; Wakeham, W. A.

    1986-07-01

    The IUPAC Thermodynamic Tables Project Centre in London has at its disposal considerable expertise on the production and utilization of high-accuracy equations of state which represent the thermodynamic properties of substances. For some years they have been content to propagate this information by the traditional method of book production, but the increasing use of the computer in industry for process design has shown that an additional method was needed. The setting up of the IUPAC Transport Properties Project Centre, also at Imperial College, whose products would also be in demand by industry, afforded the occasion for a new look at the problem. The solution has been to set up the Imperial College Thermophysical Properties Data Centre, which embraces the two IUPAC Project Centres, and for it to establish a link with the existing Physical Properties Data Service of the Institution of Chemical Engineers, thus providing for the dissemination of the available information without involving the Centres in problems such as those of marketing and advertising. This paper outlines the activities of the Centres and discusses the problems in bringing their products to the attention of industry in suitable form.

  18. Perspectives on recycling centres and future developments.

    Science.gov (United States)

    Engkvist, I-L; Eklund, J; Krook, J; Björkman, M; Sundin, E

    2016-11-01

    The overall aim of this paper is to draw combined, all-embracing conclusions based on a long-term multidisciplinary research programme on recycling centres in Sweden, focussing on working conditions, environment and system performance. A second aim is to give recommendations for their development of new and existing recycling centres and to discuss implications for the future design and organisation. Several opportunities for improvement of recycling centres were identified, such as design, layout, ease with which users could sort their waste, the work environment, conflicting needs and goals within the industry, and industrialisation. Combining all results from the research, which consisted of different disciplinary aspects, made it possible to analyse and elucidate their interrelations. Waste sorting quality was recognized as the most prominent improvement field in the recycling centre system. The research identified the importance of involving stakeholders with different perspectives when planning a recycling centre in order to get functionality and high performance. Practical proposals of how to plan and build recycling centres are given in a detailed checklist. PMID:26826952

  19. Optical anisotropy in vertically coupled quantum dots

    DEFF Research Database (Denmark)

    Yu, Ping; Langbein, Wolfgang Werner; Leosson, Kristjan;

    1999-01-01

    We have studied the polarization of surface and edge-emitted photoluminescence (PL) from structures with vertically coupled In0.5Ga0.5As/GaAs quantum dots (QD's) grown by molecular beam epitaxy. The PL polarization is found to be strongly dependent on the number of stacked layers. While single...... number due to increasing dot size....

  20. Double Acceptor Interaction in Semimagnetic Quantum Dot

    Directory of Open Access Journals (Sweden)

    A. Merwyn Jasper D. Reuben

    2011-01-01

    Full Text Available The effect of geometry of the semimagnetic Quantum Dot on the Interaction energy of a double acceptor is computed in the effective mass approximation using the variational principle. A peak is observed at the lower dot sizes as a magnetic field is increased which is attributed to the reduction in confinement.

  1. Thick-shell nanocrystal quantum dots

    Science.gov (United States)

    Hollingsworth, Jennifer A.; Chen, Yongfen; Klimov, Victor I.; Htoon, Han; Vela, Javier

    2011-05-03

    Colloidal nanocrystal quantum dots comprising an inner core having an average diameter of at least 1.5 nm and an outer shell, where said outer shell comprises multiple monolayers, wherein at least 30% of the quantum dots have an on-time fraction of 0.80 or greater under continuous excitation conditions for a period of time of at least 10 minutes.

  2. Photoinduced electron transfers with carbon dots

    OpenAIRE

    Wang, Xin; Cao, Li; Lu, Fushen; Meziani, Mohammed J.; Li, Heting; Qi, Gang; Zhou, Bing; Harruff, Barbara A.; Kermarrec, Fabien; Sun, Ya-Ping

    2009-01-01

    The photoluminescence in carbon dots (surface-passivated small carbon nanoparticles) could be quenched efficiently by electron acceptor or donor molecules in solution, namely that photo-excited carbon dots are both excellent electron donors and excellent electron acceptors, thus offering new opportunities for their potential uses in light energy conversion and related applications.

  3. Medication errors: pharmacovigilance centres in detection and prevention

    OpenAIRE

    Bencheikh, Rachida Soulaymani; Benabdallah, Ghita

    2009-01-01

    Detecting medication errors needs collaboration between various organizations, such as patient safety institutions, pharmacovigilance centres, and poison control centres. In order to evaluate the input of pharmacovigilance centres and poison control centres in detecting and evaluating medication errors a pilot project was initiated by the World Alliance for Patient Safety in collaboration with the Uppsala Monitoring Centre; the Moroccan pharmacovigilance centre acted as project coordinator. A...

  4. Photoluminescence of hybrid quantum dots

    Czech Academy of Sciences Publication Activity Database

    Král, Karel; Menšík, Miroslav

    Bratislava: Slovak Expert Group of Solid State Chemistry and Physics , 2013 - (Koman, M.; Jorík, V.; Kožíšek, Z.). s. 28-28 ISBN 978-80-970896-5-8. [Joint Seminar – Development of materials science in research and education /23./. 09.09.2013-13.09.2013, Kežmarské Žľaby] R&D Projects: GA MŠk LH12236; GA MŠk LH12186 Institutional support: RVO:68378271 ; RVO:61389013 Keywords : energy transfer * quantum dots Subject RIV: BM - Solid Matter Physics ; Magnetism; JA - Electronics ; Optoelectronics, Electrical Engineering (UMCH-V)

  5. Coherent control of quantum dots

    DEFF Research Database (Denmark)

    Johansen, Jeppe; Lodahl, Peter; Hvam, Jørn Märcher

    In recent years much effort has been devoted to the use of semiconductor quantum dotsystems as building blocks for solid-state-based quantum logic devices. One importantparameter for such devices is the coherence time, which determines the number ofpossible quantum operations. From earlier...... measurements the coherence time of the selfassembledquantum dots (QDs) has been reported to be limited by the spontaneousemission rate at cryogenic temperatures1.In this project we propose to alter the coherence time of QDs by taking advantage of arecent technique on modifying spontaneous emission rates with...

  6. Semiconductor double quantum dot micromaser.

    Science.gov (United States)

    Liu, Y-Y; Stehlik, J; Eichler, C; Gullans, M J; Taylor, J M; Petta, J R

    2015-01-16

    The coherent generation of light, from masers to lasers, relies upon the specific structure of the individual emitters that lead to gain. Devices operating as lasers in the few-emitter limit provide opportunities for understanding quantum coherent phenomena, from terahertz sources to quantum communication. Here we demonstrate a maser that is driven by single-electron tunneling events. Semiconductor double quantum dots (DQDs) serve as a gain medium and are placed inside a high-quality factor microwave cavity. We verify maser action by comparing the statistics of the emitted microwave field above and below the maser threshold. PMID:25593187

  7. Model-based clustered-dot screening

    Science.gov (United States)

    Kim, Sang Ho

    2006-01-01

    I propose a halftone screen design method based on a human visual system model and the characteristics of the electro-photographic (EP) printer engine. Generally, screen design methods based on human visual models produce dispersed-dot type screens while design methods considering EP printer characteristics generate clustered-dot type screens. In this paper, I propose a cost function balancing the conflicting characteristics of the human visual system and the printer. By minimizing the obtained cost function, I design a model-based clustered-dot screen using a modified direct binary search algorithm. Experimental results demonstrate the superior quality of the model-based clustered-dot screen compared to a conventional clustered-dot screen.

  8. Photoluminescence of a quantum-dot molecule

    International Nuclear Information System (INIS)

    The coherent coupling of quantum dots is a sensitive indicator of the energy and phase relaxation processes taking place in the nanostructure components. We formulate a theory of low-temperature, stationary photoluminescence from a quantum-dot molecule composed of two spherical quantum dots whose electronic subsystems are resonantly coupled via the Coulomb interaction. We show that the coupling leads to the hybridization of the first excited states of the quantum dots, manifesting itself as a pair of photoluminescence peaks with intensities and spectral positions strongly dependent on the geometric, material, and relaxation parameters of the quantum-dot molecule. These parameters are explicitly contained in the analytical expression for the photoluminescence differential cross section derived in the paper. The developed theory and expression obtained are essential in interpreting and analyzing spectroscopic data on the secondary emission of coherently coupled quantum systems

  9. Antioxidant Activity of The Ancient Herb, Holy Basil in CCl4-Induced Liver Injury in Rats

    OpenAIRE

    Ponnusam, Yuvaraj; Louis, Therasilin; Madhavachandran, V; Kumar, Suresh; Thoprani, Neelam; Hamblin, Michael R.; Lakshmanan, Shanmugamurthy

    2015-01-01

    An herbal preparation called “holy basil plus herbal powder” (HBPP) containing Ocimum santum, Withania somnifera, Pongamia pinnata, Plumbago indica, Emblica officinalis and Curcuma longa was investigated as an antioxidant and hepatoprotective agent. The antioxidant activity of HBPP was investigated in rats with liver injury induced by oral administration of carbon tetrachloride:olive oil (1:1). HBPP was administered orally at 500 mg/kg daily for 7 days before. HBPP exhibited statistically sig...

  10. Immunomodulatory effect of oxymatrine on induced CCl4-hepatic fibrosis in rats

    Institute of Scientific and Technical Information of China (English)

    余小虎; 朱金水; 俞华芳; 朱励

    2004-01-01

    @@ Liver fibrosis is a serious but reversible consequence of liver injuries. The treatment should include clearance of pathogeny, anti-fibrosis and heteropathy. As a potent ingredient extracted from traditional Chinese medicial herbs Sophora flavecientis and S. subprostratae, oxymatrine contains a variety of alkaloids. Studies have shown that oxymatrine could relieve the inflammatory activity in liver tissue and has the effect of anti-fibrosis as well, whereas the therapeutic mechanism is not clear yet. The present study was designed to investigate the immunological mechanism of oxymatrine therapy for hepatic fibrosis.

  11. Protective effect of Livactine against CCl4 and paracetamol induced hepatotoxicity in adult Wistar rats

    Directory of Open Access Journals (Sweden)

    Candasamy Mayuren

    2010-10-01

    Full Text Available Background: Liver disease has become one of the serious health problems as it is exposed to many kinds of xenobiotics and therapeutic agents. Moreover the rapidly growing morbidity and mortality from liver disease are attributable to the increasing number of chemical compounds and environmental pollution. Unfortunately, so far, in the modern era of medicine there is no specific treatment to counter the menacing impact of these dreaded diseases. Many polyherbal formulations are used widely to treat these disorders. Livactine is a polyherbal formulation and is claimed to be useful in jaundice and biliary dysfunctions. Most of these formulations do not have standard and approved reports stating their pharmacological action or therapeutic efficacy. Therefore, there is a need for experimental confirmation of the pharmacological effects of this formulation. The rationale behind the selection of carbon tetrachloride is due to its free radical mechanism based liver injury, and paracetamol is consumed widely by the human population and it is also a potential liver hazard. Aim: To evaluate the anti-hepatotoxic activity of Livactine against carbon tetrachloride & paracetamol induced toxicity in rats. Material and Methods: Albino rats of Wistar strain were used to evaluate the hepatoprotective activity of Livactine against carbon tetrachloride & paracetamol induced toxicity. Liver damage was assessed by estimating various biochemical parameters such as serum glutamate oxaloacetate transaminase, serum glutamate pyruvate transaminase, lactate dehydrogenase, alkaline phosphatase, acid phosphatase, total bilirubin, and total protein. The results of the rats treated with Livactine were compared with that of Liv-52.Results: Livactine showed significant dose dependent hepatoprotective effect by reducing elevated serum enzyme levels when compared to that of Liv-52.Conclusion: Our findings confirm that the formulation was found to be effective pharmacologically at higher dose against carbon tetrachloride and paracetamol induced hepatotoxic models and were comparable to that of Liv-52.The resultant hepatoprotective activity of Livactine could be due to its free radical scavenging property of the ingredients.

  12. A demonstration of in situ bioremediation of CCL4 at the Hanford Site

    International Nuclear Information System (INIS)

    The United States Department of Energy's VOC-Arid Integrated Demonstration Program (VOC/Arid-ID) is developing an in situ bioremediation technology to meet the need for a cost-effective method to clean ground water contaminated with chlorinated solvents, nitrates, or other organic and inorganic contaminants. Currently, a field demonstration of the technology is being conducted at the Hanford site in southeastern Washington state. The goal of this demonstration is to stimulate native denitrifying microorganisms to destroy carbon tetrachloride and nitrate. Contaminants are destroyed by mixing an electron donor (acetate) and an electron acceptor (nitrate) into the aquifer, using a matrix of recirculation wells. This work also evaluates the effectiveness.of applying scale-up techniques developed in the petrochemical industry to bioremediation. The scale-up process is based on combining fluid mixing and transport predictions with numerical descriptions for biological transport and reaction kinetics. This paper focuses on the necessity of this design approach to select nutrient feeding strategies that limit biofouling while actively destroying contaminants

  13. Electron transport in quantum dots

    CERN Document Server

    2003-01-01

    When I was contacted by Kluwer Academic Publishers in the Fall of 200 I, inviting me to edit a volume of papers on the issue of electron transport in quantum dots, I was excited by what I saw as an ideal opportunity to provide an overview of a field of research that has made significant contributions in recent years, both to our understanding of fundamental physics, and to the development of novel nanoelectronic technologies. The need for such a volume seemed to be made more pressing by the fact that few comprehensive reviews of this topic have appeared in the literature, in spite of the vast activity in this area over the course of the last decade or so. With this motivation, I set out to try to compile a volume that would fairly reflect the wide range of opinions that has emerged in the study of electron transport in quantum dots. Indeed, there has been no effort on my part to ensure any consistency between the different chapters, since I would prefer that this volume instead serve as a useful forum for the...

  14. Silicon quantum dots: surface matters

    International Nuclear Information System (INIS)

    Silicon quantum dots (SiQDs) hold great promise for many future technologies. Silicon is already at the core of photovoltaics and microelectronics, and SiQDs are capable of efficient light emission and amplification. This is crucial for the development of the next technological frontiers—silicon photonics and optoelectronics. Unlike any other quantum dots (QDs), SiQDs are made of non-toxic and abundant material, offering one of the spectrally broadest emission tunabilities accessible with semiconductor QDs and allowing for tailored radiative rates over many orders of magnitude. This extraordinary flexibility of optical properties is achieved via a combination of the spatial confinement of carriers and the strong influence of surface chemistry. The complex physics of this material, which is still being unraveled, leads to new effects, opening up new opportunities for applications. In this review we summarize the latest progress in this fascinating research field, with special attention given to surface-induced effects, such as the emergence of direct bandgap transitions, and collective effects in densely packed QDs, such as space separated quantum cutting. (topical review)

  15. Visits to Tier-1 Computing Centres

    CERN Multimedia

    Dario Barberis

    At the beginning of 2007 it became clear that an enhanced level of communication is needed between the ATLAS computing organisation and the Tier-1 centres. Most usual meetings are ATLAS-centric and cannot address the issues of each Tier-1; therefore we decided to organise a series of visits to the Tier-1 centres and focus on site issues. For us, ATLAS computing management, it is most useful to realize how each Tier-1 centre is organised, and its relation to the associated Tier-2s; indeed their presence at these visits is also very useful. We hope it is also useful for sites... at least, we are told so! The usual participation includes, from the ATLAS side: computing management, operations, data placement, resources, accounting and database deployment coordinators; and from the Tier-1 side: computer centre management, system managers, Grid infrastructure people, network, storage and database experts, local ATLAS liaison people and representatives of the associated Tier-2s. Visiting Tier-1 centres (1-4). ...

  16. UV LED lighting for automated crystal centring

    International Nuclear Information System (INIS)

    A low-cost light-emitting diode (LED) UV source has been developed for facilitating macromolecular sample centring in the X-ray beam. A direct outcome of the exponential growth of macromolecular crystallography is the continuously increasing demand for synchrotron beam time, both from academic and industrial users. As more and more projects entail screening a profusion of sample crystals, fully automated procedures at every level of the experiments are being implemented at all synchrotron facilities. One of the major obstacles to achieving such automation lies in the sample recognition and centring in the X-ray beam. The capacity of UV light to specifically react with aromatic residues present in proteins or with DNA base pairs is at the basis of UV-assisted crystal centring. Although very efficient, a well known side effect of illuminating biological samples with strong UV sources is the damage induced on the irradiated samples. In the present study the effectiveness of a softer UV light for crystal centring by taking advantage of low-power light-emitting diode (LED) sources has been investigated. The use of UV LEDs represents a low-cost solution for crystal centring with high specificity

  17. Scavenger hunt in the CERN Computing Centre

    CERN Multimedia

    CERN Bulletin

    2013-01-01

    Hidden among the racks of servers and disks in the CERN Computing Centre, you’ll find Hawaiian dancers, space aliens, gorillas… all LEGO® figurines! These characters were placed about the Centre for the arrival of Google’s Street View team for the world to discover.   PLEASE NOTE THAT THE COMPETITION IS OVER. ONLY FOR REFERENCE, HERE IS THE ORIGINAL ARTICLE. We’re pleased to announce our first global scavenger hunt! Spot three LEGO® figurines using Google’s Street View and you’ll be entered to win a gift of your choice from our CERN Gift Guide. A LEGO® figurine in the CERN Computing Centre, as seen on Google Street View. Here are the details: Find at least three LEGO® figurines hidden around the CERN Computing Centre using Google Street View.   Take screencaps of the figurines and e-mail the pictures to TreasureHunt-ComputingCentre@cern.ch. This email is no longer active.   The...

  18. The Aube centre. 1997 statement; Le centre de l`Aube. Bilan 1997

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-09-01

    Since January 1992 the Aube centre ensures the storage of 90% of the short life radioactive wastes produced in France. This educational booklet describes the organization of the activities in the centre from the storage of wastes to the radioactivity surveillance of the environment (air, surface and ground waters, river sediments, plants and milk). (J.S.)

  19. Effect of different uranium compounds on the properties of U-Pt-Y-Ba-O double-perovskite pinning centres in textured Y-Ba-Cu-O superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Sawh, Ravi-Persad; Weinstein, Roy; Parks, Drew; Gandini, Alberto [Beam Particle Dynamics Laboratories, University of Houston, Houston, TX 77204-5005 (United States); Department of Physics, University of Houston, Houston, TX 77204-5005 (United States); Texas Center for Superconductivity and Advanced Materials, University of Houston, Houston, TX 77204-5005 (United States)

    2005-02-01

    An experiment was performed to test the effect of different uranium compounds on the properties of chemical pinning centres. UO{sub 2}, UO{sub 3}, and UO{sub 4}{center_dot}2H{sub 2}O wereadmixed to Y 123+Pt, and textured. Tests of J{sub c} via measurements of trapped field (B{sub trap}) indicate a clear dependence of B{sub trap} on the U compound admixed to create the pinning centres. In all three cases there is a monotonic increase in B{sub trap} as the mass (M{sub U}) of U is increased. However, the magnitude of the increase in B{sub trap} depends on the admixed U compound. The highest increase in B{sub trap} is measured in samples doped with UO{sub 4}{center_dot}2H{sub 2}O, and the lowest is obtained in samples doped with UO{sub 2}. Microstructure studies indicate that the composition of the U-rich pinning deposits is the same in all three cases, i.e. all are the previously identified (U{sub 0.6}Pt{sub 0.4})Y Ba{sub 2}O{sub 6} compound. The primary difference among the three types of samples is that the size of the U-Pt-Y-Ba-O pinning deposits depends on the admixed U compound. While all are in the nanometre domain, the diameter of these deposits was markedly larger in UO{sub 2} doped samples than in UO{sub 3} doped samples, and smallest in UO{sub 4}{center_dot}2H{sub 2}O doped samples. Because some form of poisoning limits the amount of U that can be added to create pinning centres, to M{sub U} {approx}1 wt%, smaller deposits result in a greater number of pinning centres. We conclude that UO{sub 4}{center_dot}2H{sub 2}O is more effective than either UO{sub 3} or UO{sub 2} in the formation of U-Pt-Y-Ba-O pinning centres because of diminished pinning centre size, and consequent increase in pinning centre density.

  20. A day in the CERN Control Centre

    CERN Multimedia

    Rosaria Marraffino

    2015-01-01

    The CERN Control Centre (CCC) is the nerve centre of the CERN beam systems. From this room, the experts prepare, monitor, adjust, and control the particle beams that circulate throughout the accelerator complex while ensuring that the services and the technical infrastructure work flawlessly. Buttons, screens, telephones, lights (but no sound): in the CCC, everything is ready to make it possible for the LHC to reach the unprecedented energies expected at Run 2.   Seen from above, the CERN Control Centre resembles the shape of a quadrupole magnet. The consoles are distributed in four circles, called “islands”, dedicated to the LHC, the SPS, the PS Complex and the Technical Infrastructure (TI) respectively. Spread between TI and LHC are the Cryogenics consoles. Being in the same room allows the 24h-manned islands to be constantly in touch with one another, thus ensuring the best performance of the machines. At the LHC island, operators are currently busy training the magnet...

  1. Medical applications in a nuclear research centre

    International Nuclear Information System (INIS)

    In these days of public aversion to nuclear power, it can be important to point at the medical applications of ionising radiation. Not only the general public, but also the authorities and research centres have to be aware of these medical applications, which are not without risk for public health. Now that funding for nuclear research is declining, an opening to the medical world can give new opportunities to a nuclear research centre. A lot of research could be done where the tools developed for the nuclear power world are very useful. Even new applications for the research reactors like BNCT (boron neutron capture therapy) can be envisaged for the near future. In this contribution an overview will be given of the different techniques used in the medical world with ionising radiation. The specific example of the Belgian Nuclear Research Centre will be given where the mission statement was changed to include a certain number of medical research topics. (authors)

  2. Occupational deprivation in an asylum centre:

    DEFF Research Database (Denmark)

    Morville, Anne-Le; Erlandsson, Lena-Karin

    2013-01-01

    This article presents a study of three asylum-seeking men from Iran and Afghanistan. It aimed to explore how and if they experienced occupations as occupations in a Danish asylum centre and how their life experience shaped their choice and value of current occupations. In-depth narrative interviews...... explored the participants’ occupational history and its influence on their occupations in the asylum centre. A thematic analysis showed that the participants had been subjected to occupational disruption and deprivation by politically oppressive systems even before their flight. Their occupations in...... Denmark were to a certain extent influenced by their earlier occupations and the current occupational deprivation they all experienced was due to limited possibilities in the centre. Although they tried their best to fill their days and create structure, there was a loss of valued occupations and a...

  3. Optimizing Data Centre Energy and Environmental Costs

    Science.gov (United States)

    Aikema, David Hendrik

    Data centres use an estimated 2% of US electrical power which accounts for much of their total cost of ownership. This consumption continues to grow, further straining power grids attempting to integrate more renewable energy. This dissertation focuses on assessing and reducing data centre environmental and financial costs. Emissions of projects undertaken to lower the data centre environmental footprints can be assessed and the emission reduction projects compared using an ISO-14064-2-compliant greenhouse gas reduction protocol outlined herein. I was closely involved with the development of the protocol. Full lifecycle analysis and verifying that projects exceed business-as-usual expectations are addressed, and a test project is described. Consuming power when it is low cost or when renewable energy is available can be used to reduce the financial and environmental costs of computing. Adaptation based on the power price showed 10--50% potential savings in typical cases, and local renewable energy use could be increased by 10--80%. Allowing a fraction of high-priority tasks to proceed unimpeded still allows significant savings. Power grid operators use mechanisms called ancillary services to address variation and system failures, paying organizations to alter power consumption on request. By bidding to offer these services, data centres may be able to lower their energy costs while reducing their environmental impact. If providing contingency reserves which require only infrequent action, savings of up to 12% were seen in simulations. Greater power cost savings are possible for those ceding more control to the power grid operator. Coordinating multiple data centres adds overhead, and altering at which data centre requests are processed based on changes in the financial or environmental costs of power is likely to increase this overhead. Tests of virtual machine migrations showed that in some cases there was no visible increase in power use while in others power use

  4. Time-bin Entanglement from Quantum Dots

    CERN Document Server

    Weihs, Gregor; Predojević, Ana

    2016-01-01

    The desire to have a source of single entangled photon pairs can be satisfied using single quantum dots as emitters. However, we are not bound to pursue only polarization entanglement, but can also exploit other degrees of freedom. In this chapter we focus on the time degree of freedom, to achieve so-called time-bin entanglement. This requires that we prepare the quantum dot coherently into the biexciton state and also build special interferometers for analysis. Finally this technique can be extended to achieve time-bin and polarization hyper-entanglement from a suitable quantum dot.

  5. Magnon-driven quantum dot refrigerators

    Science.gov (United States)

    Wang, Yuan; Huang, Chuankun; Liao, Tianjun; Chen, Jincan

    2015-12-01

    A new model of refrigerator consisting of a spin-splitting quantum dot coupled with two ferromagnetic reservoirs and a ferromagnetic insulator is proposed. The rate equation is used to calculate the occupation probabilities of the quantum dot. The expressions of the electron and magnon currents are obtained. The region that the system can work in as a refrigerator is determined. The cooling power and coefficient of performance (COP) of the refrigerator are derived. The influences of the magnetic field, applied voltage, and polarization of two leads on the performance are discussed. The performances of two different magnon-driven quantum dot refrigerators are compared.

  6. Introduction to the physics of quantum dots

    International Nuclear Information System (INIS)

    Quantum dots contain only a few well-defined energy levels for electron and/or holes as a result of the confinement of charge in all three spatial dimensions. Here, we describe both the application of photoluminescence spectroscopy and transport measurements to the characterisation of quantum dots and the novel phenomena that they exhibit. These include the Coulomb blockade, single electron tunneling and single photon detection. The impact of quantum dots on future electronics and directions for future research, such as in quantum computing and cryptography, are discussed. (author)

  7. Nonuniform magnetization reversals in elliptical permalloy dots

    Energy Technology Data Exchange (ETDEWEB)

    Lai, M.-F.; Wei, Z.-H. E-mail: zhwei@phys.ntu.edu.tw; Chang, Ching-Ray; Usov, N.A.; Wu, J.C.; Lai, Jun-Yang

    2004-11-01

    Reversible and irreversible magnetization processes of the single-domain elliptical permalloy dot are studied by simulation. The magnetization curve of the reversible process obtained by applying the field along the hard axis of the elliptical dot is almost linear, as is the case in the single-domain ellipsoidal particle. Due to the occurrence of the non uniform reversal, the switching field is reduced significantly compared to that predicted by the Stoner-Wohlfarth model. The nucleation fields of elliptical dots are calculated as a function of ellipse's aspect ratio, and the function reveals a step-like behavior.

  8. Structural and optical characterization of Si/Ge quantum dots

    OpenAIRE

    Wigblad, Dan

    2008-01-01

    In this study silicon-germanium quantum dots grown on silicon have been investigated. The aim of the work was to find quantum dots suitable for use as a thermistor material. The quantum dots were produced at KTH, Stockholm, using a RPCVD reactor that is designed for industrial production. The techniques used to study the quantum dots were: HRSEM, AFM, HRXRD, FTPL, and Raman spectroscopy. Quantum dots have been produced in single and multilayer structures. As a result of this work a multilayer...

  9. Imperial College Reactor Centre annual report. 1984

    International Nuclear Information System (INIS)

    The following new equipment is noted; for atomic absorption spectrometry to supplement the neutron activation analysis, and an additional nuclear data analysis system to improve the quality and speed of the service to users of the Centre's facilities. Users include undergraduates from the University of London, outside bodies such as the British Musueum, as well as departments of Colleges of the University of London. The reactor lost only three days through failures or faults. Two replacement fuel elements were put into the reactor during the year. The report contains brief accounts of 34 research programmes at the Centre. (U.K.)

  10. User-Centred BCI Videogame Design

    OpenAIRE

    Loup-Escande, Emilie; Lotte, Fabien; LOUP, Guillaume; Lécuyer, Anatole

    2015-01-01

    This chapter aims to offer a user-centred methodological framework to guide the design and evaluation of Brain-Computer Interface videogames. This framework is based on the contributions of ergonomics to ensure these games are well suited for their users (i.e., players). It provides methods, criteria and metrics to complete the different phases required by ae human-centred design process. This aims to understand the context of use, specify the user needs and evaluate the solutions in order to...

  11. A study on socio-demographic profile and feasibility of DOTS provider registered under RNTCP in Varanasi district Uttar Pradesh

    Directory of Open Access Journals (Sweden)

    Mohd. Afzalul Haque

    2014-03-01

    Full Text Available Introduction: Tuberculosis is a major chronic disorder affecting the larger population more than any other disease in the country. DOTS was introduced in India in 1993 as part of the Revised National Tuberculosis Programme (RNTCP following a review of India’s National Tuberculosis Programme (NTP a year earlier (1 .Patient satisfaction is an important parameter for assessing the quality of patient care services. There is need to assess the health care provider regarding the consumer satisfaction as often as possible, this paper summarizes our experience about role of DOTS provider in the management of TB patient in rural population of Varanasi districts Utter Pradesh. Objective: (1 To assess the perception of registered tuberculosis patients regarding DOTS provider for the treatment of tuberculosis. (2 To assess the accessibility, acceptability & availability of community DOTS provider. Design: A longitudinal study. Setting: Three microscopic centre of Cholapur Tuberculosis unit of Varanasi districts. Methods: Registered patients were interviewed twice: once in the beginning and another at the completion of the treatment or after the permanent discontinuation of the treatment. Patients were interviewed for their socio-demographic profiles, opinion about DOTS and its providers. Side effects experienced and action taken etc. Data was collected on a semi-structured, pre-tested questionnaire. DOTS providers were interviewed and treatment cards analyzed for any interruption of treatment and action taken. Data was collected from 1st June 2004 to 31th June 2005 till the completion of the regimen. Results: Majority of DOTS providers were young males (82.7% of 26 years to 40 years, while the representation of females was only 5 (17.3%. Almost more than 80% of the patients started their treatment within 1-10 days. For majority of cases (83% the distance of DOTS provider from patient’s house was within 1 km. Mean time spent to go to DOTS provider was 27

  12. Quantum dot devices for optical communications

    DEFF Research Database (Denmark)

    Mørk, Jesper

    2005-01-01

    record-low threshold currents and amplifiers with record-high power levels. In this tutorial we will review the basic properties of quantum dots, emphasizing the properties which are important for laser and amplifier applications, as well as devices for all-optical signal processing. The high....... The main property of semiconductor quantum dots compared to bulk material or even quantum well structures is the discrete nature of the allowed states, which means that inversion of the medium can be obtained for very low electron densities. This has led to the fabrication of quantum dot lasers with......Semiconductor quantum dots are often described as "artificial atoms": They are small nanometre-sized structures in which electrons only are allowed to exist at certain discrete levels due to size quantization, thus allowing the engineering of fundamental properties such as the coupling to light...

  13. Ge Quantum Dot Infrared Imaging Camera Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Luna Innovations Incorporated proposes to develop a high performance Ge quantum dots-based infrared (IR) imaging camera on Si substrate. The high sensitivity, large...

  14. Large quantum dots with small oscillator strength

    DEFF Research Database (Denmark)

    Stobbe, Søren; Schlereth, T.W.; Höfling, S.;

    2010-01-01

    We have measured the oscillator strength and quantum efficiency of excitons confined in large InGaAs quantum dots by recording the spontaneous emission decay rate while systematically varying the distance between the quantum dots and a semiconductor-air interface. The size of the quantum dots is...... measured by in-plane transmission electron microscopy and we find average in-plane diameters of 40 nm. We have calculated the oscillator strength of excitons of that size assuming a quantum-dot confinement given by a parabolic in-plane potential and a hard-wall vertical potential and predict a very large...... oscillator strength due to Coulomb effects. This is in stark contrast to the measured oscillator strength, which turns out to be so small that it can be described by excitons in the strong confinement regime. We attribute these findings to exciton localization in local potential minima arising from alloy...

  15. Quantum Phase Transitions in Quantum Dots

    OpenAIRE

    Rau, I. G.; Amasha, S.; Oreg, Y.; Goldhaber-Gordon, D.

    2013-01-01

    This review article describes theoretical and experimental advances in using quantum dots as a system for studying impurity quantum phase transitions and the non-Fermi liquid behavior at the quantum critical point.

  16. The Australian Centre for Minesite Rehabilitation Research

    International Nuclear Information System (INIS)

    The Australian Centre for Minesite Rehabilitation Research (ACMRR) is a joint venture between the Australian mining industry through the Australian Mineral Industries Research Association Ltd. (AMIRA) and three of the organizations working most actively in this area in Australia: CSIRO Minesite Rehabilitation Research Program; University of Queensland Centre for Mined Land Rehabilitation; and Curtin University Mulga Research Centre. The ACMRR was established in July 1993 to provide a national framework to conduct Strategic Research into minesite rehabilitation. It is an industry led and funded initiative. The Goals of the Centre include: to conduct strategic research into minesite rehabilitation to provide sustainable environmental solutions which are acceptable to industry, government and the community; to be recognized as a center of excellence undertaking commissioned research on minesite rehabilitation in an independent and thorough manner; to provide scientific and technological foundations to facilitate industry and government in setting acceptable standards; to act as networking and communications focus; and to enhance education and training in minesite rehabilitation. Strategic Research Programs in: Water Systems--downstream surface and groundwater quality; Land--the long-term behavior and stability of constructed landforms; Ecosystems--the long-term sustainability of constructed landforms; Waste--the long-term treatment and disposal of waste products; will allow the ACMRR to achieve these goals through specific research projects in these areas, developed with industry sponsors. This paper will discuss their progress to date, research projects underway, and plans for the future

  17. Learner-Centred Education and "Cultural Translation"

    Science.gov (United States)

    Thompson, Paul

    2013-01-01

    This paper contests the proposal that learner-centred education (LCE) may simply be a western construct, irrelevant to the current educational needs of developing countries, by arguing that its specific forms will be more effective when introduced through small-scale institutional relationships than through large-scale contracts with national…

  18. The young centre of the Earth

    DEFF Research Database (Denmark)

    Uggerhøj, Ulrik Ingerslev; Mikkelsen, Rune E.; Faye, Jan

    2016-01-01

    We treat, as an illustrative example of gravitational time dilation in relativity, the observation that the centre of the Earth is younger than the surface by an appreciable amount. Richard Feynman first made this insightful point and presented an estimate of the size of the effect in a talk; a...

  19. Student-Centred Learning: A Humanist Perspective

    Science.gov (United States)

    Tangney, Sue

    2014-01-01

    The notion of student-centred learning is often not defined; within the pedagogic literature it is generally associated with constructivism or principles associated with a constructivist environment such as building on prior knowledge, purposeful active learning and sense-making. An informal enquiry into conceptions of university staff prior to…

  20. The BNFL technology centre at Sellafield

    International Nuclear Information System (INIS)

    A description is given of the BNFL technology centre at Sellafield. Special emphasis is on the facility plan and construction, the high active hot-cells, the laboratories, the high energy interrogation facility, and the rigg hall. Further, the servicing well as the contract strategy are discussed

  1. The fragility of human-centred design

    NARCIS (Netherlands)

    Steen, M.G.D.

    2008-01-01

    In human-centred design (HCD), researchers and designers develop products in cooperation with the potential users of these products. They attempt to give users a voice or a role in their projects, with the intention of developing products that match users' needs and preferences. This approach is esp

  2. Centring the Subject in Order to Educate

    Science.gov (United States)

    Webster, R. Scott

    2007-01-01

    It is important for educators to recognise that the various calls to decentre the subject--or self--should not be interpreted as necessarily requiring the removal of the subject altogether. Through the individualism of the Enlightenment the self was centred. This highly individualistic notion of the sovereign self has now been decentred especially…

  3. Renovation of the CERN Computer Centre

    CERN Multimedia

    Patrice Loïez

    2003-01-01

    The Computer Centre at CERN is seen after half of the equipment is the large ground floor room has been removed. A large-scale spring-cleaning operation took place before renovation work for the new CERN Grid system began. Fifteen kilometres of cables that were no longer needed were removed from the cavity floor for recycling.

  4. Enhancing person-centred communication in NICU

    DEFF Research Database (Denmark)

    Weis, Janne; Zoffmann, Vibeke; Egerod, Ingrid

    2015-01-01

    Aims of this article were (a) to explore how parents of premature infants experience guided family-centred care (GFCC), and (b) to compare how parents receiving GFCC versus standard care (SC) describe nurse-parent communication in the neonatal intensive care unit....

  5. Cactus: The Centres of a Triangle

    Science.gov (United States)

    Hyde, Hartley

    2009-01-01

    This is the first of two articles which describe how to use "JavaSketchPad" to explore the centres of a triangle. This introductory exercise is suggested in the GSP "Workshop Guide". Students can use "JavaSketchPad Interactive Geometry" (JSP) at home at no cost. They are likely to impress their parents with their enthusiasm for geometry and all…

  6. Interorganisatorisk styring i Shared Service Centre

    DEFF Research Database (Denmark)

    Harritz, Daniel

    2011-01-01

    I den offentlige sektor er der en stigende udbredelse af Shared Service Centre (SSC). Men der er endnu meget lidt viden om de interorganisatoriske styringsproblemstillinger, der opstår når et SSC oprettes. I denne artikel præsenteres, ud fra et interorganisatorisk perspektiv, en styringsramme der...

  7. In the Field: The Canadian Ecology Centre.

    Science.gov (United States)

    Magee, Clare

    2000-01-01

    The Canadian Ecology Centre (Ontario) offers year-round residential and day programs in outdoor and environmental education for secondary students, field placement and internship opportunities for college students, and ecotourism programs, while providing employment and tax revenues to the local community. Dubbed consensus environmentalism, the…

  8. Magnetic quantum dots and magnetic edge states

    International Nuclear Information System (INIS)

    Starting with defining the magnetic edge state in a magnetic quantum dot, which becomes quite popular nowadays conjunction with a possible candidate for a high density memory device or spintronic materials, various magnetic nano-quantum structures are reviewed in detail. We study the magnetic edge states of the two dimensional electron gas in strong perpendicular magnetic fields. We find that magnetic edge states are formed along the boundary of the magnetic dot, which is formed by a nonuniform distribution of magnetic fields. These magnetic edge states circulate either clockwise or counterclockwise, depending on the number of missing flux quanta, and exhibit quite different properties, as compared to the conventional ones which are induced by electrostatic confinements in the quantum Hall system. We also find that a close relation between the quantum mechanical eigenstates and the classical trajectories in the magnetic dot. When a magnetic dot is located inside a quantum wire, the edge-channel scattering mechanism by the magnetic quantum dot is very different from that by electrostatic dots. Here, the magnetic dot is formed by two different magnetic fields inside and outside the dot. We study the ballistic edge-channel transport and magnetic edge states in this situation. When the inner field is parallel to the outer one, the two-terminal conductance is quantized and shows the features of a transmission barrier and a resonator. On the other hand, when the inner field is reversed, the conductance is not quantized and all channels can be completely reflected in some energy ranges. The difference between the above two cases results from the distinct magnetic confinements. We also describe successfully the edge states of magnetic quantum rings and others in detail

  9. Coherent scattering in a small quantum dot

    International Nuclear Information System (INIS)

    Ballistic transport in an open small (100 nm) three-terminal quantum dot based on the high-mobility two-dimensional electron gas of the AlGaAs/GaAs heterojunction has been analyzed. It has been shown that the gate oscillations of resistance of such a dot arise due to the coherent scattering of electrons on its quasidiscrete levels being suppressed by a weak magnetic field

  10. Exploring Extragalactic Emission: The Hα Dot Survey

    Science.gov (United States)

    Rampalli, Rayna; Salzer, John Joseph

    2016-01-01

    The Hα Dot Survey was established as a result of finding point sources of strong line emission in the data obtained for the ALFALFA Hα Survey (Van Sistine et al. 2015). In the latter survey, broad-band R and narrow-band Hα filters were used to examine target galaxies from the ALFALFA blind HI survey (Giovanelli et al. 2005, Haynes et al. 2011). In the process of reducing the ALFALFA Hα Survey data the "Hα Dots" were discovered (Kellar et al. 2008, 2012). Using specialized image analysis tools, a large population of dots has already been detected in the more than 1500 ALFALFA Hα narrow-band images taken with the 0.9m WIYN and 2.1m KPNO telescopes. Follow-up spectra of over 200 Hα Dots discovered from the 0.9m images reveal that these objects are a mix of nearby low-luminosity star-forming galaxies, compact starbursts and Seyfert 2 galaxies at intermediate redshifts, and high-redshift QSOs. Here we present the first list of Hα Dots detected using 2.1m telescope data. The 2.1m images yield a sample of Dots that average almost two magnitudes fainter than those detected with the 0.9m. The current REU project is designed to characterize the set of Hα Dots detected in the deeper 2.1m telescope images, while the broad goals of the Hα Dot Survey include the desire to understand better the chemical evolution of galaxies over cosmic time. This project was supported in part by the NSF REU grant 1358980, by the Maria Mitchell Association (Nantucket, MA), and by the Massachusetts Space Grant Consortium.

  11. Quantum dot cascade laser: Arguments in favor

    OpenAIRE

    Dmitriev, I. A.; Suris, R. A.

    2007-01-01

    Quantum cascade lasers are recognized as propitious candidates for future terahertz optoelectronics. Here we demonstrate several definite advantages of quantum dot cascade structures over quantum well devices, which suffer fundamental performance limitations owing to continuous carrier spectrum. The discrete spectrum of quantum dots opens an opportunity to control the non-radiative relaxation and optical loss and also provides for more flexibility in the choice of an optical and electrical de...

  12. Electronic Commerce Beyond the "dot com" Boom

    OpenAIRE

    James A. Senn

    2000-01-01

    The explosion of interest in electronic commerce stemming from commercial use of the Internet triggered high expectations, and accompanying high stock market value for public companies specializing in the delivery of products and services through this channel. However, the boom in the market value of these so-called "dot com" companies appears to be over. This paper examines the factors underlying the fall off in the value of "dot com" companies, focusing on the manner in which fundamental bu...

  13. Nuclear Electric Visitor Centres - Innovation and inspiration

    International Nuclear Information System (INIS)

    Full text: This eight minute video demonstrates the approach taken by Nuclear Electric to exhibitions that are open to the public. The information is given both visually - with excerpts from some of the attractions on display at the centres - and in comments from interviews with visitors, the centre guides and the man responsible for many of the exhibits featured in the video. on one side are the schoolchildren who are visiting the exhibition and are seen both playing and learning as they press buttons, watch videos, 'meet' Michael Faraday, and learn about radiation - its disposal and its safe transportation. The headmaster of the school is interviewed and explains that the exhibition is helping his children understand the importance of electricity to their world. on the other side is Jackie Lucas, the visitor centre manager, explaining what the public make of the exhibition. We see her staff greeting the children and helping them to understand the show. The designer of the exhibition, Len Upton explains how you go about making an exhibition such as this both informative and fun. Also interviewed is the man behind many of the exhibitions featured at Nuclear Electric's visitor centres up and down the country, Nicholas Mullane. He explains the purpose of the exhibition and what messages it imparts. The video is presented in split-screen or composite format, whereby the interviewee and children are often presented together. Excerpts from the various videos on display are presented as both how they are seen from the floor, as well as the full screen effect of the various programmes. The video gives much of the feeling of fun to be gained at the exhibition, as well as showing the educational benefits to be gained from a couple of hours at one of Nuclear Electric's visitor centres. Copies of the video can be obtained from Bob Fenton at Nuclear Electric. (Fax: ++44 1 452 652 443). (author)

  14. Person-centred care in nursing documentation.

    LENUS (Irish Health Repository)

    Broderick, Margaret C

    2012-12-07

    BACKGROUND: Documentation is an essential part of nursing. It provides evidence that care has been carried out and contains important information to enhance the quality and continuity of care. Person-centred care (PCC) is an approach to care that is underpinned by mutual respect and the development of a therapeutic relationship between the patient and nurse. It is a core principle in standards for residential care settings for older people and is beneficial for both patients and staff (International Practice Development in Nursing and Healthcare, Chichester, Blackwell, 2008 and The Implementation of a Model of Person-Centred Practice in Older Person Settings, Dublin, Health Service Executive, 2010a). However, the literature suggests a lack of person-centredness within nursing documentation (International Journal of Older People Nursing 2, 2007, 263 and The Implementation of a Model of Person-Centred Practice in Older Person Settings, Dublin, Health Service Executive, 2010a). AIMS AND OBJECTIVES: To explore nursing documentation in long-term care, to determine whether it reflected a person-centred approach to care and to describe aspects of PCC as they appeared in nursing records. METHOD: A qualitative descriptive study using the PCN framework (Person-centred Nursing; Theory and Practice, Oxford, Wiley-Blackwell, 2010) as the context through which nursing assessments and care plans were explored. RESULTS: Findings indicated that many nursing records were incomplete, and information regarding psychosocial aspects of care was infrequent. There was evidence that nurses engaged with residents and worked with their beliefs and values. However, nursing documentation was not completed in consultation with the patient, and there was little to suggest that patients were involved in decisions relating to their care. IMPLICATIONS FOR PRACTICE: The structure of nursing documentation can be a major obstacle to the recording of PCC and appropriate care planning. Documentation

  15. Positioning of quantum dots on metallic nanostructures

    International Nuclear Information System (INIS)

    The capability to position individual emitters, such as quantum dots, near metallic nanostructures is highly desirable for constructing active optical devices that can manipulate light at the single photon level. The emergence of the field of plasmonics as a means to confine light now introduces a need for high precision and reliability in positioning any source of emission, which has thus far been elusive. Placing an emission source within the influence of plasmonic structures now requires accuracy approaching molecular length scales. In this paper we report the ability to reliably position nanoscale functional objects, specifically quantum dots, with sub-100-nm accuracy, which is several times smaller than the diffraction limit of a quantum dot's emission light. Electron beam lithography-defined masks on metallic surfaces and a series of surface chemical functionalization processes allow the programmed assembly of DNA-linked colloidal quantum dots. The quantum dots are successfully functionalized to areas as small as (100 nm)2 using the specific binding of thiolated DNA to Au/Ag, and exploiting the streptavidin-biotin interaction. An analysis of the reproducibility of the process for various pattern sizes shows that this technique is potentially scalable to the single quantum dot level with 50 nm accuracy accompanied by a moderate reduction in yield.

  16. Quantum-dot-in-perovskite solids

    KAUST Repository

    Ning, Zhijun

    2015-07-15

    © 2015 Macmillan Publishers Limited. All rights reserved. Heteroepitaxy - atomically aligned growth of a crystalline film atop a different crystalline substrate - is the basis of electrically driven lasers, multijunction solar cells, and blue-light-emitting diodes. Crystalline coherence is preserved even when atomic identity is modulated, a fact that is the critical enabler of quantum wells, wires, and dots. The interfacial quality achieved as a result of heteroepitaxial growth allows new combinations of materials with complementary properties, which enables the design and realization of functionalities that are not available in the single-phase constituents. Here we show that organohalide perovskites and preformed colloidal quantum dots, combined in the solution phase, produce epitaxially aligned \\'dots-in-a-matrix\\' crystals. Using transmission electron microscopy and electron diffraction, we reveal heterocrystals as large as about 60 nanometres and containing at least 20 mutually aligned dots that inherit the crystalline orientation of the perovskite matrix. The heterocrystals exhibit remarkable optoelectronic properties that are traceable to their atom-scale crystalline coherence: photoelectrons and holes generated in the larger-bandgap perovskites are transferred with 80% efficiency to become excitons in the quantum dot nanocrystals, which exploit the excellent photocarrier diffusion of perovskites to produce bright-light emission from infrared-bandgap quantum-tuned materials. By combining the electrical transport properties of the perovskite matrix with the high radiative efficiency of the quantum dots, we engineer a new platform to advance solution-processed infrared optoelectronics.

  17. Coherent transport through interacting quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Hiltscher, Bastian

    2012-10-05

    The present thesis is composed of four different works. All deal with coherent transport through interacting quantum dots, which are tunnel-coupled to external leads. There a two main motivations for the use of quantum dots. First, they are an ideal device to study the influence of strong Coulomb repulsion, and second, their discrete energy levels can easily be tuned by external gate electrodes to create different transport regimes. The expression of coherence includes a very wide range of physical correlations and, therefore, the four works are basically independent of each other. Before motivating and introducing the different works in more detail, we remark that in all works a diagrammatic real-time perturbation theory is used. The fermionic degrees of freedom of the leads are traced out and the elements of the resulting reduced density matrix can be treated explicitly by means of a generalized master equation. How this equation is solved, depends on the details of the problem under consideration. In the first of the four works adiabatic pumping through an Aharonov-Bohm interferometer with a quantum dot embedded in each of the two arms is studied. In adiabatic pumping transport is generated by varying two system parameters periodically in time. We consider the two dot levels to be these two pumping parameters. Since they are located in different arms of the interferometer, pumping is a quantum mechanical effect purely relying on coherent superpositions of the dot states. It is very challenging to identify a quantum pumping mechanism in experiments, because a capacitive coupling of the gate electrodes to the leads may yield an undesired AC bias voltage, which is rectified by a time dependent conductance. Therefore, distinguishing features of these two transport mechanisms are required. We find that the dependence on the magnetic field is the key feature. While the pumped charge is an odd function of the magnetic flux, the rectified current is even, at least in

  18. Coherent transport through interacting quantum dots

    International Nuclear Information System (INIS)

    The present thesis is composed of four different works. All deal with coherent transport through interacting quantum dots, which are tunnel-coupled to external leads. There a two main motivations for the use of quantum dots. First, they are an ideal device to study the influence of strong Coulomb repulsion, and second, their discrete energy levels can easily be tuned by external gate electrodes to create different transport regimes. The expression of coherence includes a very wide range of physical correlations and, therefore, the four works are basically independent of each other. Before motivating and introducing the different works in more detail, we remark that in all works a diagrammatic real-time perturbation theory is used. The fermionic degrees of freedom of the leads are traced out and the elements of the resulting reduced density matrix can be treated explicitly by means of a generalized master equation. How this equation is solved, depends on the details of the problem under consideration. In the first of the four works adiabatic pumping through an Aharonov-Bohm interferometer with a quantum dot embedded in each of the two arms is studied. In adiabatic pumping transport is generated by varying two system parameters periodically in time. We consider the two dot levels to be these two pumping parameters. Since they are located in different arms of the interferometer, pumping is a quantum mechanical effect purely relying on coherent superpositions of the dot states. It is very challenging to identify a quantum pumping mechanism in experiments, because a capacitive coupling of the gate electrodes to the leads may yield an undesired AC bias voltage, which is rectified by a time dependent conductance. Therefore, distinguishing features of these two transport mechanisms are required. We find that the dependence on the magnetic field is the key feature. While the pumped charge is an odd function of the magnetic flux, the rectified current is even, at least in

  19. Treatment outcomes of patients placed on treatment under directly observed therapy short-course (DOTS

    Directory of Open Access Journals (Sweden)

    Kaur Gurpreet

    2008-01-01

    Full Text Available Background : Tuberculosis continues to be a pressing health problem in India. The Revised National Tuberculosis Programme (RNTCP, an application of Directly Observed Treatment Short-course (DOTS in India, launched in 1997 needs contin-uous evaluation. Objective : To study the outcomes of treatment among the patients put on DOTS under RNTCP in Chandigarh, UT. Material & Methods : A Longitudi-nal study was conducted during 2004-2005 in 13 Microscopic centres (MC′s spread over 2 Tuberculosis Units (TU′s under District Tuberculosis Centre (DTC in Union Territory (UT, Chandigarh. A sample of 265 respondents, selected by two-stage stratified random sampling technique, was recruited in the study cohort. Data analysis was done using SPSS-10 statistical software package. Results : For Category I and Category II patients, the Success rate was 98.6% and 90.4% respectively. The overall default rate was 1.1% and failure rate was 2.6%. For re-treatment cases, failure rate was higher i.e. 5.8%. The sputum conversion rate among the new smear positive cases was 93.8% at 3 months of treatment. For the re-treatment cases, spu-tum conversion rate at 3 months was 94.1%. Conclusion : The study concludes that RNTCP is running successfully in UT Chandigarh, having high success rate and low default rate. The reasons for high failure rate should be explored in depth.

  20. Low temperature method for synthesis of ZnS quantum dots and its luminescence characterization studies

    International Nuclear Information System (INIS)

    Highlights: ► We prepared zinc sulfide (ZnS) quantum dots of sizes 2.68–4.8 nm. ► It is embedded on polyvinyl alcohol (PVA) matrix, have been synthesized at 70° C by wet chemical method. ► Optical absorption spectra showed strong blue shift, which is an indication of strong quantum confinement. ► ZnS quantum dots exhibit strong quantum confinement effect as the optical band gap increases significantly, from 3.96 eV to 4.06 eV, compared to bulk value 3.68 eV. - Abstract: Zinc Sulfide (ZnS) quantum dots of sizes 2.68–4.8 nm, embedded on polyvinyl alcohol (PVA) matrix, have been synthesized at 70° C by wet chemical method. X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), UV–vis spectroscopy and photoluminescence (PL) Spectroscopy has been adopted for sample characterization. Optical absorption spectra showed strong blue shift, which is an indication of strong quantum confinement. Photoluminescence spectra of the sample have been recorded at room temperature and observed two peaks centred around 415 nm and 440 nm. We have assigned the first peak due to band gap transitions while the later due to sulfur vacancy in the sample.

  1. A new structure to increase the photostability of CdTe quantum dot sensitized solar cells

    International Nuclear Information System (INIS)

    In this paper a new cell structure is introduced to reduce the rate of CdTe corrosion in quantum dot sensitized solar cells (QDSSCs) using I-/I3- electrolyte. In this cell, one electrode is a titania nanorod that was sensitized with CdTe quantum dots as the working electrode. A thin gold layer is sputtered on the electrode to act as a protective layer against the I-/I3- corrosive electrolyte and to passivate the CdTe surface traps which are the main recombination centres in a QDSSC. In addition, a Schottky barrier formed at the interface of Au and CdTe prevents direct electron recombination from the CdTe conduction band with I3- ions. The mechanism of charge transfer and quantum dot regeneration in the presence of gold layer is discussed and our results show that the solar cells made of TiO2/CdTe/Au photoanode have more photostability and a higher fill factor relative to the TiO2/CdTe photoanodes.

  2. The Manche storage centre: Annual report 2010; Centre de stockage de la Manche Rapport annuel 2010

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    This report presents the installations of the CSM (Centre de Stockage de la Manche), the first French centre for the surface storage of low and intermediate level radioactive wastes. It briefly describes the site and its buildings, the multi-layer principle which is used to cover the wastes, how surface and drainage waters are managed, which controls are performed. It presents the different nuclear safety measures: principles, prevention measures, technical measures to meet the requirements, the legal plan for the control of the Centre and its environment, the quality management organization. It presents the measures regarding radioprotection and safety, indicates incidents and accidents which occurred in 2010, gives information and data on release management (effluents, controls, obtained data on surface and underground waters in different points). It briefly comments how the Centre's wastes are managed, evokes the case of other pollutions, and indicates actions performed in terms of public information

  3. Realistic model of a vertical pillar quantum dot: Analysis of individual dot data

    NARCIS (Netherlands)

    Maksym, P.A.; Nishi, Y.; Austing, D.G.; Hatano, T.; Kouwenhoven, L.P.; Aoki, H.; Tarucha, S.

    2009-01-01

    An accurate model of a vertical pillar quantum dot is described. The full three-dimensional structure of the device containing the dot is taken into account and this leads to an effective two-dimensional model in which electrons move in the two lateral dimensions, the confinement is parabolic, and t

  4. Measurement of Eccentricity of the Centre of Mass from the Geometric Centre of a Sphere

    Institute of Scientific and Technical Information of China (English)

    郭俊起; 胡忠坤; 顾邦明; 罗俊

    2004-01-01

    The eccentricity of the centre of mass from the geometric centre of a spherical attracting mass in determining the Newtonian gravitational constant G is tested by means of an electronic balance. The experimental result shows that the eccentricity of the sample is about 0.31 μm with uncertainty of 0.05 μm. Two density distribution models are discussed to estimate the uncertainty to G by the eccentricities of the attracting masses.

  5. (In,Mn)As multilayer quantum dot structures

    International Nuclear Information System (INIS)

    (In,Mn)As multilayer quantum dots structures were grown by molecular beam epitaxy using a Mn selective doping of the central parts of quantum dots. The study of the structural and magneto-optical properties of the samples with three and five layers of (In,Mn)As quantum dots has shown that during the quantum dots assembly, the out-diffusion of Mn from the layers with (In,Mn)As quantum dots can occur resulting in the formation of the extended defects. To produce a high quality structures using the elaborated technique of selective doping, the number of (In,Mn)As quantum dot layers should not exceed three

  6. Submonolayer Quantum Dot Infrared Photodetector

    Science.gov (United States)

    Ting, David Z.; Bandara, Sumith V.; Gunapala, Sarath D.; Chang, Yia-Chang

    2010-01-01

    A method has been developed for inserting submonolayer (SML) quantum dots (QDs) or SML QD stacks, instead of conventional Stranski-Krastanov (S-K) QDs, into the active region of intersubband photodetectors. A typical configuration would be InAs SML QDs embedded in thin layers of GaAs, surrounded by AlGaAs barriers. Here, the GaAs and the AlGaAs have nearly the same lattice constant, while InAs has a larger lattice constant. In QD infrared photodetector, the important quantization directions are in the plane perpendicular to the normal incidence radiation. In-plane quantization is what enables the absorption of normal incidence radiation. The height of the S-K QD controls the positions of the quantized energy levels, but is not critically important to the desired normal incidence absorption properties. The SML QD or SML QD stack configurations give more control of the structure grown, retains normal incidence absorption properties, and decreases the strain build-up to allow thicker active layers for higher quantum efficiency.

  7. Non-Equilibrium Electron Transport through a Double Quantum Dot System: Study of Two Exchange Coupled Quantum Dots in a 4-Terminal Geometry

    OpenAIRE

    Koerting, Verena

    2007-01-01

    In this thesis we study two exchange-coupled quantum dots with an emphasis on non-equilibrium physics. Assuming a single electron on each quantum dot, the double quantum dot system is characterized by an interplay between the Kondo spin coupling of the dots with the leads and the spin-exchange coupling between the dots. We find that a finite voltage on one quantum dot drives the other quantum dot out of equilibrium.

  8. JOB CENTRE FOR DOMESTIC STAFF IN SWITZERLAND

    CERN Multimedia

    Relations with the Host States Service; http://www.cern.ch/relations/

    2001-01-01

    The Permanent mission of Switzerland to the International Organisations in Geneva has informed CERN that the Geneva Welcome Centre has set up an employment registration desk for the domestic staff of international civil servants. The aim of this pilot project is, on the one hand, to help international civil servants find domestic staff and, on the other hand, to help domestic staff holding an 'F'-type carte de légitimation find employment within 30 days after the expiry of a contract. For more information, please contact the Geneva Welcome Centre, La Pastorale, 106, route de Ferney, Case postale 103, 1211 Genève 20, tel. (+41.22) 918 02 70, fax (+41.22) 918 02 79), http://geneva-international.org/Welcome.E.html.

  9. Danish Polymer Centre annual report 2001

    DEFF Research Database (Denmark)

    Hassager, O.; Hvilsted, S.; Mortensen, Kell

    campus in Lyngby as shown in the pictures on this page. In addition to well equipped laboratories at Risø which will be expanded in 2002 and 2003, thesefacilities provide a common ground for polymer chemists, polymer physicists, chemical engineers and mechanical engineers from the two institutions. The......The centre is a collaboration between the Risø National Laboratory and the Technical University of Denmark (DTU). At the DTU the Department of Chemical Engineering and the Department of Manufacturing Engineering and Management participate in the centre.From 2001 the Polymer Department at Risø...... coordinates the activities at Risø From the outset it was considered important with common laboratories to obtain the full effect of the collaboration between the two departments at the DTU and Risø NationalLaboratory. In 2001 new laboratories for polymer research and education were established at the DTU...

  10. Patient-centred Prevention among PAD Patients

    DEFF Research Database (Denmark)

    Pii, Kathrine Hoffmann

    2014-01-01

    Intro: This paper discusses a central professional dilemma in patient-centred education: on one hand the concern for ensuring patients autonomy and right to make their own decisions regarding their treatment and, on the other hand, a concern for getting patients to make the “right” decisions that...... will improve their health condition. The patient-centred approach (and related concepts: patient participation, involvement, and empowerment) is being promoted both in healthcare politics and by healthcare professionals as a way to achieve more active self-managing and self-caring patients. Patient......-centredness is thus promoted as a way to organize health more effectively (in terms of cost and treatment outcomes) and as a way to ensure patients’ autonomy and fundamental right to make their own decisions regarding their treatment. Critical voices within social and nursing theory have however argued that the...

  11. It's all change at the Computer Centre

    CERN Multimedia

    Laëtitia Pedroso

    2011-01-01

    The IT and EN Departments are modernising the infrastructure of the Computer Centre to improve the conditions in which the equipment has to operate and to increase capacity. The construction work has already begun and is due to be completed in October 2012.   Every year CERN experiences around ten power cuts lasting from less than a second to several hours. In most cases the two protection systems - the UPS* and the diesel generators – are able to ensure that the operation of the Computer Centre is not affected. As Vincent Doré, the project leader for the IT Department, and Paul Pepinster, the EN Department's technical coordinator in charge of modernising the infrastructure, explains: "Building 513 has two types of computing facilities – the "non-critical" ones, such as the servers for "off-line" computing, which have UPS systems ensuring that they can operate for 10 minutes after a power cut, and the "critical&...

  12. Display-centred applications in ubiquitous computing

    OpenAIRE

    José, Rui; Pinto, Helder

    2006-01-01

    Public displays can play an important enabling role in ubiquitous computing environments. This paper describes an on-going work for a multipurpose, multi-display infrastructure, designed to address the requirements of display-centred applications in ubiquitous computing environments. The system provides an infrastructure in which situated displays can act as portals to the physical space, allowing ubicomp applications to support their association with the physical world by providing them with...

  13. Training science centre Explainers. The Techniquest experience

    Directory of Open Access Journals (Sweden)

    Colin Johnson

    2005-12-01

    Full Text Available Techniquest was established in 1986, and in 1995 moved to its current premises at Cardiff Bay, South Wales. This was the first purpose-built science centre in the UK. It receives around 200,000 visitors every year to its exhibition, and to its programmes for schools and public audiences in the theatre, laboratory, discovery room and planetarium. The author joined the Techniquest project in 1985, became a staff member in 1990 and was the Chief Executive from 1997 until his retirement in 2004. Techniquest has three “out-stations” in Wales, and is responsible for the supply and maintenance of exhibits to the Look Out Discovery Centre in Bracknell, England. There is a Techniquest gallery at the Lisbon Pavilhão do Conhecimento - Ciência Viva, and a traveling exhibition, SciQuest, in South Africa which was also supplied by Techniquest. All these centres rely on the effective intervention of “Explainers” (at Techniquest we call them “Helpers” to provide the best possible experience for visitors. At its most demanding, the tasks of an Explainer are varied and intensive, yet there may be times when the duties are mundane or even dull. When you rely on people to act as both hosts and housekeepers, to provide both support and stimulus, and to be both welcoming and watchful, you are asking a great deal. This article raises some of the issues concerned with the recruitment and retention of Explainers, their training and management, and the way in which their role is recognized and valued by the science centre as a whole.

  14. CMS Centres Worldwide - a New Collaborative Infrastructure

    CERN Document Server

    Taylor, Lucas

    2011-01-01

    Webcasts, and generic Web tools such as CMS-TV for broadcasting live monitoring and outreach information. Being Web-based and experiment-independent, these systems could easily be extended to other organizations. We describe the experiences of using CMS Centres Worldwide in the CMS data-taking operations as well as for major media events with several hundred TV channels, radio stations, and many more press journalists simultaneously around the world.

  15. Learning Styles of Independent Learning Centre Users

    OpenAIRE

    Tarik Uzun

    2014-01-01

    Learning style research has been a significant field within language teaching and learning. There have been very few attempts, however, to seek possible links between independent learning and learning style preferences. This paper aims to identify the learning styles of students who use the Independent Learning Centre (ILC) on a regular basis at a state university in Turkey (n=102). The findings of the learning style analysis revealed that, contrary to expectations, most of the regular users ...

  16. The Researcher : The Refugee Documentation Centre Newsletter

    OpenAIRE

    Ahmed, Elisabeth; Goggins, David

    2014-01-01

    Contents: Subsidiary Protection – a distinct and autonomous form of complementary protection / Enda O’Neill, Jennifer Higgins, UNHCR Ireland; Recent Changes at the Refugee Appeals Tribunal / Barry Magee, Refugee Appeals Tribunal; The Use of Decision Templates for Refugee Status Determination / Seán O’Connell, Refugee Appeals Tribunal; Forced Marriage in Afghanistan / David Goggins, Refugee Documentation Centre; Houses of the Holy: Iraq and the last days of the Mandeans / Patrick Dowling, R...

  17. Structure and Responsibilities of Radiation Protection Centre

    International Nuclear Information System (INIS)

    Constitution of Radiation Protection Centre (RPC) in Lithuania is presented. RPC was established in 1997, in 1999 the Government granted the status of the regulatory authority of Lithuania on radiation protection issues. Currently there are two departments at RPC: two in Vilnius - Department of Radiation Protection Supervision and Control and Department of Programs and Expertise, and four in the districts. Main tasks of RPC are listed

  18. Introducing the PET Centre Bydgoszcz - Poland

    International Nuclear Information System (INIS)

    Opening the PET station held 26th February, 2003 was an excellent opportunity to present Regional Centre of Oncology in Bydgoszcz, the city in northern Poland. Department of Nuclear Medicine and its building, equipment, CT/PET station and scanning parameters, the cyclotron with basic technical data have been shortly described. A future of PET diagnostics in Poland taking into account the economical factors has been also discussed

  19. The Elusiveness of Learner-centred Teaching

    OpenAIRE

    Kovačević, Ervin; AKBAROV, Azamat

    2016-01-01

    This research will explore teaching styles of university professors. Teaching style is an umbrella term for teaching decisions made during the entire teaching process – planning, delivery, and evaluation. Contemporary university teachers are advised to adopt the learner-centred teaching style which is assumed to produce remarkable possibilities. In the Fall Semester 2015 fifty-two respondents in different faculties of International University of Sarajevo were surveyed using The Principles of ...

  20. Bismuth centred magnetic perovskite: A projected multiferroic

    International Nuclear Information System (INIS)

    In recent time substantial attention has been initiated to understand the physics behind multiferroism and to design new multiferroic materials. BiMnO3 and BiFeO3 are the well-studied Bi-centred multiferroic oxides. BiMnO3 is a ferromagnetic–ferroelectric (metastable) phase and require drastic conditions to synthesize. However, lanthanum substituted BiMnO3 phases stabilized at ambient pressure. It is thus of major importance to increase the number of ferromagnetic perovskites with Bi cations that could be designed under ambient conditions. In this article, we have presented an up to date report of investigations on Bi-centred magnetic perovskites, a prospective material for multiferroic application. Central focus is concentrated on La0.5Bi0.5MnO3 perovskite with various substitutions at different levels. A few of these perovskites are found to be of practical importance e.g. La0.5Bi0.5Mn0.67Co0.33O3 with high dielectric permittivity coupled with ferromagnetism. A comprehensive analysis of different physical functionalities and their interrelation for a wide range of compositions of these Bi-centred perovskites is presented. It has been found that the complex magnetic behaviour originates from mixed valence metal ions. The ferroelectricity is associated with the 6s2 lone pair of Bi3+ cations. The magnetic ground state influences the dielectric properties reflecting the multiferroism in a single material. - Highlights: • Multiferroics have attracted increasing attention due to their possible device applications. • Bismuth centred magnetic perovskite is one kind of such promising multiferroic materials. • Ferromagnetic Bi-perovskites, which are synthesized at ambient conditions, have been discussed

  1. Shielding design for ETOILE hadron therapy centre

    International Nuclear Information System (INIS)

    The Ion Beam Applications Company is developing a compact superconducting cyclotron for hadron therapy able to deliver various ion beams with an energy of 400 MeV per nucleon and proton beams with an energy of 260 MeV. This system is being proposed to equip ETOILE hadron therapy centre in Lyon. Shielding design based on PHITS and MCNPX Monte Carlo simulation codes is presented, together with some performance figures for the energy degrader. (authors)

  2. Benefits of Reliability Centred Asset Management

    OpenAIRE

    Hilber, Patrik; Wallnerström, Carl Johan; Rosenlind, Johanna; Babu, Sajeesh; Westerlund, Per

    2013-01-01

    This paper provides an overview of risk and reliability assessment techniques, some which are available for distribution system operators, and others that are in the process of development. The main contribution of this paper is showing the possibilities and benefits of detailed risk and reliability analysis. Six samples of findings from research developed over the last decade within the RCAM group (Reliability Centred Asset Management) at the Royal Institute of Technology, Stockholm Sweden, ...

  3. LSE centre for economic performance: bankers’ bonuses

    OpenAIRE

    Bell, Brian

    2010-01-01

    A new series of Election Analyses is now available from the LSE’s Centre for Economic Performance (CEP). The series will discuss the research evidence on some of the key policy battlegrounds of the 2010 General Election, including macroeconomic policy, immigration, health, education, crime, poverty and inequality, labour market policy, regional policy, energy and the environment, financial regulation and bankers’ bonuses, and foreign aid. The latest CEP Election Analysis, by Brian Bell, g...

  4. Mathematical modelling of Regional Fuel Cycle Centres

    International Nuclear Information System (INIS)

    The concept of Regional Fuel Cycle Centres (RFCC) has attracted wide interest as a possible approach towards meeting the nuclear fuel cycle needs of many countries. As part of its study of the RFCC concept, the International Atomic Energy Agency is developing mathematical models and associated computer codes to analyse the economics and logistics of various strategies for management of spent nuclear fuel and waste materials. (author)

  5. The LifeWatch Service Centre Plan

    OpenAIRE

    Parr, Terry; Spinelli, Oliviero; Mauri, Maria Paola; Billisari, Livia; Hardisty, Alex; Ludlow, David; Khan, Zaheer; Roberts, Dave; Sleep, Chris; Sier, Andrew

    2011-01-01

    This report summarises the construction plan for the Lifewatch Service Centre. The main purpose of LifeWatch is to serve the biodiversity and ecosystem research community in its work on the understanding and rational management of our ecosystems for use by policy makers, resource managers, the private sector and the general public. To do this the LifeWatch infrastructure will provide capabilities to analyse, model and simulate with integrated biodiversity and ecosystem data from many dive...

  6. Studies of the CNESTEN's Nuclear Research Centre

    International Nuclear Information System (INIS)

    The different steps of the methodology applied to the site selection of Maamora's Nuclear Research Centre, within a 20 km wide coastal band preliminarily fixed between Kenitra and Casablanca cities, are outlined: delimitation of potential zones, identification of potential sites, selection of preferred sites. A particular attention is given to the criterium of the methodology applied to the preferred sites classifying. 1 map, 2 tabs, 2 refs. (F.M.)

  7. Imperial College Reactor Centre annual report. 1983

    International Nuclear Information System (INIS)

    It is reported that the reactor operated reliably during the year with less than half a day of operating time lost by faults or failures. Brief accounts of the 34 research projects at the Centre are given, and a list of teaching experiments or visits is included. These include undergraduate and post-graduate teaching. Commercial requests for irradiations and neutron activation analysis are reported as increasing. (U.K.)

  8. Stability of some centres in quartz

    OpenAIRE

    Falguères, Christophe; Yokoyama, Yuji; Miallier, Didier

    1991-01-01

    Electron spin resonance (ESR) is a promising dating method for Quaternary sediments. A preliminary ESR analysis was done on quartz grains extracted from sediments baked by lava-flows of Massif Central (France). For this type of sample, zeroing occurs during heating. To test the reliability of the method, the palaeodoses were determined from centres (Al and Ti) and compared with those obtained by the thermoluminescence (TL) method.The annealing temperature and sunlight have an effect upon the ...

  9. Swasti: An International Health Resource Centre

    OpenAIRE

    N. S. Kumar

    2013-01-01

    Swasti, an International Health Resource Centre was established in 2002 in India. The objective was to enhance the health and well-being of communities, particularly the marginalized. Swasti’s main focus lies in the areas of primary health, sexual and reproductive health including HIV, communicable and non-communicable diseases, water, sanitation and hygiene and gender based violence. The organization, during the last decade has grown in leaps and bounds reaching out to the most affected comm...

  10. Upcoming opening of CERN's new Mobility Centre

    CERN Multimedia

    2016-01-01

    On 29 February, CERN’s brand new Mobility Centre opened in the Globe car park. The Centre has been created to cater to the transport needs of everyone at CERN, to simplify procedures and to centralise all the transport services on offer: the rental of CERN bikes and cars, the CERN car-sharing scheme and SIXT car rental.   From 29 February onwards, the Mobility Centre in the Globe car park will be the place to go for all your duty travel needs: rental of CERN cars (with or without the CERN logo), SIXT car rental, CERN bike rental, distribution of cards allowing the use of CERN’s self-service bike- and car-sharing schemes. That same day, the premises currently housing the Car Pool in Building 130 will become the CERN garage, responsible for: upkeep and repairs on CERN bikes, minor maintenance work on CERN vehicles (e.g. replacing windscreen wipers, bulbs and fuses, refilling windscreen washer fluid, pumping up tyres, etc.), arranging and following up the repair and maintenan...

  11. INFOTERM – Information Disseminating Centre for Terminology

    Directory of Open Access Journals (Sweden)

    Albina Auksoriūtė

    2014-12-01

    Full Text Available International Information Centre for Terminology (INFOTERM was founded in 1971 by contract with the United Nations Educational, Scientific and Cultural Organization (UNESCO and the Austrian Standards Institute (ASI. In 1996, INFOTERM was reorganized and established as an independent non-profit organization. INFOTERM promotes and supports the cooperation of existing and the establishment of new terminology centres and networks with the general aim to improve domain communication, knowledge transfer and provision of content with view to facilitating the participation of all in the global multilingual knowledge society. The article presents not only a history of the foundation of INFOTERM, the tasks and activities of INFOTERM and its members, which are international, regional or national terminology institutions, organizations and networks, as well as specialized public or semi-public or other non-profit institutions engaged in terminological activities, but also analyses “Guidelines for terminology policies”, preparied by INFOTERM, and cooperation between INFOTERM and the Institute of the Lithuanian Language.In conclusion, the experience and sharing expertise of INFOTERM regarding harmonized methods and guidelines for terminology management and policies, the management of terminology centres, terminology standardization, the use of terminological data, methods and tools in all applications etc are very important for all countries and language communities especially for countries and language communities with less mature terminologies. The Institute of the Lithuanian Language as a member of INFOTERM has a possibility to get information on terminology research and training, terminology publications, terminological events and activities all over the world.

  12. A new visitor centre for CMS

    CERN Multimedia

    2001-01-01

    At the inauguration of the new CMS visitor centre. The CMS experiment inaugurated a new visitor centre at its Cessy site on 14 June. This will allow the thousands of people who come to CERN each year to follow the construction of one the Laboratory's flagship experiments first-hand. CERN receives over 20,000 visitors each year. Until recently, many of them were taken on a guided tour of one of the LEP experiments. With the closure of LEP, however, trips underground are no longer possible, and the Visits' Service has put in place a number of other itineraries (Bulletin 46/2000). Since the CMS detector will be almost entirely constructed in a surface hall, it is now taking a big share of the limelight. The CMS visitor centre has been built on a platform overlooking CMS construction. It contains a set of clear descriptive posters describing the experiment, along with a video projection showing animations and movies about CMS construction. In the coming weeks, a display of CMS detector elements will be added, as...

  13. Gamma Rays frim the Galactic Centre

    CERN Document Server

    Erlykin, A D

    2007-01-01

    Recent results from the HESS gamma ray telescope have shown the presence of both a diffuse, extended, flux of gamma rays above ~0.4 TeV and discrete sources in and near the Galactic Centre. Here, we put forward a possible explanation in terms of the diffusion of cosmic ray protons from a succession of supernova remnants (SNR) in the SgrA* region of the Galaxy plus a contribution from SNR in the rest of the Galactic Centre Region, to be called the Galactic Centre Ridge (GCR). Protons are favoured over electrons because the mG magnetic fields in the Region will attenuate energetic electrons severely. Prominent features are the need for 'anomalous diffusion' of the protons in the whole region and the adoption of low efficiency for SNR acceleration in the high density regions. The latter is related by us to the well-known low 'cosmic ray gradient' in the Galaxy. A corroborating feature is the close correlation of inferred cosmic ray intensity with the smoothed intensity of 5 GHZ radio radiation. We attribute this...

  14. Spin Relaxation in Spherical CdS Quantum Dots

    Science.gov (United States)

    Nahalkova, P.; Sprinzl, D.; Nemec, P.; Maly, P.; Gladilin, V. N.; Devreese, J. T.

    2006-03-01

    We present results of the time-resolved spin-sensitive differential transmission experiments and the quantitative theoretical analysis of the spin relaxation mechanism in quasi-spherical CdS quantum dots (QD) in a glass matrix. The measured decay of the degree of circular polarization (DCP) on ns timescale can be explained well by intralevel exciton transitions with electron spin flip, driven by the electron-hole exchange interaction and assisted by two LO phonons. The predicted spin relaxation rates for different QD sizes and temperatures are in line with experimentally determined values. The developed theoretical model provides also a qualitative understanding of the observed behavior of DCP as a function of central energy of pump and probe pulses. This work was supported by the Ministry of Education of the Czech Republic in the framework of research plan MSM 0021620834 and the research centre LC510, as well as by the GOA BOF UA 2000, IUAP, FWO-V projects G.0274.01N, G.0435.03, WOG WO.035.04N (Belgium) and the European Commission SANDiE Network of Excellence, contract No. NMP4-CT-2004-500101.

  15. Colloidal Quantum dot photovoltaics: Tuning optoelectronic properties

    International Nuclear Information System (INIS)

    Full text: Colloidal quantum dots combine processing from the solution phase with tunability of the bandgap. Via the size-effect the optical properties can be matched to the solar spectrum for a wide-range photon harvesting. To engineer photovoltaic devices, quantum dots are compressed from their colloidal form into a close-packed nanocrystal matrix, while undergoing a systematic layer-by-layer process. The resulting quantum dot solid is treated as semiconductor medium - one having electron-hole mobilites, free carrier densities and a dielectric constant. While the size-effect determined the band-gap before, it is now the nature of ligand and the treatment route, that influences mentioned electronic parameters. We took the view on the processing steps and found a concept for analysing trap states, moblility and device performance in real quantum dot solids. Our findings emphasize the interplay of mobility and trap-distribution with routes that take special care on the nanocrystal surface and hence conserve optoelectronic qualities of quantum dots for efficient photovoltaic cells. (author)

  16. IAEA establishes International Seismic Safety Centre

    International Nuclear Information System (INIS)

    Full text: The IAEA today officially inaugurated an international centre to coordinate efforts for protecting nuclear installations against the effects of earthquakes. The International Seismic Safety Centre (ISSC), which has been established within the IAEA's Department of Nuclear Safety and Security, will serve as a focal point on seismic safety for nuclear installations worldwide. ISSC will assist countries on the assessment of seismic hazards of nuclear facilities to mitigate the consequences of strong earthquakes. 'With safety as our first priority, it is vital that we pool all expert knowledge available worldwide to assist nuclear operators and regulators to be well prepared for coping with major seismic events,' said Antonio Godoy, Acting Head of the IAEA's Engineering Safety Section and leader of the ISSC. 'The creation of the ISSC represents the culmination of three decades of the IAEA's active and recognized involvement in this matter through the development of an updated set of safety standards and the assistance to Member States for their application.' To further seismic safety at nuclear installations worldwide, the ISSC will: - Promote knowledge sharing among the international community in order to avoid or mitigate the consequences of extreme seismic events on nuclear installations; - Support countries through advisory services and training courses; and - Enhance seismic safety by utilizing experience gained from previous seismic events in member states. The centre is supported by a scientific committee of high-level experts from academic, industrial and nuclear safety authorities that will advise the ISSC on implementation of its programme. Experts have been nominated from seven specialized areas, including geology and tectonics, seismology, seismic hazard, geotechnical engineering, structural engineering, equipment, and seismic risk. Japan and the United States have both contributed initial funds for creation of the centre, which will be based at

  17. Addressing the challenges of patient-centred design

    Directory of Open Access Journals (Sweden)

    Karen LaBat

    2009-11-01

    Full Text Available Patient-centred design is a relatively new term, but a longstanding concept in clinical practice. This discussion looks at patient-centred design and explores the relationships of patient-centred design to universal design, user-centred design and the newer human-centred design. It also explores why interdisciplinary approaches are needed for patient-centred design and how interdisciplinary collaboration works to address the challenges of patient centred design. Successful patient-centred solutions can grow from collaborations which include shared visions, understanding of both the nature and degree of variation in the patient,materials, and the designed solution, clear regular communication among all parties with careful definition of terms, and respect for the inherent cultures of all disciplines involved.

  18. Nanosized Carbon Dots from Organic Matter and Biomass

    Institute of Scientific and Technical Information of China (English)

    LI Yuanyuan; CHEN Tong; MA Yulong

    2016-01-01

    Carbon nanoparticles (C-dots) were prepared by relfuxing the combustion soots of candles and corn stalk in nitric acid. The synthesized C-dots were characterized. The results showed a sharp increase in oxygen content and a sharp decrease in carbon content after oxidation. The C-dots had -OH and -CO2H groups introduced which made them hydrophilic. However, their difference was also obvious. The C-dots from candle soot had a 10-45 nm broad particle size distribution, and those from corn stalk soot had a 6-18 nm relatively small and narrow size distribution. The C-dots were mainly ofsp2 andsp3 carbon structure different from the C-dots of diamond-like structure from candle soot. Interestingly, two kinds of C-dots all exhibited unique photoluminescent properties. The obtained C-dots have potential applications in a broad range of areas.

  19. Origins and optimization of entanglement in plasmonically coupled quantum dots

    Science.gov (United States)

    Otten, Matthew; Larson, Jeffrey; Min, Misun; Wild, Stefan M.; Pelton, Matthew; Gray, Stephen K.

    2016-08-01

    A system of two or more quantum dots interacting with a dissipative plasmonic nanostructure is investigated in detail by using a cavity quantum electrodynamics approach with a model Hamiltonian. We focus on determining and understanding system configurations that generate multiple bipartite quantum entanglements between the occupation states of the quantum dots. These configurations include allowing for the quantum dots to be asymmetrically coupled to the plasmonic system. Analytical solution of a simplified limit for an arbitrary number of quantum dots and numerical simulations and optimization for the two- and three-dot cases are used to develop guidelines for maximizing the bipartite entanglements. For any number of quantum dots, we show that through simple starting states and parameter guidelines, one quantum dot can be made to share a strong amount of bipartite entanglement with all other quantum dots in the system, while entangling all other pairs to a lesser degree.

  20. Quantum dot optoelectronic devices: lasers, photodetectors and solar cells

    International Nuclear Information System (INIS)

    Nanometre-scale semiconductor devices have been envisioned as next-generation technologies with high integration and functionality. Quantum dots, or the so-called ‘artificial atoms’, exhibit unique properties due to their quantum confinement in all 3D. These unique properties have brought to light the great potential of quantum dots in optoelectronic applications. Numerous efforts worldwide have been devoted to these promising nanomaterials for next-generation optoelectronic devices, such as lasers, photodetectors, amplifiers, and solar cells, with the emphasis on improving performance and functionality. Through the development in optoelectronic devices based on quantum dots over the last two decades, quantum dot devices with exceptional performance surpassing previous devices are evidenced. This review describes recent developments in quantum dot optoelectronic devices over the last few years. The paper will highlight the major progress made in 1.3 μm quantum dot lasers, quantum dot infrared photodetectors, and quantum dot solar cells. (topical review)

  1. Inorganic passivation and doping control in colloidal quantum dot photovoltaics

    KAUST Repository

    Hoogland, Sjoerd H.

    2012-01-01

    We discuss strategies to reduce midgap trap state densities in colloidal quantum dot films and requirements to control doping type and magnitude. We demonstrate that these improvements result in colloidal quantum dot solar cells with certified 7.0% efficiency.

  2. THE IMPLEMENTATION OF PROFIT CENTRES INSIDE AN ECONOMIC ENTITY

    OpenAIRE

    ADRIAN GROSANU; PAULA RAMONA RACHISAN

    2008-01-01

    The first part of this paper presents, from a conceptual point of view, the responsibility centres and we used a theoretical and methodological approach that allows us to understand the role generally played by the responsibility centres, profit centres in particular, concerning the optimization of economic efficiency of a business. According to the existing particularities of economic entities of the cosmetic industry, we delimited some responsibility centres and identified some of the relat...

  3. Few-quantum-dot lasing in photonic crystal nanocavities

    DEFF Research Database (Denmark)

    Liu, Jin; Ates, Serkan; Stobbe, Søren; Lorke, Michael; Lodahl, Peter

    2012-01-01

    A very smooth lasing transition in photonic crystal nanocavities with embedded quantum dots is observed and compared to the theory. Decay rate measurements reveal that only a few quantum dots are feeding the cavity.......A very smooth lasing transition in photonic crystal nanocavities with embedded quantum dots is observed and compared to the theory. Decay rate measurements reveal that only a few quantum dots are feeding the cavity....

  4. Luminescence Spectra of a Quantum-Dot Cascade Laser

    OpenAIRE

    Apalkov, Vadim; Chakraborty, Tapash

    2000-01-01

    A quantum cascade laser where the quantum wells in the active regions are replaced by quantum dots with their atom-like discrete energy levels is an interesting system to study novel features in optical spectroscopy. We study structures suitable for diagonal lasing transitions in coupled dots, and vertical lasing transitions in a single dot, in the active regions of the laser device. The luminescence spectra as a function of electron number and dot size show that for diagonal transitions, a s...

  5. Short-wave infrared colloidal quantum dot photodetectors on silicon

    OpenAIRE

    Hu, Chen; Gassenq, Alban; Justo, Yolanda; Yakunin, Sergii; Heiss, Wolfgang; Hens, Zeger; Roelkens, Gunther

    2013-01-01

    In this paper, two kinds of colloidal quantum dots, PbS and HgTe, are explored for SWIR photodetectors application. The colloidal dots are prepared by hot injection chemical synthesis, with organic ligands around the dots keeping them stable in solution. For the purpose of achieving efficient carrier transport between the dots in a film, these long organic ligands are replaced by shorter, inorganic ligands. We report uniform, ultra-smooth colloidal QD films without cracks realized by dip-coat...

  6. Optical properties of a Quantum-Dot Cascade Structure

    OpenAIRE

    Apalkov, V. M.; Chakraborty, Tapash

    2001-01-01

    We report on our theoretical studies of the luminescence spectra of a quantum cascade laser where the quantum wells in the active regions are replaced by parabolic quantum dots. We analyze the influence of shape and size of the dots on the luminescence spectra. The emission spectra have interaction induced blueshift which increases almost linearly with increasing electron number. The blueshift is smaller for larger and non-circular dots. For large dots, shape of the emission line has weak dep...

  7. Excitonic Properties in GaAs Parabolic Quantum Dots

    OpenAIRE

    Jaziri, S.; Bennaceur, R.

    1995-01-01

    Certain classes of semiconductor quantum dots being actually fabricated exhibit a nearly parabolic confinement for both the electron and the hole. In undoped quantum dots, excitonic effects are important. In this work, first we present theoretical results on exciton properties in parabolic quantum dots: resonance energy, binding energy and oscillator strength. Then, we investigate the effects of external electric and magnetic fields on exciton in quantum dots.

  8. Canadian Educational Development Centre Websites: More Ebb than Flow?

    Science.gov (United States)

    Simmons, Nicola

    2010-01-01

    This paper examines information portrayed on Canadian educational development (ED) centre websites and, in particular, whether information that corresponds to questions compiled from a literature search of ED centre practices is readily available from centre websites. This study phase is part of a larger national study of Canadian educational…

  9. Tele-centres as a way of achieving universal access

    DEFF Research Database (Denmark)

    Falch, Morten; Anyimadu, Amos

    2003-01-01

    The success of tele-centres in Ghana is discussed. The tele-centres offer a low cost opportunity to empower local communities in developed and developing countries to meet the challenges of the information society. The tele-centres can also contribute more directly to the supply of non-commercial...

  10. Barrier Li Quantum Dots in Magnetic Fields

    Institute of Scientific and Technical Information of China (English)

    LIUYi-Min; LIXiao-Zhu; YANWen-Hong; BAOCheng-Guang

    2003-01-01

    The methods for the few-body system are introduced to investigate the states of the barrier Li quantum dots (QDs) in an arbitrary strength of magnetic field. The configuration, which consists of a positive ion located on the z-axis at a distaneed from the two-dimensional QD plane (the x-y plane) and three electrons in the dot plane bound by the positive ion, is called a barrier Li center. The system, which consists of three electrons in the dot plane bound by the ion,is called a barrier Li QD. The dependence of energy of the state of the barrier Li QD on an external magnetic field B and the distance d is obtained. The angular momentum L of the ground states is found to jump not only with the variation orB but also with d.

  11. Branch management into micropipeline joint dot

    Directory of Open Access Journals (Sweden)

    Dimitar Tyanev

    2011-11-01

    Full Text Available This paper considers problems related to hardware implementation of computational process with conditional jumps. Hardware refers to asynchronous pipeline organization at microoperational level. Exploration is dedicated to one of the tasks presented in (Tyanev, D., 2009 concerning to micropipeline controller design to control micropipeline stage into joint dot of branch algorithm. Joint dot is the point at which few preceding branches are combined. It appears inevitably into conditional jump structures and this is the reason for the actuality of its problem. Analysis of this new task is presented and request arbitration functioning principles are formulated for the incoming to joint dot requests. The arbiter is responsible for the fair choice on which depends steady peformance of separate pipeline brances. Paper also describes pipeline controller synthesis and analysis of its operation in two variants: about 2-phase and 4-phase data transfer protocol. The synthesized asynchronous arbiter scheme is invariant to the type of pipeline protocol.

  12. Bright infrared LEDs based on colloidal quantum-dots

    KAUST Repository

    Sun, Liangfeng

    2013-01-01

    Record-brightness infrared LEDs based on colloidal quantum-dots have been achieved through control of the spacing between adjacent quantum-dots. By tuning the size of quantum-dots, the emission wavelengths can be tuned between 900nm and 1650nm. © 2013 Materials Research Society.

  13. Correlated Coulomb drag in capacitively coupled quantum-dot structures

    DEFF Research Database (Denmark)

    Kaasbjerg, Kristen; Jauho, Antti-Pekka

    2016-01-01

    We study theoretically Coulomb drag in capacitively coupled quantum dots (CQDs) -- a biasdriven dot coupled to an unbiased dot where transport is due to Coulomb mediated energy transfer drag. To this end, we introduce a master-equation approach which accounts for higher-order tunneling (cotunneli...

  14. Weak localization in arrays of metallic quantum dots

    OpenAIRE

    Golubev, Dmitri S.; Zaikin, Andrei D.

    2006-01-01

    Combining scattering matrix formalism with non-linear $\\sigma$-model technique we analyze weak localization effects in arrays of chaotic quantum dots connected via barriers with arbitrary distribution of channel transmissions. With the aid of our approach we evaluate magnetoconductance of two arbitrarily connected quantum dots as well as of $N\\times M$ arrays of identical quantum dots.

  15. AHE measurements of very thin films and nanosized dots

    NARCIS (Netherlands)

    Kikuchi, N.; Murillo, R.; Lodder, J.C.

    2005-01-01

    In this paper we present anomalous Hall effect analysis from very thin Co (0.5 nm) film, Co/Pt multilayers and large areas of nanosized dots as well as from a few magnetic dots having a diameter of 120 nm. The dot arrayis prepared from Co/Pt multilayer by using laser interference lithography (LIL) w

  16. Optical properties of charged semiconductor quantum dots

    Science.gov (United States)

    Jha, Praket P.

    The effect of n-type doping on the luminescence properties of II-VI quantum dots is studied. The addition of two shells of CdS on CdSe quantum dots prevents the creation of surface traps and makes the system stable under reducing environment. The injection of electrons into films of quantum dots leads to lower photoluminescence (PL) efficiency, with the extent of quenching dependent on both the number and the quantum states of the spectator charges in the nanocrystal. It is found that a 1Pe electron is an eightfold better PL quencher than the 1Se electron. Reduced threshold for stimulated emission is also observed in doped CdSe/CdS films. Time resolved photoluminescence measurements are used to extract the recombination rates of a charged exciton, called trion. It is observed that the negative trion has a radiative rate ˜2.2 +/- 0.4x faster than a neutral exciton, while its non-radiative recombination rate is slower than the biexciton non-radiative recombination rate by a factor of 7.5 +/- 1.7. The knowledge of the recombination rates of the trion enables us to calculate the quantum yield of a negative trion to be ˜10% for the nanocrystals investigated in our work. This is larger than the off state quantum yield from a single quantum dot photoluminescence trajectory and eliminates the formation of negative trion as the possible reason for the PL blinking of single quantum dots. Single quantum dot electrochemistry has also been achieved. It is shown that by varying the Fermi level of the system electrons can be reversibly injected into and extracted out of single CdSe/CdS and CdSe/ZnS nanoparticles to modulate the photoluminescence.

  17. Optical studies of capped quantum dots

    OpenAIRE

    Wuister, S.F.

    2005-01-01

    This thesis describes the synthesis and spectroscopy of CdSe and CdTe semiconductor quantum dots (QDs). The first chapter gives an introduction into the unique size dependent properties of semiconductor quantum dots. Highly luminescent QDs of CdSe and CdTe were prepared via a high temperature method in a glovebox. These QDs are soluble in organics but can be transferred into water or ethanol after exchange of the surfactants by various thiols (HS-R). For CdTe the exchange with thiols has a be...

  18. Nonuniform micromagnetic states in thin circular dots

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Z.-H. E-mail: zhwei@phys.ntu.edu.tw; Lai, M.-F.; Chang, C.-R.; Usov, N.A.; Wu, J.C.; Lai, J.-Y

    2004-11-01

    Micromagnetic states are strongly related to sizes of nano-dots. The quasiuniform state becomes unstable and transforms to a new nonuniform state as the diameter of the permalloy circular dot exceeds some critical size. The magnetization curvature increases gradually as the diameter increases. Finally, when the diameter is larger than another critical size, the new nonuniform state becomes unstable and a vortex enters the particle. Hence the new nonuniform state plays an intermediate role in the evolution from the quasiuniform state to the vortex state as the diameter increases.

  19. Cadmium telluride quantum dots advances and applications

    CERN Document Server

    Donegan, John

    2013-01-01

    Optical Properties of Bulk and Nanocrystalline Cadmium Telluride, Núñez Fernández and M.I. VasilevskiyAqueous Synthesis of Colloidal CdTe Nanocrystals, V. Lesnyak, N. Gaponik, and A. EychmüllerAssemblies of Thiol-Capped CdTe Nanocrystals, N. GaponikFörster Resonant Energy Transfer in CdTe Nanocrystal Quantum Dot Structures, M. Lunz and A.L. BradleyEmission of CdTe Nanocrystals Coupled to Microcavities, Y.P. Rakovich and J.F. DoneganBiological Applications of Cadmium Telluride Semiconductor Quantum Dots, A. Le Cign

  20. Engineered Quantum Dot Single Photon Sources

    CERN Document Server

    Buckley, Sonia; Vuckovic, Jelena

    2012-01-01

    Fast, high efficiency, and low error single photon sources are required for implementation of a number of quantum information processing applications. The fastest triggered single photon sources to date have been demonstrated using epitaxially grown semiconductor quantum dots (QDs), which can be conveniently integrated with optical microcavities. Recent advances in QD technology, including demonstrations of high temperature and telecommunications wavelength single photon emission, have made QD single photon sources more practical. Here we discuss the applications of single photon sources and their various requirements, before reviewing the progress made on a quantum dot platform in meeting these requirements.

  1. Spintronic transport through an interacting Rashba dot

    International Nuclear Information System (INIS)

    We investigate the spin-dependent transport property through a quantum wire with local Rashba interaction based on fRG method. The Rashba field forms quasi-bound states which couple to the continuum states with an opposite spin direction. It is found that the transport through the Rashba dot strongly depends on an assumed spin polarization of the continuum states and on the Coulomb interaction U in the dot. The interaction U (U>UC) leads to the appearance of three conductance peaks. Two outer peaks are associated with the Coulomb blockade and the center peak is induced by correlation of the electrons with different spin

  2. Addiction research centres and the nurturing of creativity The Norwegian Centre for Addiction Research (SERAF).

    Science.gov (United States)

    Bramness, Jørgen G; Clausen, Thomas; Duckert, Fanny; Ravndal, Edle; Waal, Helge

    2011-08-01

    The Norwegian Centre for Addiction Research (SERAF) at the University of Oslo is a newly established, clinical addiction research centre. It is located at the Oslo University Hospital and has a major focus on opioid dependency, investigating Norwegian opioid maintenance treatment (OMT), with special interest in OMT during pregnancy, mortality, morbidity and criminality before, during and after OMT and alternatives to OMT, such as the use of naltrexone implants. The well-developed health registries of Norway are core assets that also allow the opportunity for other types of substance abuse research. This research includes health services, abuse of prescription drugs and drugs of abuse in connection with traffic. The centre also focuses upon comorbidity, investigating the usefulness and limitations of psychometric instruments, drug abuse in different psychiatric treatment settings and internet-based interventions for hazardous alcohol consumption. PMID:20735364

  3. Bhabha Atomic Research Centre: annual report 1988

    International Nuclear Information System (INIS)

    The research and development (R and D) work carried out in the Bhabha Atomic Research Centre (BARC), Bombay during 1988 is summarised and presented in the sections entitled Physical Sciences, Chemical Sciences, Materials and Materials Science, Radioisotopes, Reactors, Fuel cycle, Radiological Safety and Protection, Electronics and Instrumentation, Engineering Services, Life Sciences and General. At the end of each section a list of publications is also given. The R and D work of the outstation units of BARC, namely, Nuclear Research Laboratory, Srinagar; High Altitute Research Laboratory, Gulmarg and Variable Energy Cyclotron Centre, Calcutta are also described in this report. Some of the highlights of the work during the year are: (1) Medium Energy Heavy Ion Accelerator (MEHIA) facility set up jointly by BARC and the Tata Institute of Fundamental Research (TIFR) at TIFR premises became fully operational in September 1988. A number of new compositions of high temperature supconducting materials were synthesized. The highest transition temperature achieved was 125 K. Research work to improve the quality of sintered uranium oxide pellets achieved the purpose. Nuclear fuels were fabricated by using sol-gel process. R and D work for 235 MWe and 500 MWe PHWR type reactors is continuing. Conceptual design of the fuel handling system for the prototype fast breeder reactor was finalised. 233U+Al alloy fuel for Kamini reactor was fabricated. Progress has been made in industrial applications of enzymes. Various applications of radioisotopes are being continued. Certain technologies and processes developed in the Centre were transferred to commercial agencies for large scale exploitation. (M.G.B.)

  4. Human-centred approaches in slipperiness measurement

    Science.gov (United States)

    Grönqvist, Raoul; Abeysekera, John; Gard, Gunvor; Hsiang, Simon M.; Leamon, Tom B.; Newman, Dava J.; Gielo-Perczak, Krystyna; Lockhart, Thurmon E.; Pai, Clive Y.-C.

    2010-01-01

    A number of human-centred methodologies—subjective, objective, and combined—are used for slipperiness measurement. They comprise a variety of approaches from biomechanically-oriented experiments to psychophysical tests and subjective evaluations. The objective of this paper is to review some of the research done in the field, including such topics as awareness and perception of slipperiness, postural and balance control, rating scales for balance, adaptation to slippery conditions, measurement of unexpected movements, kinematics of slipping, and protective movements during falling. The role of human factors in slips and falls will be discussed. Strengths and weaknesses of human-centred approaches in relation to mechanical slip test methodologies are considered. Current friction-based criteria and thresholds for walking without slipping are reviewed for a number of work tasks. These include activities such as walking on a level or an inclined surface, running, stopping and jumping, as well as stair ascent and descent, manual exertion (pushing and pulling, load carrying, lifting) and particular concerns of the elderly and mobility disabled persons. Some future directions for slipperiness measurement and research in the field of slips and falls are outlined. Human-centred approaches for slipperiness measurement do have many applications. First, they are utilized to develop research hypotheses and models to predict workplace risks caused by slipping. Second, they are important alternatives to apparatus-based friction measurements and are used to validate such methodologies. Third, they are used as practical tools for evaluating and monitoring slip resistance properties of foot wear, anti-skid devices and floor surfaces. PMID:11794763

  5. The "Magic" of Tutorial Centres in Hong Kong: An Analysis of Media Marketing and Pedagogy in a Tutorial Centre

    Science.gov (United States)

    Koh, Aaron

    2014-01-01

    Why do more than three-quarters of Hong Kong's senior secondary students flock to tutorial centres like moths to light? What is the "magic" that is driving the popularity of the tutorial centre enterprise? Indeed, looking at the ongoing boom of tutorial centres in Hong Kong (there are almost 1,000 of them), it is difficult not to ask…

  6. Biological Inspiration in Human Centred Robotics

    Institute of Scientific and Technical Information of China (English)

    HU Huo-sheng; LIU Jin-dong; Calderon Carlos A

    2004-01-01

    Human centred robotics (HCR) concerns with the development of various kinds of intelligent systems and robots that will be used in environments coexisting with humans. These systems and robots will be interactive and useful assistants/companions for people in different ages, situations, activities and environments in order to improve the quality of life. This paper presents the autors' current research work toward the development of advanced theory and technologies for HCR applications, based on inspiration from biological systems. More specifically, both bio-mimetic system modelling and robot learning by imitation are discussed respectively, and some preliminary results are demonstrated.

  7. Frequency selectivity at very low centre frequencies

    DEFF Research Database (Denmark)

    Orellana, Carlos Andrés Jurado; Pedersen, Christian Sejer; Marquardt, Torsten

    2010-01-01

    measurements based on OAE suppression techniques and notched-noise masking data psychophysically measured for centre frequencies in the range 50-125 Hz, this study examines how individual differences in frequency selectivity, as well as in masking, may occur at very low CFs due to individual differences in the...... shape of the METFs, thought to be affected by the helicotrema impedance. Preliminary analysis indicates that individual differences in the METFs might underlay the observed individual differences in frequency selectivity. Main effects predicted by the calculations are a pronounced flattening off of the...

  8. STEPS Centre research: our approach to impact

    OpenAIRE

    Ely, Adrian; Oxley, Nathan

    2014-01-01

    The ‘impact’ of research has seen a dramatic rise up the UK’s policy agenda in recent years. But what does ‘impact’ really mean? How do researchers and others respond to the new ‘impact agenda’ and how might we best plan, monitor and report on impact? This working paper attempts to provide answers to some of these questions by reviewing various understandings of ‘impact’ and describing the approach used by the ESRC STEPS Centre in its second five-year phase of funding. In particular, we draw ...

  9. Hunting for hardware changes in data centres

    International Nuclear Information System (INIS)

    With many servers and server parts the environment of warehouse sized data centres is increasingly complex. Server life-cycle management and hardware failures are responsible for frequent changes that need to be managed. To manage these changes better a project codenamed “hardware hound” focusing on hardware failure trending and hardware inventory has been started at CERN. By creating and using a hardware oriented data set - the inventory - with detailed information on servers and their parts as well as tracking changes to this inventory, the project aims at, for example, being able to discover trends in hardware failure rates.

  10. The INTEGRAL science data centre (ISDC)

    DEFF Research Database (Denmark)

    Courvoisier, T.J.L.; Walter, Rasmus; Beckmann, V.;

    2003-01-01

    The INTEGRAL Science Data Centre (ISDC) provides the INTEGRAL data and means to analyse them to the scientific community. The ISDC runs a gamma ray burst alert system that provides the position of gamma ray bursts on the sky within seconds to the community. It operates a quick-look analysis of the...... data within few hours that detects new and unexpected sources as well as it monitors the instruments. The ISDC processes the data through a standard analysis the results of which are provided to the observers together with their data....

  11. Quantum phase transition in trigonal triple quantum dots: The case of quantum dots deviated from particle–hole symmetric point

    International Nuclear Information System (INIS)

    We consider a triple quantum dot system in a triangular geometry with one of the dots connected to metallic leads. We investigate quantum phase transition between local moment phase and Kondo screened strong coupling phase in triple quantum dots where energy levels of dots are deviated from the particle–hole symmetric point. The effect of on-site energy of dots on quantum phase transition between local moment phase and Kondo screened strong coupling phase in triple quantum dots is studied based on the analytical arguments and the numerical renormalization group method. The results show that the critical value of tunnel coupling between side dots decreases when the energy level of embedded dot rises up from the symmetric point to the Fermi level and the critical value increases when the energy levels of two side dots rise up. The study of the influence of on-site-energy changes on the quantum phase transitions in triple quantum dots has the importance for clarifying the mechanism of Kondo screening in triple quantum dots where energy levels of dots are deviated from the particle–hole symmetric point

  12. A study of the lunisolar secular resonance $2\\dot{\\omega}+\\dot{\\Omega}=0$

    CERN Document Server

    Celletti, Alessandra

    2016-01-01

    The dynamics of small bodies around the Earth has gained a renewed interest, since the awareness of the problems that space debris can cause in the nearby future. A relevant role in space debris is played by lunisolar secular resonances, which might contribute to an increase of the orbital elements, typically of the eccentricity. We concentrate our attention on the lunisolar secular resonance described by the relation $2\\dot{\\omega}+\\dot{\\Omega}=0$, where $\\omega$ and $\\Omega$ denote the argument of perigee and the longitude of the ascending node of the space debris. We introduce three different models with increasing complexity. We show that the growth in eccentricity, as observed in space debris located in the MEO region at the inclination about equal to $56^\\circ$, can be explained as a natural effect of the secular resonance $2\\dot{\\omega}+\\dot{\\Omega}=0$, while the chaotic variations of the orbital parameters are the result of interaction and overlapping of nearby resonances.

  13. A study of the lunisolar secular resonance $2dot{omega}+dot{Omega}=0$

    Directory of Open Access Journals (Sweden)

    Alessandra eCelletti

    2016-03-01

    Full Text Available The dynamics of small bodies around the Earth has gained a renewed interest,since the awareness of the problems that space debris can cause in thenearby future. A relevant role in space debris is played by lunisolarsecular resonances, which might contribute to an increase of the orbitalelements, typically of the eccentricity. We concentrate our attention onthe lunisolar secular resonance described by the relation$2dot{omega}+dot{Omega}=0$, where $omega$ and $Omega$ denotethe argument of perigee and the longitude of the ascending node of the space debris.We introduce three different models with increasing complexity. We show that the growth in eccentricity, as observed in space debris located in the MEO region at the inclination about equal to $56^circ$, can be explained as a natural effect of the secular resonance $2dot{omega}+dot{Omega}=0$, while the chaotic variations of the orbital parameters are the result of interaction and overlapping of nearby resonances.

  14. A study of the lunisolar secular resonance 2dot{ω}+dot{Ω}=0

    Science.gov (United States)

    Celletti, Alessandra; Gales, Catalin

    2016-03-01

    The dynamics of small bodies around the Earth has gained a renewed interest, since the awareness of the problems that space debris can cause in the nearby future. A relevant role in space debris is played by lunisolar secular resonances, which might contribute to an increase of the orbital elements, typically of the eccentricity. We concentrate our attention on the lunisolar secular resonance described by the relation 2dot{ω}+dot{Ω}=0, where ω and Ω denote the argument of perigee and the longitude of the ascending node of the space debris. We introduce three different models with increasing complexity. We show that the growth in eccentricity, as observed in space debris located in the MEO region at the inclination about equal to 56°, can be explained as a natural effect of the secular resonance 2dot{ω}+dot{Ω}=0, while the chaotic variations of the orbital parameters are the result of interaction and overlapping of nearby resonances.

  15. The Australian centre for RF bioeffects research (ACRBR) - an NHMRC centre of research excellence

    International Nuclear Information System (INIS)

    Full text: The Australian Centre for Radiofrequency Bioeffects Research (ACRBR) is a newly established multi-institutional research centre which seeks to research questions pertaining to possible health effects of exposure to radiofrequency devices, such as mobile phones and which is funded under the Australian National Health and Medical Research Council (NHMRC) Centres of Research Excellence funding program. The Centre of Research Excellence in Electromagnetic Energy is combining the efforts of engineers, epidemiologists, physicists, psychophysiologists and veterinary pathologists from RMIT University, the Institute of Medical and Veterinary Science in South Australia (IMVS), Monash University, Swinburne University of Technology and Telstra Research Laboratories (TRL). The centre is funded at $2.5 M over five years and will undertake a program of research to address the issue of exposure to radiofrequency (RF) devices and health. It will also train new scientists, keep the community informed of ongoing developments and help the development of government policies in this area of considerable public concern. The 5-year program has the following components: Neurobiology: One important area where there is a perceived research gap is in the area of potential neurological effects, which will hence be a major focus of this Centre. The proposed studies range from in vitro and in vivo research studies of RF effects on neuron and neural system functioning in rodents, to that of RF effects on simple neural function, cognition and subjective report in humans. The latter series of studies have been developed to account for the consensus view that more emphasis needs to be placed on possible differences in RF population sensitivity (e.g. youth versus aged, and ' electromagnetic hypersensitives'). Epidemiological studies are an important tool in studying the impact on public health from exposure of whole populations to modern radio technologies. Cancer outcomes in this area of

  16. Electrically addressing a single self-assembled quantum dot

    CERN Document Server

    Ellis, D J P; Atkinson, P; Ritchie, D A; Shields, A J

    2006-01-01

    We report on the use of an aperture in an aluminum oxide layer to restrict current injection into a single self-assembled InAs quantum dot, from an ensemble of such dots within a large mesa. The insulating aperture is formed through the wet-oxidation of a layer of AlAs. Under photoluminescence we observe that only one quantum dot in the ensemble exhibits a Stark shift, and that the same single dot is visible under electroluminescence. Autocorrelation measurements performed on the electroluminescence confirm that we are observing emission from a single quantum dot.

  17. Photoluminescence studies of single InGaAs quantum dots

    DEFF Research Database (Denmark)

    Leosson, Kristjan; Jensen, Jacob Riis; Hvam, Jørn Märcher

    1999-01-01

    Semiconductor quantum dots are considered a promising material system for future optical devices and quantum computers. We have studied the low-temperature photoluminescence properties of single InGaAs quantum dots embedded in GaAs. The high spatial resolution required for resolving single dots...... to resolve luminescence lines from individual quantum dots, revealing an atomic-like spectrum of sharp transition lines. A parameter of fundamental importance is the intrinsic linewidth of these transitions. Using high-resolution spectroscopy we have determined the linewidth and investigated its dependence...... on temperature, which gives information about how the exciton confined to the quantum dot interacts with the surrounding lattice....

  18. High-resolution photoluminescence studies of single semiconductor quantum dots

    DEFF Research Database (Denmark)

    Leosson, Kristjan; Østergaard, John Erland; Jensen, Jacob Riis;

    2000-01-01

    Semiconductor quantum dots, especially those formed by self-organized growth, are considered a promising material system for future optical devices [1] and the optical properties of quantum dot ensembles have been investigated in detail over the past years. Recently, considerable interest has...... developed in the study of single quantum dots, characterized by sharp atomic-like transition lines revealing their zero-dimensional density of states. Substantial information about the fundamental properties of individual quantum dots, as well as their interactions with other dots and the host lattice, can...

  19. Lateral excitonic switching in vertically stacked quantum dots

    Science.gov (United States)

    Jarzynka, Jarosław R.; McDonald, Peter G.; Shumway, John; Galbraith, Ian

    2016-06-01

    We show that the application of a vertical electric field to the Coulomb interacting system in stacked quantum dots leads to a 90° in-plane switching of charge probability distribution in contrast to a single dot, where no such switching exists. Results are obtained using path integral quantum Monte Carlo with realistic dot geometry, alloy composition, and piezo-electric potential profiles. The origin of the switching lies in the strain interactions between the stacked dots hence the need for more than one layer of dots. The lateral polarization and electric field dependence of the radiative lifetimes of the excitonic switch are also discussed.

  20. Information validation tool for technical support centres

    International Nuclear Information System (INIS)

    The French National Emergency Organisation relies on the expert advice given by the different Technical Support Centres (EDF/SEPTEN, CEA/IPSN, Framatome). For several years a great effort has been made to improve tools. The first generation was mainly concerned with computational aids such as real-time plant data acquisition and visualisation, break size calculations, containment release estimations... These tools were presented at the OECD NEA Specialist Meeting in 1993. Currently work is performed in the field of validation of information available to the Technical Support Centres. The three partners (EDF, CEA and Framatome) have developed a prototype implementing the diagnosis and the quality of the information pertaining to the 3D/3P method. The philosophy of this tool is to present to the expert a set of essential information (e.g. state of the fuel barrier, primary water inventory...) for the diagnosis with a confidence level associated to each information and the adequate explications. In fact the expert has not only to know the diagnosis but also how reliable the information is and why. Subsequently, the algorithms used to elaborate the diagnoses and the confidence factor have to be simple enough so that the user is able to consult the explanations in a fast and easy way. The paper details the three-step process to elaborate the diagnosis and the confidence factor