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  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. Improved ACE-FTS observations of carbon tetrachloride (CCl4)

    Science.gov (United States)

    Harrison, Jeremy; Chipperfield, Martyn; Boone, Chris; Bernath, Peter

    2016-04-01

    The Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS), on board the SCISAT satellite, has been recording solar occultation spectra through the Earth's atmosphere since 2004 and continues to take measurements with only minor loss in performance. ACE-FTS time series are available for a range of chlorine 'source' gases, including CCl3F (CFC-11), CCl2F2 (CFC-12), CHF2Cl (HCFC-22), CH3Cl and CCl4. Recently there has been much community interest in carbon tetrachloride (CCl4), a substance regulated by the Montreal Protocol because it leads to the catalytic destruction of stratospheric ozone. Estimated sources and sinks of CCl4 remain inconsistent with observations of its abundance. Satellite observations of CCl4 in the stratosphere are particularly useful in validating stratospheric loss (photolysis) rates; in fact the atmospheric loss of CCl4 is essentially all due to photolysis in the stratosphere. However, the latest ACE-FTS v3.5 CCl4 retrieval is biased high by ˜ 20-30%. A new ACE-FTS retrieval scheme utilising new laboratory spectroscopic measurements of CCl4 and improved microwindow selection has recently been developed. This improves upon the v3.5 retrieval and resolves the issue of the high bias; this new scheme will form the basis for the upcoming v4 processing version of ACE-FTS data. This presentation will outline the improvements made in the retrieval, and a subset of data will be compared with modelled CCl4 distributions from SLIMCAT, a state-of-the-art three-dimensional chemical transport model. The use of ACE-FTS data to evaluate the modelled stratospheric loss rate of CCl4 will also be discussed. The evaluated model, which also includes a treatment of surface soil and ocean sinks, will then be used to quantify current uncertainties in the global budget of CCl4.

  4. 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

  5. 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...

  6. Decomposition of CCl4 and CHCl3 on gliding are plasma.

    Science.gov (United States)

    Indarto, Antonius; 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. PMID:20050553

  7. 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.

  8. 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

  9. 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

  10. Lygodium flexuosum extract down regulates the expression of proinflammatory cytokines in CCl4 -induced hepatotoxicity

    Institute of Scientific and Technical Information of China (English)

    Pallara Janardhanan Wills; Velikkakathu Vasumathi Asha

    2012-01-01

    Objective:To examine the downregulation of proinflammatory cytokines in a time dependant manner on carbon tetrachloride induced toxicity in experimental animals.Methods:CCl4(150 μL/100 g) was dissolved in corn oil(1:1 v/v%) and administered orally.GroupI was treated as normal control and received corn oil on8th day.GroupII was toxic control and was given a single dose ofCCl4 on8th days.GroupIII wastreated withLygodium flexuosum(L. flexuosum)n-hexane extract(200 mg/kg) for8 days and on8th day a single dose ofCCl4 was received.GroupIV(negative control) receivedL. flexuosumn-hexane extract(200 mg/kg) alone for8 days.Results:Treatment withn-hexane extract prior to the administration ofCCl4 significantly prevented an increase in serumAST,ALT,LDH activity and lipid peroxidation and prevented the depletion of glutathione (GSH).Rats treated withL. flexuosum had reduced mRNA levels ofTGF-β1,TNF-α andIL-1βgenes in liver ofCCl4 intoxicated rats when compared toCCl4 control as evidenced byRT-PCR. Conclusions:The data suggest that L. flexuosum, a widely available fern, significantly reduces CCl4 induced acute hepatotoxicity by down-regulating the expression of pro-inflammatory cytokines in rats.

  11. 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

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

    Science.gov (United States)

    Butler, James H.; Yvon-Lewis, Shari A.; Lobert, Jurgen M.; King, Daniel B.; Montzka, Stephen A.; Bullister, John L.; Koropalov, Valentin; Elkins, James W.; Hall, Bradley D.; Hu, Lei; Liu, Yina

    2016-09-01

    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 commonly on the order of -5 to -10 %, with no clear relationship to temperature, productivity, or other gross surface water characteristics other than being more negative in association with upwelling. The atmospheric flux required to sustain these undersaturations is 12.4 (9.4-15.4) Gg yr-1, a loss rate implying a partial atmospheric lifetime with respect to the oceanic loss of 183 (147-241) yr and that ˜ 18 (14-22) % of atmospheric CCl4 is lost to the ocean. Although CCl4 hydrolyzes in seawater, published hydrolysis rates for this gas are too slow to support such large undersaturations, given our current understanding of air-sea gas exchange rates. The even larger undersaturations in intermediate depth waters associated with reduced oxygen levels, observed in this study and by other investigators, strongly suggest that CCl4 is ubiquitously consumed at mid-depth, presumably by microbiota. Although this subsurface sink creates a gradient that drives a downward flux of CCl4, the gradient alone is not sufficient to explain the observed surface undersaturations. Since known chemical losses are likewise insufficient to sustain the observed undersaturations, this suggests a possible biological sink for CCl4 in surface or near-surface waters of the ocean. The total atmospheric lifetime for CCl4, based on these results and the most recent studies of soil uptake and loss in the stratosphere is now 32 (26-43) yr.

  13. 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.

  14. Isorhamnetin-3-O-galactoside Protects against CCl4-Induced Hepatic Injury in Mice

    OpenAIRE

    Kim, Dong-Wook; Cho, Hong-Ik; Kim, Kang-Min; Kim, So-Jin; Choi, Jae Sue; Kim, Yeong Shik; Lee, Sun-Mee

    2012-01-01

    This study was performed to examine the hepatoprotective effect of isorhamnetin-3-O-galactoside, a flavonoid glycoside isolated from Artemisia capillaris Thunberg (Compositae), against carbon tetrachloride (CCl4)-induced hepatic injury. Mice were treated intraperitoneally with vehicle or isorhamnetin-3-O-galactoside (50, 100, and 200 mg/kg) 30 min before and 2 h after CCl4 (20 μl/kg) injection. Serum aminotransferase activities and hepatic level of malondialdehyde were significantly higher af...

  15. 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.

  16. Experimental study on CCl4/CH)4/O2/N2 oxidation

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Oxidation within the system CCl4/CH4/O2/N2 is studied at atmospheric pressure in a tubular flow reactor to investigate the influence of reaction temperature and chlorine content on chlorinated waste combustion and find incineration process optimization methods for pollution control.The reaction temperature varies from 700℃ to 1000℃ and the CCl4/CH4(or Cl/H) mole ratio of the inlet mixture varies from 0.21 to 0.84.Products profiles are measured with FT-IR.It is shown that at the same initial CCl4 concentration and reaction temperature adding CH4 favors CCl4 destruction and CO2 formation.But the destruction and removal efficiency(DRE) of CH4 decreases with lower Cl/H and higher concentrations of toxic products of incomplete combustion such as COCl2 and CH3Cl are formed at the same time.The chlorine in the system favors CH4 decomposition,but it also inhibits further oxidation of CO.Higher temperature assists in both CCl4 destruction and CH4 conversion,and the concentration of toxic combustion intermediates is reduced.Increasing the temperature is the most effective way to enhance CCl4 oxidation.The CO2 concentration increases with temperature.A CO concentration peak is observed around 800℃:with a certain Cl/H,the CO concentration first increases with temperature and then declines.The effect of increasing CH4 concentration on CCl4 destruction becomes mild above 900℃.Rather,it enhances the interaction between chlorine and carbonaceous radicals,which leads to higher concentration of toxic products.

  17. STRATIGRAPHIC CONTROL ON CCL4 AND CHCL3 CONCENTRATIONS IN THE 200 WEST AREA, HANFORD SITE

    Energy Technology Data Exchange (ETDEWEB)

    Winsor, K.; Last, G.V.

    2008-01-01

    An extensive subsurface contaminant plume of carbon tetrachloride (CCl4) is the focus of a remedial effort in the 200 West Area of the U.S. Department of Energy’s Hanford Site in eastern Washington. Remediation requires a high-resolution understanding of the region’s spatially variable lithofacies and of the effect these lithofacies have on CCl4 migration through the unconfi ned aquifer. To increase the level of detail of our current understanding, a transect was chosen along the primary groundwater fl ow path in the most heavily contaminated area. Borehole logs of wells along this 3.7 km-long transect were standardized and used to create a cross section displaying the depth and continuity of lithofacies. Natural and spectral gamma geophysical logs were examined to pinpoint the depths of geologic units. Depth discrete concentrations of CCl4 and its reductive dechlorination product, chloroform (CHCl3), were overlain on this cross section. Comparison of stratigraphy to contaminant levels shows that peaks in CCl4 concentration occur in thin, fine-grained layers and that other fine-grained layers frequently form lower boundaries to regions of high concentration. Peaks in CCl4 concentrations are frequently located at different depths from those of CHCl3, suggesting that these concentrations are affected by dechlorination of CCl4. Transformation of CCl4 to CHCl3 appears to be more prevalent within reduced, iron-containing sediments. The infl uence of thin, fine-grained layers within the larger aquifer unit indicates that characterization of contamination in this locality should consider subsurface geology with at least as much resolution as provided in this study.

  18. The Effect of rhCygb on CCl4-Induced Hepatic Fibrogenesis in Rat

    Science.gov (United States)

    Li, Zhen; Wei, Wei; Chen, Bohong; Cai, Gaotai; Li, Xin; Wang, Ping; Tang, Jinping; Dong, Wenqi

    2016-01-01

    This study aims to investigate whether the use of recombinant human cytoglobin (rhCygb) impact on hepatic fibrogenesis caused by CCl4. SD (n = 150) rats were randomly divided into three groups of normal, CCl4 model and rhCygb groups. After model establishment, rats in rhCygb groups were administered daily with rhCygb (2 mg/kg, s.c.). Histological lesions were staged according to metavir. Serum parameters including ALT, AST, HA, LN, Col III and Col IV were determined. The liver proteins were separated by 2-DE and identified. As a result, the stage of hepatic damage and liver fibrosis in rhCygb groups were significantly milder than that in CCl4 model groups. Meanwhile, rhCygb dramatically reversed serum levels of ALT and AST, and also markedly decreased the liver fibrosis markers levels of LN, HA, Col III and Col IV. In 2-DE, 33 proteins among three groups with the same changing tendency in normal and rhCygb treated groups compared with CCl4 model group were identified. GO analysis showed that several identified proteins involved in oxidative stress pathway. The study provides new insights and data for administration of rhCygb reversing CCl4-induced liver fibrosis suggesting that rhCygb might be used in the treatment of liver fibrosis. PMID:27006085

  19. 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.

  20. 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

  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. 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

  3. 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.

  4. 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.

  5. Face-Centred-Cubic Artificial Opal Embedded with CdS Quantum Dots

    Institute of Scientific and Technical Information of China (English)

    徐岭; 李明海; 张宇; 马懿; 徐骏; 黄信凡; 陈坤基

    2002-01-01

    Highly monodispersed colloidal silica spheres in sub-micrometre size with distribution standard deviation less than 5% were synthesized by a chemical method. Using the self-crystallization of the silica spheres, we successfully obtained the three-dimensional close-packed face-centred-cubic silica matrices and artificial opals. Then,a colloidal photonic crystal embedded with CdS quantum dots (QDs) was also chemically prepared by using artificial opals as a template. A reflection spectra study reveals that both artificial opals with and without CdS QDs possess (111) directional photonic bandgap features.

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

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    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.

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

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    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. 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...

  10. 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.

  11. Antioxidant and protective effect of inulin and catechin grafted inulin against CCl4-induced liver injury.

    Science.gov (United States)

    Liu, Jun; Lu, Jian-feng; Wen, Xiao-yuan; Kan, Juan; Jin, Chang-hai

    2015-01-01

    In this study, the antioxidant activity and hepatoprotective effect of inulin and catechin grafted inulin (catechin-g-inulin) against carbon tetrachloride (CCl4)-induced acute liver injury were investigated. Results showed that both inulin and catechin-g-inulin had moderate scavenging activity on superoxide radical, hydroxyl radical and H2O2, as well as lipid peroxidation inhibition effect. The antioxidant activity decreased in the order of Vc > catechin >catechin-g-inulin > inulin. Administration of inulin and catechin-g-inulin could significantly reduce the elevated levels of serum aspartate transaminase, alanine transaminase and alkaline phosphatase as compared to CCl4 treatment group. Moreover, inulin and catechin-g-inulin significantly increased the levels of hepatic superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione and total antioxidant capacity, whereas markedly decreased the malondialdehyde level when compared with CCl4 treatment group. Notably, catechin-g-inulin showed higher hepatoprotective effect than inulin. In addition, the hepatoprotective effect of catechin-g-inulin was comparable to positive standard of silymarin. Our results suggested that catechin-g-inulin had potent antioxidant activity and potential protective effect against CCl4-induced acute liver injury.

  12. 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

  13. 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

  14. Protective role of Juniperus phoenicea and Cupressus sempervirens against CCl4

    Institute of Scientific and Technical Information of China (English)

    Sanaa; Ahmed; Ali; Maha; Zaki; Rizk; Nabawia; Ali; Ibrahim; Mohga; Shafik; Abdallah; Hayat; Mohamed; Sharara; Magda; Mohamed; Moustafa

    2010-01-01

    AIM: To investigate the role of Cupressus sempervirens (C. sempervirens) and Juniperus phoenicea (J. phoe-nicea) extracts as therapeutic effect against CCl4 with biochemical, histopathological evaluations. METHODS: A single intraperitoneal dose of 10% CCl4 in olive oil (1 mL/kg body weight) was administered to a group of female Wister rats, sacrificed after 24 h (as the injury group). The other groups were given CCl4 as de-scribed above and divided as follows: two groups of ten rats each were orally administered either J. phoenicea extract or C. sempervirens extract three times per week for six weeks and a further group administered CCl4 was left for six weeks to allow self-recovery. At the end of experiment, the rats from all groups were sacrificed for sampling and for biochemical and histological analysis. RESULTS: Remarkable disturbances were observed in the levels of all tested parameters. On the other hand,rats injected with the toxic agent and left for one and a half month to self recover showed moderate improve-ments in the studied parameters while, treatment with both medicinal herbal extracts ameliorated the levels of the disturbed biochemical parameters. The group treated with J. phoenicea extract showed a remarkable improvement in comparison to the CCl4 treated group. The C. sempervirens group revealing an even more re-markable effect showing histopathological liver& kidney profiles close to those of the control group.CONCLUSION: C. sempervirens and J. phoenicea leaf extracts show a remarkable effect in enhancing liver and kidney functions and may thus be of therapeutic potential in treatment hepatotoxicity and nephrotoxicity.

  15. Decorin prevents the development of CCl4-induced liver fibrosis in mice

    Institute of Scientific and Technical Information of China (English)

    Ma Rui; He Shilin; Liang Xiao; Yu Hong; Liang Yuelong; Cai Xiujun

    2014-01-01

    Background Liver fibrosis normally progresses to cirrhosis and destroys the normal architecture of the liver,resulting in liver dysfunction and irreversible cirrhosis.The aim of this study was to investigate the anti-fibrosis effect and the possible underlying mechanisms of decorin.Methods The mice model of liver fibrosis was induced by intraperitoneal injection of 50% (v/v) of carbon tetrachloride (CCl4) diluted in olive oil (1 ml/kg body weight) once every 2 days for 5 weeks.Three weeks after injecting CCl4 intraperitoneally,mice were randomly divided into normal control with vehicles only (olive oil),mouse model given CCl4 only,and CCl4 plus decorin (DCN,250 μg/kg).Two weeks later,all the mice were sacrificed and their liver tissues were analyzed for the expressions of genes related to liver fibrosis and under hematoxylin-eosin staining,Masson staining,and immunohistochemical staining of all groups.Aspartate transaminase,alanine transaminase,and total bilirubin of the serum were determined for evaluation of the liver function.Results Exogenous protein decorin could reduce liver fibrosis induced by CCl4 in mice.The degree of fibrosis in the experimental group was alleviated,and the contents of collagen fibers were lower in the experimental group than those of the control group.In addition,expressions of transforming growth factor β1 and α-smooth muscle actin decreased in the experimental group.Conclusions Taking liver fibrosis model of mouse as the experimental target and by injecting exogenous protein decorin into the model,we confirmed that decorin could inhibit the expression of proteins related to fibrosis and reduce the formation of liver fibrosis in mice.

  16. The biofunction of orange-spotted grouper (Epinephelus coioides) CC chemokine ligand 4 (CCL4) in innate and adaptive immunity.

    Science.gov (United States)

    Hsu, Yi-Jiou; Hou, Chia-Yi; Lin, Shih-Jie; Kuo, Wan-Ching; Lin, Han-Tso; Lin, John Han-You

    2013-12-01

    CC chemokine (motif) ligand 4 (CCL4) is indispensable to the chemoattraction of macrophages, natural killer cells, and lymphocytes in mammals; however, it has only been cloned in a limited number of fish species and information related to its biofunction remains ambiguous with regard to teleosts. To explore the role of teleost CCL4, we first evaluated the mRNA expression of the Epinephelus coioides CCL4 (gCCL4) gene in various organs under LPS and poly (I:C) stimulated; secondary, we evaluated the immune-related genes expression of fish under the recombinant gCCL4 protein stimulated. Our results revealed an increase in the mRNA of gCCL4 in immune organs immediately following stimulation by poly (I:C); however, in LPS stimulated fish, the expression did not increase until nearly 24 h after induction. In biofunction assays, recombinant gCCL4 was found to induce chemotactic activity in the peripheral blood leukocytes of groupers and up-regulate the gene expressions of grouper TNFA1 (TNF-α1), TNFA2 (TNF-α2), IFNG (IFN-γ), MX, TBX21 (T-bet), CD8 (α and β chain). These findings indicate that grouper CCL4 attracts leukocytes, induces an inflammatory response, and drives lymphocyte differentiation into the Th1 pathway.

  17. 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

  18. 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.

  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. 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.

  1. Hepatoprotective effects of baicalein against CCl4-induced acute liver injury in mice

    Institute of Scientific and Technical Information of China (English)

    Hai-Li Huang; Ya-Jing Wang; Qing-Yu Zhang; Bin Liu; Fang-Yuan Wang; Jing-Jing Li; Run-Zhi Zhu

    2012-01-01

    AIM:To investigate the hepatoprotective effect of baicalein against carbon tetrachloride (CCl4)-induced liver damage in mice.METHODS:Mice were orally administered with baicalein after CCl4 injection,and therapeutic baicalein was given twice a day for 4 d.The anti-inflammation effects of baicalein were assessed directly by hepatic histology and serum alanine aminotranferease and aspartate aminotransferase measurement.Proliferating cell nuclear antigen was used to evaluate the effect of baicalein in promoting hepatocyte proliferation.Serum interleukin (IL)-6,IL-1β and tumor necrosis factor-α (TNF-α) levels were measured by enzyme-linked immunosorbent assay and liverIL-6,TNF-α,transforming growth factor-α (TGF-α),hepatocyte growth factor (HGF) and epidermal growth factor (EGF) genes expression were determined by quantitative real-time polymerase chain reaction.RESULTS:CCl4-induced acute liver failure model offers a survival benefit in baicalein-treated mice.The data indicated that the mRNA levels of IL-6 and TNF-α significantly increased within 12 h after CCl4 treatment in baicalein administration groups,but at 24,48 and 72h,the expression of IL-6 and TNF-α was kept at lower levels compared with the control.The expression of TGF-α,HGF and EGF was enhanced dramatically in baicalein administration group at 12,24,48 and 72 h.Furthermore,we found that baicalein significantly elevated the serum level of TNF-α and IL-6 at the early phase,which indicated that baicalein could facilitate the initiating events in liver regeneration.CONCLUSION:Baicalein may be a therapeutic candidate for acute liver injury.Baicalein accelerates liver regeneration by regulating TNF-α and IL-6 mediated pathways.

  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. 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...

  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. The protective effect of ENA Actimineral resource A on CCl4-induced liver injury in rats.

    Science.gov (United States)

    Hong, Il-Hwa; Ji, Hoon; Hwa, Sung-Yong; Jeong, Won-Il; Jeong, Da-Hee; Do, Sun-Hee; Kim, Ji-Min; Ki, Mi-Ran; Park, Jin-Kyu; Goo, Moon-Jung; Hwang, Ok-Kyung; Hong, Kyung-Sook; Han, Jung-Youn; Chung, Hae-Young; Jeong, Kyu-Shik

    2011-06-01

    ENA Actimineral Resource A (ENA-A) is alkaline water that is composed of refined edible cuttlefish bone and two different species of seaweed, Phymatolithon calcareum and Lithothamnion corallioides. In the present study, ENA-A was investigated as an antioxidant to protect against CCl(4)-induced oxidative stress and hepatotoxicity in rats. Liver injury was induced by either subacute or chronic CCl(4) administration, and the rats had free access to tap water mixed with 0% (control group) or 10% (v/v) ENA-A for 5 or 8 weeks. The results of histological examination and measurement of antioxidant activity showed that the reactive oxygen species production, lipid peroxidation, induction of CYP2E1 were decreased and the antioxidant activity, including glutathione and catalase production, was increased in the ENA-A groups as compared with the control group. On 2-DE gel analysis of the proteomes, 13 differentially expressed proteins were obtained in the ENA-A groups as compared with the control group. Antioxidant proteins, including glutathione S-transferase, kelch-like ECH-associated protein 1, and peroxiredoxin 1, were increased with hepatocyte nuclear factor 3-beta and serum albumin precursor, and kininogen precursor decreased more in the ENA-A groups than compared to the control group. In conclusion, our results suggest that ENA-A does indeed have some protective capabilities against CCl(4)-induced liver injury through its antioxidant function.

  6. Protective effect of Sida cordata leaf extract against CCl4 induced acute liver toxicity in rats

    Institute of Scientific and Technical Information of China (English)

    Sunil Mistry; KR Dutt; J Jena

    2013-01-01

    Objective: To investigate the hepatoprotective potential of Sida cordata (Malvaceae) (S. cordata) in experimental rats to validate its traditional claim. Methods: Wister albino rats were divided into 6 groups: Group Ⅰ served as control; Group Ⅱ served as hepatotoxic (CCl4 treated) group;Group Ⅲ, Ⅳ and Ⅴ served as (100, 200 and 400 mg/kg b.w.) S. cordata leaf extract (SCLE) treated groups; Group Ⅵ served as positive control (Silymarin) treated group. Liver marker enzymes serum glutamate oxyloacetic transaminase, serum glutamic pyruvic transaminase, pancreatic enzymatic antioxidants superoxide dismutase (SOD), lipid peroxidation, catalase (CAT), reduced glutathione (GSH) were measured and compared along with histopathological studies. Results:Obtained results show that the treatment with SCLE significantly (P<0.05-<0.001) and dose-dependently reduced CCl4 induced elevated serum level of hepatic enzymes. Furthermore, SCLE significantly (up to P<0.001) reduced the lipid peroxidation in the liver tissue and restored activities of defence antioxidant enzymes GSH, SOD and CAT towards normal levels, which was confirmed by the histopathological studies. Conclusions: The results of this study strongly indicate the protective effect of SCLE against CCl4 induced acute liver toxicity in rats and thereby scientifically support its traditional use.

  7. 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.

  8. 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.

  9. 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

  10. Differential hepatoprotective mechanisms of rutin and quercetin in CCl4-intoxicated BALB/cN mice

    Institute of Scientific and Technical Information of China (English)

    Robert DOMITROVI(C); Hrvoje JAKOVAC; Vanja VASILJEV MARCHESI; Sanda VLADIMIR-KNE(Z)EVI(C); Olga CVIJANOVI(C); (Z)arko TADI(C); (Z)eljko ROMI(C); Dario RAHELI(C)

    2012-01-01

    Aim:To investigate the mechanisms underlying the protective effects of quercetin-rutinoside (rutin) and its aglycone quercetin against CCl4-induced liver damage in mice.Methods:BALB/cN mice were intraperitoneally administered rutin (10,50,and 150 mg/kg) or quercetin (50 mg/kg) once daily for 5 consecutive days,followed by the intraperitoneal injection of CCl4 in olive oil (2 mL/kg,10% v/v).The animals were sacrificed 24 h later.Blood was collected for measuring the activities of ALT and AST,and the liver was excised for assessing Cu/Zn superoxide dismutase (SOD) activity,GSH and protein concentrations and also for immunoblotting.Portions of the livers were used for histology and immunohistochemistry. Results:Pretreatment with rutin and,to a lesser extent,with quercetin significantly reduced the activity of plasma transaminases and improved the histological signs of acute liver damage in CCl4-intoxicated mice.Quercetin prevented the decrease in Cu/Zn SOD activity in CCl4-intoxicated mice more potently than rutin.However,it was less effective in the suppression of nitrotyrosine formation.Quercetin and,to a lesser extent,rutin attenuated the inflammation in the liver by down-regulating the CCl4-induced activation of nuclear factor-kappa B (NF-κB),tumor necrosis factor-α (TNF-α) and cyclooxygenase (COX-2).The expression of inducible nitric oxide synthase (iNOS) was more potently suppressed by rutin than by quercetin.Treatment with both flavonoids significantly increased NF-E2-related factor 2 (Nrf2) and heme oxygenase (HO-1) expression in injured livers,although quercetin was less effective than rutin at an equivalent dose.Quercetin more potently suppressed the expression of transforming growth factor-β1 (TGF-β1) than rutin.Conclusion:Rutin exerts stronger protection against nitrosative stress and hepatocellular damage but has weaker antioxidant and antiinflammatory activities and antifibrotic potential than quercetin,which may be attributed to the presence of a

  11. Hepatoprotective potential of kumaryasava and its concentrate against CCl4-induced hepatic toxicity in Wistar rats

    Science.gov (United States)

    Khan, Mohammad Ahmed; Gupta, Arun; Sastry, J. L. N.; Ahmad, Sayeed

    2015-01-01

    Objective: Kumaryasava (KS) is a marketed Ayurvedic formulation containing Aloe vera as the main ingredient. It has been used widely for the treatment of liver disorders; however, there is a lack of modern scientific data on hepatoprotection. The recommended dose of KS is high and up to 60 mL/day. The present study describes the preparation of new KS concentrate and evaluation of comparative hepatoprotective activity of KS and prepared KS concentrate at one-third of KS dose against CCl4-induced hepatic toxicity. Materials and Methods: Animals were divided into different groups (n = 6). The first group received normal saline (control) 1.0 mL/Kg/day p.o. for 10 days. The second group (toxicant) was given normal saline 1.0 mL/Kg/day p.o. for 10 days with CCl4 in olive oil (1:1 v/v) at 1.0 mL/Kg/day p.o. Third, fourth, and fifth groups received KS, KS concentrate and a marketed formulation as standard) at doses of 5.0 mL/Kg/day p.o., 1.6 mL/Kg/day p.o., and 100 mL/Kg/day p.o. (tablet suspended in water using 0.1% carboxymethyl cellulose) respectively for 10 days along with CCl4 as given to the toxicant group. On the 11th day, blood was withdrawn from retro-orbital plexus and serum was separated for biochemical estimation of serum glutamic-oxaloacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT), alkaline phosphatase (ALP), and albumin levels. Later, animals were sacrificed under high dose of anesthesia to remove liver tissue, which were removed and washed with ice cold saline for the estimation of lipid peroxidation. Liver tissue from each group was also fixed in 10% formalin for histopathological analysis. Results: Results demonstrated that both KS and KS concentrate showed the protection against CCl4-induced hepatic toxicity. This was evident from the reduction in serum SGOT, SGPT, ALP levels, and elevation in serum albumin levels observed post treatment of CCl4 treated rats with KS and KS concentrate, which were supported by histopathological data

  12. 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...

  13. 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...

  14. 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).

  15. 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.

  16. 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.

  17. Curcumin or saikosaponin a improves hepatic antioxidant capacity and protects against CCl4-induced liver injury in rats.

    Science.gov (United States)

    Wu, Shu-Ju; Lin, Yun-Ho; Chu, Chia-Chou; Tsai, Ya-Hui; Chao, Jane C-J

    2008-06-01

    Curcumin and saikosaponin a, the bioactive phytochemicals of turmeric and Bupleurum, act as antioxidants. This study investigated the effects of supplementation with curcumin and/or saikosaponin a on hepatic lipids and antioxidant status in rats with CCl(4)-induced liver injury. Male Sprague-Dawley rats were randomly divided into control, CCl(4), CCl(4) + curcumin (0.005%; CU), CCl(4) + saikosaponin a (0.004%; SS), and CCl(4) + curcumin + saikosaponin a (0.005% + 0.004%; CU+SS) groups. CCl(4) (40% in olive oil) was injected intraperitoneally at a dose of 0.75 mL/kg once a week. Curcumin and/or saikosaponin a was administered orally 1 week before CCl(4) injection for 8 weeks. The pathological results showed that liver fibrosis was ameliorated in the SS and CU+SS groups. After 8 weeks, supplementation with curcumin and/or saikosaponin a significantly decreased plasma alanine aminotransferase and aspartate aminotransferase activities, as well as plasma and hepatic cholesterol and triglyceride levels. The CU+SS group showed reversal of the impaired hepatic superoxide dismutase activity and an increase in total glutathione level. Supplementation with curcumin and/or saikosaponin a significantly improved hepatic antioxidant status and suppressed malondialdehyde formation. Therefore, supplementation with curcumin and/or saikosaponin a protects against CCl(4)-induced liver injury by attenuating hepatic lipids and lipid peroxidation and enhancing antioxidant defense. Curcumin and saikosaponin a had no additive effects on hepatoprotection except for greater improvement in the total glutathione level and antioxidant status.

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

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    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.

  19. 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.

  20. THE ROLE OF ENALAPRIL IN PATHOGENESIS OF CCL4 INDUCED HEPATIC FIBROSIS

    Institute of Scientific and Technical Information of China (English)

    魏红山; 李定国; 陆汉明; 展玉涛; 王志荣; 黄新; 徐芹芳

    2001-01-01

    Objective The present study was designed to examine whether the renin-angiotensin system would be implicated in the development of hepatic fibrosis induced by CCl4. The effects of enalapril on the expression of platelet derived growth factor receptor (PDGFR) in liver tissue were also investigated. Methods 50 Sprague-Dawley rats were randomly divided into 5 groups (control group, model group, and 3 enalapril treated groups ). Except rats of the model group, all rats received subcutanous injection of 40% CCl4 (every 3d for 6 weeks). Rats of enalapril treated groups were given enalapril (10mg/kg, 5mg/kg, 2.5mg/kg per day, orally) for 6 weeks before they were killed. Serum levels of hyaluronic acid (HA) and laminin ( LN) were deterrnined by radioimmunoassay techniques. Van Gieson collagen staining was used to evaluate the extracellular matrix of the liver. The expressions of PDGFR and a-smooth muscle actin ( α-SMA ) were confirmed by immunohistochemical methods. Results Compared with those in the model group, it was found in enalapril treated groups: (1) serum levels of collagen type Ⅳ and LN were significantly reduced (P<0.01); (2) the progression of fibrosis was delayed (P<0.01); (3) the expressions of PDGFR and a-SMA were decreased. Conclusion The renin-angiotensin system was involved in the development of hepatic fibrosis induced by CCl4. Angiotensin-converting enzyme (ACE) inhibitor and enalapril could slow down the rate of hepatic fibrosis. This effect might be due to the ability of this drug in suppressing the expression of PDGFR of liver tissue.

  1. Embryonic stem cells develop into hepatocytes after intrasplenic transplantation in CCl4-treated mice

    Institute of Scientific and Technical Information of China (English)

    Kei Moriya; Masahide Yoshikawa; Ko Saito; Yukiteru Ouji; Mariko Nishiofuku; Noriko Hayashi; Shigeaki Ishizaka; Hiroshi Fukui

    2007-01-01

    AIM: To transplant undifferentiated embryonic stem (ES) cells into the spleens of carbon tetrachloride (CCl4)-treated mice to determine their ability to differentiate into hepatocytes in the liver.METHODS: CCU, 0.5 mL/kg body weight, was injected into the peritoneum of C57BL/6 mice twice a week for 5 wk. In group 1 (n = 12), 1 x 105 undifferentiated ES cells (0.1 mL of 1 x 106/mL solution), genetically labeled with GFP, were transplanted into the spleens 1 d after the second injection. Group 2 mice (n = 12) were injected with 0.2 mL of saline twice a week, instead of CCU, and the same amount of ES cells was transplanted into the spleens. Group 3 mice (n = 6) were treated with CCU and injected with 0.1 mL of saline into the spleen, instead of ES cells. Histochemical analyses of the livers were performed on post-transplantation d (PD) 10, 20, and 30.RESULTS: Considerable numbers of GFP-immunopositive cells were found in the periportal regions in group 1 mice (CCl4-treated) on PD 10, however, not in those untreated with CCl4 (group 2). The GFP-positive cells were also immunopositive for albumin (ALB), alpha-1 antitrypsin, cytokeratin 18, and hepatocyte nuclear factor 4 alpha on PD 20. Interestingly, most of the GFP-positive cells were immunopositive for DLK, a hepatoblast marker, on PD 10. Although very few ES-derived cells were demonstrated immunohistologically in the livers of group 1 mice on PD 30, improvements in liver fibrosis were observed. Unexpectedly, liver tumor formation was not observed in any of the mice that received ES cell transplantation during the experimental period.CONCLUSION: Undifferentiated ES cells developed into hepatocyte-like cells with appropriate integration into tissue, without uncontrolled cell growth.

  2. 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

  3. 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.

  4. 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

  5. Protective effects of Carissa opaca fruits against CCl4-induced oxidative kidney lipid peroxidation and trauma in rat

    Directory of Open Access Journals (Sweden)

    Sumaira Sahreen

    2015-09-01

    Full Text Available Background: Carbon tetrachloride (CCl4 is a potent nephrotoxin, as it causes acute as well as chronic toxicity in kidneys. Therefore, this study was carried out to assess the pharmacological potential of different fractions of Carissa opaca fruits on CCl4-induced oxidative trauma in the kidney. Methods: The parameters studied in this respect were the kidney function tests viz, serum profile, urine profile, genotoxicity, characteristic morphological findings, and antioxidant enzymatic level of kidneys. Result: The protective effects of various fractions of C. opaca fruits against CCl4 administration were reviewed by rat renal function alterations. Chronic toxicity caused by 8-week treatment of CCl4 to the rats significantly decreased the pH level, activities of antioxidant enzymes, and glutathione contents, whereas a significant increase was found in the case of specific gravity, red blood cells, white blood cells, level of urea, and lipid peroxidation in comparison to control group. Administration of various fractions of C. opaca fruit with CCl4 showed protective ability against CCl4 intoxication by restoring the urine profile, activities of antioxidant enzymes, and lipid peroxidation in rat. CCl4 induction in rats also caused DNA fragmentation and glomerular atrophy by means of dilation, disappearance of Bowmen's space, congestion in the capillary loops, dilation in renal tubules, and foamy look of epithelial cells of tubular region, which were restored by co-admiration of various fractions of C. opaca. Conclusion: Results revealed that the methanolic fractions of C. opaca are the most potent and helpful in kidney trauma.

  6. COMPARATIVE EFFECT BETWEEN CHITOSAN AND CHITOSAN-Cu COMPLEX ON CARBON-TETRACHLORIDE (CCL4 INDUCED LIVER DAMAGE IN RATS

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    El-Habibi, E.M.; Sirag, H.M. and Edrees, G.M.

    2009-09-01

    Full Text Available BACKGROUND: Carbon tetrachloride (CCl4 is a toxic material known to induce lipid peroxidation and liver damage. The possible protective roles that involved by chitosan or chitosan-Cu complex against CCl4 induced liver intoxication were investigated in male rats. RESULTS: CCl4 administred at dose 20 mg/kg body weight i.p., exceed malondialdehyde (MDA and protein carbonyle (PC, depleted superoxide dismutase (SOD and glutathione (GSH, in concomitant with marked increase in investigated liver function parameters , alanine aminotransferase and aspartate aminotransferase (ALT, AST, impaired serum and liver total protein , albumin and globulin. An elevation in serum and hepatic total lipids, total cholesterol, triglycerides and serum LDL and VLDL levels as well as a low level of HDL were recorded. In the same time, there was a significant increase in sodium and iron contents in the serum while a significant decrease in potassium and zinc contents were recorded. Animals pretreated with chitosan (200 mg /kg body weight orally by stomach tube for 21 consecutive days prior to CCl4 challenge significantly attenuated most of the tested parameters, strengthen antioxidant defense system, ameliorated liver function effectively. Chitosan-Cu complex has a protective effect by a higher degree than that of chitosan only. CONCLUSION: These findings suggest that pretreatment with chitosan-Cu complex has higher hepato-protective effects than that of only chitosan against CCl4 induced toxicity in rat.

  7. 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.

  8. 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.

  9. 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)

  10. 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.

  11. 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.

  12. Effect of Yiguanjian decoction on cell differentiation and proliferation in CCl4-treated mice

    Institute of Scientific and Technical Information of China (English)

    Xiao-Ling Wang; Dong-Wei Jia; Hui-Yang Liu; Xiao-Feng Yan; Ting-Jie Ye; Xu-Dong Hu; Bo-Qin Li

    2012-01-01

    AIM:To investigate the cellular mechanisms of action of Yiguanjian (YGJ) decoction in treatment of chronic hepatic injury.METHODS:One group of mice was irradiated,and received enhanced green fluorescent protein (EGFP)-positive bone marrow transplants followed by 13 wk of CCl4 injection and 6 wk of oral YGJ administration.A second group of Institute for Cancer Research mice was treated with 13 wk of CCl4 injection and 6 wk of oral YGJ administration.Liver function,histological changes in the liver,and Hyp content were analyzed.The expression of α-smooth muscle actin (α-SMA),F4/80,albumin (Alb),EGFP,mitogen-activated protein kinase-2 (PKM2),Ki-67,α fetoprotein (AFP),monocyte chemotaxis protein-1 and CC chemokine receptor 2 were assayed.RESULTS:As hepatic damage progressed,EGFP-positive marrow cells migrated into the liver and were mainly distributed along the fibrous septa.They showed a conspicuous coexpression of EGFP with α-SMA and F4/80 but no coexpression with AIb.Moreover,the expression of PKM2,AFP and Ki-67 was enhanced dynamically and steadily over the course of liver injury.YGJ abrogated the increases in the number of bone marrow-derived fibrogenic cells in the liver,inhibited expression of both progenitor and mature hepatocyte markers,and reduced fibrogenesis.CONCLUSION:YGJ decoction improves liver fibrosis by inhibiting the migration of bone marrow cells into the liver as well as inhibiting their differentiation and suppressing the proliferation of both progenitors and hepatocytes in the injured liver.

  13. Investigation on improving characteristics of two-cell SBS system with CCl4/C2H5OH liquid mixture

    Institute of Scientific and Technical Information of China (English)

    Hasi Wu-Li-Ji; Lü Li-Qiang; He Wei-Ming

    2007-01-01

    In order to improve the performance of the two-cell stimulated Brillouin scattering(SBS) system,this paper proposes the methods of using mixtures,which require amplifier media to have small absorption rate,and generator media to have high optical breakdown threshold and Brillouin frequency shift equal to that of the amplification media.The characteristics of the two-cell SBS system are studied experimentally by using CCl4 as amplifier medium and CCl4,C2H5OH and CCl4/C2H5OH liquid mixture as generator medium pumped by Nd:YAG Q-switched laser.The obtained results show that liquid mixture in generator cell improves the power load ability,phase conjugation fidelity,energy reflectivity (ER) and ER stability.

  14. Group IVA phospholipase A(2) deficiency prevents CCl4-induced hepatic cell death through the enhancement of autophagy.

    Science.gov (United States)

    Ishihara, Keiichi; Kanai, Shiho; Tanaka, Kikuko; Kawashita, Eri; Akiba, Satoshi

    2016-02-26

    Group IVA phospholipase A2 (IVA-PLA2), which generates arachidonate, plays a role in inflammation. IVA-PLA2-deficiency reduced hepatotoxicity and hepatocyte cell death in mice that received a single dose of carbon tetrachloride (CCl4) without any inhibitory effects on CCl4-induced lipid peroxidation. An immunoblot analysis of extracts from wild-type mouse- and IVA-PLA2 KO mouse-derived primary hepatocytes that transiently expressed microtubule-associated protein 1 light chain 3B (LC3) revealed a higher amount of LC3-II, a typical index of autophagosome formation, in IVA-PLA2-deficient cells, suggesting the enhancement of constitutive autophagy. IVA-PLA2 may promote CCl4-induced cell death through the suppression of constitutive autophagy in hepatocytes.

  15. 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

  16. 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

  17. 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。

  18. Protective effects of polyphenols-enriched extract from Huangshan Maofeng green tea against CCl4-induced liver injury in mice.

    Science.gov (United States)

    Cui, Yanmang; Yang, Xingbin; Lu, Xinshan; Chen, Jinwen; Zhao, Yan

    2014-09-01

    The study was to characterize the polyphenolic composition, antioxidant properties, and hepatoprotective effects of a polyphenols-enriched extract (HMTP) from Huangshan Maofeng green tea. HPLC analysis showed that three predominantly polyphenolic compounds present in HMTP were epigallocatechin (271.2 μg/mg extract), rutin (239.3 μg/mg) and epicatechin (89.3 μg/mg). HMTP was shown to exhibit strong scavenging activities against DPPH, O2(-), and OH, and ferric-reducing antioxidant power in vitro. Administration of HMTP at 200, 400 and 800 mg/kg bw in mice prior to CCl4 injury significantly decreased the CCl4-induced elevation of serum ALT, AST and ALP activities, and prevented an increase in hepatic MDA levels (p<0.05). Mice with HMTP pretreatment displayed a better profile of hepatosomatic index and the improved GSH-Px and SOD activities in the liver, relative to CCl4-intoxicated mice. Liver pathological observation also confirmed the protection on CCl4-caused histological alteration, suggesting that HMTP has potential to be explored as valuable hepatoprotective function food.

  19. 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

  20. 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

    2016-01-01

    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. PMID:27273426

  1. 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.

  2. 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

  3. Protective effect of selenium-enriched lactobacillus on CCl4-induced liver injury in mice and its possible mechanisms

    Institute of Scientific and Technical Information of China (English)

    Long Chen; Dao-Dong Pan; Juan Zhou; Ying-Zi Jiang

    2005-01-01

    AIM: To study the protective effects and mechanisms of Se-enriched lactobacillus on liver injury caused by carbon tetrachloride (CCl4) in mice.MWTHODS: Seventy-two ICR mice were randomly divided into four groups: normal group, CCl4-induced model group,low Se-enriched lactobacillus treatment group (L-Se group),and high Se-enriched lactobacillus treatment group (H-Se group). During a 3-wk experimental period, the common complete diet was orally provided daily for normal group and model group, and the mice in L-Se and H-Se groups were given a diet with 2 and 4 mg of organoselenium from Se-enriched lactobacillus per kg feed, respectively. From the 2nd wk of experiment, the model group, L-Se group,and H-Se group received abdominal cavity injection of olive oil solution containing 500 mL/L CCl4 (0.07 mL/100 g body mass) to induce liver injury, and the normal group was given olive oil on every other day for over 2 wk. In the first 2 wk post injection with CCl4, mice in each group were killed. The specimens of blood, liver tissue, and macrophages in abdominal cavity fluid were taken. Then the activities of the following liver tissue injury-associated enzymes including glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) as well as malondialdehyde (MDA) content were assayed. Changes of phagocytic rate and phagocytic index in macrophages were observed with Wright-Giemsa stain. Plasma TNF-α level was measured by radioimmunoassay. The level of intracellular free Ca2+ ([Ca2+]i) in hepatocytes was detected under a laser scanning confocal microscope.RESULTS: During the entire experimental period, the AST and ALT activities in liver were greatly enhanced by CCl4 and completely blunted by both low and high doses of Se-enriched lactobacillus. The Se-enriched lactobacillus-protected liver homogenate GSH-Px and SOD activities were higher or significantly higher than those in model group and were close to

  4. Hepatoprotective effect of flavonol glycosides rich fraction from Egyptian Vicia calcarata Desf. against CCl4-induced liver damage in rats.

    Science.gov (United States)

    Singab, Abdel Nasser B; Youssef, Diaa T A; Noaman, Eman; Kotb, Saeed

    2005-07-01

    The hepatoprotective activity of flavonol glycosides rich fraction (F-2), prepared from 70% alcohol extract of the aerial parts of V. calcarata Desf., was evaluated in a rat model with a liver injury induced by daily oral administration of CCl4 (100 mg/kg, b.w) for four weeks. Treatment of the animals with F-2 using a dose of (25 mg/kg, b.w) during the induction of hepatic damage by CCl4 significantly reduced the indices of liver injuries. The hepatoprotective effects of F-2 significantly reduced the elevated levels of the following serum enzymes: alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH). The antioxidant activity of F-2 markedly ameliorated the antioxidant parameters including glutathione (GSH) content, glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), plasma catalase (CAT) and packed erythrocytes glucose-6-phosphate dehydrogenase (G6PDH) to be comparable with normal control levels. In addition, it normalized liver malondialdehyde (MDA) levels and creatinine concentration. Chromatographic purification of F-2 resulted in the isolation of two flavonol glycosides that rarely occur in the plant kingdom, identified as quercetin-3, 5-di-O-beta-D-diglucoside (5) and kaempferol-3, 5-di-O-beta-D-diglucoside (4) in addition to the three known compounds identified as quercetin-3-O-alpha-L-rhamnosyl- (1-->6)-beta-D-glucoside [rutin, 3], quercetin-3-O-beta-D-glucoside [isoquercitrin, 2] and kaempferol-3-O-beta-D-glucoside [astragalin, 1]. These compounds were identified based on interpretation of their physical, chemical, and spectral data. Moreover, the spectrophotometric estimation of the flavonoids content revealed that the aerial parts of the plant contain an appreciable amount of flavonoids (0.89%) calculated as rutin. The data obtained from this study revealed that the flavonol glycosides of F-2 protect the rat liver from hepatic damage induced by CCl4 through inhibition of

  5. Effect of compound rhodiola sachalinensis A Bor on CCl4-induced liver fibrosis in rats and its probable molecular mechanisms

    Institute of Scientific and Technical Information of China (English)

    Xiao-Ling Wu; Wei-Zheng Zeng; Pi-Long Wang; Chun-Tao Lei; Ming-De Jiang; Xiao-Bin Chen; Yong Zhang; Hui Xu; Zhao Wang

    2003-01-01

    AIM: To explore the anti-fibrotic effect of a traditional Chinese medicine, compound rhodiola sachalinensis A Bor on CCl4-induced liver fibrosis in rats and its probable molecular mechanisms.METHODS: Ninety healthy male SD rats were randomly divided into three groups: normal group (n=10), treatment group of compound rhodiola sachalinensis A Bor (n=40) and CCl4-induced model group (n=40). The liver fibrosis was induced by CCl4 subcutaneous injection. Treatment group was administered with compound rhodiola sachalinensis A Bor (0.5 g/kg) once a day at the same time. Then the activities of several serum fibrosis-associated enzymes: alanine aminotransferase (ALT), aspartate aminotransferase (AST),N-acetyl-beta-D-glucosaminidase (β-NAG) and the levels of serum procollagen Ⅲ (PCⅢ), collagen IV (CIV), hyaluronic acid (HA) were assayed. The histopathological changes were observed with HE, VG and Masson stain. The expression of TGF-β1 mRNA, α1 (I) mRNA and Na+/Ca2+ exchanger (NCX)mRNA was detected by reverse transcription polymerase chain reaction (RT-PCR) in situ.RESULTS: Compound rhodiola sachalinensis A Bor significantly reduced serum activities of ALT, AST, β-NAG and decreased the levels of PCⅢ, CIV, HA, improved the liver histopathological changes, inhibited the expression of TGFβ1 mRNA, α(I) mRNA and Na+/Ca2+ exchanger mRNA in rats.CONCLUSION: Compound rhodiola sachalinensis A Bor can intervene in CCl4-induced liver fibrosis in rats, in which potential mechanisms may be decreasing the production of TGF-β1, reducing the production of collagen, preventing the activation of hepatic stellate cell (HSC) and inhibiting the expression of TGF-β1 mRNA, α1(I) mRNA and Na+/Ca2+exchanger mRNA.

  6. 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...

  7. 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.

  8. 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...

  9. 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.

  10. 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.

  11. 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.

  12. The ethanolic extract of Juglans sinensis leaves and twigs attenuates CCl4-induced hepatic oxidative stress in rats

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    Heejung Yang

    2015-01-01

    Full Text Available Background: The nuts of Juglans sinensis Dode, walnut tree, are rich in unsaturated fatty acids and bioactive compounds with antioxidant activity on liver damages. However, hepatoprotective activity of the leaves and twigs of J. sinensis have not intensively studied yet. Objective: Hepatoprotective activity of the refined ethanolic extract of J. sinensis (JSE3 was evaluated using carbon tetrachloride (CCl4 intoxicated rats. Materials and Methods: Hepatotoxicity was induced in Sprague Dawley rats by intraperitoneal injection of CCl4 for 6 weeks in the presence or absence of JSE3 (100 and 200 mg/kg body weight. The hepatoprotective activity of JSE3 was assessed by biochemical parameters including plasma aspartate aminotransferase (AST, alanine aminotransferase (ALT, and antioxidant enzymes, such as superoxide dismutase (SOD, glutathione reductase, glutathione peroxide, reduced glutathione and oxidized glutathione, along with histopathological studies on hepatic tissue. Results: JSE3 significantly decreased the elevated levels of AST and ALT and restored the reduced levels of antioxidant enzymes. JSE3 also decreased the amounts of collagen content accumulated by CCl4 intoxication. Conclusion: These results suggested that the refined extract of J. sinensis may have a potential to be developed as a therapeutic agent to treat hepatic diseases, such as fatty liver and hepatic fibrosis.

  13. Hepatoprotective potential of ethanolic and aqueous extract of flowers of Sesbania grandiflora (Linn) induced by CCl4

    Institute of Scientific and Technical Information of China (English)

    Ishwer Kale; Mohd Asif Khan; Yusufuddin Irfan; Veerana Goud A

    2012-01-01

    Objective: To investigate the hepatoprotective activity of ethanolic and aqueous extract of Sesbania grandiflora(Linn) flower in CCl4 induced hepatotoxicity models in rats. Methods:The ethanolic and aqueous extract of Sesbania grandiflora (Linn) flower are screened for its hepatoprotective activity in CCl4 (0.5 ml/kg, i.p) induced liver damage in Swiss albino rats at a dose of 200 mg/kg bw. Results: The ethanolic and aqueous extract of Sesbania grandiflora (Linn) flower significantly (P<0.001) decreases the biochemical parameters (SGOT, SGPT, ALP, TP, and TB). Silymarin (25 mg/kg), a known hepatoprotective drug used for comparison exhibited significant activity (P<0.001). The extract did not shown any mortality up to a dose of 2000 g/kg bw. These findings suggest that the ethanolic and aqueous extract of Sesbania grandiflora (Linn) flower (500mg/kg) was effective in bringing about functional improvement of hepatocytes. The healing effect of this extract was also confirmed by histological observations. Conclusions: The ethanolic extract at doses of 250 and 500 mg/kg, p.o. and aqueous extract at a dose of 500 mg/kg, p.o. of Sesbania grandiflora (Linn) flower have significant effect on the liver of CCl4 induced hepatotoxicity animal models.

  14. 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

  15. 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.

  16. Hepatocurative potential of Vitex doniana root bark, stem bark and leaves extracts against CCl4-induced liver damage in rats

    Institute of Scientific and Technical Information of China (English)

    James Dorcas Bolanle; Kadejo Olubukola Adetoro; Sallau Abdullahi Balarabe; Owolabi Olumuyiwa Adeyemi

    2014-01-01

    Objective: To evaluate the hepatocurative effects of aqueous root bark, stem bark and leaves ofVitex doniana in carbon tetrachloride (CCl albino rats.Methods:4) induced liver damage and non induced liver damage were assigned into liver damage and non liver damage groups of 6 rats in a group. The animals in the CCl4 induced liver damage groups, were induced by intraperitoneal injection with a single dose of CCl4 (1 mL/kg body weight) as a 1:1(v/v) solution in olive oil and were fasted for 36 h before the subsequent treatment with aqueous root bark, stem bark and leaves extracts of Vitex doniana and vitamin E as standard drug (100 mg/kg body weight per day) for 21 d, while the animals in the non induced groups were only treated with the daily oral administration of these extracts at the same dose. The administration of CCl4 was done once a week for a period of 3 weeks.Results:There was significant (P<0.05) increase in concentration of all liver marker enzymes, A total of 60 albino rats (36 induced liver damage and 24 non induced liver damage) alanine aminotransferase, aspartate aminotransferase and alkaline aminotransferase (ALT, AST and ALP) and significant (P<0.05) decrease in albumin in the CCl4 induced liver damage control when compared to the normal control. The extracts caused a significant (P<0.05) reduction in the serum activities of liver marker enzymes (ALT, AST and ALP) and a significant (P<0.05) increase in albumin of all the induced treated groups. Only stem bark extract and vitamin E significantly (P<0.05) increased total protein. All the extracts significantly (P<0.05) lowered serum creatinine whereas only root bark extract significantly (P<0.05) lowered serum level of urea in the rats with CCl4 induced liver damage.Conclusion:Hepatocurative study shows that all the plant parts (root bark, stem bark and leaves) possess significant hepatocurative properties among other therapeutic values justifying their use in folklore medicine.

  17. 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.

  18. Protective effect of rhizoma polygoni cuspidati decoction on liver fibrosis induced by CCL4%中药虎杖水煎液对CCL4诱导肝纤维化的保护作用

    Institute of Scientific and Technical Information of China (English)

    杨先振; 赵有亮; 秦红兵

    2011-01-01

    目的 观察虎杖水煎液对四氯化碳(CCL4)诱导肝纤维化的作用.方法 40只大鼠随机均分为正常对照(A)组、肝纤维化模型(B)组、虎杖水煎液低剂量3 g/kg(C)组和高剂量6 g/kg(D)组.10周后,检测血清ALT、AST以及肝纤维化血清标志物透明质酸(HA)与Ⅵ型胶原(C-Ⅳ)水平,测定肝组织匀浆中超氧化物歧化酶(SOD)活性与丙二醛(MDA)含量,并取肝组织做病理形态学检查.结果 与B组相比,C、D组血清ALT、AST、HA和C-Ⅳ水平降低,肝组织中MDA含量减少,而SOD活性增加(P<0.05或P<0.01),肝纤维化的组织学改变亦减轻.结论 虎杖水煎液对CCL4诱导的肝纤维化具有一定保护作用.%Objective To investigate the effect of rhizoma polygoni cuspidati(RPC) decoction on the liver fibrosis induced by carbon tetrachloride ( CCL4 ). Methods Forty rats were equally randomized into four groups of A(normal controls),B(liver fibrosis model),C(liver fibrosis treated with RPC decoction 3 g/kg) and D( liver fibrosis treated with RPC decoction 6 g/kg). After 10 weeks of administration, serum alanine aminotransferase( ALT), aspartate aminotransf erase (AST) and liver fibrosis markers such as hyaluronic acid(HA) and collagen type W(C-IV) were detected, the activity of superoxide dismutase(SOD) and content of malondialdehyde(MDA) in the hepatic homogenates were measured and the changes of pathomorphology were observed by light microscopy. Results Compared with group B.the levels of ALT, AST, HA,C-IV and the content of MDA were decreased, while the activity of SOD was increased (P<0. 05 or P<0. 01) and the histological changes of liver fibrosis were also improved in groups of C and D. Conclusion RPC decoction has a protective effect on the liver fibrosis induced by CCL4.

  19. 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.

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

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    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.

  1. 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

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

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    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.

  3. 苯巴比妥联合 CCl4法建立肝硬化腹水大鼠模型%To establish the model of cirrhotic rats with ascites phenobarbital combined with CCl4 method

    Institute of Scientific and Technical Information of China (English)

    方庆; 王成业; 姚瑶; 王满媛; 许钒

    2015-01-01

    Objective To establish a stable rat model of liver cirrhosis by using carbon tetrachloride combined with Phenobarbital Sodi-um.Methods 35%Phenobarbital Sodium was carried out in SD rats for 7 days to activate hepatic microsomal enzyme P450.From the second week,gradient carbon tetrachloride oil solution was offered by intraperitoneal injection (twice per week for 14 weeks).24 h u-rine of rats was collected and measured at the end time of the trial.HE staining of liver tissue was used to observe pathological process of liver.Results After induced with Phenobarbital Sodium for 7 days and then injected with carbon tetrachloride into abdominal cavity continuously for 13 weeks,a stable rat model of liver cirrhosis could be achieved.Conclusion The procedure is stable and reliable for building liver cirrhosis model,and the model has lower mortality and shorter cycle time than traditional one.%目的:采用苯巴比妥联合四氯化碳构建稳定的肝硬化腹水大鼠模型,为抗肝硬化腹水药物的研究提供有效可靠的动物模型。方法采用苯巴比妥联合CCl4法复制肝硬化腹水大鼠模型。35%苯巴比妥溶液诱导1周,激活肝脏肝药酶P450活性,第二周开始,按梯度腹腔注射CCl4油溶液,每周2次至第14周。实验进行至中后期,收集大鼠24 h尿液,测量尿量;检查腹腔积液量;肝组织HE染色观察肝脏病理进程。结果大鼠经苯巴比妥溶液诱导1周后,连续腹腔注射CCl4油溶液13周,可复制稳定的肝硬化腹水模型。结论该法可建立稳定、可靠的肝硬化腹水模型,比传统模型降低了死亡率,且造模时间缩短。

  4. UV absorption cross sections of nitrous oxide (N2O and carbon tetrachloride (CCl4 between 210 and 350 K and the atmospheric implications

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    C. H. Jackman

    2010-07-01

    Full Text Available Absorption cross sections of nitrous oxide (N2O and carbon tetrachloride (CCl4 are reported at five atomic UV lines (184.95, 202.548, 206.200, 213.857, and 228.8 nm at temperatures in the range 210–350 K. In addition, UV absorption spectra of CCl4 are reported between 200–235 nm as a function of temperature (225–350 K. The results from this work are critically compared with results from earlier studies. For N2O, the present results are in good agreement with the current JPL recommendation enabling a reduction in the estimated uncertainty in the N2O atmospheric photolysis rate. For CCl4, the present cross section results are systematically greater than the current recommendation at the reduced temperatures most relevant to stratospheric photolysis. The new cross sections result in a 5–7% increase in the modeled CCl4 photolysis loss, and a slight decrease in the stratospheric lifetime, from 51 to 50 years, for present day conditions. The corresponding changes in modeled inorganic chlorine and ozone in the stratosphere are quite small. A CCl4 cross section parameterization for use in atmospheric model calculations is presented.

  5. UV absorption cross sections of nitrous oxide (N2O and carbon tetrachloride (CCl4 between 210 and 350 K and the atmospheric implications

    Directory of Open Access Journals (Sweden)

    C. H. Jackman

    2010-04-01

    Full Text Available Absorption cross sections of nitrous oxide (N2O and carbon tetrachloride (CCl4 are reported at five atomic UV lines (184.95, 202.548, 206.200, 213.857, and 228.8 nm at temperatures in the range 210–350 K. In addition, UV absorption spectra of CCl4 are reported between 200–235 nm as a function of temperature (225–350 K. The results from this work are critically compared with results from earlier studies. For N2O, the present results are in good agreement with the current JPL recommendation enabling a reduction in the estimated uncertainty in the N2O atmospheric photolysis rate. For CCl4, the present cross section results are systematically greater than the current recommendation at the reduced temperatures most relevant to stratospheric photolysis. The new cross sections result in a 5–7% increase in the modeled CCl4 photolysis loss, and a slight decrease in the stratospheric lifetime, from 51 to 50 years, for present day conditions. The corresponding changes in modeled inorganic chlorine and ozone in the stratosphere are quite small. A CCl4 cross section parameterization for use in atmospheric model calculations is presented.

  6. 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

  7. 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.

  8. 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

  9. [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

  10. Structures of human CCL18, CCL3, and CCL4 reveal molecular determinants for quaternary structures and sensitivity to insulin-degrading enzyme.

    Science.gov (United States)

    Liang, Wenguang G; Ren, Min; Zhao, Fan; Tang, Wei-Jen

    2015-03-27

    CC chemokine ligands (CCLs) are 8- to 14-kDa signaling proteins involved in diverse immune functions. While CCLs share similar tertiary structures, oligomerization produces highly diverse quaternary structures that protect chemokines from proteolytic degradation and modulate their functions. CCL18 is closely related to CCL3 and CCL4 with respect to both protein sequence and genomic location, yet CCL18 has distinct biochemical and biophysical properties. Here, we report a crystal structure of human CCL18 and its oligomerization states in solution based on crystallographic and small-angle X-ray scattering analyses. Our data show that CCL18 adopts an α-helical conformation at its N-terminus that weakens its dimerization, explaining CCL18's preference for the monomeric state. Multiple contacts between monomers allow CCL18 to reversibly form a unique open-ended oligomer different from those of CCL3, CCL4, and CCL5. Furthermore, these differences hinge on proline 8, which is conserved in CCL3 and CCL4 but is replaced by lysine in human CCL18. Our structural analyses suggest that a mutation of proline 8 to alanine stabilizes a type 1 β-turn at the N-terminus of CCL4 to prevent dimerization but prevents dimers from making key contacts with each other in CCL3. Thus, the P8A mutation induces depolymerization of CCL3 and CCL4 by distinct mechanisms. Finally, we used structural, biochemical, and functional analyses to unravel why insulin-degrading enzyme degrades CCL3 and CCL4 but not CCL18. Our results elucidate the molecular basis for the oligomerization of three closely related CC chemokines and suggest how oligomerization shapes CCL chemokine function.

  11. 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.

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

    Institute of Scientific and Technical Information of China (English)

    Huang Wei-Qi; Chen Hang-Qiong; Shu Qin; Liu Shi-Rong; Qin Chao-Jian

    2012-01-01

    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.

  13. 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

  14. 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.

  15. 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

  16. 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.

  17. Involvement of the TNF and FasL produced by CD11b Kupffer cells/macrophages in CCl4-induced acute hepatic injury.

    Directory of Open Access Journals (Sweden)

    Atsushi Sato

    Full Text Available We previously reported that F4/80(+ Kupffer cells are subclassified into CD68(+ Kupffer cells with phagocytic and ROS producing capacity, and CD11b(+ Kupffer cells with cytokine-producing capacity. Carbon tetrachloride (CCl4-induced hepatic injury is a well-known chemical-induced hepatocyte injury. In the present study, we investigated the immunological role of Kupffer cells/macrophages in CCl4-induced hepatitis in mice. The immunohistochemical analysis of the liver and the flow cytometry of the liver mononuclear cells showed that clodronate liposome (c-lipo treatment greatly decreased the spindle-shaped F4/80(+ or CD68(+ cells, while the oval-shaped F4/80+ CD11b(+ cells increased. Notably, severe hepatic injury induced by CCl4 was further aggravated by c-lipo-pretreatment. The population of CD11b(+ Kupffer cells/macrophages dramatically increased 24 hour (h after CCl4 administration, especially in c-lipo-pretreated mice. The CD11b(+ Kupffer cells expressed intracellular TNF and surface Fas-ligand (FasL. Furthermore, anti-TNF Ab pretreatment (which decreased the FasL expression of CD11b(+ Kupffer cells, anti-FasL Ab pretreatment or gld/gld mice attenuated the liver injury induced by CCl4. CD1d-/- mouse and cell depletion experiments showed that NKT cells and NK cells were not involved in the hepatic injury. The adoptive transfer and cytotoxic assay against primary cultured hepatocytes confirmed the role of CD11b(+ Kupffer cells in CCl4-induced hepatitis. Interestingly, the serum MCP-1 level rapidly increased and peaked at six h after c-lipo pretreatment, suggesting that the MCP-1 produced by c-lipo-phagocytized CD68(+ Kupffer cells may recruit CD11b(+ macrophages from the periphery and bone marrow. The CD11b(+ Kupffer cells producing TNF and FasL thus play a pivotal role in CCl4-induced acute hepatic injury.

  18. 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.

  19. Recovery of the Cell Cycle Inhibition in CCl4-Induced Cirrhosis by the Adenosine Derivative IFC-305

    Directory of Open Access Journals (Sweden)

    Victoria Chagoya de Sánchez

    2012-01-01

    Full Text Available Introduction. Cirrhosis is a chronic degenerative illness characterized by changes in normal liver architecture, failure of hepatic function, and impairment of proliferative activity. The aim of this study is to know how IFC-305 compound induces proliferation of the liver during reversion of cirrhosis. Methods. Once cirrhosis has been installed by CCl4 treatment for 10 weeks in male Wistar rats, they were divided into four groups: two received saline and two received the compound; all were euthanized at 5 and 10 weeks of treatment. Liver homogenate, mitochondria, and nucleus were used to measure cyclins, CDKs, and cell cycle regulatory proteins PCNA, pRb, p53, E2F, p21, p27, HGF, liver ATP, and mitochondrial function. Results. Diminution and small changes were observed in the studied proteins in the cirrhotic animals without treatment. The IFC-305-treated rats showed a clear increase in most of the proteins studied mainly in PCNA and CDK6, and a marked increased in ATP and mitochondrial function. Discussion/Conclusion. IFC-305 induces a recovery of the cell cycle inhibition promoting recovery of DNA damage through the action of PCNA and p53. The increase in energy and preservation of mitochondrial function contribute to recovering the proliferative function.

  20. 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.

  1. 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.

  2. 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

  3. 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

  4. 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...

  5. Highly potent HIV inhibition: engineering a key anti-HIV structure from PSC-RANTES into MIP-1 beta/CCL4.

    Science.gov (United States)

    Gaertner, Hubert; Lebeau, Olivier; Borlat, Irène; Cerini, Fabrice; Dufour, Brigitte; Kuenzi, Gabriel; Melotti, Astrid; Fish, Richard J; Offord, Robin; Springael, Jean-Yves; Parmentier, Marc; Hartley, Oliver

    2008-02-01

    The HIV coreceptor CCR5 is a validated target for both the prevention and therapy of HIV infection. PSC-RANTES, an N-terminally modified analogue of one of the natural chemokine ligands of CCR5 (RANTES/CCL5), is a potent inhibitor of HIV entry into target cells. Here, we set out to engineer the anti-HIV activity of PSC-RANTES into another natural CCR5 ligand (MIP-1beta/CCL4), by grafting into it the key N-terminal pharmacophore region from PSC-RANTES. We were able to identify MIP-1beta/CCL4 analogues that retain the receptor binding profile of MIP-1beta/CCL4, but acquire the very high anti-HIV potency and characteristic inhibitory mechanism of PSC-RANTES. Unexpectedly, we discovered that in addition to N-terminal structures from PSC-RANTES, the side chain of Lys33 is also necessary for full anti-HIV potency.

  6. «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.

  7. Snailase Preparation of Ginsenoside M1 from Protopanaxadiol-Type Ginsenoside and Their Protective Effects Against CCl4-Induced Chronic Hepatotoxicity in Mice

    Directory of Open Access Journals (Sweden)

    Li Chen

    2011-12-01

    Full Text Available To investigate the protective effects of protopanaxadiol-type ginsenoside (PDG and its metabolite ginsenoside M1 (G-M1 on carbon tetrachloride (CCl4-induced chronic liver injury in ICR mice, we carried out conversion of protopanaxadiol-type ginsenosides to ginsenoside M1 using snailase. The optimum time for the conversion was 24 h at a constant pH of 4.5 and an optimum temperature of 50 °C. The transformation products were identified by high-performance liquid chromatography and electrospray ion-mass spectrometry. Subsequently, most of PDG was decomposed and converted into G-M1 by 24 h post-reaction. During the study on hepatoprotective in a mice model of chronic liver injury, PDG or G-M1 supplement significantly ameliorated the CCl4-induced liver lesions, lowered the serum levels of select hepatic enzyme markers (alanine aminotransferase, ALT, and aspartate aminotransferase, AST and malondialdehyde and increased the activity of superoxide dismutase in liver. Histopathology of the liver tissues showed that PDG and G-M1 attenuated the hepatocellular necrosis and led to reduction of inflammatory cell infiltration. Therefore, the results of this study show that PDG and G-M1 can be proposed to protect the liver against CCl4-induced oxidative injury in mice, and the hepatoprotective effect might be attributed to amelioration of oxidative stress.

  8. 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.

  9. 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

  10. Systemic levels of CCL2, CCL3, CCL4 and CXCL8 differ according to age, time period and season among children newly diagnosed with type 1 diabetes and their healthy siblings

    DEFF Research Database (Denmark)

    Thorsen, S U; Eising, S; Mortensen, H B;

    2014-01-01

    -based registry of children diagnosed with T1D from 1997 to 2005, we studied five different inflammatory chemokines (CCL2, CCL3, CCL4, CCL5 and CXCL8). Four hundred and eighty-two cases and 479 sibling frequencies matched on age and sample year distribution were included. Patients showed lower levels of CCL4...... compared to siblings, but this result was not significant after correction for multiple testing. CCL2, CCL3, CCL4 and CXCL8 levels were highest in the most recent cohorts (P

  11. 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.

  12. 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.

  13. 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

  14. 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)

  15. Aspects of the historical development of targetry for heavy ions of 0.05-2000 A centre dot MeV at GSI

    CERN Document Server

    Folger, H

    1999-01-01

    The progressively improved GSI accelerators provide beams of heavy ions from energies of 0.05-2000 A centre dot MeV at high particle intensities now. Therefore, a wide variety of common and new heavy-ion target techniques had to be installed and developed during the past 25 years to prepare and characterize self-supported or backed heavy-ion-targets of chemical elements and compounds from hydrogen (as polyethylene) to uranium. The thickness ranged from 2x10 sup - sup 6 to 20 g/cm sup 2 for beam spots of about 5 mm in diameter. Homogeneity, surface structure or individual shape had to be adapted to the needs of each experiment. Special setups were required for targets of poisonous materials, of highly enriched stable isotopes or those of radioactive species in minute amounts. The capability of thin-layer technologies was as well applied to prepare and measure stripper foils or various high-vacuum deposits for experimental or accelerator purposes. The development of different rotating target wheels and control ...

  16. Hepatoprotective activity of petroleum ether, diethyl ether, and methanol extract of Scoparia dulcis L. against CCl4-induced acute liver injury in mice

    Directory of Open Access Journals (Sweden)

    Praveen T

    2009-01-01

    Full Text Available Objectives: The present study was aimed at assessing the hepatoprotective activity of 1:1:1 petroleum ether, diethyl ether, and methanol (PDM extract of Scoparia dulcis L. against carbon tetrachloride-induced acute liver injury in mice. Materials and Methods: The PDM extract (50, 200, and 800 mg/kg, p.o. and standard, silymarin (100 mg/kg, p.o were tested for their antihepatotoxic activity against CCl4-induced acute liver injury in mice. The hepatoprotective activity was evaluated by measuring aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, and total proteins in serum, glycogen, lipid peroxides, superoxide dismutase, and glutathione reductase levels in liver homogenate and by histopathological analysis of the liver tissue. In addition, the extract was also evaluated for its in vitro antioxidant activity using 1, 1-Diphenyl-2-picrylhydrazyl scavenging assay. Results: The extract at the dose of 800 mg/kg, p.o., significantly prevented CCl4-induced changes in the serum and liver biochemistry (P < 0.05 and changes in liver histopathology. The above results are comparable to standard, silymarin (100 mg/kg, p.o.. In the in vitro 1, 1-diphenyl-2-picrylhydrazyl scavenging assay, the extract showed good free radical scavenging potential (IC 50 38.9 ± 1.0 µg/ml. Conclusions: The results of the study indicate that the PDM extract of Scoparia dulcis L. possesses potential hepatoprotective activity, which may be attributed to its free radical scavenging potential, due to the terpenoid constituents.

  17. 慈菇对CCl4致大鼠肝纤维化血清cyfra21-1和CEA影响的探讨%The Effect of Sagittaria Agittifolia on Changes of Cyfra21-1 and CEA in Rats of CCl4 Experimental Liver Fibrosis

    Institute of Scientific and Technical Information of China (English)

    吴小南; 汪家梨; 盛健; 黄建宏

    2001-01-01

    目的探讨慈菇对CCl4致大鼠肝纤维化的干预作用.方法对5月龄Wistar大鼠,用CCl4染毒致大鼠形成肝组织纤维化,以ELISA法和放射免疫分析法检测大鼠血清cyfra21-1和CEA的浓度的变化,并观察慈菇的干预效果.结果染毒组大鼠cyfra21-1和CEA明显高于对照组,慈菇可减轻CCl4致大鼠肝纤维化程度并减少cyfra21-1和CEA的产生.结论大鼠肝纤维化后血清cyfra21-1和CEA升高,提示慈菇干预作用的机理值得深入探讨.

  18. Study on Protective Effect of Mongolian Medicine Lomatogonium rotatum Water Extract against Acute Liv-er Injury in Mice Induced by D-GlaN and CCl4%蒙药肋柱花水提物对D-GlaN和CCl4致小鼠急性肝损伤的保护作用研究

    Institute of Scientific and Technical Information of China (English)

    包明兰; 巴根那; 辛颖; 白梅荣; 何那拉

    2016-01-01

    目的:研究蒙药肋柱花水提物对D-氨基半乳糖胺(D-GlaN)和四氯化碳(CCl4)致小鼠急性肝损伤的保护作用.方法:取60只小鼠随机分为正常(生理盐水)组、D-GlaN模型(生理盐水)组、阳性对照(葵花护肝片,0.56 g/kg)组和肋柱花水提物高、中、低剂量[3、1.5、0.75 g(生药)/kg]组,每组10只,ig给药,qd,连续23 d;末次给药30 min后,除正常组外,其余各组小鼠ip D-GlaN复制急性肝损伤模型.检测小鼠血清中天冬氨酸转氨酶(AST)、丙氨酸转氨酶(ALT)、碱性磷酸酶(ALP)活性和胆碱酯酶(CHE)含量,计算肝脏指数,对肝组织病理形态进行观察并评分.另取60只小鼠,除造模方法(ig 0.1%CCl4)不同外,按相同分组、给药及指标检测方法进行实验.结果:与正常组比较,两种模型组小鼠肝细胞明显坏死或变性,病理评分升高;血清中AST、ALT、ALP活性升高,CHE含量减少;且D-GlaN模型组肝脏指数升高、CCl4模型组肝脏指数降低(P<0.05).与D-GlaN模型组比较,肋柱花水提物各剂量组小鼠血清AST、ALT、ALP活性及肝脏指数降低,CHE含量增加(P<0.05);肝组织病理形态改善,评分降低.与CCl4模型组比较,肋柱花水提物低剂量组小鼠血清ALT活性降低、CHE含量增加,肝脏指数升高;肋柱花水提物中剂量组小鼠血清CHE含量减少,肝脏指数升高;肋柱花水提物高剂量组小鼠血清AST、ALT、ALP活性降低,CHE含量增加(P<0.05).肋柱花水提物各剂量组小鼠肝组织病理形态都得到一定改善,评分降低.结论:肋柱花水提物对D-GlaN或CCl4致小鼠急性肝损伤有一定保护作用.%OBJECTIVE:To study the protective effects of Mongolian medicine Lomatogonium rotatum water extract against acute liver injury in mice caused by D-GlaN and CCl4. METHODS:60 mice were randomly divided into normal group(normal sa-line),D-GlaN model group(normal saline),positive control group(Kuihua hugan tablet,0.56 g/kg)and L. rotatum water extract high

  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. 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.

  1. 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

  2. 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)

  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. 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.

  6. 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

  7. 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)

  8. 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

  9. Altered thymocyte migration during experimental acute Trypanosoma cruzi infection: combined role of fibronectin and the chemokines CXCL12 and CCL4.

    Science.gov (United States)

    Mendes-da-Cruz, Daniella Arêas; Silva, João Santana; Cotta-de-Almeida, Vinícius; Savino, Wilson

    2006-06-01

    We previously showed migration disturbances in the thymus during experimental infection with Trypanosoma cruzi, the causative agent of Chagas disease. These changes were related to the enhanced expression of extracellular matrix ligands and receptors, leading to the escape of immature cells to the periphery. Here, we analyzed the expression and role of selected chemokines (CXCL12 and CCL4) and their receptors (CXCR4 and CCR5) in regulating thymocyte migration in conjunction with extracellular matrix during acute T. cruzi infection. We found increased chemokine deposition in the thymus of infected mice when compared to controls, accompanied by enhanced co-localization with fibronectin as well as up-regulated surface expression of CXCR4 and CCR5 in thymocytes. We also noticed altered thymocyte migration towards the chemokines analyzed. Such an enhancement was even more prominent when fibronectin was added as a haptotatic stimulus in combination with a given chemokine. Our findings suggest that thymocyte migration results from a combined action of chemokines and extracellular matrix (ECM), which can be altered during pathological conditions such as T. cruzi infection, and may be at the origin of the changes in the T cell repertoire seen in this pathological process.

  10. 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.

  11. Improvement and optimization of CCl4 induced liver cirrhosis rats model accompanied with ascites%四氯化碳诱导大鼠肝硬化腹水模型的改进与优化

    Institute of Scientific and Technical Information of China (English)

    唐倩; 王卓; 赵雄; 吕茂贞; 吕茂民; 章金刚

    2012-01-01

    Objective To establish a stable, homogeneous, well-tolerated and efficient protocol to induce rat cirrhosis models accompanied with ascites using an improved carbon tetrachloride(CCl4) combined with phenobarbital sodium and alcohol method, thus establishing a basis for serum albumin effectiveness evaluation test. Methods Ninety male Wistar rats were randomly divided into five groups: blank control group containing 10 rats, CCl4 group, CC14 + phenobarbital sodium group, CCl4 + alcohol group and CC14 + phenobarbital sodium + alcohol group containing 20 rats respectively as model groups. The control group was given normal drinking water and injected with olive oil intraperitoneally. Rats in model groups were given different drinking water and an intraperitoneal injection of CC14 in a 2: 3 mixture with olive oil. The drugs given intraperitoneally were all at a dose of 2 ml/kg body mass, twice weekly for 12 weeks. We further measured the body mass and abdominal circumference, and tested the biochemical liver function indices as well as the colloid osmotic pressure ( COP) to evaluate the different processes in these groups. At the end of the induced operation the randomly selected rats in each group were sacrificed, and a section of right liver lobe was obtained and examined by histopathological method. The statistical analysis data were performed. Results Cirrhosis accompanied with ascites developed in all model groups between 8 and 12 weeks. However, at the end of the eighth week, rats in CCl4 + phenobarbital sodium + alcohol group were firstly detected to correspond with the model standards, CC14 + phenobarbital sodium group and CC14 + alcohol group were detected to have positive model signs at the ninth week. Only at the tenth week a few rats appeared to have ascites in CC14 group. All the model groups showed significant differences in the biochemical liver function indices, COP and body mass than the rats in control group, and the most significant differences were

  12. 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.

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

    Science.gov (United States)

    de-Oliveira-Pinto, Luzia Maria; Gandini, Mariana; Freitas, Laís Picinini; Siqueira, Marilda Mendonça; Marinho, Cíntia Ferreira; Setúbal, Sérgio; Kubelka, Claire Fernandes; Cruz, Oswaldo Gonçalves; Oliveira, Solange Artimos de

    2012-02-01

    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. PENGARUH PERLINDUNGAN EKSTRAK RIMPANG BANGLE (Zingiber cassumunar ROXB TERHADAP KERUSAKAN HATI TIKUS YANG DIINDUKSI CCI4 [Protective Effect of Bangle (Zingiber cassumunar ROXB Rhizome Extract on CCl4-Induced Liver Damage of Rats

    Directory of Open Access Journals (Sweden)

    Elmeizy Arafah1

    2004-12-01

    Full Text Available Zingiber cassumunar Roxb known as Bangle, has antioxidative and antiinflammatory activities. It has been used for medicinal purposes traditionally. The aim of this study was to investigate whether administration of Z. cassumunar extracts orally may prevent acute liver damage induced by carbontetrachloride (CCl4 in rats. The study was carried out on 5 groups of male Sprague-Dawley rats (n=5. Group 1 was given ethyl acetate fraction of Bangle rhizome extract (30 mg/kg bw (KS, group 2 was given dry juice of Bangle rhizome (30 mg/kg bw (SK, group 3 was given curcuminoid (30 mg/kg bw (KUR, group 4 as negative control (KN given 5% Tween 80 solution (10 ml/kg bw and Group 5 as control (K. Carbontetrachloride 0,1 ml/kg bw was given orally after 7 days to group KS, SK, KUR and KN. Rats were terminated 24 hours after CCl4-induction. Liver injury was evaluated by analyzed SGPT and SGOT activities from the serum and histopathologycal examination was conducted on the liver. The results clearly indicated that extracts of Z. cassumunar could reduced significantly the degree of liver damage induced by CCl4. It may be concluded that Z. cassumunar rhizome could be used as substance for hepatoprotector

  16. 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.

  17. 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

  18. Stratospheric lifetimes of CFC-12, CCl4, CH4, CH3Cl and N2O from measurements made by the Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS

    Directory of Open Access Journals (Sweden)

    A. T. Brown

    2013-07-01

    Full Text Available Long lived halogen-containing compounds are important atmospheric constituents since they can act both as a source of chlorine radicals, which go on to catalyse ozone loss, and as powerful greenhouse gases. The long-term impact of these species on the ozone layer is dependent on their stratospheric lifetimes. Using observations from the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS we present calculations of the stratospheric lifetimes of CFC-12, CCl4, CH4, CH3Cl and N2O. The lifetimes were calculated using the slope of the tracer–tracer correlation of these species with CFC-11 at the tropopause. The correlation slopes were corrected for the changing atmospheric concentrations of each species based on age of air and CFC-11 measurements from samples taken aboard the Geophysica aircraft – along with the effective linear trend of the volume mixing ratio (VMR from tropical ground based AGAGE (Advanced Global Atmospheric Gases Experiment sites. Stratospheric lifetimes were calculated using a CFC-11 lifetime of 45 yr. These calculations produced values of 113 + (− 26 (18 yr (CFC-12, 35 + (− 11 (7 yr (CCl4, 69 + (− 65 (23 yr (CH3Cl, 123 + (− 53 (28 yr (N2O and 195 + (− 75 (42 yr (CH4. The errors on these values are the weighted 1σ non-systematic errors. Systematic errors were estimated by recalculating lifetimes using VMRs which had been modified to reflect differences between ACE-FTS retrieved VMRs and those from other instruments. The results of these calculations, including systematic errors, were as follows: 113 + (− 32 (20 for CFC-12, 123 + (− 83 (35 for N2O, 195 + (− 139 (57 for CH4, 35 + (− 14 (8 for CCl4 and 69 + (− 2119 (34 yr for CH3Cl. For CH3Cl & CH4 this represents the first calculation of the stratospheric lifetime using data from a space based instrument.

  19. Magnetic susceptibility of Co sup 2 sup + pairs in [Co sub 2 (ox)tpmc](ClO sub 4) sub 2 centre dot 3H sub 2 O cluster complex

    CERN Document Server

    Spasojevic, V; Sovilj, S P; Mrozinski, J

    2000-01-01

    Calculation of the magnetic susceptibility of Co sup 2 sup + pairs in the recently synthesized cobaltous cluster complex [Co sub 2 (ox)tpmc](ClO sub 4) sub 2 centre dot 3H sub 2 O has been conducted by the use of two different theoretical models. The calculated results were compared to the experimental data collected in a wide temperature region. Conclusions on both the magnetic properties of Co sup 2 sup + dimers and the validity of the proposed models have been drawn. In the temperature region above chi(T) maximum, the best results are obtained with the Heisenberg model that includes spin-orbit coupling and excited single-ion levels. In the low-temperature region anisotropy of the magnetic properties dominates and Ising dimer ground-state model gives a more appropriate description. Obtained g-values (g sub p sub a sub r sub a sub l sub l sub e sub l a=5.67, g sub p sub a sub r sub a sub l sub l sub e sub l b=5.73, and g sub p sub e sub r sub p sub e sub n sub d sub i sub c sub u sub l sub a sub r =1.54) con...

  20. 氨基葡萄糖、N-乙酰氨基葡萄糖和小分子壳聚糖对C_2H_5OH和CCl_4所致肝细胞损伤的预防和修复作用%Preventive and recoverable effects of GlcNH_2,GlcNAc and low molecular CS against C_2H_5OH or CCl_4-induced hepatocytes damage

    Institute of Scientific and Technical Information of China (English)

    王永恒; 党奇峰; 陈军; 陈丽媛; 宋磊; 刘成圣

    2011-01-01

    研究了氨基葡萄糖(D-glucosamine,Glc-NH2),N-乙酰氨基葡萄糖(N-acetyl-D-glucosamine,GlcNAc)和小分子壳聚糖(chitosan,CS)对酒精(C2H5OH)或四氯化碳(CCl4)诱导的小鼠肝细胞损伤的预防和修复作用。采用组织块培养法获取小鼠肝细胞,通过对小鼠传代培养过程中肝细胞活性的测定,证实该细胞在第6d达到最佳生长状态。分别用无糖培养基,含500或1000μg/mL GlcNH2、GlcNAc或小分子CS的培养基对肝细胞培养3d后用C2H5OH或CCl%The protective effects of D-glucosamine(GlcNH2),N-acetyl-D-glucosamine(GlcNAc) and low molecular chitosan(CS) on C2H5OH-induced or CCl4-induced mouse hepatocytes damage were investigated in the present study.The mouse hepatocytes were obtained through tissue culture.The cells activity was investigated during the subculture and the results showed the mouse hepatocytes had optimal growth condition at 6d culture.The hepatocytes were exposed to C2H5OH or CCl4 for different times after 3d culture of sugar-free medium,500 or 1000μg/mL of GlcNH2,GlcNAc or low molecular CS medium,and the MTT assay was measured after 6d culture.The results indicated the GlcNH2,GlcNAc and low molecular CS all had preventive effect to CCl4-induced damage and only the low molecular CS had preventive effect to the C2H5OH-induced hepatocytes damage.2000μg/mL of GlcNH2,GlcNAc and low molecular CS all had positively effects on C2H5OH-induced hepatocytes damage recovery,indicating the potential applications in the treatment of C2H5OH-induced liver disease.

  1. TA1 oncofetal rat liver cDNA and putative amino acid permease: temporal correlation with c-myc during acute CCl4 liver injury and variation of RNA levels in response to amino acids in hepatocyte cultures.

    Science.gov (United States)

    Shultz, V D; Campbell, W; Karr, S; Hixson, D C; Thompson, N L

    1999-01-01

    TA1 is a rat liver oncofetal cDNA and a member of an emerging family of evolutionarily conserved molecules with homology to amino acid transporters and permeases. The aim of these studies was to characterize the regulation and role of TA1 in acute rat liver injury by examining its relation to regeneration and metabolic stress. Following a single dose of CCl4, TA1 message was expressed 3-48 h. The major 3.3-kb TA1 transcript correlated temporally with c-myc expression. A novel 2.9-kb TA1 transcript was expressed more variably 24-48 h. TA1 protein was restricted to hepatocytes in G0 and G1 phases of the cell cycle. Relative to CCl4, a much smaller increase in TA1 was noted after partial hepatectomy and TA1 preceded the peak of c-myc expression. In vitro TA1 was not induced in hepatocytes by EGF or the acute-phase cytokines IL-6 and TNF-alpha, but was found to be modulated in response to amino acid availability. TA1 expression increased in media without arginine and glutamine and was repressed by total amino acid levels 5-fold over basal MEM. Together, these results contrast with the constitutive expression observed in transformed cells and suggest an adaptive role for TA1 during liver injury.

  2. Stratospheric lifetimes of CFC-12, CCl4, CH4, CH3Cl and N2O from measurements made by the Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS

    Directory of Open Access Journals (Sweden)

    P. F. Bernath

    2013-02-01

    Full Text Available Long lived halogen-containing compounds are important atmospheric constituents since they can act both as a source of chlorine radicals, which go on to catalyse ozone loss, and as powerful greenhouse gases. The long term impact of these species on the ozone layer is dependent on their stratospheric lifetimes. Using observations from the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS we present calculations of the stratospheric lifetimes of CFC-12, CCl4, CH4, CH3Cl and N2O. The lifetimes were calculated using the slope of the tracer-tracer correlation of these species with CFC-11 at the tropopause. The correlation slopes were corrected for the changing atmospheric concentrations of each species based on age of air and CFC-11 measurements from samples taken aboard the Geophysica aircraft – along with the effective linear trend of the VMR from tropical ground-based AGAGE sites. Stratospheric lifetimes were calculated using a CFC-11 lifetime of 45 yr. These calculations produced values of 113 + (− 26 (18 yr (CFC-12, 35 + (− 11 (7 yr (CCl4, 195 + (− 75 (42 yr (CH4, 69 + (− 65 (23 yr (CH3Cl and 123 + (− 53 (28 yr (N2O. The errors on these values are the weighted 1-σ non-systematic errors. The stratospheric lifetime of CH3Cl represents the first calculations of the stratospheric lifetime of CH3Cl using data from a space based instrument.

  3. Absorption by XeCl* excimer molecules of their own emission of the B-X transition (λ = 308 nm) in a dense Ar-Xe-CCl4 medium upon pumping by fast electrons and uranium-235 fission fragments

    Science.gov (United States)

    Mis'kevich, A. I.; Dyuzhov, Yu. A.; Suvorov, A. A.

    2016-08-01

    Luminescence of dense Ar-Xe-CCl4 gas mixtures with a low CCl4 content upon pumping by fast electrons and uranium-235 fission fragments is studied by spectroscopic methods. It is found that, in a cell with a resonator tuned to the B-X transition of the XeCl* molecule (λ = 308 nm), the D-state population of the XeCl* excimer molecule (the D-X transition, λ = 235 nm) depends on the B-state population and increases by many times with increasing B-state population of the XeCl* molecule. The stimulated absorption coefficient k = 1.2 × 10-16 of B-X transition emission of the XeCl* molecule (λmax = 308 nm), which leads to population of the D-state of this molecule, and the coefficient of amplification μ = 2.5 × 10-4 cm-1 of B-X transition emission of the Xe Cl* molecule (λ = 308 nm) are measured upon pumping by uranium- 235 fission fragments with the specific energy input into the gas medium of ~60 mJ/cm3 and a specific power of energy input of about 240 W/cm3.

  4. 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.

  5. 柿叶提取物对CCl4致小鼠急性肝损伤保护作用的研究%Protective effects of extract from persimmon leaves on tetrachloride-induced hepatotoxicity in mice

    Institute of Scientific and Technical Information of China (English)

    张艳; 杨建雄; 马蕊; 王芳

    2013-01-01

    探讨了柿叶醇提物的乙酸乙酯萃取制剂(EAF)对小鼠急性肝损伤的保护作用.腹腔注射四氯化碳(CCl4)致小鼠急性肝损伤模型,测定不同剂量的EAF对血清谷丙转氨酶(ALT)、谷草转氨酶(AST)和碱性磷酸酶(AKP)活性,肝超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GPx)、过氧化氢酶(CAT)活性及丙二醛(MDA)含量的影响,同时对肝组织进行病理学检查.结果表明,EAF具有剂量依赖性地降低血清中ALT、AST、AKP值,增强肝中SOD、GPx、CAT的活性,降低肝组织匀浆中MDA的含量,减轻CCl4对肝脏细胞的病理损伤.100mg/kg是EAF对肝损伤的合适保护剂量.适量的EAF对CCl4所致小鼠急性肝损伤有较好的保护作用.%The effects of ethyl acetate fraction (EAF) containing substances ethanol extracted from persimmon leaves on carbon tetrachloride-induced hepatotoxicity in mice were inrestigated. The acute hepatic injury model was carried out by CC14 injected intraperitoneally. Then, the therapeutic effects of EAF were evaluated based on the activities of alanine aminotransferas (ALT), aspartate aminotransf erase ( AST) , alkaline phosphatase (AKP), superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) and the content of malondialdehyde (MDA) in liver, and the changes of hepatic pathohistology. The results indicated that different doses of EAF significantly lowered ALT, AST, AKP levels in serum and MDA level in liver along with the restoring of hepatic enzymes like SOD, GPx, and CAT against CC14 treated mice. The pathological changes were also significantly improved in the mice of treating group. Furthermore, it was found that 100 mg/kg was the optimal dose for exhibiting the greatest hepatoprotective effects on CCL,-induced liver injury, indicating that EAF of adequate dose exhibits potent hepatoprotective effects on CC14-induced acute liver damages in mice.

  6. Administration of Myelin Basic Protein Peptides Encapsulated in Mannosylated Liposomes Normalizes Level of Serum TNF-α and IL-2 and Chemoattractants CCL2 and CCL4 in Multiple Sclerosis Patients

    Directory of Open Access Journals (Sweden)

    Yakov Lomakin

    2016-01-01

    Full Text Available We have previously shown that immunodominant MBP peptides encapsulated in mannosylated liposomes (Xemys effectively suppressed experimental allergic encephalomyelitis (EAE. Within the frames of the successfully completed phase I clinical trial, we investigated changes in the serum cytokine profile after Xemys administration in MS patients. We observed a statistically significant decrease of MCP-1/CCL2, MIP-1β/CCL4, IL-7, and IL-2 at the time of study completion. In contrast, the serum levels of TNF-α were remarkably elevated. Our data suggest that the administration of Xemys leads to a normalization of cytokine status in MS patients to values commonly reported for healthy subjects. These data are an important contribution for the upcoming Xemys clinical trials.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. Genetically graded activation of Nrf2 protects mice against carbon tetrachloride-induced hepatotoxicity%Nrf2抗氧化损伤通路在CCl4所致小鼠肝毒性中的保护作用

    Institute of Scientific and Technical Information of China (English)

    陆远富; Connie Wu; 刘杰; Curtis Dean Klaassen

    2015-01-01

    目的 观察核转录相关因子2(nuclear factor erythroid 2-related factor 2,Nrf2)抗氧化损伤通路对四氯化碳(CCl4)所致小鼠肝毒性的保护作用.方法 选取Nrt2-null、Wild-type、Keap1-KD、Keapl-HKO小鼠,按基因型分为4组,分别给予40 mg/kg CCl4腹腔注射,腹腔注射生理盐水(10 mL/kg)作对照,16 h后收集血浆和肝组织样本,检测血中谷丙转氨酶(alanine transaminase,ALT)和乳酸脱氢酶(lactic dehydrogenase,LDH)活性以及肝组织中丙二醛(malondialdehyde,MDA)含量;HE染色观察肝组织病理学变化,Real-time PCR和Western blot法检测相关基因表达.结果 CCl4增加Nrf2-null组和Wild-type组血中ALT、LDH活性及肝组织MDA含量,同时造成肝组织病理损伤,而在Keap1-KD组和Keap1-HKO组影响不明显;Nrf2因子靶基因(Nqo1和Gclc)在CCl4的诱导表达逐渐增高(顺序为Nrf2-null、Wild-type、Keapl-KD、Keap1-HKO),继而使炎症因子、内质网应激基因、细胞凋亡基因、细胞坏死基因的表达(mKC、MIP-2、IL-1β、TNFα、Gadd45、Chop10、Bax、Caspase3、Mcl、Noxa)按Nrf2-null、Wild-type、Keap1-KD、Keap1-HKO顺序逐渐下降.结论 Nrf2因子激活保护CCl4所致小鼠肝损伤反应.

  14. Morphology of portal hypertension at the early stage of liver damage induced by CCl4:an experimental study with dogs%四氯化碳诱导犬早期肝损害所致门静脉高压的形态学观察

    Institute of Scientific and Technical Information of China (English)

    张日平; 张伟辉; 薛东波; 魏云巍

    2004-01-01

    目的探讨实验性犬肝脏早期损害所致的门静脉高压形成的形态学基础.方法以小剂量四氯化碳(CCl4)腹腔内注射诱导犬早期肝损害,制备门静脉高压犬模型.通过光镜、电镜观察肝脏形态学的改变.结果腹腔内注射CCl4 7周后,共有15头犬形成门静脉高压(门静脉压力22.7 cm H2O±1.5 cm H2O,1 cm H2O=0.098 kPa,与给药前相比,P<0.05).HE染色示肝脏损害轻微.Masson染色、电镜,示肝窦毛细血管化.α-平滑肌肌动蛋白(α-SMA)免疫组化染色示肝星形细胞(HSC)大量活化.结论肝脏受损早期,门静脉高压形成的可能原因是肝窦毛细血管化和HSC活化所致的肝窦血流阻力增加.

  15. 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).

  16. 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...

  17. 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.

  18. 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...

  19. 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....

  20. 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

  1. 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

  2. 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.

  3. 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....

  4. 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

  5. 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

  6. 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

  7. 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)

  8. 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.

  9. 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...

  10. 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.

  11. 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

  12. 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

  13. Quantum dot density studies for quantum dot intermediate band solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Thomassen, Sedsel Fretheim; Zhou, Dayong; Vitelli, Stefano; Mayani, Maryam Gholami; Fimland, Bjoern-Ove; Reenaas, Turid Worren

    2010-07-01

    Quantum dots (QDs) have been an active area of research for many years and have been implemented in several applications, such as lasers and detectors. During the last years, some attempts have been made to increase the absorption and efficiency of solar cells by inserting QDs into the intrinsic region of pin solar cells. So far, these attempts have been successful in increasing the absorption, but not the cell efficiency. There are probably several reasons for this lack of efficiency increase, but we believe that one important reason is the low density of the implemented QDs. In this work, samples of single layer InAs QDs on n-GaAs(001) substrates have been grown by molecular beam epitaxy (MBE) and we have performed a systematic study of how deposition parameters affect the QD density. The aim is to achieve densities > 1011 cm-2. The nominal substrate temperature (360 - 500 deg. C), the InAs growth rate (0.085 - 1 ML/s) and thickness (2.0 - 2.8 ML) have been varied in a systematic way for two different deposition methods of InAs, i.e. continuous deposition or deposition with interruptions. In addition, we have for the continuous growth samples also varied the As-flux (0.5 - 6 centre dot10-6 torr). Scanning electron microscopy (SEM) has been the main characterization method to determine quantum dot sizes and densities, and atomic force microscopy (AFM) has been used for evaluation of the quantum dot heights. We find that the QD density increases with reduced growth temperature and that it is higher for samples grown continuously than for samples grown with growth interruptions. The homogeneity is also strongly affected by temperature, InAs deposition method and the As-flux. We have observed QD densities as high as 2.5 centre dot1011 cm-2 for the samples grown at the lowest growth temperatures. (Author)

  14. 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...

  15. Implementing Responsibility Centre Budgeting

    Science.gov (United States)

    Vonasek, Joseph

    2011-01-01

    Recently, institutes of higher education (universities) have shown a renewed interest in organisational structures and operating methodologies that generate productivity and innovation; responsibility centre budgeting (RCB) is one such process. This paper describes the underlying principles constituting RCB, its origin and structural elements, and…

  16. 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.

  17. CCl4诱导大鼠纤维化肝组织 microRNA 差异表达及其初步分析%Differentially expressed and preliminary analysis of microRNA profiles in liver tissue of rat induced by carbon tetrachloride

    Institute of Scientific and Technical Information of China (English)

    刘业方; 张传涛; 李白雪; 郭尹玲; 王宝家; 唐洪屈; 王政; 张凤; 杨宇

    2015-01-01

    Objective To explore the differences of expression profiles and significance of the microRNA in liver tissue of rat induced by carbon tetrachloride(CCl4 ).Methods The microRNA differential expression analysis between normal group(n = 10) and model group(n=10)was conducted on high-throughput methods.Gene ontology enrichment analysis and kyoto encyclopedia of genes and genomes pathway analysis of the targets of miRNA were carried out in this study.Results Some differentally expressed microRNA with 29 up-regulated and 8 down-regulated were identified in our study.Through evaluaing the value of microRNA in the network,we find that the key microRNA of rising are miR-184,miR-10b-5p,miR-1 99a-3p,and the key microRNA of cutting are miR-200b-3p,miR-1 99a-5p,miR-125b-5p and so on.Conclusion The microRNA expression level in the model group has a signifi-cant change.Therefore,the courses of liver fibrosis is related to some process which microRNA control the regulation of cell prolif-eration,cell apoptosis,cell cycle,and so on.%目的:探索 microRNA 在四氯化碳(CCl4)诱导的大鼠纤维化肝组织中的差异表达及其意义。方法采用 microR-NA 高通量测序分析技术检测对照组(n=10)与模型组(n=10)肝脏组织 microRNA 表达,对差异 microRNA 进行靶基因预测,对靶基因进行基因本(GO)分析、pathway 分析。结果对照组与模型组间筛选出37个差异 microRNA,上调29个,下调8个;从microRNA-基因网络图中发现关键上调为 miR-184、miR-10b-5p、miR-199a-3p 等;关键下调为 miR-200b-3p、miR-199a-5p、miR-125b-5p 等。结论模型组 microRNA 表达谱变化明显,肝纤维化的形成与 microRNA 调控细胞增殖、凋亡、细胞周期等有关。

  18. 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.

  19. 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

  20. 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.

  1. 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

  2. Tele-centres in Ghana

    DEFF Research Database (Denmark)

    Falch, Morten

    2004-01-01

    Tele-centres offer a low cost opportunity for the many who cannot afford their own phone or Internet connection. This paper presents a field study of tele-centres in Ghana and analyses how they contribute to universal access.......Tele-centres offer a low cost opportunity for the many who cannot afford their own phone or Internet connection. This paper presents a field study of tele-centres in Ghana and analyses how they contribute to universal access....

  3. 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...

  4. Binding Energies of Negatively Charged Donors in a Gaussian Potential Quantum Dot

    Institute of Scientific and Technical Information of China (English)

    XIE Wen-Fang

    2005-01-01

    @@ We investigate a negatively charged donor centre (D-) trapped by a quantum dot, which is subjected to a Gaussian potential confinement. Calculations are carried out by using the method of numerical diagonalization of Hamiltonian within the effective-mass approximation. The dependence of the ground state of the negatively charged donor on the dot size and the potential depth is studied. The same calculations performed with the parabolic approximation of the Gaussian potential lead to the results that are qualitatively and quantitatively different.

  5. Transition energies and magnetic properties of a neutral donor complex in a Gaussian GaAs quantum dot

    Science.gov (United States)

    Boda, Aalu; Chatterjee, Ashok

    2016-09-01

    The problem of a neutral hydrogenic donor (D0) centre located at the centre of a GaAs quantum dot with Gaussian confinement is studied in the presence of an external magnetic field. The ground and the first excited state energies and the corresponding binding energies are obtained as functions of the potential strength, quantum dot radius and the magnetic field using a variational method. It is suggested that the first excited state of the D0 centre is bound for sufficiently strong confinement potential. The 1 s - 2p- transition energy and the magnetic susceptibilities for the ground and the first excited states are also determined.

  6. DGNB certified Healthcare Centres

    DEFF Research Database (Denmark)

    Brunsgaard, Camilla; Larsen, Tine Steen

    2015-01-01

    for 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...... a dialog about DGNB and energy concept is important even before anyone start sketching. Experiences with the different approaches will be further outlined in the paper.Future research has the intention to collect further knowledge about DGNB and DMaDP in practise. This project was limited to Healthcare...

  7. 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...

  8. Town Centre Redevelopment Strategies

    DEFF Research Database (Denmark)

    Vagnby, Bo Hellisen

    urban planning and design strategieswhich have been practised in most of the larger Danish towns: pedestrian streets, shopping centres, preservation of historic features, waterfronts, concentration of offices, conference and sports facilities, improvement og traffic and transport conditions as well...... as 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...

  9. 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...

  10. [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

  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. 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...

  13. 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.

  14. Carbon nanotube quantum dots

    NARCIS (Netherlands)

    Sapmaz, S.

    2006-01-01

    Low temperature electron transport measurements on individual single wall carbon nanotubes are described in this thesis. Carbon nanotubes are small hollow cylinders made entirely out of carbon atoms. At low temperatures (below ~10 K) finite length nanotubes form quantum dots. Because of its small si

  15. 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

  16. 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...

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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...

  3. Nanocrystal quantum dots

    CERN Document Server

    Klimov, Victor I

    2010-01-01

    ""Soft"" Chemical Synthesis and Manipulation of Semiconductor Nanocrystals, J.A. Hollingsworth and V.I. Klimov Electronic Structure in Semiconductor Nanocrystals: Optical Experiment, D.J. NorrisFine Structure and Polarization Properties of Band-Edge Excitons in Semiconductor Nanocrystals, A.L. EfrosIntraband Spectroscopy and Dynamics of Colloidal Semiconductor Quantum Dots, P. Guyot-Sionnest, M. Shim, and C. WangMultiexciton Phenomena in Semiconductor Nanocrystals, V.I. KlimovOptical Dynamics in Single Semiconductor Quantum Do

  4. 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.

  5. 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.)

  6. 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

  7. The centre of the action

    CERN Document Server

    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.

  8. 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.

  9. 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.)

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

    Science.gov (United States)

    Alert, Bianca; Michalik, Andreas; Helduser, Sascha; Mouritsen, Henrik; Güntürkün, Onur

    2015-01-01

    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.

  11. 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.

  12. 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)

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. LDE centres: sprint or marathon?

    NARCIS (Netherlands)

    Bonger, S.; Van Rein, E.

    2015-01-01

    The aim of the Strategic Leiden-Delft-Erasmus Alliance, established by the three universities in 2012, was to improve research and education and competitiveness. Projects are intended to develop from the ground up, which led to the establishment of eight joint centres in 2013. A quick look around re

  18. Fossil Dot Com

    DEFF Research Database (Denmark)

    2011-01-01

    Since the start of the industrial revolution in 1800, with breakthrough innovations in iron production, textile industry and the steam engine, society has sustained incredible growth and transformation. During the 200 years, worldwide individual productivity has grown more than 32 times...... 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...

  19. 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.

  20. 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

  1. 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...

  2. 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...

  3. 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...

  4. 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

  5. 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.

  6. 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)

  7. Single to quadruple quantum dots with tunable tunnel couplings

    Energy Technology Data Exchange (ETDEWEB)

    Takakura, T.; Noiri, A.; Obata, T.; Yoneda, J.; Yoshida, K. [Department of Applied Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Otsuka, T.; Tarucha, S. [Department of Applied Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); RIKEN, Center for Emergent Matter Science, 3-1 Wako-shi, Saitama 351-0198 (Japan)

    2014-03-17

    We prepare a gate-defined quadruple quantum dot to study the gate-tunability of single to quadruple quantum dots with finite inter-dot tunnel couplings. The measured charging energies of various double dots suggest that the dot size is governed by the gate geometry. For the triple and quadruple dots, we study the gate-tunable inter-dot tunnel couplings. For the triple dot, we find that the effective tunnel coupling between side dots significantly depends on the alignment of the center dot potential. These results imply that the present quadruple dot has a gate performance relevant for implementing spin-based four-qubits with controllable exchange couplings.

  8. Near-infrared quantum dots for HER2 localization and imaging of cancer cells

    OpenAIRE

    Rizvi SB; Rouhi S; Taniguchi S; Yang SY; Green M; Keshtgar M; Seifalian AM

    2014-01-01

    Sarwat B Rizvi,1 Sepideh Rouhi,1 Shohei Taniguchi,2 Shi Yu Yang,1 Mark Green,2 Mo Keshtgar,1,3 Alexander M Seifalian1,3 1UCL Centre for Nanotechnology and Regenerative Medicine, University College London, 2Department of Physics, King's College London, 3Royal Free London NHS Foundation Trust Hospital, London, UK Background: Quantum dots are fluorescent nanoparticles with unique photophysical properties that allow them to be used as diagnostic, therapeutic, and theranostic agents, part...

  9. 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.

  10. 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.

  11. Scheduling participants of Assessment Centres

    DEFF Research Database (Denmark)

    Lysgaard, Jens; Løber, Janni

      Assessment Centres are used as a tool for psychologists and coaches to observe a number of dimensions in a person's behaviour and test his/her potential within a number of chosen focus areas. This is done in an intense course, with a number of different exercises which expose each participant......'s ability level in the chosen focus areas. The participants are observed by assessors with the purpose of gathering material for reaching a conclusion on each participant's personal profile. We consider the particular case that arises at the company Human Equity (www.humanequity.dk), where Assessment...

  12. 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...

  13. 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.

  14. 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 ...

  15. 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....

  16. 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.

  17. 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

  18. 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...

  19. 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

  20. 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

  1. 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

  2. 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.

  3. 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.

  4. 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

  5. Vertical asymmetric double quantum dots

    Science.gov (United States)

    Roßbach, R.; Reischle, M.; Beirne, G. J.; Schweizer, H.; Jetter, M.; Michler, P.

    2007-01-01

    Two layers of differently sized self-assembled InP-quantum dots (QDs) separated by a GaInP spacer layer with varying thickness were grown by metal organic vapor phase epitaxy (MOVPE). Photoluminescence measurements of the QD ensembles and of individual asymmetric double QDS show coupling due to the tunnelling of carriers.

  6. Powering the Future Data Centre

    DEFF Research Database (Denmark)

    Zhang, Zhe

    2010-01-01

    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......: • Optimized design method for dual active bridge (DAB) converter and its derived circuits; • A novel hybrid dc-dc converter and its corresponding optimal design method are proposed; • An improved dual input current-fed DC-DC converter with bidirectional power conversion ability is investigated; • Extend...... the circuit level decoupling modulation scheme into 3LNPC inverter. As to the DAB converter, through the power factor and harmonics analysis, the dominated loss factor is found in variable input voltage range. Optimized parameter choosing method is used to decide the ac inductance and switching frequency...

  7. 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.

  8. 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

  9. 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.

  10. Spin transport through quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Lima, A.T. da Cunha; Anda, Enrique V. [Pontificia Univ. Catolica do Rio de Janeiro (PUC-Rio), RJ (Brazil)

    2003-07-01

    Full text: We investigate the spin polarized transport properties of a nanoscopic device constituted by a quantum dot connected to two leads. The electrical current circulates with a spin polarization that is modulated via a gate potential that controls the intensity of the spin-orbit coupling, the Rashba effect. We study a polarized field-effect transistor when one of its parts is constituted by a small quantum dot, which energies are controlled by another gate potential operating inside the confined region. The high confinement and correlation suffered by the charges inside the dot gives rise to novel phenomena. We show that through the manipulation of the gate potential applied to the dot it is possible to control, in a very efficient way, the intensity and polarization of the current that goes along the system. Other crucial parameters to be varied in order to understand the behavior of this system are the intensity of the external applied electric and magnetic field. The system is represented by the Anderson Impurity Hamiltonian summed to a spin-orbit interaction, which describes the Rashba effect. To obtain the current of this out-of-equilibrium system we use the Keldysh formalism.The solution of the Green function are compatible with the Coulomb blockade regime. We show that under the effect of a external magnetic field, if the dot is small enough the device operates as a complete spin filter that can be controlled by the gate potential. The behavior of this device when it is injected into it a polarized current and modulated by the Rashba effect is as well studied. (author)

  11. 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...... development and environmental sustainability, and further, that technology may not even be the most important feature needed to make them function as such....

  12. Activities of Radiation Protection Centre in 2000

    CERN Document Server

    Radiat. Prot. Cent. Vilnius

    2001-01-01

    Description of the activities of Radiation Protection Centre in 2000 is presented. Radiation Protection Centre is responsible for radiation protection issues. Currently there are six departments at Radiation Protection Centre: two in Vilnius - Department of Radiation Protection Supervision and Control and Department of Programs and Expertise, and four in the districts. Brief information on subject controlled by each departments is provided focusing on main achievements and events.

  13. 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...

  14. 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....

  15. The European NEO Coordination Centre

    Science.gov (United States)

    Perozzi, E.; Borgia, B.; Micheli, M.

    An operational approach to NEO (Near-Earth Object) hazard monitoring has been developed at European level within the framework of the Space Situational Awareness Program (SSA) of the European Space Agency (ESA). Through federating European assets and profiting of the expertise developed in European Universities and Research Centers, it has been possible to start the deployment of the so-called SSA NEO Segment. This initiative aims to provide a significant contribution to the worldwide effort to the discovery, follow-up and characterization of the near-Earth object population. A major achievement has been the inauguration in May 2013 of the ESA NEO Coordination Centre located at ESRIN (Frascati, Italy). The goal of the NEOCC Precursor Service operations is twofold: to make available updated information on the NEO population and the associated hazard and to contribute to optimize the NEO observational efforts. This is done by maintaining and improving a Web Portal publicly available at http://neo.ssa.esa.int and by performing follow-up observations through a network of collaborating telescopes and facilities. An overview of the SSA-NEO System and a summary of the first two years of NEOCC operations is presented.

  16. 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.

  17. 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.

  18. Danish Anaesthesia Allergy Centre - preliminary results

    DEFF Research Database (Denmark)

    Garvey, L H; Roed-Petersen, J; Menné, T;

    2001-01-01

    BACKGROUND: Anaphylactoid reactions in anaesthesia are rare and should ideally be investigated in specialist centres. At Gentofte University Hospital, we established such a centre in 1998 as a joint venture between the Departments of Anaesthesiology and Dermatology. We present the methodology...

  19. 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...

  20. Constructions from Dots and Lines

    CERN Document Server

    Rodriguez, Marko A

    2010-01-01

    A graph is a data structure composed of dots (i.e. vertices) and lines (i.e. edges). The dots and lines of a graph can be organized into intricate arrangements. The ability for a graph to denote objects and their relationships to one another allow for a surprisingly large number of things to be modeled as a graph. From the dependencies that link software packages to the wood beams that provide the framing to a house, most anything has a corresponding graph representation. However, just because it is possible to represent something as a graph does not necessarily mean that its graph representation will be useful. If a modeler can leverage the plethora of tools and algorithms that store and process graphs, then such a mapping is worthwhile. This article explores the world of graphs in computing and exposes situations in which graphical models are beneficial.

  1. 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.

  2. 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.

  3. 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)

  4. Near-infrared quantum dots for HER2 localization and imaging of cancer cells

    Directory of Open Access Journals (Sweden)

    Rizvi SB

    2014-03-01

    Full Text Available Sarwat B Rizvi,1 Sepideh Rouhi,1 Shohei Taniguchi,2 Shi Yu Yang,1 Mark Green,2 Mo Keshtgar,1,3 Alexander M Seifalian1,3 1UCL Centre for Nanotechnology and Regenerative Medicine, University College London, 2Department of Physics, King's College London, 3Royal Free London NHS Foundation Trust Hospital, London, UK Background: Quantum dots are fluorescent nanoparticles with unique photophysical properties that allow them to be used as diagnostic, therapeutic, and theranostic agents, particularly in medical and surgical oncology. Near-infrared-emitting quantum dots can be visualized in deep tissues because the biological window is transparent to these wavelengths. Their small sizes and free surface reactive groups that can be conjugated to biomolecules make them ideal probes for in vivo cancer localization, targeted chemotherapy, and image-guided cancer surgery. The human epidermal growth factor receptor 2 gene (HER2/neu is overexpressed in 25%–30% of breast cancers. The current methods of detection for HER2 status, including immunohistochemistry and fluorescence in situ hybridization, are used ex vivo and cannot be used in vivo. In this paper, we demonstrate the application of near-infrared-emitting quantum dots for HER2 localization in fixed and live cancer cells as a first step prior to their in vivo application. Methods: Near-infrared-emitting quantum dots were characterized and their in vitro toxicity was established using three cancer cell lines, ie, HepG2, SK-BR-3 (HER2-overexpressing, and MCF7 (HER2-underexpressing. Mouse antihuman anti-HER2 monoclonal antibody was conjugated to the near-infrared-emitting quantum dots. Results: In vitro toxicity studies showed biocompatibility of SK-BR-3 and MCF7 cell lines with near-infrared-emitting quantum dots at a concentration of 60 µg/mL after one hour and 24 hours of exposure. Near-infrared-emitting quantum dot antiHER2-antibody bioconjugates successfully localized HER2 receptors on SK-BR-3 cells

  5. 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...

  6. 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...

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. Thermoelectric energy harvesting with quantum dots.

    Science.gov (United States)

    Sothmann, Björn; Sánchez, Rafael; Jordan, Andrew N

    2015-01-21

    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.

  12. POLARON IN CYLINDRICAL AND SPHERICAL QUANTUM DOTS

    Directory of Open Access Journals (Sweden)

    L.C.Fai

    2004-01-01

    Full Text Available Polaron states in cylindrical and spherical quantum dots with parabolic confinement potentials are investigated applying the Feynman variational principle. It is observed that for both kinds of quantum dots the polaron energy and mass increase with the increase of Frohlich electron-phonon coupling constant and confinement frequency. In the case of a spherical quantum dot, the polaron energy for the strong coupling is found to be greater than that of a cylindrical quantum dot. The energy and mass are found to be monotonically increasing functions of the coupling constant and the confinement frequency.

  13. Semiconductor quantum-dot lasers and amplifiers

    DEFF Research Database (Denmark)

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

    2002-01-01

    -power 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 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...

  14. 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

  15. 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...

  16. From micro- to nanomagnetic dots: evolution of the eigenmode spectrum on reducing the lateral size

    Science.gov (United States)

    Carlotti, G.; Gubbiotti, G.; Madami, M.; Tacchi, S.; Hartmann, F.; Emmerling, M.; Kamp, M.; Worschech, L.

    2014-07-01

    Brillouin light scattering experiments and micromagnetic simulations have been exploited to investigate the spectrum of thermally excited magnetic eigenmodes in 10 nm-thick elliptical Permalloy dots, when the longer axis D is scaled down from about 1000 to 100 nm. It is shown that for D larger than about 200 nm the characteristics of the spin-wave eigenmodes are dominated by dipolar energy, while for D in the range of about 100 to 200 nm exchange energy effects cause qualitative and quantitative differences in the spin-wave spectrum. In this ‘mesoscopic’ regime, the usual classification scheme, involving one fundamental mode with large average magnetization and many other modes collected in families with specific symmetries, no longer holds. Rather, one finds the simultaneous presence of two modes with ‘fundamental’ character, i.e. with a significant and comparable value of the average dynamical magnetization: the former is at larger frequency and has its maximum amplitude at the dot's centre, while the latter occurs at lower frequency and is localized at the dot's edges. Interestingly, the maximum intensity swaps from the higher frequency mode to the lower frequency one, just when the dot size is reduced from about 200 to 100 nm. This is relevant in view of the exploitation of nanodots for the design of nanomagnetic devices with lateral dimensions in the above interval, such as memory cells, logic gates, reading heads and spin-torque oscillators.

  17. 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.

  18. 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.

  19. 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...

  20. 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

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. Optical Properties of Semiconductor Quantum Dots

    NARCIS (Netherlands)

    Perinetti, U.

    2011-01-01

    This thesis presents different optical experiments performed on semiconductor quantum dots. These structures allow to confine a small number of electrons and holes to a tiny region of space, some nm across. The aim of this work was to study the basic properties of different types of quantum dots mad

  7. Detecting the chirality for coupled quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Cao Huijuan [Institute for Condensed Matter Physics, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510631 (China); Hu Lian [Institute for Condensed Matter Physics, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510631 (China)], E-mail: huliancaohj@yahoo.com

    2008-04-21

    We propose a scheme to detect the chirality for a system consisting of three coupled quantum dots. The chirality is found to be determined by the frequency of the transition between chiral states under the chiral symmetry broken perturbation. The results are important to construct quantum gates and to demonstrate chiral entangle states in the triangle spin dots.

  8. 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.

  9. 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.)

  10. 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 ...

  11. 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...

  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. 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...

  14. 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

  15. 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...

  16. 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.

  17. Substitutional impurity in the graphene quantum dots

    Science.gov (United States)

    Sierański, K.; Szatkowski, J.

    2015-09-01

    The process of formation of the localized defect states due to substitutional impurity in sp2-bonded graphene quantum dot is considered using a simple tight-binding-type calculation. We took into account the interaction of the quantum dot atoms surrounding the substitutional impurity from the second row of elements. To saturate the external dangling sp2 orbitals of the carbon additionally 18 hydrogen atoms were introduced. The chemical formula of the quantum dot is H18C51X, where X is the symbol of substitutional atom. The position of the localized levels is determined relative to the host-atoms (C) εp energies. We focused on the effect of substitutional doping by the B, N and O on the eigenstate energies and on the total energy change of the graphene dots including for O the effect of lattice distorsion. We conclude that B, N, and O can form stable substitutional defects in graphene quantum dot.

  18. 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...

  19. 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...

  20. A novel fluorinated stilbene exerts hepatoprotective properties in CCl(4)-induced acute liver damage.

    Science.gov (United States)

    Rivera, Horacio; Morales-Ríos, Martha S; Bautista, Wendy; Shibayama, Mineko; Tsutsumi, Víctor; Muriel, Pablo; Pérez-Álvarez, Víctor

    2011-10-01

    There has been a recently increase in the development of novel stilbene-based compounds with in vitro anti-inflamatory properties. For this study, we synthesized and evaluated the anti-inflammatory properties of 2 fluorinated stilbenes on carbon tetrachloride (CCl₄)-induced acute liver damage. To achieve this, CCl₄ (4 g·kg(-1), per os) was administered to male Wistar rats, followed by either 2-fluoro-4'-methoxystilbene (FME) or 2,3-difluoro-4'-methoxystilbene (DFME) (10 mg·kg(-1), per os). We found that although both of the latter compounds prevented cholestatic damage (γ-glutamyl transpeptidase activity), only DFME showed partial but consistent results in the prevention of necrosis, as assessed by both alanine aminotransferase activity and histological analysis. Since inflammatory responses are mediated by cytokines, mainly tumour necrosis factor α (TNF-α), we used the Western blot technique to determine the action of FME and DFME on the expression level of this cytokine. The observed increase in the level of TNF-α caused by CCl₄ administration was only prevented by treatment with DFME, in agreement with our biochemical findings. This result was confirmed by measuring interleukin-6 (IL-6) levels, since the expression of this protein depends on the level of TNF-α. In this case, DFME completely blocked the CCl₄-induced increase of IL-6. Our results suggest that DFME possesses greater anti-inflammatory properties in vivo than FME. DFME constitutes a possible therapeutic agent for liver disease and could serve as a template for structure optimization.

  1. 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.

  2. 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.

  3. Transmission of HIV in dialysis centre.

    Science.gov (United States)

    Velandia, M; Fridkin, S K; Cárdenas, V; Boshell, J; Ramirez, G; Bland, L; Iglesias, A; Jarvis, W

    1995-06-01

    In August, 1993, 13 dialysis patients at one dialysis centre in Colombia, South America, were found to be HIV positive, and this prompted an epidemiological investigation. We carried out a cohort study of all dialysis centre patients during January, 1992 to December, 1993 (epidemic period) to determine risk factors for HIV seroconversion. Haemodialysis and medical records were reviewed, dialysis centre staff and surviving patients were interviewed, and dialysis practices were observed. Stored sera from all dialysis centre patients were tested for HIV antibody. 12 (52%) of 23 patients tested positive for HIV antibody by enzyme immunoassay and western blot during the epidemic period. Of the 23 tested, 9 (39%) converted from HIV antibody negative to positive (seroconverters) and 10 (44%) remained HIV negative (seronegatives). The HIV seroconversion rate was higher among patients dialysed at the centre while a new patient, who was HIV seropositive, was dialysed there (90% vs 0%; p dialysis centre reprocessed access needles, dialysers, and bloodlines (60% vs 0%). While 2 of 9 HIV seroconverters had had sex with prostitutes, none had received unscreened blood products or had other HIV risk factors. No surgical or dental procedures were associated with HIV seroconversion. Dialysers were reprocessed separately with 5% formaldehyde and were labelled for use on the same patient. Access needles were reprocessed by soaking them in a common container with a low-level disinfectant, benzalkonium chloride; 4 pairs of needles were placed in one pan creating the potential for cross-contamination or use of one patient's needles on another patient. HIV transmission at the dialysis centre was confirmed. Improperly reprocessed patient-care equipment, most probably access needles, is the likely mechanism of transmission. This outbreak was discovered by accident and similar transmission may be occurring in many other countries where low-level disinfectants are used to sterilise critical

  4. 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...

  5. 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). ...

  6. 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.)

  7. Quantum Dots Investigated for Solar Cells

    Science.gov (United States)

    Bailey, Sheila G.; Castro, Stephanie L.; Raffaelle, Ryne P.; Hepp, Aloysius F.

    2001-01-01

    The NASA Glenn Research Center has been investigating the synthesis of quantum dots of CdSe and CuInS2 for use in intermediate-bandgap solar cells. Using quantum dots in a solar cell to create an intermediate band will allow the harvesting of a much larger portion of the available solar spectrum. Theoretical studies predict a potential efficiency of 63.2 percent, which is approximately a factor of 2 better than any state-of-the-art devices available today. This technology is also applicable to thin-film devices--where it offers a potential four-fold increase in power-to-weight ratio over the state of the art. Intermediate-bandgap solar cells require that quantum dots be sandwiched in an intrinsic region between the photovoltaic solar cell's ordinary p- and n-type regions (see the preceding figure). The quantum dots form the intermediate band of discrete states that allow sub-bandgap energies to be absorbed. However, when the current is extracted, it is limited by the bandgap, not the individual photon energies. The energy states of the quantum dot can be controlled by controlling the size of the dot. Ironically, the ground-state energy levels are inversely proportional to the size of the quantum dots. We have prepared a variety of quantum dots using the typical organometallic synthesis routes pioneered by Ba Wendi et al., in the early 1990's. The most studied quantum dots prepared by this method have been of CdSe. To produce these dots, researchers inject a syringe of the desired organometallic precursors into heated triocytlphosphine oxide (TOPO) that has been vigorously stirred under an inert atmosphere (see the following figure). The solution immediately begins to change from colorless to yellow, then orange and red/brown, as the quantum dots increase in size. When the desired size is reached, the heat is removed from the flask. Quantum dots of different sizes can be identified by placing them under a "black light" and observing the various color differences in

  8. Fluorescent Quantum Dots for Biological Labeling

    Science.gov (United States)

    McDonald, Gene; Nadeau, Jay; Nealson, Kenneth; Storrie-Lomardi, Michael; Bhartia, Rohit

    2003-01-01

    Fluorescent semiconductor quantum dots that can serve as "on/off" labels for bacteria and other living cells are undergoing development. The "on/off" characterization of these quantum dots refers to the fact that, when properly designed and manufactured, they do not fluoresce until and unless they come into contact with viable cells of biological species that one seeks to detect. In comparison with prior fluorescence-based means of detecting biological species, fluorescent quantum dots show promise for greater speed, less complexity, greater sensitivity, and greater selectivity for species of interest. There are numerous potential applications in medicine, environmental monitoring, and detection of bioterrorism.

  9. 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.

  10. Learning Styles of Independent Learning Centre Users

    Directory of Open Access Journals (Sweden)

    Tarik Uzun

    2014-09-01

    Full Text Available 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 of the centre were synoptic learners, which implies that these learners might not necessarily have conscious control over their own learning processes. An in-depth analysis of learning styles and recommendations to improve the services offered in the centre are also included in the paper.

  11. 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...

  12. 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...

  13. 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.......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....

  14. 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.)

  15. 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

  16. An evaluation of the dot-ELISA procedure as a diagnostic test in an area with a high prevalence of human Toxocara canis infection

    Directory of Open Access Journals (Sweden)

    María V Bojanich

    2012-03-01

    Full Text Available The aim of this work was to evaluate a dot-enzyme-linked immunosorbent assay (dot-ELISA using excretory-secretory antigens from the larval stages of Toxocara canis for the diagnosis of toxocariasis. A secondary aim was to establish the optimal conditions for its use in an area with a high prevalence of human T. canis infection. The dot-ELISA test was standardised using different concentrations of the antigen fixed on nitrocellulose paper strips and increasing dilutions of the serum and conjugate. Both the dot-ELISA and standard ELISA methods were tested in parallel with the same batch of sera from controls and from individuals living in the problem area. The best results were obtained with 1.33 µg/mL of antigen, dilutions of 1/80 for the samples and controls and a dilution of 1/5,000 for the anti-human IgG-peroxidase conjugate. All steps of the procedure were performed at room temperature. The coincidence between ELISA and dot-ELISA was 85% and the kappa index was 0.72. The dot-ELISA test described here is rapid, easy to perform and does not require expensive equipment. Thus, this test is suitable for the serological diagnosis of human T. canis infection in field surveys and in the primary health care centres of endemic regions.

  17. 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...

  18. 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...

  19. Spin current in double quantum dot

    Institute of Scientific and Technical Information of China (English)

    Zhao Hua; Zhang Guo-Feng; Yin Wen; Liang Jiu-Qing

    2004-01-01

    We have studied the dynamical behaviours of two electrons confined in a double quantum dot driven by rotating magnetic fields in terms of the theory of Lewis-Riesenfeld Hermitian invariants for the explicitly time-dependent Hamiltonian. The coherent spin oscillations in the dot provide a generation source for spin current. Exact solutions obtained allow us to investigate the dynamical properties of the spin localization for various initial localized states.

  20. 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

  1. 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

  2. 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.

  3. [The coordination of care in health centres].

    Science.gov (United States)

    Ribardière, Olivia

    2016-06-01

    Health centres are structurally designed to facilitate the coordination of care. However, evolutions in society have resulted in forms of consumption of health care which are not necessarily compatible with efficient care coordination. On a local level, teams are nevertheless organising and structuring themselves to offer the right form of care, to the right patient and at the right time. PMID:27338687

  4. 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.

  5. 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

  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. [The coordination of care in health centres].

    Science.gov (United States)

    Ribardière, Olivia

    2016-06-01

    Health centres are structurally designed to facilitate the coordination of care. However, evolutions in society have resulted in forms of consumption of health care which are not necessarily compatible with efficient care coordination. On a local level, teams are nevertheless organising and structuring themselves to offer the right form of care, to the right patient and at the right time.

  8. 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…

  9. 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…

  10. 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

  11. 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…

  12. 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...

  13. 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.

  14. 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

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

    Science.gov (United States)

    Kaur, Gurpreet; Goel, N.K.; Kumar, Dinesh; Janmeja, A.K.; Swami, H.M.; 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 continuous evaluation. Objective: To study the outcomes of treatment among the patients put on DOTS under RNTCP in Chandigarh, UT. Material & Methods: A Longitudinal 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. PMID:20165654

  16. 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.

  17. Dot-dye-immunoassay for the diagnosis of schistosomiasis mansoni

    Directory of Open Access Journals (Sweden)

    Ana Lúcia Teles Rabello

    1992-06-01

    Full Text Available A new serological assay dot-dye-immunoassay (dot-DIA was evaluated for the diagnosis of schistosomiasis mansoni. This method consist of four steps: (a biding of antigens to a nitrocellulose membrane (NC; (b blocking of free sites of the NC; (c incubation in specific primary antibody; (d detection of primary antibody reactivity by color development using second antibody coupled to textile dyes. Sera from 82 individuals, 61 with Schistosoma mansoni eggs in the stool and 21 stool negative were tested by ELISA, dot-ELISA, and dotDIA. A high level of agreement between the methods tested was observed for all sera tested: ELISA x dot-ELISA: 95.1%, ELISA x dot-DIA: 92.7% and dot-ELISA x dot-DIA: 97.6%. In this study, dot-DIA proved to be a feasible, sensitive, rapid and practical test for the diagnosis of shcistosomiasis.

  18. 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

  19. 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)

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. Understanding electronic systems in semiconductor quantum dots

    Science.gov (United States)

    Ciftja, Orion

    2013-11-01

    Systems of confined electrons are found everywhere in nature in the form of atoms where the orbiting electrons are confined by the Coulomb attraction of the nucleus. Advancement of nanotechnology has, however, provided us with an alternative way to confine electrons by using artificial confining potentials. A typical structure of this nature is the quantum dot, a nanoscale system which consists of few confined electrons. There are many types of quantum dots ranging from self-assembled to miniaturized semiconductor quantum dots. In this work we are interested in electrostatically confined semiconductor quantum dot systems where the electrostatic confining potential that traps the electrons is generated by external electrodes, doping, strain or other factors. A large number of semiconductor quantum dots of this type are fabricated by applying lithographically patterned gate electrodes or by etching on two-dimensional electron gases in semiconductor heterostructures. Because of this, the whole structure can be treated as a confined two-dimensional electron system. Quantum confinement profoundly affects the way in which electrons interact with each other, and external parameters such as a magnetic field. Since a magnetic field affects both the orbital and the spin motion of the electrons, the interplay between quantum confinement, electron-electron correlation effects and the magnetic field gives rise to very interesting physical phenomena. Thus, confined systems of electrons in a semiconductor quantum dot represent a unique opportunity to study fundamental quantum theories in a controllable atomic-like setup. In this work, we describe some common theoretical models which are used to study confined systems of electrons in a two-dimensional semiconductor quantum dot. The main emphasis of the work is to draw attention to important physical phenomena that arise in confined two-dimensional electron systems under various quantum regimes.

  5. Effects of unstratified and centre-stratified randomization in multi-centre clinical trials.

    Science.gov (United States)

    Anisimov, Vladimir V

    2011-01-01

    This paper deals with the analysis of randomization effects in multi-centre clinical trials. The two randomization schemes most often used in clinical trials are considered: unstratified and centre-stratified block-permuted randomization. The prediction of the number of patients randomized to different treatment arms in different regions during the recruitment period accounting for the stochastic nature of the recruitment and effects of multiple centres is investigated. A new analytic approach using a Poisson-gamma patient recruitment model (patients arrive at different centres according to Poisson processes with rates sampled from a gamma distributed population) and its further extensions is proposed. Closed-form expressions for corresponding distributions of the predicted number of the patients randomized in different regions are derived. In the case of two treatments, the properties of the total imbalance in the number of patients on treatment arms caused by using centre-stratified randomization are investigated and for a large number of centres a normal approximation of imbalance is proved. The impact of imbalance on the power of the study is considered. It is shown that the loss of statistical power is practically negligible and can be compensated by a minor increase in sample size. The influence of patient dropout is also investigated. The impact of randomization on predicted drug supply overage is discussed.

  6. 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&...

  7. 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.

  8. Frequency selectivity at very low centre frequencies

    DEFF Research Database (Denmark)

    Orellana, Carlos Andrés Jurado; Pedersen, Christian Sejer; Marquardt, Torsten

    2010-01-01

    A significant factor in the decrease of sensitivity to low-frequency sound is the helicotrema shunt effect. In humans, it causes a slope increase of the middle-ear transfer function (METF) from 6 dB/oct to 12 dB/oct below approximately 50 Hz [Marquardt et al., J.Acoust. Soc. Am. 121, 3628...... 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......-3638 (2007)]. Recent experiments showed that the exact frequency varies from individual to individual. Besides, the helicotrema region in the METF has been found to highly influence frequency selectivity for centre frequencies (CFs) below 80 Hz (Jurado and Moore in prep). By using individual METF...

  9. Patient-centred Prevention among PAD Patients

    DEFF Research Database (Denmark)

    Pii, Kathrine Hoffmann

    2014-01-01

    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 patient-centred approach does not ensure patient autonomy, but continues to be organized according to biomedical regimes and thereby carry on a paternalistic approach. In this paper, I present findings from a PhD project, which investigates how the ideal of patient-centredness is practiced in the case...

  10. Danish Polymer Centre annual report 2001

    DEFF Research Database (Denmark)

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

    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...... 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...

  11. 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...

  12. 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...

  13. 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

  14. 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.)

  15. 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.

  16. 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 ...

  17. 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...

  18. Enhancing Safety at Airline Operations Control Centre

    Directory of Open Access Journals (Sweden)

    Lukáš Řasa

    2015-04-01

    Full Text Available In recent years a new term of Safety Management System (SMS has been introduced into aviation legislation. This system is being adopted by airline operators. One of the groundbased actors of everyday operations is Operations Control Centre (OCC. The goal of this article has been to identify and assess risks and dangers which occur at OCC and create a template for OCC implementation into SMS.

  19. 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...

  20. User-Centred Design Using Gamestorming.

    Science.gov (United States)

    Currie, Leanne

    2016-01-01

    User-centered design (UX) is becoming a standard in software engineering and has tremendous potential in healthcare. The purpose of this tutorial will be to demonstrate and provide participants with practice in user-centred design methods that involve 'Gamestorming', a form of brainstorming where 'the rules of life are temporarily suspended'. Participants will learn and apply gamestorming methods including persona development via empathy mapping and methods to translate artefacts derived from participatory design sessions into functional and design requirements.

  1. 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.

  2. 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.

  3. 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...

  4. 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...

  5. 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...

  6. 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)

  7. Photoluminescence of carbon dots from mesoporous silica

    Science.gov (United States)

    Nelson, D. K.; Razbirin, B. S.; Starukhin, A. N.; Eurov, D. A.; Kurdyukov, D. A.; Stovpiaga, E. Yu; Golubev, V. G.

    2016-09-01

    Photophysical properties of carbon dots were investigated under various excitation conditions and over a wide temperature region - from room to liquid helium temperatures. The carbon dots (CDs) were synthesized using mesoporous silica particles as a reactor and (3-aminopropyl)triethoxysilane (APTES) as a precursor. The photoluminescence spectra of CDs exhibit a strong dependence on the excitation wavelength and demonstrate a significant inhomogeneous broadening. Lowering sample temperature reveals the doublet structure of the spectra, which is associated with the vibronic structure of radiative transitions. The vibration energy ∼1200 cm-1 is close to the energy of Csbnd O stretching vibration. Long-lived phosphorescence of carbon dots with its decay time ∼0.2 s at T = 80 K was observed. The fluorescence and phosphorescence spectra are shown to be spectrally separated. The long-lived component of the emission was ascribed to optically forbidden triplet-singlet transitions. The value of the singlet-triplet splitting was found to be about 0.3 eV. Photo-induced polarization of the luminescence of carbon dots was revealed. The degree of the linear polarization is dependent on the wavelengths of both excitation and emitted light. The effect indicates a hidden anisotropy of optical dipole transitions in the dots and demonstrates the loss of the dipole orientation during the electron energy relaxation.

  8. 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.

  9. 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.

  10. 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.

  11. Filtering algorithm for dotted interferences

    Energy Technology Data Exchange (ETDEWEB)

    Osterloh, K., E-mail: kurt.osterloh@bam.de [Federal Institute for Materials Research and Testing (BAM), Division VIII.3, Radiological Methods, Unter den Eichen 87, 12205 Berlin (Germany); Buecherl, T.; Lierse von Gostomski, Ch. [Technische Universitaet Muenchen, Lehrstuhl fuer Radiochemie, Walther-Meissner-Str. 3, 85748 Garching (Germany); Zscherpel, U.; Ewert, U. [Federal Institute for Materials Research and Testing (BAM), Division VIII.3, Radiological Methods, Unter den Eichen 87, 12205 Berlin (Germany); Bock, S. [Technische Universitaet Muenchen, Lehrstuhl fuer Radiochemie, Walther-Meissner-Str. 3, 85748 Garching (Germany)

    2011-09-21

    An algorithm has been developed to remove reliably dotted interferences impairing the perceptibility of objects within a radiographic image. This particularly is a major challenge encountered with neutron radiographs collected at the NECTAR facility, Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II): the resulting images are dominated by features resembling a snow flurry. These artefacts are caused by scattered neutrons, gamma radiation, cosmic radiation, etc. all hitting the detector CCD directly in spite of a sophisticated shielding. This makes such images rather useless for further direct evaluations. One approach to resolve this problem of these random effects would be to collect a vast number of single images, to combine them appropriately and to process them with common image filtering procedures. However, it has been shown that, e.g. median filtering, depending on the kernel size in the plane and/or the number of single shots to be combined, is either insufficient or tends to blur sharp lined structures. This inevitably makes a visually controlled processing image by image unavoidable. Particularly in tomographic studies, it would be by far too tedious to treat each single projection by this way. Alternatively, it would be not only more comfortable but also in many cases the only reasonable approach to filter a stack of images in a batch procedure to get rid of the disturbing interferences. The algorithm presented here meets all these requirements. It reliably frees the images from the snowy pattern described above without the loss of fine structures and without a general blurring of the image. It consists of an iterative, within a batch procedure parameter free filtering algorithm aiming to eliminate the often complex interfering artefacts while leaving the original information untouched as far as possible.

  12. 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.

  13. Coherence and dephasing in self-assembled quantum dots

    DEFF Research Database (Denmark)

    Hvam, Jørn Märcher; Leosson, K.; Birkedal, Dan

    2003-01-01

    We measured dephasing times in InGaAl/As self-assembled quantum dots at low temperature using degenerate four-wave mixing. At 0K, the coherence time of the quantum dots is lifetime limited, whereas at finite temperatures pure dephasing by exciton-phonon interactions governs the quantum dot...... coherence. The inferred homogeneous line widths are significantly smaller than the line widths usually observed in the photoluminescence from single quantum dots indicating an additional inhomogeneours broadening mechanism in the latter....

  14. 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...

  15. Quantum Dots in Photonic Crystal Waveguides

    DEFF Research Database (Denmark)

    Sollner, Immo Nathanael

    This Thesis is focused on the study of quantum electrodynamics in photonic crystal waveguides. We investigate the interplay between a single quantum dot and the fundamental mode of the photonic crystal waveguide. We demonstrate experimental coupling eciencies for the spontaneous emission...... into the mode exceeding 98% for emitters spectrally close to the band-edge of the waveguide mode. In addition we illustrate the broadband nature of the underlying eects, by obtaining coupling eciencies above 90% for quantum dots detuned from the band edge by as far as 20nm. These values are in good agreement...... quantum-dot-waveguide coupling. Such a structure is ideally suited for a number of applications in quantum information processing and among others we propose an on-chip spin-photon interface, a single photon transistor, and a deterministic cNOT gate....

  16. Charged-Exciton Complexes in Quantum Dots

    Institute of Scientific and Technical Information of China (English)

    XIE Wen-Fang

    2001-01-01

    It is known experimentally that stable charged-exciton complexes can exist in low-dimensional semiconductor nanostructures. Much less is known about the properties of such charged-exciton complexes since three-body problems are very difficult to be solved, even numerically. Here we introduce the correlated hyperspherical harmonics as basis functions to solve the hyperangular equation for negatively and positively charged excitons (trions) in a harmonic quantum dot. By using this method, we have calculated the energy spectra of the low-lying states of a charged exciton as a function of the radius of quantum dot. Based on symmetry analysis, the level crossover as the dot radius increases can be fully explained as the results of symmetry constraint.``

  17. 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.

  18. 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.

  19. Epidemiological features of skeletal tuberculosis at an urban district tuberculosis centre.

    Science.gov (United States)

    Chopra, Rajat; Bhatt, Rama; Biswas, S K; Bhalla, R

    2016-04-01

    Skeletal tuberculosis is an important component of extra-pulmonary tuberculosis. It can lead to substantial morbidity and poses serious occupational and economic problem. We conducted a study in an urban District Tuberculosis Centre (DTC) to assess the burden and distribution of skeletal tuberculosis in the community. Our centre was catering to a population of 6-7 lakhs between 2007 and 2012. During this period, we treated 11,274 cases of tuberculosis. Out of these, 3086 (27.3%) were cases of extrapulmonary tuberculosis and 219 (1.94%) were cases of skeletal tuberculosis. Skeletal TB predominantly affects the young Indian population with incidence peaking in the second and third decades of life. 172 patients (78.5%) in our study were new cases. There were no drugs resistant (DRTB) skeletal TB cases till we concluded our study. Tuberculosis commonly involves joints more than long bones. The spinal column was the most commonly involved skeletal site affecting 62.6% of all cases. The rate of spinal TB in our study is much higher than that reported in literature. The high number of patients calls for close co-ordination between managing orthopaedic surgeons, treating physicians and DOT providers to ensure adequate patient care. PMID:27451817

  20. 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.

  1. 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...

  2. 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…

  3. 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...

  4. Imaging vasculature and lymphatic flow in mice using quantum dots

    DEFF Research Database (Denmark)

    Ballou, Byron; Ernst, Lauren A.; Andreko, Susan;

    2009-01-01

    Quantum dots are ideal probes for fluorescent imaging of vascular and lymphatic tissues. On injection into appropriate sites, red- and near-infrared-emitting quantum dots provide excellent definition of vasculature, lymphoid organs, and lymph nodes draining both normal tissues and tumors. We detail...... methods for use with commercially available quantum dots and discuss common difficulties....

  5. 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

  6. 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.

  7. 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.

  8. 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...

  9. 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

  10. Resonant tunneling in graphene pseudomagnetic quantum dots.

    Science.gov (United States)

    Qi, Zenan; Bahamon, D A; Pereira, Vitor M; Park, Harold S; Campbell, D K; Neto, A H Castro

    2013-06-12

    Realistic relaxed configurations of triaxially strained graphene quantum dots are obtained from unbiased atomistic mechanical simulations. The local electronic structure and quantum transport characteristics of y-junctions based on such dots are studied, revealing that the quasi-uniform pseudomagnetic field induced by strain restricts transport to Landau level- and edge state-assisted resonant tunneling. Valley degeneracy is broken in the presence of an external field, allowing the selective filtering of the valley and chirality of the states assisting in the resonant tunneling. Asymmetric strain conditions can be explored to select the exit channel of the y-junction.

  11. Mitigation of quantum dot cytotoxicity by microencapsulation.

    Directory of Open Access Journals (Sweden)

    Amelia Romoser

    Full Text Available When CdSe/ZnS-polyethyleneimine (PEI quantum dots (QDs are microencapsulated in polymeric microcapsules, human fibroblasts are protected from acute cytotoxic effects. Differences in cellular morphology, uptake, and viability were assessed after treatment with either microencapsulated or unencapsulated dots. Specifically, QDs contained in microcapsules terminated with polyethylene glycol (PEG mitigate contact with and uptake by cells, thus providing a tool to retain particle luminescence for applications such as extracellular sensing and imaging. The microcapsule serves as the "first line of defense" for containing the QDs. This enables the individual QD coating to be designed primarily to enhance the function of the biosensor.

  12. 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…

  13. 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.)

  14. 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

  15. Biological Inspiration in Human Centred Robotics

    Institute of Scientific and Technical Information of China (English)

    HUHuo-sheng; LIUJin-dong; CalderonCarlosA

    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.

  16. 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....

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. The Influence of Formulating a Damping Solution on Dot Gain

    Directory of Open Access Journals (Sweden)

    Povilas Mikalainis

    2011-02-01

    Full Text Available Difference in dot gain using various additives to the damping solution was investigated on two offset web presses. Dot gain was measured using a densitometer and calculated considering CIE L*a*b* coordinates. It was found that while using a non alcohol additive instead of the alcohol one, dot gain became smaller and printing stability was lower. Changes in dot gain depend on the ink that may vary in colours. The influence of changes in dot gain on the colour was determined. Besides, it was found that differences in colour were unacceptable in many cases.Article in Lithuanian

  3. Synthesis of CdSe quantum dots for quantum dot sensitized solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Neetu, E-mail: singh.neetu1985@gmail.com; Kapoor, Avinashi [Department of Electronic Science, University of Delhi South Campus, New Delhi-110 021 (India); Kumar, Vinod [Department of Physics, University of the Free State, Bloemfontein, ZA9300 (South Africa); Mehra, R. M. [School of Engineering and Technology, Sharda University, Greater Noida-201 306, U.P. (India)

    2014-04-24

    CdSe Quantum Dots (QDs) of size 0.85 nm were synthesized using chemical route. ZnO based Quantum Dot Sensitized Solar Cell (QDSSC) was fabricated using CdSe QDs as sensitizer. The Pre-synthesized QDs were found to be successfully adsorbed on front ZnO electrode and had potential to replace organic dyes in Dye Sensitized Solar Cells (DSSCs). The efficiency of QDSSC was obtained to be 2.06 % at AM 1.5.

  4. Synthesis of CdSe quantum dots for quantum dot sensitized solar cell

    International Nuclear Information System (INIS)

    CdSe Quantum Dots (QDs) of size 0.85 nm were synthesized using chemical route. ZnO based Quantum Dot Sensitized Solar Cell (QDSSC) was fabricated using CdSe QDs as sensitizer. The Pre-synthesized QDs were found to be successfully adsorbed on front ZnO electrode and had potential to replace organic dyes in Dye Sensitized Solar Cells (DSSCs). The efficiency of QDSSC was obtained to be 2.06 % at AM 1.5

  5. 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

  6. Ostwald's ripening of nanostructures with quantum dots

    CERN Document Server

    Vengrenovich, R D; Yarema, S V

    2001-01-01

    The scenario of quantum dots shaping during ripening three-dimensional islands obtained by heteroepitaxy in a Stranski-Krastanow mode, is offered. It is shown that throughout the growth of dislocations with their subsequent separation from the island bottom, the size distribution function becomes narrower with noticeable diminishing the dispersion. The possible reasons for signal attenuation of Ostwald's ripening islands are analyzed

  7. Ostwald's ripening of nanostructures with quantum dots

    International Nuclear Information System (INIS)

    The scenario of quantum dots shaping during ripening three-dimensional islands obtained by heteroepitaxy in a Stranski-Krastanow mode, is offered. It is shown that throughout the growth of dislocations with their subsequent separation from the island bottom, the size distribution function becomes narrower with noticeable diminishing the dispersion. The possible reasons for signal attenuation of Ostwald's ripening islands are analyzed

  8. Saturating optical resonances in quantum dots

    Science.gov (United States)

    Nair, Selvakumar V.; Rustagi, K. C.

    Optical bistability in quantum dots, recently proposed by Chemla and Miller, is studied in a two-resonance model. We show that for such classical electromagnetic resonances the applicability of a two-resonance model is far more restrictive than for those in atoms.

  9. Quantum dot devices for optical communications

    DEFF Research Database (Denmark)

    Mørk, Jesper

    2005-01-01

    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. ...

  10. Single Molecule Applications of Quantum Dots

    DEFF Research Database (Denmark)

    Rasmussen, Thomas Elmelund; Jauffred, Liselotte; Brewer, Jonathan R.;

    2013-01-01

    Fluorescent nanocrystals composed of semiconductor materials were first introduced for biological applications in the late 1990s. The focus of this review is to give a brief survey of biological applications of quantum dots (QDs) at the single QD sensitivity level. These are described as follows: 1...

  11. 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...

  12. Decoherence in Nearly-Isolated Quantum Dots

    DEFF Research Database (Denmark)

    Folk, J.; M. Marcus, C.; Harris jr, J.

    2000-01-01

    Decoherence in nearly-isolated GaAs quantum dots is investigated using the change in average Coulomb blockade peak height upon breaking time-reversal symmetry. The normalized change in average peak height approaches the predicted universal value of 1/4 at temperatures well below the single...

  13. Producing Quantum Dots by Spray Pyrolysis

    Science.gov (United States)

    Banger, Kulbinder; Jin, Michael H.; Hepp, Aloysius

    2006-01-01

    An improved process for making nanocrystallites, commonly denoted quantum dots (QDs), is based on spray pyrolysis. Unlike the process used heretofore, the improved process is amenable to mass production of either passivated or non-passivated QDs, with computer control to ensure near uniformity of size.

  14. System and method for making quantum dots

    KAUST Repository

    Bakr, Osman M.

    2015-05-28

    Embodiments of the present disclosure provide for methods of making quantum dots (QDs) (passivated or unpassivated) using a continuous flow process, systems for making QDs using a continuous flow process, and the like. In one or more embodiments, the QDs produced using embodiments of the present disclosure can be used in solar photovoltaic cells, bio-imaging, IR emitters, or LEDs.

  15. Amphoteric CdSe nanocrystalline quantum dots.

    Science.gov (United States)

    Islam, Mohammad A

    2008-06-25

    The nanocrystal quantum dot (NQD) charge states strongly influence their electrical transport properties in photovoltaic and electroluminescent devices, optical gains in NQD lasers, and the stability of the dots in thin films. We report a unique electrostatic nature of CdSe NQDs, studied by electrophoretic methods. When we submerged a pair of metal electrodes, in a parallel plate capacitor configuration, into a dilute solution of CdSe NQDs in hexane, and applied a DC voltage across the pair, thin films of CdSe NQDs were deposited on both the positive and the negative electrodes. Extensive characterizations including scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared (FTIR) and Raman studies revealed that the films on both the positive and the negative electrodes were identical in every respect, clearly indicating that: (1) a fraction (<1%) of the CdSe NQDs in free form in hexane solution are charged and, more importantly, (2) there are equal numbers of positive and negative CdSe NQDs in the hexane solution. Experiments also show that the number of deposited dots is at least an order of magnitude higher than the number of initially charged dots, indicating regeneration. We used simple thermodynamics to explain such amphoteric nature and the charging/regeneration of the CdSe NQDs.

  16. Quantum Dot Devices for Optical Signal Processing

    DEFF Research Database (Denmark)

    Chen, Yaohui

    with other semiconductor materials. The understanding of such properties is important in order to improve the performance of existing devices and to trigger the development of new semiconductor devices for dierent optical signal processing functionalities in the future. We present a detailed quantum dot...

  17. Competing interactions in semiconductor quantum dots

    NARCIS (Netherlands)

    R. van den Berg; G.P. Brandino; O. El Araby; R.M. Konik; V. Gritsev; J.S. Caux

    2014-01-01

    We introduce an integrability-based method enabling the study of semiconductor quantum dot models incorporating both the full hyperfine interaction as well as a mean-field treatment of dipole-dipole interactions in the nuclear spin bath. By performing free-induction decay and spin-echo simulations w

  18. Enabling biomedical research with designer quantum dots

    NARCIS (Netherlands)

    Tomczak, N.; Janczewski, D.; Dorokhin, D.V.; Han, M-Y; Vancso, G.J.; Navarro, Melba; Planell, Josep A.

    2012-01-01

    Quantum Dots (QDs) are a new class of semiconductor nanoparticulate luminophores, which are actively researched for novel applications in biology and nanomedicine. In this review, the recent progress in the design and applications of QD labels for in vitro and in vivo imaging of cells is presented.

  19. Quantum dot waveguides: ultrafast dynamics and applications

    DEFF Research Database (Denmark)

    Chen, Yaohui; Mørk, Jesper

    2009-01-01

    In this paper we analyze, based on numerical simulations, the dynamics of semiconductor devices incorporating quantum dots (QDs). In particular we emphasize the unique ultrafast carrier dynamics occurring between discrete QD bound states, and its influence on QD semiconductor optical amplifiers...

  20. Tunneling Processes in Optically Excited Quantum Dots

    Institute of Scientific and Technical Information of China (English)

    LI Xiu-Ping; WEI Hua-Rong; XU Li-Ping; GONG Jian-Ping; YAN Wei-Xian

    2011-01-01

    The single-electron tunneling processes in optically excited coupled quantum dots can be divided into two parts: the electron and the hole parts, which are analytically obtained in the framework of the Keldysh formalism. The tunneling process is selective tunneling, which results in dark tunneling states. The tunneling currents are co-determined by the resonance energies and probability distributions of the particular quantum channels defined by the electron-hole complex resonant states.%The single-electron tunneling processes in optically excited coupled quantum dots can be divided into two parts:the electron and the hole parts,which are analytically obtained in the framework of the Keldysh formalism.The tunneling process is selective tunneling,which results in dark tunneling states.The tunneling currents are co-determined by the resonance energies and probability distributions of the particular quantum channels defined by the electron-hole complex resonant states.Probing the fine-energy structure of the exciton complexes[1-10] in an optically excited quantum dot is an important way of exploring new mechanisms in nanostructures.Single electron tunneling (SET) devices consisting of a central quantum dot (QD) and a tunneling coupled source and drain have become important optoelectronic nano-devices.[11,12

  1. Inter-dot strain field effect on the optoelectronic properties of realistic InP lateral quantum-dot molecules

    International Nuclear Information System (INIS)

    We report on numerical simulations of InP surface lateral quantum-dot molecules on In0.48Ga0.52 P buffer, using a model strictly derived by experimental results by extrapolation of the molecules shape from atomic force microscopy images. Our study has been inspired by the comparison of a photoluminescence spectrum of a high-density InP surface quantum dot sample with a numerical ensemble average given by a weighted sum of simulated single quantum-dot spectra. A lack of experimental optical response from the smaller dots of the sample is found to be due to strong inter-dot strain fields, which influence the optoelectronic properties of lateral quantum-dot molecules. Continuum electromechanical, k→·p→ bandstructure, and optical calculations are presented for two different molecules, the first composed of two dots of nearly identical dimensions (homonuclear), the second of two dots with rather different sizes (heteronuclear). We show that in the homonuclear molecule the hydrostatic strain raises a potential barrier for the electrons in the connection zone between the dots, while conversely the holes do not experience any barrier, which considerably increases the coupling. Results for the heteronuclear molecule show instead that its dots do not appear as two separate and distinguishable structures, but as a single large dot, and no optical emission is observed in the range of higher energies where the smaller dot is supposed to emit. We believe that in samples of such a high density the smaller dots result as practically incorporated into bigger molecular structures, an effect strongly enforced by the inter-dot strain fields, and consequently it is not possible to experimentally obtain a separate optical emission from the smaller dots

  2. Inter-dot strain field effect on the optoelectronic properties of realistic InP lateral quantum-dot molecules

    Energy Technology Data Exchange (ETDEWEB)

    Barettin, Daniele, E-mail: Daniele.Barettin@uniroma2.it; Auf der Maur, Matthias [Department of Electronic Engineering, University of Rome “Tor Vergata,” Via del Politecnico 1, 00133, Rome (Italy); De Angelis, Roberta; Prosposito, Paolo; Casalboni, Mauro [Department of Industrial Engineering, University of Rome Tor Vergata, Via del Politecnico 1 00133 Rome, Italy and INSTM, Unitá di ricerca dell' Universitá di Roma “Tor Vergata,” Via della Ricerca Scientifica 1, 00133, Rome (Italy); Pecchia, Alessandro [CNR-ISMN, via Salaria Km. 29.300, 00017 Monterotondo, Rome (Italy)

    2015-03-07

    We report on numerical simulations of InP surface lateral quantum-dot molecules on In{sub 0.48}Ga{sub 0.52 }P buffer, using a model strictly derived by experimental results by extrapolation of the molecules shape from atomic force microscopy images. Our study has been inspired by the comparison of a photoluminescence spectrum of a high-density InP surface quantum dot sample with a numerical ensemble average given by a weighted sum of simulated single quantum-dot spectra. A lack of experimental optical response from the smaller dots of the sample is found to be due to strong inter-dot strain fields, which influence the optoelectronic properties of lateral quantum-dot molecules. Continuum electromechanical, k{sup →}·p{sup →} bandstructure, and optical calculations are presented for two different molecules, the first composed of two dots of nearly identical dimensions (homonuclear), the second of two dots with rather different sizes (heteronuclear). We show that in the homonuclear molecule the hydrostatic strain raises a potential barrier for the electrons in the connection zone between the dots, while conversely the holes do not experience any barrier, which considerably increases the coupling. Results for the heteronuclear molecule show instead that its dots do not appear as two separate and distinguishable structures, but as a single large dot, and no optical emission is observed in the range of higher energies where the smaller dot is supposed to emit. We believe that in samples of such a high density the smaller dots result as practically incorporated into bigger molecular structures, an effect strongly enforced by the inter-dot strain fields, and consequently it is not possible to experimentally obtain a separate optical emission from the smaller dots.

  3. External Electric Field Effect on Hydrogenic Donor Impurity in Zinc-Blende InGaN Quantum Dot

    Institute of Scientific and Technical Information of China (English)

    JIANG Li-Ming; WANG Hai-Long; WU Hui-Ting; GONG Qian; FENG Song-Lin

    2008-01-01

    @@ The binding energy of a hydrogenic donor impurity in zinc-blende (ZB) InGaN quantum dot (QD) is calculatedin the framework of effective-mass envelope-function theory using the plane wave basis. It is shown that the donor binding energy is highly dependent on the impurity position, QD size and the external electric field. The symmetry of the electron probability distribution is broken and the maximum of the donor binding energy is shifted from the centre of QD in the presence of the external electric field. The degenerating energy levels for symmetrical positions with respect to the centre of QD are split. The splitting increases with the increase of QD height while the splitting increases up to a maximum value and then decreases with the increase of QD radius.

  4. Annealing-induced change in quantum dot chain formation mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Park, Tyler D.; Colton, John S.; Farrer, Jeffrey K. [Department of Physics and Astronomy, Brigham Young University, Provo UT 84602 (United States); Yang, Haeyeon [Department of Nanoscience and Nanoengineering, South Dakota School of Mines and Technology, Rapid City, SD 57701 (United States); Kim, Dong Jun [IPG Photonics Corporation, Oxford, MA 01540 (United States)

    2014-12-15

    Self-assembled InGaAs quantum dot chains were grown using a modified Stranski-Krastanov method in which the InGaAs layer is deposited under a low growth temperature and high arsenic overpressure, which suppresses the formation of dots until a later annealing process. The dots are capped with a 100 nm GaAs layer. Three samples, having three different annealing temperatures of 460°C, 480°C, and 500°C, were studied by transmission electron microscopy. Results indicate two distinct types of dot formation processes: dots in the 460°C and 480°C samples form from platelet precursors in a one-to-one ratio whereas the dots in the sample annealed at 500°C form through the strain-driven self-assembly process, and then grow larger via an additional Ostwald ripening process whereby dots grow into larger dots at the expense of smaller seed islands. There are consequently significant morphological differences between the two types of dots, which explain many of the previously-reported differences in optical properties. Moreover, we also report evidence of indium segregation within the dots, with little or no indium intermixing between the dots and the surrounding GaAs barrier.

  5. Annealing-induced change in quantum dot chain formation mechanism

    Science.gov (United States)

    Park, Tyler D.; Colton, John S.; Farrer, Jeffrey K.; Yang, Haeyeon; Kim, Dong Jun

    2014-12-01

    Self-assembled InGaAs quantum dot chains were grown using a modified Stranski-Krastanov method in which the InGaAs layer is deposited under a low growth temperature and high arsenic overpressure, which suppresses the formation of dots until a later annealing process. The dots are capped with a 100 nm GaAs layer. Three samples, having three different annealing temperatures of 460°C, 480°C, and 500°C, were studied by transmission electron microscopy. Results indicate two distinct types of dot formation processes: dots in the 460°C and 480°C samples form from platelet precursors in a one-to-one ratio whereas the dots in the sample annealed at 500°C form through the strain-driven self-assembly process, and then grow larger via an additional Ostwald ripening process whereby dots grow into larger dots at the expense of smaller seed islands. There are consequently significant morphological differences between the two types of dots, which explain many of the previously-reported differences in optical properties. Moreover, we also report evidence of indium segregation within the dots, with little or no indium intermixing between the dots and the surrounding GaAs barrier.

  6. Annealing-induced change in quantum dot chain formation mechanism

    Directory of Open Access Journals (Sweden)

    Tyler D. Park

    2014-12-01

    Full Text Available Self-assembled InGaAs quantum dot chains were grown using a modified Stranski-Krastanov method in which the InGaAs layer is deposited under a low growth temperature and high arsenic overpressure, which suppresses the formation of dots until a later annealing process. The dots are capped with a 100 nm GaAs layer. Three samples, having three different annealing temperatures of 460°C, 480°C, and 500°C, were studied by transmission electron microscopy. Results indicate two distinct types of dot formation processes: dots in the 460°C and 480°C samples form from platelet precursors in a one-to-one ratio whereas the dots in the sample annealed at 500°C form through the strain-driven self-assembly process, and then grow larger via an additional Ostwald ripening process whereby dots grow into larger dots at the expense of smaller seed islands. There are consequently significant morphological differences between the two types of dots, which explain many of the previously-reported differences in optical properties. Moreover, we also report evidence of indium segregation within the dots, with little or no indium intermixing between the dots and the surrounding GaAs barrier.

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

    Directory of Open Access Journals (Sweden)

    Rizvi SB

    2012-08-01

    Full Text Available 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 photophysical properties. They can potentially be used as fluorescent probes for various biomedical imaging applications, including cancer localization, detection of micrometastasis, image guided surgery, and targeted drug delivery. Their main limitation is toxicity, which requires a biologically compatible surface coating to shield the toxic core from the surrounding environment. However, this leads to an increase in QD size that may lead to problems of excretion and systemic sequestration. We describe a one pot synthesis, characterization, and in vitro cytotoxicity of a novel polyhedral oligomeric silsesquioxane (POSS-coated CdTe-cored QD using mercaptosuccinic acid (MSA and D-cysteine as stabilizing agents. Characterization was performed using transmission electron microscopy Fourier transform infrared spectroscopy, and photoluminescence studies. POSS-coated QDs demonstrated high colloidal stability and enhanced photostability on high degrees of ultraviolet (UV excitation compared to QDs coated with MSA and D-cysteine alone (P value < 0.05. In vitro toxicity studies showed that both POSS and MSA-QDs were significantly less toxic than ionized salts of Cd+2 and Te-2. Confocal microscopy confirmed high brightness of POSS-QDs in cells at both 1 and 24 hours, indicating that these QDs are rapidly taken up by cells and remain photostable in a biological environment. We therefore conclude that a POSS coating confers biological compatibility, photostability, and colloidal

  8. 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

  9. ALICE opens its new nerve centre

    CERN Multimedia

    Antonella Del Rosso

    2014-01-01

    Twenty-nine fully equipped and ergonomic workstations, one meeting area and 11 large format screens in a completely refurbished room: the ALICE Run Control Centre (ARC) implements the best and newest solutions for its shift workers and expert operators, including access for persons with reduced mobility and very soon a magic window for Point 2 visitors.   The ALICE Run Control Centre. “Our initial intention was just to optimise the old layout,” says Federico Ronchetti from Laboratori Nazionali di Frascati (Italy), a CERN scientific associate currently appointed as ALICE Run Coordinator and person in charge of the ALICE Consolidation Task Force. “However, during the review process, we carried out a study of all the existing control rooms at CERN and became aware we needed a radical change. Hence we started planning a complete redesign of the workspace.” Designed and equipped over many years, the old ALICE control room did not have enough space to fit al...

  10. KNMI Data Centre: Easy access for all

    Science.gov (United States)

    van de Vegte, John; Som de Cerff, Wim; Plieger, Maarten; de Vreede, Ernst; Sluiter, Raymond; Willem Noteboom, Jan; van der Neut, Ian; Verhoef, Hans; van Versendaal, Robert; van Binnendijk, Martin; Kalle, Henk; Knopper, Arthur; Spit, Jasper; Mastop, Joeri; Klos, Olaf; Calis, Gijs; Ha, Siu-Siu; van Moosel, Wim; Klein Ikkink, Henk-Jan; Tosun, Tuncay

    2013-04-01

    KNMI is the Dutch institute for weather, climate research and seismology. It disseminates weather information to the public at large, the government, aviation and the shipping industry in the interest of safety, the economy and a sustainable environment. To gain insight into long-term developments KNMI conducts research on climate change. Making the knowledge, data and information on hand at KNMI accessible is one core activity. A huge part of the KNMI information is from numerical models, insitu sensor networks and remote sensing satellites. This digital collection is mostly internal only available and is a collection of non searchable , non standardized file formats, lacking documentation and has no references to scientific publications. With the KNMI Data Centre (KDC) project these issues are tackled. In the project a user driven development approach with SCRUM was chosen to get maximum user involvement in a relative short development timeframe. Building on open standards and proven open source technology (which includes in-house developed software like ADAGUC WMS and Portal) resulted in a first release in December 2012 This presentation will focus on the aspects of KDC relating to its technical challenges, the development strategy and the initial usage results of the data centre.

  11. Bhabha Atomic Research Centre annual report : 1989

    International Nuclear Information System (INIS)

    The main thrust of the various research and development (R and D) activities of the Bhabha Atomic Research Centre (BARC), Bombay, is towards the implementation of India's nuclear power programme. To that end, its R and D activities cover the entire nuclear fuel cycle, reactor technology; applications of radioisotopes and radiations in agriculture, medicine and industries; and radiation protection in nuclear installations. The report presents in summarised form the R and D activities carried out during 1989 in the chapters entitled: Physical Sciences, Chemical Sciences, Materials and Materials Sciences, Radioisotopes, Reactors, Fuel Cycle, Radiological Safety and Protection, Electronics and Instrumentation, Engineering Services, Life Sciences and General. At the end of each chapter, a list of publications by the staff scientists in the corresponding subject field is given. The list includes published journal articles and technical reports, and papers presented at conferences, symposia etc. The report also covers the R and D activities of the outstation units of BARC, namely, Nuclear Research Laboratory, Srinagar; High Altitude Research Laboratory, Gulmarg; and Variable Energy Cyclotron Centre, Calcutta. BARC is also engaged in basic an applied research in frontier areas of science such as plasma and fusion physics, accelerators and lasers, high temperature superconductivity, condensed matter physics, high pressure physics, high resolution spectroscopy, chemical reaction dynamics and laser induced chemistry, electronics and robotics: radiation biology, and genetic engineering. Report is illustrated with a number of figures, graphs, and coloured pictures. (M.G.B.) figs., refs

  12. CMS tracker slides into centre stage

    CERN Multimedia

    2006-01-01

    As preparations for the magnet test and cosmic challenge get underway, a prototype tracker has been carefully inserted into the centre of CMS. The tracker, in its special platform, is slowly inserted into the centre of CMS. The CMS prototype tracker to be used for the magnet test and cosmic challenge coming up this summer has the same dimensions -2.5 m in diameter and 6 m in length- as the real one and tooling exactly like it. However, the support tube is only about 1% equipped, with 2 m2 of silicon detectors installed out of the total 200 m2. This is already more than any LEP experiment ever used and indicates the great care needed to be taken by engineers and technicians as these fragile detectors were installed and transported to Point 5. Sixteen thousand silicon detectors with a total of about 10 million strips will make up the full tracker. So far, 140 modules with about 100 000 strips have been implanted into the prototype tracker. These silicon strips will provide precision tracking for cosmic muon...

  13. Pharmacist involvement in a diabetic education centre.

    Science.gov (United States)

    Kanitz, J; Birken, B; Ward, V

    1982-01-01

    During the past two years, a multi-discipline health team has been meeting with selected diabetic "problem" patients on a regular basis at the North York General Hospital (NYGH). The patients are referred to the programme by their physicians when they appear to be having difficulty handling or coping with their diabetes. The participants in the programme attend the Diabetic Education Centre (DEC) for one week as day patients in the hospital and are exposed to various types of counselling from members of the Diabetic Education Centre Team (DECT), one of which is the pharmacist. Follow-up from this week of intensive education is made at annual intervals. The main purpose of the pharmacist in the clinic is to provide information for the patients regarding their prescriptions and over the counter (OTC) medication. This is achieved by means of individual patient interviews and informal group discussions, as well as rounds with other team members and contact with patients' families. This programme provides a forum for the patient and the patient's family to obtain valid information about diabetes, as well as problems associated with the disease, and aids in coping with these problems. The team concept enables the patient to be analyzed by all disciplines in order to assess his teaching needs and fulfill them. The pharmacist is continually involved in this information system and plays a valuable role on the team. PMID:10257341

  14. WISB: Warwick Integrative Synthetic Biology Centre.

    Science.gov (United States)

    McCarthy, John

    2016-06-15

    Synthetic biology promises to create high-impact solutions to challenges in the areas of biotechnology, human/animal health, the environment, energy, materials and food security. Equally, synthetic biologists create tools and strategies that have the potential to help us answer important fundamental questions in biology. Warwick Integrative Synthetic Biology (WISB) pursues both of these mutually complementary 'build to apply' and 'build to understand' approaches. This is reflected in our research structure, in which a core theme on predictive biosystems engineering develops underpinning understanding as well as next-generation experimental/theoretical tools, and these are then incorporated into three applied themes in which we engineer biosynthetic pathways, microbial communities and microbial effector systems in plants. WISB takes a comprehensive approach to training, education and outreach. For example, WISB is a partner in the EPSRC/BBSRC-funded U.K. Doctoral Training Centre in synthetic biology, we have developed a new undergraduate module in the subject, and we have established five WISB Research Career Development Fellowships to support young group leaders. Research in Ethical, Legal and Societal Aspects (ELSA) of synthetic biology is embedded in our centre activities. WISB has been highly proactive in building an international research and training network that includes partners in Barcelona, Boston, Copenhagen, Madrid, Marburg, São Paulo, Tartu and Valencia.

  15. WISB: Warwick Integrative Synthetic Biology Centre.

    Science.gov (United States)

    McCarthy, John

    2016-06-15

    Synthetic biology promises to create high-impact solutions to challenges in the areas of biotechnology, human/animal health, the environment, energy, materials and food security. Equally, synthetic biologists create tools and strategies that have the potential to help us answer important fundamental questions in biology. Warwick Integrative Synthetic Biology (WISB) pursues both of these mutually complementary 'build to apply' and 'build to understand' approaches. This is reflected in our research structure, in which a core theme on predictive biosystems engineering develops underpinning understanding as well as next-generation experimental/theoretical tools, and these are then incorporated into three applied themes in which we engineer biosynthetic pathways, microbial communities and microbial effector systems in plants. WISB takes a comprehensive approach to training, education and outreach. For example, WISB is a partner in the EPSRC/BBSRC-funded U.K. Doctoral Training Centre in synthetic biology, we have developed a new undergraduate module in the subject, and we have established five WISB Research Career Development Fellowships to support young group leaders. Research in Ethical, Legal and Societal Aspects (ELSA) of synthetic biology is embedded in our centre activities. WISB has been highly proactive in building an international research and training network that includes partners in Barcelona, Boston, Copenhagen, Madrid, Marburg, São Paulo, Tartu and Valencia. PMID:27284024

  16. Inhomogeneous charging and screening effects in semiconductor quantum dot arrays

    Energy Technology Data Exchange (ETDEWEB)

    Wetzler, R [Institut fuer Theoretische Physik, Technische Universitaet Berlin, Hardenbergstr. 36, 10623 Berlin (Germany); Kunert, R [Institut fuer Theoretische Physik, Technische Universitaet Berlin, Hardenbergstr. 36, 10623 Berlin (Germany); Wacker, A [Fysiska Institutionen, Lunds Universitet, Box 118, 22100 Lund (Sweden); Schoell, E [Institut fuer Theoretische Physik, Technische Universitaet Berlin, Hardenbergstr. 36, 10623 Berlin (Germany)

    2004-07-01

    The electronic properties of quantum dot (QD) arrays are strongly influenced by the Coulomb interaction of electrons within the dot as well as with those in neighbouring dots. In this paper, we investigate this behaviour taking into account screening by a free electron gas in the vicinity of the QDs. We find pronounced effects for standard capacitance[ndash]voltage (CV) measurements of QD structures embedded in a pn-diode. In particular, we show that the three-dimensional nature of the problem is crucial for devices with low dot-density, whereas the self-consistency between electron depletion in the bulk layer and dot occupation is important for high dot-densities. The Coulomb interaction between the dots induces a broadening of the peaks in the CV characteristic which is comparable with the effect of disordered QD arrays, where we considered realistic size and position fluctuations obtained by a kinetic Monte Carlo simulation.

  17. Quantum dot-sized organic fluorescent dots for long-term cell tracing

    Science.gov (United States)

    Li, Kai; Tang, Ben Zhong; Liu, Bin

    2014-03-01

    Fluorescence techniques have been extensively employed to develop non-invasive methodologies for tracking and understanding complex biological processes both in vitro and in vivo, which is of high importance in modern life science research. Among a variety of fluorescent probes, inorganic semiconductor quantum dots (QDs) have shown advantages in terms of better photostability, larger Stokes shift and more feasible surface functionalization. However, their intrinsic toxic heavy metal components and unstable fluorescence at low pH greatly impede the applications of QDs in in vivo studies. In this work, we developed novel fluorescent probes that can outperform currently available QD based probes in practice. Using conjugated oligomer with aggregation-induced emission characteristics as the fluorescent domain and biocompatible lipid-PEG derivatives as the encapsulation matrix, the obtained organic dots have shown higher brightness, better stability in biological medium and comparable size and photostability as compared to their counterparts of inorganic QDs. More importantly, unlike QD-based probes, the organic fluorescent dots do not blink, and also do not contain heavy metal ions that could be potentially toxic when applied for living biosubstrates. Upon surface functionalization with a cell-penetrating peptide, the organic dots greatly outperform inorganic quantum dots in both in vitro and in vivo long-term cell tracing studies, which will be beneficial to answer crucial questions in stem cell/immune cell therapies. Considering the customized fluorescent properties and surface functionalities of the organic dots, a series of biocompatible organic dots will be developed to serve as a promising platform for multifarious bioimaging tasks in future.

  18. Children's Centre "3 in 1 - together"

    Science.gov (United States)

    Gancheva, Hristina

    2013-04-01

    "There are only two ways to life your live. One is as though nothing is a miracle. The other is as though everything is a miracle." Albert Einstein Children's Centre "3 in 1" is an extracurricular unit linked to the High School of Zlatartitsa, St. Cyril and St. Methodius, accomplished with the help of the municipality and many volunteers from the local community. With its activity it forms in children patriotic spirit, love for nature, active citizenship, and an impulse for a healthy life through communication with nature, saving the traditions and history, insurance of equality of the kids of the local five ethnicities and participation in activities in the sphere of science, art, sport and tourism. The educational work is mainly directed towards kids with difficulties with communication, hyperactivity, aggression, problems in their families, or those deprived of parental care. For a few years in the Children's Centre there have been clubs of interests: "Gardeners" - kids cultivate a garden. They plow, dig, plant, put in, irrigate and weed under the watch of Ms Stafka Nikolova, parents, and volunteers of the local community. The ecologically clean products - vegetables and fruits, kids use to cook delicious meals, sell, or give away. Weeds are also utilized; they are making herbarium out of them. "Cooks" - "What to have for lunch, when mom is out?". One can learn a lot of wonderful recipes from the club "Cooks". Products are own made, raised with love. In 2010, on the on the annual traditional holiday of the garden soup in Zlataritsa, the little cooks won third prize for making a delicious vegetable soup. On the same day, the 26 years old Nadezhda Savova, Cultural and Social Anthropology PhD in Princeton, founded the second community bakery in Bulgaria in Children's Centre "3 in1". Nadezhda Savova was declared traveler of 2012 by National Geographic. After the baking house in Gabrovo and Zlataritsa, Nadezhda also founded such projects in Sofia, Varna and Ruse

  19. Project for a renewable energy research centre

    Directory of Open Access Journals (Sweden)

    Andrea Giachetta

    2011-04-01

    Full Text Available In Liguria, where sustainable approaches to the design, construction and management of buildings enjoy scant currency, the idea of a company from Milan (FERA s.r.l. setting up a research centre for studies into renewable energy resources, could well open up very interesting development opportunities.The project includes: environmental rehabilitation (restoration projects; strategies for the protection of water resources and waste management systems; passive and active solar systems (solar thermal and experiments with thermodynamic solar energy; hyperinsulation systems, passive cooling of buildings; use of natural materials; bio-climatic use of vegetation. The author describes the project content within the context of the multidisciplinary work that has gone into it.

  20. Annual report 1992 - Austrian Research Centre Seibersdorf

    International Nuclear Information System (INIS)

    This is a non-technical progress report (in English) of the activities of the Research Centre Seibersdorf in the fields of energy and safety, materials research, isotope and radiation techniques, environment protection, health and food and industrial consulting. Within other non nuclear related highlights the newly built radio-pharmaceutical laboratory is described, which will guarantee the reliable supply of products and develop new diagnostic and therapeutic preparations. A newly developed whole-body counter for measuring internal radiation is in use in the Vienna General Hospital to obtain better information of the patient's metabolism and can thus assess the efficiency of pharmaceuticals. The research in the field of toxicology and carcinogenicity was intensified. Geological dating was performed for the 'Continental Deep-Drilling Programme' on behalf of the Max Planck Institute. Environmental data acquisition was mainly conducted in the field of ozone, water quality, air pollution and electro-smog (quittner, rieger)

  1. Stimulated emission from NV centres in diamond

    CERN Document Server

    Jeske, Jan; McGuinness, Liam P; Reineck, Philip; Johnson, Brett C; McCallum, Jeffrey C; Jelezko, Fedor; Volz, Thomas; Cole, Jared H; Gibson, Brant C; Greentree, Andrew D

    2016-01-01

    Stimulated emission is the process fundamental to laser operation, thereby producing coherent photon output. Despite negatively-charged nitrogen-vacancy (NV$^-$) centres being discussed as a potential laser medium since the 1980's, there have been no definitive observations of stimulated emission from ensembles of NV$^-$ to date. Reasons for this lack of demonstration include the short excited state lifetime and the occurrence of photo-ionisation to the neutral charge state by light around the zero-phonon line. Here we show both theoretical and experimental evidence for stimulated emission from NV$^-$ states using light in the phonon-sidebands. Our system uses a continuous wave pump laser at 532 nm and a pulsed stimulating laser that is swept across the phononic sidebands of the NV$^-$. Optimal stimulated emission is demonstrated in the vicinity of the three-phonon line at 700 nm. Furthermore, we show the transition from stimulated emission to photoionisation as the stimulating laser wavelength is reduced fro...

  2. MATERNAL MORTALITY IN A TERTIARY CARE CENTRE

    Directory of Open Access Journals (Sweden)

    Harpreet

    2013-06-01

    Full Text Available ABSTRACT: Maternal Mortality in A Tertiary Care Centre. OBJECTIVE: To study maternal mortality and the complications leading to maternal death. METHODS: A retrospective study of hospital record to study maternal mortality and its causes over 3 years from January 2010 to December 2012. RESULTS: There were a total of 58 maternal deaths out of 2823 live births giving a maternal mortality ratio of 2054.55 per one lakh live births. Unbooked and late referrals account for 77.58% of maternal deaths. The majority of deaths around 75.86% were in 20-30 years age group. Haemorrhage was the commonest causes of death (24.12% followed by sepsis (18.96% and pregnancy induced hypertension 15.51% Anemia contributed to the most common indirect cause of maternal morality. CONCLUSION: Haemorrhage, sepsis and pregnancy induced hypertension including eclampsia were the direct major causes of death. Anaemia and cardiac diseases were other indirect causes of death.

  3. Data communication at the CERN computer centre

    CERN Document Server

    Bruins, T; Pieters, R; Slettenhaar, Hendrik J; Van de Kerk, P

    1972-01-01

    The growing interest for on-line computer service and process control at CERN decentralises certain computer activities. Small process computers, remote batch stations and user terminals are to be backed by a powerful central computer. The present data network is principally star shaped. At the centre of it is a CDC 6600-6500 computer combination. It has a front end CDC 3100 computer with a Hewlett Packard 2116 as multiplexer. Some details about the fast parallel connections between the CDC 3100 and the HP 2116B are given in the paper, as well as descriptions of some computer simulation techniques used to test the present systems. Finally some plans on a future network are given. (12 refs).

  4. Surviving stroke in an Ebola Treatment Centre.

    Science.gov (United States)

    Dhillon, Paul; McCarthy, Sinead; Gibbs, Michael

    2015-01-01

    A middle aged woman presented to an Ebola Treatment Centre in West Africa with a 4-day history of fever, fatigue, joint pain and vomiting. She tested positive for Ebola virus disease (EVD) and a standard treatment platform of care was started. On day 3 of her admission, she was found to have suffered a left-sided CVA of unknown aetiology. Treatment was largely supportive within a resource-constrained environment and the added layer of providing care with extensive personal protective equipment, and human resource and safety constraints. The patient was able to clear the EVD and did regain some functional use of her arm and leg. She was discharged on day 15 of her stay, as a survivor of both stroke and Ebola. PMID:26516244

  5. Bhabha Atomic Research Centre : annual report 1990

    International Nuclear Information System (INIS)

    Research and development (R and D) activities of the Bhabha Atomic Research Centre (BARC) carried out during 1990 are reported. The main thrust of the R and D activities of BARC is on : (1)providing support to the nuclear power programme, (2)designing, building and utilising research reactors, (3)working in related frontline technologies, and also (4)basic research in frontier areas of science. These activities are described in brief under the chapters entitled : (1)Physical Sciences (2)Chemical Sciences (3)Materials and Material Science (4)Radioisotopes (5)Reactions (6)Fuel Cycle (7)Radiological Safety and Protection (8)Electronics and Instrumentation (9)Engineering Services (10)Life Sciences and (11)General. At the end of each chapter a list of papers and reports published in the subject field indicated by the title of the chapter is given. (N.B.). figs., tabs

  6. Beef quality assessed at European research centres.

    Science.gov (United States)

    Dransfield, E; Nute, G R; Roberts, T A; Boccard, R; Touraille, C; Buchter, L; Casteels, M; Cosentino, E; Hood, D E; Joseph, R L; Schon, I; Paardekooper, E J

    1984-01-01

    Loin steaks and cubes of M. semimembranosus from eight (12 month old) Galloway steers and eight (16-18 month old) Charolais cross steers raised in England and from which the meat was conditioned for 2 or 10 days, were assessed in research centres in Belgium, Denmark, England, France, the Federal Republic of Germany, Ireland, Italy and the Netherlands. Laboratory panels assessed meat by grilling the steaks and cooking the cubes in casseroles according to local custom using scales developed locally and by scales used frequently at other research centres. The meat was mostly of good quality but with sufficient variation to obtain meaningful comparisons. Tenderness and juiciness were assessed most, and flavour least, consistently. Over the 32 meats, acceptability of steaks and casseroles was in general compounded from tenderness, juiciness and flavour. However, when the meat was tough, it dominated the overall judgement; but when tender, flavour played an important rôle. Irish and English panels tended to weight more on flavour and Italian panels on tenderness and juiciness. Juciness and tenderness were well correlated among all panels except in Italy and Germany. With flavour, however, Belgian, Irish, German and Dutch panels ranked the meats similarly and formed a group distinct from the others which did not. The panels showed a similar grouping for judgements of acceptability. French and Belgian panels judged the steaks from the older Charolais cross steers to have more flavour and be more juicy than average and tended to prefer them. Casseroles from younger steers were invariably preferred although the French and Belgian panels judged aged meat from older animals equally acceptable. These regional biases were thought to be derived mainly from differences in cooking, but variations in experience and perception of assessors also contributed. PMID:22055992

  7. Hadron production in nuclear collisions from the NA49 experiment at 158GeV/c centre dot A

    CERN Document Server

    Siklér, F; Barna, D; Barnby, L S; Bartke, Jerzy; Barton, R A; Betev, L; Bialkowska, H; Billmeier, A; Blume, C; Blyth, C O; Boimska, B; Bracinik, J; Brady, F P; Brun, R; Buncic, P; Carr, L; Cebra, D; Cooper, G E; Cramer, J G; Csató, P; Eckardt, V; Eckhardt, F; Ferenc, D; Fischer, H G; Fodor, Z; Foka, P; Freund, P; Friese, V; Ftácnik, J; Gál, J; Ganz, R E; Gazdzicki, M; Gladysz-Dziadus, E; Grebieszkow, J; Harris, J W; Hegyi, S; Hlinka, V; Höhne, C; Igo, G; Ivanov, M; Jacobs, P; Janik, R; Jones, P G; Kadija, K; Kolesnikov, V I; Kowalski, M; Lasiuk, B; Lednicky, R; Lévai, Peter; Malakhov, A I; Margetis, S; Markert, C; Mayes, B W; Melkumov, G L; Molnár, J; Nelson, J M; Odyniec, Grazyna Janina; Oldenburg, M; Pálla, G; Panagiotou, A D; Petridis, A; Pikna, M; Pinsky, L; Poskanzer, A M; Prindle, D J; Pühlhofer, F; Reid, J G; Renfordt, R E; Retyk, W; Ritter, H G; Röhrich, D; Roland, C; Roland, G; Rybicki, A; Sammer, T; Sandoval, A; Sann, H; Semenov, A Yu; Schäfer, E; Schmitz, N; Seyboth, P; Sitár, B; Skrzypczak, E; Snellings, R; Squier, G T A; Stock, R; Strmen, P; Ströbele, H; Susa, T; Szarka, I; Szentpétery, I; Sziklai, J; Toy, M; Trainor, T A; Trentalange, S; Ullrich, T; Varga, D; Vassiliou, Maria; Veres, G I; Vesztergombi, G; Voloshin, S A; Vranic, D; Wang, F; Weerasundara, D D; Wenig, S; Whitten, C; Xu, N; Yates, T A; Yoo, I K; Zimányi, J

    1999-01-01

    With its large acceptance and particle identification coverage the NA49 experiment (Fig. 1) can study hadron production in a wide range of high energy reactions [1]. Originally aimed at examining central Pb+Pb collisions for signatures of quark-gluon plasma formation, the scope of the experiment has been enhanced with a systematic study of impact parameter and projectile size dependence, as well as the inclusion of the more elementary p+p and p+A interactions. The question is: are predicted signals of the quark-gluon plasma observed and are there discontinuities which would support the concept of hadronic phase transition?

  8. Collaborating at a distance: operations centres, tools, and trends

    Energy Technology Data Exchange (ETDEWEB)

    Gottschalk, Erik E.; /Fermilab

    2009-05-01

    Successful operation of the LHC and its experiments is crucial to the future of the worldwide high-energy physics program. Remote operations and monitoring centres have been established for the CMS experiment in several locations around the world. The development of remote centres began with the LHC{at}FNAL ROC and has evolved into a unified approach with distributed centres that are collectively referred to as 'CMS Centres Worldwide'. An overview of the development of remote centres for CMS will be presented, along with a synopsis of collaborative tools that are used in these centres today and trends in the development of remote operations capabilities for high-energy physics.

  9. International Centre for Theoretical Physics, Trieste Scientific activities in 1991

    International Nuclear Information System (INIS)

    The document contains three parts. Part 1 is a general review of the scientific activities of the Centre in 1991, including a statistical digest. Part II presents the scientific programme of the Centre in the following fields: Fundamental Physics, Condensed Matter Physics, Mathematics, Physics and Energy, Physics and Environment, Applied Physics, Adriatico Research Conferences, as well as other aspects of the Centre activities in 1991. Part III lists the publications issued in 1991. Tabs

  10. Routing algorithms for recursively-defined data centre networks.

    OpenAIRE

    Erickson, A.; Kiasari, A.; Navaridas, J.; Stewart, I.A.

    2015-01-01

    The server-centric data centre network architecture can accommodate a wide variety of network topologies. Newly proposed topologies in this arena often require several rounds of analysis and experimentation in order that they might achieve their full potential as data centre networks. We propose a family of novel routing algorithms on two well-known data centre networks of this type, (Generalized) DCell and FiConn, using techniques that can be applied more generally to the class of networks w...

  11. Complex Modelling Scheme Of An Additive Manufacturing Centre

    Science.gov (United States)

    Popescu, Liliana Georgeta

    2015-09-01

    This paper presents a modelling scheme sustaining the development of an additive manufacturing research centre model and its processes. This modelling is performed using IDEF0, the resulting model process representing the basic processes required in developing such a centre in any university. While the activities presented in this study are those recommended in general, changes may occur in specific existing situations in a research centre.

  12. International Centre for Theoretical Physics, Trieste. Scientific activities in 1990

    International Nuclear Information System (INIS)

    The document contains three parts: Part I is a general review of the scientific activities of the Centre in 1990, including a statistical digest. Part II describes the scientific programme of the Centre in the following fields: Fundamental physics, condensed nuclear physics, mathematics, physics and energy, physics and environment, physics of the living state, applied physics Adriatico research conferences and other aspects of the Centre activities. Part III lists the publications issued in 1990

  13. Bright infrared quantum-dot light-emitting diodes through inter-dot spacing control

    KAUST Repository

    Sun, Liangfeng

    2012-05-06

    Infrared light-emitting diodes are currently fabricated from direct-gap semiconductors using epitaxy, which makes them expensive and difficult to integrate with other materials. Light-emitting diodes based on colloidal semiconductor quantum dots, on the other hand, can be solution-processed at low cost, and can be directly integrated with silicon. However, so far, exciton dissociation and recombination have not been well controlled in these devices, and this has limited their performance. Here, by tuning the distance between adjacent PbS quantum dots, we fabricate thin-film quantum-dot light-emitting diodes that operate at infrared wavelengths with radiances (6.4 W sr \\'1 m \\'2) eight times higher and external quantum efficiencies (2.0%) two times higher than the highest values previously reported. The distance between adjacent dots is tuned over a range of 1.3 nm by varying the lengths of the linker molecules from three to eight CH 2 groups, which allows us to achieve the optimum balance between charge injection and radiative exciton recombination. The electroluminescent powers of the best devices are comparable to those produced by commercial InGaAsP light-emitting diodes. By varying the size of the quantum dots, we can tune the emission wavelengths between 800 and 1,850 nm.© 2012 Macmillan Publishers Limited.

  14. Interference effects in a double quantum dot system with inter-dot Coulomb correlations

    International Nuclear Information System (INIS)

    Electron transport through a double quantum dot system is studied with the use of the Green function formalism based on the equation of motion method, and an interplay between interference and Coulomb blockade effects due to inter-dot correlations is discussed. A double structure with two Fano resonances (or antiresonances) is found in the conductance spectrum. Fano features are weakly influenced by the presence of Coulomb interaction but the conductance is strongly suppressed in the energy region with the Fermi level in the leads close to the aligned levels of both dots. This Coulomb blockade effect takes place when the coupling between the dots is of repulsive character. On the other hand, the conductance of an artificial molecule with attractive inter-dot coupling is only slightly modified in this energy region. As a sign of the coupling can be easily changed in a presence of an external magnetic field by changes of the magnetic flux there is the possibility to control variations of the conductance, which may be important from the application point of view

  15. Ordinance on the Finnish Centre of Radiation and Nuclear Safety

    International Nuclear Information System (INIS)

    This Ordinance was adopted in implementation of the 1983 Act setting up the Finnish Centre for Radiation and Nuclear Safety and the 1987 Nuclear Energy Act and entered into force on 1 November 1990. The Ordinance specifies the tasks of the Centre, as provided under both Acts, and gives it several supplementary responsibilities. In addition to its overall competence in respect of radiation safety, the Centre will carry out research into and supervise the health effects of radiation and maintain a laboratory for national measurements in that field. The Ordinance also sets out the Centre's organisation chart and the staff duties

  16. Crystalline roof glazing - Westside shopping centre, Berne; Kristalline Dachverglasungen

    Energy Technology Data Exchange (ETDEWEB)

    Enkerli, W.

    2009-07-01

    This illustrated article takes a look at the new shopping and leisure centre on the western outskirts of Berne, Switzerland. In particular, the roof of this unusual building over the motorway with its sloping walls and zig-zag design is looked at. The centre's shopping mall, adventure baths and spa, a multiplex cinema, an old peoples' home and a hotel are briefly discussed, as is the embedding of the centre in its suburban environment. The roof construction with its crystalline skylights is examined and discussed in detail. The centre's building technical services are also briefly commented on.

  17. Entangling distant quantum dots using classical interference

    Science.gov (United States)

    Busch, Jonathan; Kyoseva, Elica S.; Trupke, Michael; Beige, Almut

    2008-10-01

    We show that it is possible to employ reservoir engineering to turn two distant and relatively bad cavities into one good cavity with a tunable spontaneous decay rate. As a result, quantum computing schemes, which would otherwise require the shuttling of atomic qubits in and out of an optical resonator, can now be applied to distant quantum dots. To illustrate this we transform a recent proposal to entangle two qubits via the observation of macroscopic fluorescence signals [J. Metz , Phys. Rev. Lett. 97, 040503 (2006)] to the electron-spin states of two semiconductor quantum dots. Our scheme requires neither the coherent control of qubit-qubit interactions nor the detection of single photons. Moreover, the scheme is relatively robust against spin-bath couplings, parameter fluctuations, and the spontaneous emission of photons.

  18. Mesoscopic Cavity Quantum Electrodynamics with Quantum Dots

    CERN Document Server

    Childress, L I; Lukin, M D

    2003-01-01

    We describe an electrodynamic mechanism for coherent, quantum mechanical coupling between spacially separated quantum dots on a microchip. The technique is based on capacitive interactions between the electron charge and a superconducting transmission line resonator, and is closely related to atomic cavity quantum electrodynamics. We investigate several potential applications of this technique which have varying degrees of complexity. In particular, we demonstrate that this mechanism allows design and investigation of an on-chip double-dot microscopic maser. Moreover, the interaction may be extended to couple spatially separated electron spin states while only virtually populating fast-decaying superpositions of charge states. This represents an effective, controllable long-range interaction, which may facilitate implementation of quantum information processing with electron spin qubits and potentially allow coupling to other quantum systems such as atomic or superconducting qubits.

  19. Many electron effects in semiconductor quantum dots

    Indian Academy of Sciences (India)

    R K Pandey; Manoj K Harbola; V Ranjan; Vijay A Singh

    2003-01-01

    Semiconductor quantum dots (QDs) exhibit shell structures, very similar to atoms. Termed as ‘artificial atoms’ by some, they are much larger (1 100 nm) than real atoms. One can study a variety of manyelectron effects in them, which are otherwise difficult to observe in a real atom. We have treated these effects within the local density approximation (LDA) and the Harbola–Sahni (HS) scheme. HS is free of the selfinteraction error of the LDA. Our calculations have been performed in a three-dimensional quantum dot. We have carried out a study of the size and shape dependence of the level spacing. Scaling laws for the Hubbard ‘’ are established.

  20. Magnetoconductance fluctuations in open bismuth quantum dots

    Science.gov (United States)

    Hackens, B.; Minet, J. P.; Farhi, G.; Crahay, A.; Faniel, S.; Gustin, C.; Bayot, V.

    2002-03-01

    We investigate the low temperature (300 mK - 10 K) magnetoconductance of open circular bismuth quantum dots (diameter: 500 nm). The structures are fabricated using a combination of electron beam lithography, lift off and plasma etching techniques on bismuth thin films evaporated on heated SiO2 substrates. We observe reproducible magnetoconductance fluctuations (UCFs) up to 5T, qualitatively similar to conductance fluctuations evidenced in open quantum dots patterned in high mobility semiconductor heterostructures. In our samples, UCFs are superposed on a slowly varying negative magnetoconductance background. We also observe a sharp conductance maximum centered in B=0, which is reminescent of the spin-orbit induced anti-localisation phenomenon. The behavior of UCFs and of the conductance maximum is discussed as a function of the temperature, thickness and degree of cristallinity of the cavity.

  1. Barrier Li Quantum Dots in Magnetic Fields

    Institute of Scientific and Technical Information of China (English)

    LIU Yi-Min; LI Xiao-Zhu; YAN Wen-Hong; BAO Cheng-Guang

    2003-01-01

    The methods for the few-body system are introduced to investigate the states of the barrier Li quantumdots (QDs) in an arbitrary strength of magnetic field. The configuration, which consists of a positive ion located on thez-axis at a distance d from the two-dimensional QD plane (the x-y plane) and three electrons in the dot plane boundby the positive ion, is called a barrier Li center. The system, which consists of three electrons in the dot plane bound bythe ion, is called a barrier Li QD. The dependence of energy of the state of the barrier Li QD on an external magneticfield B and the distance d is obtained. The angular momentum L of the ground states is found to jump not only withthe variation of B but also with d.

  2. Protease-activated quantum dot probes

    Science.gov (United States)

    Chang, Emmanuel; Sun, Jiantang; Miller, Jordan S.; Yu, William W.; Colvin, Vicki L.; West, Jennifer L.; Drezek, Rebekah

    2006-04-01

    We demonstrate a novel quantum dot based probe with inherent signal amplification upon interaction with a targeted proteolytic enzyme. This probe may be useful for imaging in cancer detection and diagnosis. In this system, quantum dots (QDs) are bound to gold nanoparticles (AuNPs) via a proteolytically-degradable peptide sequence to non-radiatively suppress luminescence. A 71% reduction in luminescence was achieved with conjugation of AuNPs to QDs. Peptide cleavage results in release of AuNPs and restores radiative QD photoluminescence. Initial studies observed a 52% rise in luminescence over 47 hours of exposure to 0.2 mg/mL collagenase. These probes can be customized for targeted degradation simply by changing the sequence of the peptide linker.

  3. Facile labeling of lipoglycans with quantum dots

    International Nuclear Information System (INIS)

    Bacterial endotoxins or lipopolysaccharides (LPS) are among the most potent activators of the innate immune system, yet mechanisms of their action and in particular the role of glycans remain elusive. Efficient non-invasive labeling strategies are necessary for studying interactions of LPS glycans with biological systems. Here we report a new method for labeling LPS and other lipoglycans with luminescent quantum dots. The labeling is achieved by partitioning of hydrophobic quantum dots into the core of various LPS aggregates without disturbing the native LPS structure. The biofunctionality of the LPS-Qdot conjugates is demonstrated by the labeling of mouse monocytes. This simple method should find broad applicability in studies concerned with visualization of LPS biodistribution and identification of LPS binding agents.

  4. Efficient Luminescence from Perovskite Quantum Dot Solids

    KAUST Repository

    Kim, Younghoon

    2015-11-18

    © 2015 American Chemical Society. Nanocrystals of CsPbX3 perovskites are promising materials for light-emitting optoelectronics because of their colloidal stability, optically tunable bandgap, bright photoluminescence, and excellent photoluminescence quantum yield. Despite their promise, nanocrystal-only films of CsPbX3 perovskites have not yet been fabricated; instead, highly insulating polymers have been relied upon to compensate for nanocrystals\\' unstable surfaces. We develop solution chemistry that enables single-step casting of perovskite nanocrystal films and overcomes problems in both perovskite quantum dot purification and film fabrication. Centrifugally cast films retain bright photoluminescence and achieve dense and homogeneous morphologies. The new materials offer a platform for optoelectronic applications of perovskite quantum dot solids.

  5. Light emission from Si quantum dots

    Directory of Open Access Journals (Sweden)

    Philippe M. Fauchet

    2005-01-01

    Full Text Available Si quantum dots (QDs as small as ∼2 nm in diameter have been synthesized by a variety of techniques. Because of quantum confinement and the elimination of bulk or surface defects, these dots can emit light from the near infrared throughout the visible with quantum efficiencies in excess of 10%. The luminescence wavelength range has been extended to longer wavelengths by the addition of light-emitting rare earths such as erbium (Er. Light-emitting devices (LEDs have been fabricated and their performances are starting to approach those of direct band gap semiconductor or organic LEDs. A search for a Si QD-based laser is even under way. The state-of-the-art in the materials science, physics, and device development of luminescent Si QDs is reviewed and areas of future research are pointed out.

  6. An addressable quantum dot qubit with fault-tolerant control-fidelity.

    Science.gov (United States)

    Veldhorst, M; Hwang, J C C; Yang, C H; Leenstra, A W; de Ronde, B; Dehollain, J P; Muhonen, J T; Hudson, F E; Itoh, K M; Morello, A; Dzurak, A S

    2014-12-01

    Exciting progress towards spin-based quantum computing has recently been made with qubits realized using nitrogen-vacancy centres in diamond and phosphorus atoms in silicon. For example, long coherence times were made possible by the presence of spin-free isotopes of carbon and silicon. However, despite promising single-atom nanotechnologies, there remain substantial challenges in coupling such qubits and addressing them individually. Conversely, lithographically defined quantum dots have an exchange coupling that can be precisely engineered, but strong coupling to noise has severely limited their dephasing times and control fidelities. Here, we combine the best aspects of both spin qubit schemes and demonstrate a gate-addressable quantum dot qubit in isotopically engineered silicon with a control fidelity of 99.6%, obtained via Clifford-based randomized benchmarking and consistent with that required for fault-tolerant quantum computing. This qubit has dephasing time T2* = 120 μs and coherence time T2 = 28 ms, both orders of magnitude larger than in other types of semiconductor qubit. By gate-voltage-tuning the electron g*-factor we can Stark shift the electron spin resonance frequency by more than 3,000 times the 2.4 kHz electron spin resonance linewidth, providing a direct route to large-scale arrays of addressable high-fidelity qubits that are compatible with existing manufacturing technologies. PMID:25305743

  7. Status of Growth Monitoring in Anganwadi Centres of a Primary Health Centre, Thirubhuvanai, Puducherry

    Directory of Open Access Journals (Sweden)

    Gurukartick J

    2013-08-01

    Full Text Available Purpose: To assess the status of growth monitoring activities and difficulties faced by anganwadi workers (AWWs at the anganwadi centres (AWCs. Methodology: A survey was conducted among AWWs under a rural Primary Health Centre. Structured observations on weight measurement were made using a check list. Secondary data on record keeping and maintenance was collected. Findings: Study participants (n=20 had a 24 (± 10.25 years of experience in Integrated Child Development Services and underwent training once in two years. For advising mothers of malnourished children, deworming and immunization was not mentioned by majority AWWs. In AWCs, children less than 6 month were weighed on bathroom scale and not by Salter’s scale. Unclothing the child before weighing was practiced by only 10% AWWs. Nonfunctional weighing machine was the major problem reported by AWWs. Conclusion: There were gaps in the growth monitoring activities in AWCs of a PHC, Thirubhuvanai which needs to be tackled.

  8. The role of the Czechoslovak Nuclear Information Centre as a reference centre

    International Nuclear Information System (INIS)

    The Nuclear Information Centre (NIC) is the sector information centre for the Czechoslovak nuclear programme which comprises the peaceful uses of nuclear energy, ionizing radiation and isotopes. Briefly characterized are the different types of services provided which include search processing, librarian services, study analytical work, publishing activity, the sector inventory of research reports, searches, trip reports and translations and of late the provision of factual data. In this respect this includes the following systems: Economics of Nuclear Power Plants, and Nuclear Power Plant Indicators. The NIC also processes computer-based analyses of selected topics from a document retrieval base. For these analyses the use of the COMMODORE personal computer and foreign firm software is being envisaged. In the first stage the analyses will be made from the INIS data base. (Z.M.)

  9. Ratiometric Temperature Sensing with Semiconducting Polymer Dots

    OpenAIRE

    Ye, Fangmao; Wu, Changfeng; Jin, Yuhui; Chan, Yang-Hsiang; Zhang, Xuanjun; Chiu, Daniel T.

    2011-01-01

    This communication describes ultra-bright single-nanoparticle ratiometric temperature sensors based on semiconducting polymer dots (Pdots). We attached the temperature sensitive dye—Rhodamine B (RhB), whose emission intensity decreases with increasing temperature—within the matrix of Pdots. The as-prepared Pdot-RhB nanoparticle showed excellent temperature sensitivity and high brightness because it took advantage of the light harvesting and amplified energy transfer capability of Pdots. More ...

  10. The Silicon:Colloidal Quantum Dot Heterojunction

    KAUST Repository

    Masala, Silvia

    2015-10-13

    A heterojunction between crystalline silicon and colloidal quantum dots (CQDs) is realized. A special interface modification is developed to overcome an inherent energetic band mismatch between the two semiconductors, and realize the efficient collection of infrared photocarriers generated in the CQD film. This junction is used to produce a sensitive near infrared photodetector. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Adiabatic description of nonspherical quantum dot models

    Energy Technology Data Exchange (ETDEWEB)

    Gusev, A. A., E-mail: gooseff@jinr.ru; Chuluunbaatar, O.; Vinitsky, S. I. [Joint Institute for Nuclear Research (Russian Federation); Dvoyan, K. G.; Kazaryan, E. M.; Sarkisyan, H. A. [Russian-Armenian (Slavonic) University (Armenia); Derbov, V. L.; Klombotskaya, A. S.; Serov, V. V. [Saratov State University (Russian Federation)

    2012-10-15

    Within the effective mass approximation an adiabatic description of spheroidal and dumbbell quantum dot models in the regime of strong dimensional quantization is presented using the expansion of the wave function in appropriate sets of single-parameter basis functions. The comparison is given and the peculiarities are considered for spectral and optical characteristics of the models with axially symmetric confining potentials depending on their geometric size, making use of the complete sets of exact and adiabatic quantum numbers in appropriate analytic approximations.

  12. Shot noise of coupled semiconductor quantum dots

    OpenAIRE

    Kiesslich, G.; Wacker, A; Schoell, E.

    2003-01-01

    The low-frequency shot noise properties of two electrostatically coupled semiconductor quantum dot states which are connected to emitter/collector contacts are studied. A master equation approach is used to analyze the bias voltage dependence of the Fano factor as a measure of temporal correlations in tunneling current caused by Pauli's exclusion principle and the Coulomb interaction. In particular, the influence of the Coulomb interaction on the shot noise behavior is discussed in detail and...

  13. SPECTRAL PROPERTIES OF SHUNGITE QUANTUM DOTS

    OpenAIRE

    RAZBIRIN B.S.; ROZHKOVA N.N.; Sheka, E. F.; Nelson, D. K.; Starukhin, A. N.; Goryunov, A. S.

    2014-01-01

    A low-temperature study has been performed for aqueous shungite, carbon tetrachloride, and toluene dispersions. Spectral characteristics for graphene quantum dots (GQDs) of shungite, attributed to individual fragments of reduced graphene oxide (rGO), reveal a dual character of the dispersions emitting centers: individual GQDs are responsible for the spectra position while fractal structure of GQD colloids provides large broadening of the spectra due to structural inhomogeneity of the colloida...

  14. Semiconductor Quantum Dots for Biomedicial Applications

    OpenAIRE

    Lijia Shao; Feng Yan; Yanfang Gao

    2011-01-01

    Semiconductor quantum dots (QDs) are nanometre-scale crystals, which have unique photophysical properties, such as size-dependent optical properties, high fluorescence quantum yields, and excellent stability against photobleaching. These properties enable QDs as the promising optical labels for the biological applications, such as multiplexed analysis of immunocomplexes or DNA hybridization processes, cell sorting and tracing, in vivo imaging and diagnostics in biomedicine. Meanwhile, QDs can...

  15. Quantum dots: synthesis, bioapplications, and toxicity

    OpenAIRE

    Valizadeh, Alireza; Mikaeili, Haleh; Samiei, Mohammad; Farkhani, Samad Mussa; Zarghami, Nosratalah; Kouhi, Mohammad; Akbarzadeh, Abolfazl; Davaran, Soodabeh

    2012-01-01

    This review introduces quantum dots (QDs) and explores their properties, synthesis, applications, delivery systems in biology, and their toxicity. QDs are one of the first nanotechnologies to be integrated with the biological sciences and are widely anticipated to eventually find application in a number of commercial consumer and clinical products. They exhibit unique luminescence characteristics and electronic properties such as wide and continuous absorption spectra, narrow emission spectra...

  16. The pinning effect in quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Monisha, P. J., E-mail: pjmonisha@gmail.com [School of Physics, University of Hyderabad, Hyderabad-500046 (India); Mukhopadhyay, Soma [Department of Physics, D V R College of Engineering and Technology, Hyderabad-502285 (India)

    2014-04-24

    The pinning effect is studied in a Gaussian quantum dot using the improved Wigner-Brillouin perturbation theory (IWBPT) in the presence of electron-phonon interaction. The electron ground state plus one phonon state is degenerate with the electron in the first excited state. The electron-phonon interaction lifts the degeneracy and the first excited states get pinned to the ground state plus one phonon state as we increase the confinement frequency.

  17. Depleted Bulk Heterojunction Colloidal Quantum Dot Photovoltaics

    KAUST Repository

    Barkhouse, D. Aaron R.

    2011-05-26

    The first solution-processed depleted bulk heterojunction colloidal quantum dot solar cells are presented. The architecture allows for high absorption with full depletion, thereby breaking the photon absorption/carrier extraction compromise inherent in planar devices. A record power conversion of 5.5% under simulated AM 1.5 illumination conditions is reported. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Magnetic field and position effects on the absorption coefficient of a shallow donor in CdSe quantum dot

    International Nuclear Information System (INIS)

    The influence of impurity position, magnetic field and size on the donor binding energy and absorption coefficient associated with transitions between the electron bound to a donor and the first conduction subband have been studied for CdSe quantum dots with infinite potential confinement. We have used a variational procedure within the effective mass approximation. We present results for the absorption coefficient as a function of the photon energy for several field strengths and arbitrary impurity positions. It is found that for all sizes of the dot the absorption peak associated with an on-centre donor impurity is negligible and the most significant contribution comes from a donor located near the edge. The threshold absorption peak is strongly shifted toward high energies when the donor moves from the edge to the center accompanied with an important diminution of the intensity. While for large dot the threshold absorption peak is approximately insensitive to the donor position, we have also found that the application of magnetic field shifts the threshold absorption peak toward high energy and reduces the intensity of absorption coefficient. (author)

  19. The quantum dot nanoconjugate tool box (Invited Paper)

    Science.gov (United States)

    Tomlinson, I. D.; Wright, D. W.; Giorgio, T. D.; Blakely, R. D.; Pennycook, S. J.; Hercules, D.; Bentzen, L.; Smith, R. A.; McBride, J.; Vergne, M. J.; Rosenthal, S.

    2005-04-01

    The surface coating of quantum dots has been characterised using Z-stem. Quantum dots have been pegylated to increase stability in aqueous solution. The fluorescence intensity of the quantum dots was modulated pegylation. PEG was coupled using different ratios of EDC, PEG and NHS. Optimum coupling conditions were found to occur when 2000 equivalents of PEG were reacted with 1 equivalent of dot in the presence of 1500 equivalents of NHS and EDC. Angiotensin II was also conjugated to quantum dots and these conjugates were shown to be biologically active. Quantum dots have also been surface functionalised with other peptides such as NGR with subsequent demonstration of cell surface binding and can be characterized by flow cytometry.

  20. Templated self-assembly of SiGe quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Dais, Christian

    2009-08-19

    This PhD thesis reports on the fabrication and characterization of exact aligned SiGe quantum dot structures. In general, SiGe quantum dots which nucleate via the Stranski-Krastanov growth mode exhibit broad size dispersion and nucleate randomly on the surface. However, to tap the full potential of SiGe quantum dots it is necessary to control the positioning and size of the dots on a nanometer length, e.g. for electronically addressing of individual dots. This can be realized by so-called templated self-assembly, which combines top-down lithography with bottom-up selfassembly. In this process the lithographically defined pits serve as pre-defined nucleation points for the epitaxially grown quantum dots. In this thesis, extreme ultraviolet interference lithography at a wavelength of e=13.4 nm is employed for prepatterning of the Si substrates. This technique allows the precise and fast fabrication of high-resolution templates with a high degree of reproducibility. The subsequent epitaxial deposition is either performed by molecular beam epitaxy or low-pressure chemical vapour deposition. It is shown that the dot nucleation on pre-patterned substrates depends strongly on the lithography parameters, e.g. size and periodicity of the pits, as well as on the epitaxy parameters, e.g. growth temperature or material coverage. The interrelations are carefully analyzed by means of scanning force microscopy, transmission electron microscopy and X-ray diffraction measurements. Provided that correct template and overgrowth parameters are chosen, perfectly aligned and uniform SiGe quantum dot arrays of different period, size as well as symmetry are created. In particular, the quantum dot arrays with the so far smallest period (35 nm) and smallest size dispersion are fabricated in this thesis. Furthermore, the strain fields of the underlying quantum dots allow the fabrication of vertically aligned quantum dot stacks. Combining lateral and vertical dot alignment results in three