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Sample records for cupric ion concentrations

  1. Measurement of the Cupric Ion Concentration in the Simulation of the Focusing effect

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Je-Young; Hong, Seung-Hyun; Chung, Bum-Jin [Kyung Hee University, Seoul (Korea, Republic of)

    2015-10-15

    The Rayleigh number and aspect ratio (H/R) ranged from 8.49x10{sup 7} to 5.43x10{sup 9} and 0.135 to 0.541 respectively. In order to simulate the different temperature conditions of top and side wall, an electrical resistance was attached to the top wall so that it is mimics hotter wall condition. The heat transfer experiments were replaced by mass transfer experiments based on the heat and mass transfer analogy concept. A sulfuric acid-copper sulfate (H{sub 2}SO{sub 4} - CuSO{sub 4}) electroplating system was adopted as the mass transfer system. The experimental study was performed to investigate the focusing effect according to the different temperature conditions and the height in metallic layer. This work devised a method to simulate the different cooling conditions of the top and side walls and adopted an electrical resistance to the top plate. The electrical resistance was varied for the height of side wall. The experimental results agreed well with the Rayleigh-Benard convection correlations of Dropkin and Somerscales and Globe and Dropkin. The heat transfer was enhanced by increasing the electrical resistance and decreasing the height of side wall. The focusing effect at the side wall was improved by the hotter top wall condition. In order to overcome the limitations of mass transfer, this work tried to measure the cupric ion concentration. The methods of concentration measurement are RGB, Brightness, ICP and PIV. The key of RGB, Brightness and PIV method is the clear images of the thermal boundary layer.

  2. Free cupric ions in contaminated agricultural soils around a copper mine in eastern Nanjing City, China

    Institute of Scientific and Technical Information of China (English)

    LUO Xiao-san; ZHOU Dong-mei; WANG Yu-jun

    2006-01-01

    To determine the environmental free metal ion activity was a recent hot issue. A method to measure low-level free cupric ion activity in soil solution extracted with 0.01 mol/L KNO3 was developed by using cupric ion-selective electrode (ISE) and calibrating with Cu-buffer solution. Three copper buffers including iminodiacetic acid (IDA), ethylenediamine (EN), and glycine (Gly)were compared for calibrating the Cu-ISE curves in the range of free cupric ions (pCu2+) 7-13. The Cu-EN buffer showed the best electrode response and thus was applied as the calibration buffer. The pCu2+ of 39 contaminated agricultural soils around a copper mine was measured, ranging from 5.03 to 9.20. Most Cu in the soil solutions was found to be complexed with dissolved soil organic matters, averaging 98.1%. The proportion of free Cu2+ ions in the soil solutions decreased with the increasing of solution pH. Soluble Cu and free Cu2+ ions concentrations were analyzed by multiple linear regressions to evaluate the effects of soil properties on metal levels and speciation. The results showed that soil solution pH was the most significant factor influencing pCu2+ (with R2 value of 0.76), while not important for the soluble Cu concentration.

  3. Leaching of complex sulphide concentrate in acidic cupric chloride solutions

    Institute of Scientific and Technical Information of China (English)

    M. TCHOUMOU; M. ROYNETTE

    2007-01-01

    The chemical analysis of a complex sulphide concentrate by emission spectrometry and X-ray diffraction shows that it contains essentially copper, lead, zinc and iron in the form of chalcopyrite, sphalerite and galena. A small amount of pyrite is also present in the ore but does not be detected with X-ray diffraction. The cupric chloride leaching of the sulphide concentrate at various durations and solid/liquid ratios at 100 ℃ shows that the rate of dissolution of the ore is the fastest in the first several hours, and after 12 h it does not evolve significantly. If oxygen is excluded from the aqueous cupric chloride solution during the leaching experiment at 100 ℃, the pyrite in the ore will not be leached. The determination of principal dissolved metals in the leaching liquor by flame atomic absorption spectrometry, and the chemical analysis of solid residues by emission spectrometry and X-ray diffraction allow to conclude that the rate of dissolution of the minerals contained in the complex sulphide concentrate are in the order of galena>sphalerite>chalcopyrite.

  4. Cupric ion release and cytotoxicity for Yuangong Cu-IUDs and the release behavior of indomethacin for medicated 220 Cu-IUD

    Institute of Scientific and Technical Information of China (English)

    CAO BianMei; XI TingFei; ZHENG YuDong; YANG LiFeng; ZHENG Qi

    2009-01-01

    These years Yuangong copper-bearing intrauterine devices (Cu-IUDs) have been used because of less side effects in use. The corrosion of copper is essential to the success of contraception,and the release behavior of indomethacin from medicated Cu-IUD is related to its therapeutic effect. In this study,analytical methods were established to investigate the release behavior of cupric ion of three kinds of Yuangong Cu-IUDs and indomethacin of medicated Yuangong 220 Cu-IUD. Cu-IUDs were incubated in simulated uterine solution (SUS). The concentrations of cupric ion and indomethacin were analyzed by flame atomic absorption spectrometer (FAAS) for 60 days and UV/vis-3310 spectrophotometer for 60 days,respectively. The morphology of copper after corrosion was characterized by SEM. In addition,we detected cytotoxicity by MTT of L929 mouse fibroblasts cells caused by extracts of the three Yuangong Cu-IUDs. The release behavior of cupric ion for three kinds of Yuangong Cu-IUDs was biphasic,which consisted of the initial burst release and then slow and constant release. In vitro release experiment confirmed a biphasic release of indomethacin from Yuangong 220. The copper wire of Yuangong Cu-IUDs showed uneven corrosion. The RGR value of Yuangong 365 Cu-IUD was smaller than that of medicated Yuangong 220 Cu-IUD and RGR value of medicated Yuangong 220 Cu-IUD was smaller than that of Yuangong 300 Cu-IUD. The cupric ion release and indomethacin release showed biphasic. Indomethacin increased the cupric ion release rate and might diminish the adverse effects caused by burst release of cupric ion. The toxicity grade of these three Yuangong Cu-IUDs was 4. We should canvass the adverse events of Cu-IUDs based on practical experiments,and try our best to reduce the toxicity of Cu-IUDs.

  5. Ferric and cupric ions requirement for DNA single-strand breakage by H2O2.

    Science.gov (United States)

    Tachon, P

    1989-01-01

    Hydrogen peroxide (H2O2), was able to nick the replicative form of the phage fd, without the addition of a reducing agent or of a metal. This DNA single-strand breakage decreased with an increase of the ionic strength, suggesting that H2O2 reacted with traces of metal bound to DNA. When cupric of ferric ions were added, the rate of DNA single-strand breakage by H2O2 greatly increased and it was 20-30 times faster with cupric than with ferric ions. The addition of EDTA at an equimolar ratio or in excess of metal prevented partially DNA single-strand cleavage by H2O2 in the presence of ferric ions and completely when cupric ions were used. Superoxide dismutase prevented DNA single-strand breakage by H2O2 and ferric ions. On the contrary, with cupric ions and H2O2, the addition of superoxide dismutase increased the rate of DNA single-strand breakage. That superoxide dismutase was acting catalytically was shown by the loss of its effects after heat inactivation of the enzyme. The results of the present study show that besides its involvement in the Fenton reaction, H2O2 is able to reduce the metal bound to DNA, generating the superoxide anion radical or/and its protonated form, the perhydroxyl radical involved in DNA nicking. On the other hand, the ability of cuprous ions unlike ferrous ions to dismutate the superoxide radical may explain some differences observed between iron and copper in the DNA single-strand breakage by H2O2.

  6. Releasing of Cupric Ion of Three types of Copper-bearing Intrauterine Contraceptive Device in Simulated Uterine Fluid

    Institute of Scientific and Technical Information of China (English)

    Jie GAO; Ying LI; Jian-ping LIU; Xuan GU

    2007-01-01

    Objective To compare the cupric ion releasing in vitro of the three IUDs.Methods The stability of cupric ion releasing of IUDs including TCu 380A IUD (TCu 380A), Multiload Cu375 IUD (MCu 375) and Yuangong 365 copper-bearing indomethacin-releasing IUD (Yuangong 365) by the determination of cupric ion releasing in simulated uterine fluid. The simulated uterine fluid was used for releasing media. Copper ion was determined by flame atomic absorption spectrometerResults The cupric ion releasing of three IUDs were instable at the beginning and tend to be stable gradually. In the stable phase, the average level of cupric ion releasing of TCu380A, MCu375 and Yuangong 365 were 4.25±2.71 -7.62±6.42 μg,4.92±1.23 -8.62±3.08 μg and 2.19±0.40-4.68±1.66 μg, respectively. TCu380A had higher instable releasing level than those of Yuangong 365 (P<0. 05).Conclusion TCu 380A and MCu 375 showed a "burst release" during the first few days and the former was of great significance(P<0. 05). The initial cupric ion releasing of Yuangong 365 appeared to be the lowest, followed by MCu375 and TCu380A in a releasing order.

  7. The influence of cupric ions on shape of potentiodynamic curves obtained on 18 K gold

    Directory of Open Access Journals (Sweden)

    Rajčić-Vujasinović Mirjana

    2002-01-01

    Full Text Available The shape of potentiodynamic curves depends mainly on the composition of investigated alloys, but also on the electrolyte used in experiments. In this work investigation were performed for pure gold, and pure silver and copper as alloying metals, then for binary alloys Au-Ag and Au-Cu containing gold as in 18 k gold (i.e. 75 % Au and Ag-Cu with mass ratio 1:1 and, finally, for three component 18 k gold. It was established a catalytic effect of cupric ions present in electrolyte on oxidation of gold and 18 k gold alloys.

  8. The cupric ion reducing antioxidant capacity and polyphenolic content of some herbal teas.

    Science.gov (United States)

    Apak, Reşat; Güçlü, Kubilay; Ozyürek, Mustafa; Esin Karademir, Saliha; Erçağ, Erol

    2006-01-01

    The total antioxidant capacity of the aqueous extracts of some endemic herbs-prepared as infusions by steeping these herbs in hot water--was assayed with bis(neocuproine)copper(II) chloride, also known as the cupric ion reducing antioxidant capacity (CUPRAC) reagent, which was easily accessible, rapid, stable and responsive to both hydrophilic and lipophilic antioxidants. The highest antioxidant capacities of some herbal teas available in the Turkish market were observed for scarlet pimpernel (Anagallis arvensis), sweet basil (Ocimum basilicum), green tea (Camellia sinensis) and lemon balm (Melissa officinalis), in this order (1.63, 1.18, 1.07, and 0.99 mmol trolox equivalent (TR)/g, respectively). For infusions prepared from ready-to-use tea bags, the CUPRAC values were highest for Ceylon blended ordinary tea (4.41), green tea with lemon (1.61), English breakfast ordinary tea (1.26) and green tea (0.94), all of which were manufactured types of C. sinensis. Following the strongest antioxidant herbs with capacities close to or slightly exceeding 1.0 mmol TR/g, sage, thyme, coriander, coltsfoot, blackberry and immortelle (Helichrysum) exhibited capacities around 0.5 mmol TR/g. The correlation of the Folin total phenolic content of herbal teas with their CUPRAC and ABTS (2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt) total antioxidant capacities gave linear curves with correlation coefficients of 0.966 and 0.936, respectively, showing that the CUPRAC assay results better correlated with total phenolic content of herbal teas. Absorbance versus concentration data at different dilutions and upon standard additions of model antioxidant compounds (trolox and quercetin) to herbal tea infusions showed that the absorbances (at 450 nm of the CUPRAC method) due to different antioxidant compounds in herbal tea infusions were additive; that is, the tested antioxidants did not chemically interact to cause apparent deviations from Beer's law.

  9. Comparative toxicity and biodistribution of copper nanoparticles and cupric ions in rats

    Directory of Open Access Journals (Sweden)

    Lee IC

    2016-06-01

    Full Text Available In-Chul Lee,1 Je-Won Ko,1 Sung-Hyeuk Park,1 Je-Oh Lim,1 In-Sik Shin,1 Changjong Moon,1 Sung-Hwan Kim,2 Jeong-Doo Heo,3 Jong-Choon Kim1 1College of Veterinary Medicine BK21 Plus Project Team, Chonnam National University, Gwangju, 2Jeonbuk Department of Inhalation Research, Korea Institute of Toxicology, Jeongeup, 3Gyeongnam Department of Environment and Toxicology, Korea Institute of Toxicology, Gyeongnam, Republic of Korea Abstract: Despite widespread use and prospective biomedical applications of copper nanoparticles (Cu NPs, their biosafety issues and kinetics remain unclear. Thus, the aim of this study was to compare the detailed in vivo toxicity of Cu NPs and cupric ions (CuCl2; Cu ions after a single oral dose. We determined the physicochemical characteristics of Cu NPs, including morphology, hydrodynamic size, zeta potential, and dissolution in gastric (pH 1.5, vehicle (pH 6.5, and intestinal (pH 7.8 conditions. We also evaluated the kinetics of Cu following a single equivalent dose (500 mg/kg of Cu NPs and Cu ions. Cu NPs had highest dissolution (84.5% only in gastric conditions when compared with complete dissolution of Cu ions under various physiological milieus. Kinetic analysis revealed that highest Cu levels in blood and tested organs of Cu NP-treated rats were 15%–25% lower than that of Cu ions. Similar to the case of Cu ions, Cu levels in the tested organs (especially liver, kidney, and spleen of Cu NP-treated rats increased significantly when compared with the vehicle control. However, delay in reaching the highest level and biopersistence of Cu were observed in the blood and tested organs of Cu NP-treated rats compared with Cu ions. Extremely high levels of Cu in feces indicated that unabsorbed Cu NPs or absorbed Cu ions were predominantly eliminated through liver/feces. Cu NPs exerted apparent toxicological effects at higher dose levels compared with Cu ions and showed sex-dependent differences in mortality, biochemistry, and

  10. Comparative toxicity and biodistribution of copper nanoparticles and cupric ions in rats.

    Science.gov (United States)

    Lee, In-Chul; Ko, Je-Won; Park, Sung-Hyeuk; Lim, Je-Oh; Shin, In-Sik; Moon, Changjong; Kim, Sung-Hwan; Heo, Jeong-Doo; Kim, Jong-Choon

    2016-01-01

    Despite widespread use and prospective biomedical applications of copper nanoparticles (Cu NPs), their biosafety issues and kinetics remain unclear. Thus, the aim of this study was to compare the detailed in vivo toxicity of Cu NPs and cupric ions (CuCl2; Cu ions) after a single oral dose. We determined the physicochemical characteristics of Cu NPs, including morphology, hydrodynamic size, zeta potential, and dissolution in gastric (pH 1.5), vehicle (pH 6.5), and intestinal (pH 7.8) conditions. We also evaluated the kinetics of Cu following a single equivalent dose (500 mg/kg) of Cu NPs and Cu ions. Cu NPs had highest dissolution (84.5%) only in gastric conditions when compared with complete dissolution of Cu ions under various physiological milieus. Kinetic analysis revealed that highest Cu levels in blood and tested organs of Cu NP-treated rats were 15%-25% lower than that of Cu ions. Similar to the case of Cu ions, Cu levels in the tested organs (especially liver, kidney, and spleen) of Cu NP-treated rats increased significantly when compared with the vehicle control. However, delay in reaching the highest level and biopersistence of Cu were observed in the blood and tested organs of Cu NP-treated rats compared with Cu ions. Extremely high levels of Cu in feces indicated that unabsorbed Cu NPs or absorbed Cu ions were predominantly eliminated through liver/feces. Cu NPs exerted apparent toxicological effects at higher dose levels compared with Cu ions and showed sex-dependent differences in mortality, biochemistry, and histopathology. Liver, kidney, and spleen were the major organs affected by Cu NPs. Collectively, the toxicity and kinetics of Cu NPs are most likely influenced by the release of Cu dissociated from Cu NPs under physiological conditions.

  11. In vitro release of cupric ion from intrauterine devices: influence of frame, shape, copper surface area and indomethacin.

    Science.gov (United States)

    Zhang, Shuangshuang; Li, Ying; Yu, Panpan; Chen, Tong; Zhou, Weisai; Zhang, Wenli; Liu, Jianping

    2015-02-01

    The release of cupric ion from copper intrauterine device (Cu-IUD) in human uterus is essential for contraception. However, excessive cupric ion will cause cytotoxic effect. In this paper, we investigated the influence of device characteristics (frame, copper surface area, shape, copper type and indomethacin) on copper release for the efficacy and adverse effects vary with IUD types which may correlate to their different release behaviors. Nine types of Cu-IUDs were selected and incubated in simulated uterine fluid. They were paired for comparison based on the device properties and the release of cupric ion was determined by flame atomic absorption spectrometer for about 160 days. The result showed that there was a burst release during the first month and the release rate tends to slow down and become steady afterwards. In addition, the copper release was mainly influenced by frame, indomethacin and copper type (copper wire and copper sleeve) while the shape variation had little effect on copper release throughout the experiment. Moreover, the influence of copper surface area was only noticeable during the first month. These findings were seldom reported before and may provide some useful information for the design of Cu-IUDs.

  12. Cupric and cuprous oxide by reactive ion beam sputter deposition and the photosensing properties of cupric oxide metal–semiconductor–metal Schottky photodiodes

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Min-Jyun; Lin, Yong-Chen; Chao, Liang-Chiun, E-mail: lcchao@mail.ntust.edu.tw; Lin, Pao-Hung; Huang, Bohr-Ran

    2015-08-15

    Highlights: • CuO and Cu{sub 2}O were deposited by reactive ion beam sputter deposition. • Single phase CuO thin film is obtained with Ar:O{sub 2} = 2:1. • CuO MSM PD shows photoresponse from 400 nm to 1.30 μm. • CuO MSM PD is RC limited with a decay time less than 1 μs. - Abstract: Cupric (CuO) and cuprous (Cu{sub 2}O) oxide thin films have been deposited by reactive ion beam sputter deposition at 400 °C with an Ar:O{sub 2} ratio from 2:1 to 12:1. With an Ar:O{sub 2} ratio of 2:1, single phase polycrystalline CuO thin films were obtained. Decreasing oxygen flow rate results in CuO + Cu{sub 2}O and Cu{sub 2}O + Cu mixed thin films. As Ar:O{sub 2} ratio reaches 12:1, Cu{sub 2}O nanorods with diameter of 250 nm and length longer than 1 μm were found across the sample. Single phase CuO thin film exhibits an indirect band gap of 1.3 eV with a smooth surface morphology. CuO metal–semiconductor–metal (MSM) Schottky photodiodes (PD) were fabricated by depositing Cu interdigitated electrodes on CuO thin films. Photosensing properties of the CuO PD were characterized from 350 to 1300 nm and a maximum responsivity of 43 mA/W was found at λ = 700 nm. The MSM PD is RC limited with a decay time constant less than 1 μs.

  13. A facile approach for cupric ion detection in aqueous media using polyethyleneimine/PMMA core-shell fluorescent nanoparticles

    Science.gov (United States)

    Chen, Jian; Zeng, Fang; Wu, Shuizhu; Su, Junhua; Zhao, Jianqing; Tong, Zhen

    2009-09-01

    A facile approach was developed to produce a dye-doped core-shell nanoparticle chemosensor for detecting Cu2+ in aqueous media. The core-shell nanoparticle sensor was prepared by a one-step emulsifier-free polymerization, followed by the doping of the fluorescent dye Nile red (9-diethylamino- 5H-benzo[alpha] phenoxazine-5-one, NR) into the particles. For the nanoparticles, the hydrophilic polyethyleneimine (PEI) chain segments serve as the shell and the hydrophobic polymethyl methacrylate (PMMA) constitutes the core of the nanoparticles. The non-toxic and biocompatible PEI chain segments on the nanoparticle surface exhibit a high affinity for Cu2+ ions in aqueous media, and the quenching of the NR fluorescence is observed upon binding of Cu2+ ions. This makes the core-shell nanoparticle system a water-dispersible chemosensor for Cu2+ ion detection. The quenching of fluorescence arises through intraparticle energy transfer (FRET) from the dye in the hydrophobic PMMA core to the Cu2+/PEI complexes on the nanoparticle surface. The energy transfer efficiency for PEI/PMMA particles with different diameters was determined, and it is found that the smaller nanoparticle sample exhibits higher quenching efficiency, and the limit for Cu2+ detection is 1 µM for a nanoparticle sample with a diameter of ~30 nm. The response of the fluorescent nanoparticle towards different metal ions was investigated and the nanoparticle chemosensor displays high selectivity and antidisturbance for the Cu2+ ion among the metal ions examined (Na+, K+, Mg2+, Ca2+, Zn2+, Hg2+, Mn2+, Fe2+, Ni2+, Co2+ and Pb2+). This emulsifier-free, biocompatible and sensitive fluorescent nanoparticle sensor may find applications in cupric ion detection in the biological and environmental areas.

  14. One-step preparation of magnetic imprinted nanoparticles adopting dopamine-cupric ion as a co-monomer for the specific recognition of bovine hemoglobin.

    Science.gov (United States)

    Gao, Ruixia; Zhang, Lili; Hao, Yi; Cui, Xihui; Liu, Dechun; Zhang, Min; Tang, Yuhai

    2015-10-01

    A novel magnetic core-shell polydopamine-cupric ion complex imprinted polymer was prepared in one-step through surface imprinting technology, which could specifically recognize bovine hemoglobin from the real blood samples. The polymerization conditions and adsorption performance of the resultant nanomaterials were investigated in detail. The results showed that the cupric ion played an important role in the recognition of template proteins. The saturating adsorption capacity of this kind of imprinted polymers was 2.23 times greater than those of imprinted polymers without cupric ion. The imprinting factor of the imprinted materials was as high as 4.23 for the template molecule. The selective separation bovine hemoglobin from the real blood sample is successfully applied. In addition, the prepared materials had excellent stability and no obvious deterioration after five adsorption-regeneration cycles. Easy preparation, rapid separation, high binding capacity and satisfactory selectivity for the template protein make this polymer attractive in the separation of high-abundance proteins. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Oxidative leaching process with cupric ion in hydrochloric acid media for recovery of Pd and Rh from spent catalytic converters

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira, C.A., E-mail: carlos.nogueira@lneg.pt [Laboratório Nacional de Energia e Geologia, I.P., Campus do Lumiar, 1649-038 Lisboa (Portugal); Paiva, A.P., E-mail: appaiva@fc.ul.pt [Centro de Química e Bioquímica, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, 1749-016 Lisboa (Portugal); Oliveira, P.C. [Laboratório Nacional de Energia e Geologia, I.P., Campus do Lumiar, 1649-038 Lisboa (Portugal); Costa, M.C., E-mail: mcorada@ualg.pt [Centro de Ciências do Mar, Departamento de Química e Farmácia, Faculdade de Ciências e de Tecnologia, Campus de Gambelas, 8005-139 Faro (Portugal); Costa, A.M. Rosa da, E-mail: amcosta@ualg.pt [Centro de Investigação em Química do Algarve, Departamento de Química e Farmácia, Faculdade de Ciências e de Tecnologia, Campus de Gambelas, 8005-139 Faro (Portugal)

    2014-08-15

    Highlights: • A new leaching process based on Cu{sup 2+}/HCl media for recovering Pd and Rh from spent autocatalytic converters is presented. • Palladium and rhodium were efficiently leached, with attained maximum yields of 95% and 86%, respectively. • Temperature, time, and HCl and Cu{sup 2+} concentrations were found to be significant factors in the leaching of Pd and Rh. - Abstract: The recycling of platinum-group metals from wastes such as autocatalytic converters is getting growing attention due to the scarcity of these precious metals and the market pressure originated by increase of demand in current and emerging applications. Hydrometallurgical treatment of such wastes is an alternative way to the most usual pyrometallurgical processes based on smelter operations. This paper focuses on the development of a leaching process using cupric chloride as oxidising agent, in HCl media, for recovery of palladium and rhodium from a spent catalyst. The chloride media allows the adequate conditions for oxidising and solubilising the metals, as demonstrated by equilibrium calculations based on thermodynamic data. The experimental study of the leaching process revealed that Pd solubilisation is clearly easier than that of Rh. The factors temperature, time, and HCl and Cu{sup 2+} concentrations were significant regarding Pd and Rh leaching, the latter requiring higher factor values to achieve the same results. Leaching yields of 95% Pd and 86% Rh were achieved under optimised conditions (T = 80 °C, t = 4 h, [HCl] = 6 M, [Cu{sup 2+}] = 0.3 M)

  16. Cupric ion reducing antioxidant capacity assay for antioxidants in human serum and for hydroxyl radical scavengers.

    Science.gov (United States)

    Apak, Reşat; Güçlü, Kubilay; Ozyürek, Mustafa; Bektaşoğlu, Burcu; Bener, Mustafa

    2010-01-01

    Tests measuring the combined antioxidant effect of the nonenzymatic defenses in biological fluids may be useful in providing an index of the organism's capability to counteract reactive species known as pro-oxidants, resist oxidative damage, and combat oxidative stress-related diseases. The selected chromogenic redox reagent for the assay of human serum should be easily accessible, stable, selective, and respond to all types of biologically important antioxidants such as ascorbic acid, alpha-tocopherol, beta-carotene, reduced glutathione (GSH), uric acid, and bilirubin, regardless of chemical type or hydrophilicity. Our recently developed cupric reducing antioxidant capacity (CUPRAC) spectrophotometric method for a number of polyphenols and flavonoids using the copper(II)-neocuproine reagent in ammonium acetate buffer is now applied to a complete series of plasma antioxidants for the assay of total antioxidant capacity of serum, and the resulting absorbance at 450 nm is recorded either directly (e.g., for ascorbic acid, alpha-tocopherol, and glutathione) or after incubation at 50 degrees C for 20 min (e.g., for uric acid, bilirubin, and albumin), quantitation being made by means of a calibration curve. The lipophilic antioxidants, alpha-tocopherol and beta-carotene, are assayed in dichloromethane. Lipophilic antioxidants of serum are extracted with n-hexane from an ethanolic solution of serum subjected to centrifugation. Hydrophilic antioxidants of serum are assayed in the centrifugate after perchloric acid precipitation of proteins. The CUPRAC molar absorptivities, linear ranges, and TEAC (trolox equivalent antioxidant capacity) coefficients of the serum antioxidants are established, and the results are evaluated in comparison with the findings of the ABTS/TEAC reference method. The intra- and inter-assay coefficients of variation (CVs) are 0.7 and 1.5%, respectively, for serum. The CUPRAC assay proved to be efficient for glutathione and thiol-type antioxidants

  17. Cupric ion reducing antioxidant capacity assay for food antioxidants: vitamins, polyphenolics, and flavonoids in food extracts.

    Science.gov (United States)

    Apak, Reşat; Güçlü, Kubilay; Ozyürek, Mustafa; Bektas Oğlu, Burcu; Bener, Mustafa

    2008-01-01

    Antioxidants are health beneficial compounds through their combat with reactive oxygen and nitrogen species and free radicals that may cause tissue damage leading to various diseases. This work reports the development of a simple and widely applicable antioxidant capacity index for dietary polyphenols, vitamins C and E, and plasma antioxidants utilizing the copper(II)-neocuproine (Cu(II)-Nc) reagent as the chromogenic oxidizing agent. This novel method based on an electron-transfer mechanism was named by our research group as 'cupric reducing antioxidant capacity', abbreviated as the CUPRAC method. The method is comprised of mixing the antioxidant solution with aqueous copper(II) chloride, alcoholic neocuproine, and ammonium acetate aqueous buffer at pH 7, and subsequently measuring the developed absorbance at 450 nm after 30 min. Since the color development is fast for compounds like ascorbic acid, gallic acid, and quercetin but slow for naringin and naringenin, the latter compounds are assayed after incubation at 50 degrees C on a water bath for 20 min. The flavonoid glycosides are hydrolyzed to their corresponding aglycones by refluxing in 1.2 M: HCl-containing 50% MeOH so as to exert maximal reducing power towards Cu(II)-Nc. The CUPRAC antioxidant capacities of synthetic mixtures are equal to the sum of individual capacities of antioxidant constituents, indicating lack of chemical deviations from Beer's law. Tests on antioxidant polyphenols demonstrate that the highest CUPRAC capacities are observed for epicatechin gallate, epigallocatechin gallate, quercetin, fisetin, epigallocatechin, catechin, and caffeic acid in this order, in accord with the number and position of the -OH groups as well the conjugation level of the molecule. The parallelism of the linear calibration curves of pure antioxidants in water and in a given complex matrix (plant extract) demonstrates that there are no chemical interactions of interferent nature among the solution constituents

  18. Oxidative leaching process with cupric ion in hydrochloric acid media for recovery of Pd and Rh from spent catalytic converters.

    Science.gov (United States)

    Nogueira, C A; Paiva, A P; Oliveira, P C; Costa, M C; da Costa, A M Rosa

    2014-08-15

    The recycling of platinum-group metals from wastes such as autocatalytic converters is getting growing attention due to the scarcity of these precious metals and the market pressure originated by increase of demand in current and emerging applications. Hydrometallurgical treatment of such wastes is an alternative way to the most usual pyrometallurgical processes based on smelter operations. This paper focuses on the development of a leaching process using cupric chloride as oxidising agent, in HCl media, for recovery of palladium and rhodium from a spent catalyst. The chloride media allows the adequate conditions for oxidising and solubilising the metals, as demonstrated by equilibrium calculations based on thermodynamic data. The experimental study of the leaching process revealed that Pd solubilisation is clearly easier than that of Rh. The factors temperature, time, and HCl and Cu(2+) concentrations were significant regarding Pd and Rh leaching, the latter requiring higher factor values to achieve the same results. Leaching yields of 95% Pd and 86% Rh were achieved under optimised conditions (T = 80 °C, t = 4h, [HCl] = 6M, [Cu(2+)] = 0.3M).

  19. Release behavior of cupric ions for TCu380A and TCu220C IUDs

    Energy Technology Data Exchange (ETDEWEB)

    Cao Bianmei; Zheng Yudong [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing (China); Xi Tingfei [National Institute for the Control of Pharmaceutical and Biological Products, Beijing (China)], E-mail: xitingfei@tom.com

    2008-12-15

    We immersed copper T380A and T220C IUDs in simulated uterine solution (SUS) and also in simulated body fluid (SBF). The release rate and corrosion products of copper ions after soaking in SUS and SBF for different time spans were studied by an atomic absorption spectrophotometer, scanning electron microscopy with energy dispersive x-ray microanalysis (SEM/EDX) and x-ray diffraction. The highest corrosion rate of the TCu380A IUD was obtained on the first day, while the highest corrosion rate of the TCu220C IUD was obtained on the third day. The copper corrosion rate of the TCu380A IUD was much faster than that of the TCu220C IUD in the first few days. The corrosion extent of copper wire was higher than that of a copper tube when first immersed in solution. For the same IUD in the same solution, the corrosion extent in SBF was higher than in SUS. The main compounds identified were cuprite (Cu{sub 2}O). Copper wire and copper tubes were implanted in the uteruses of rats. In vivo experiments were also done. The corrosion rate in vivo was higher than that in vitro.

  20. Magnetic disorder in cupric oxide

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, S.J.; Borzi, R.A.; Mercader, R.C. [Universidad Nacional de La Plata, C.C. 67, Departamento de Fisica, Facultad de Ciencias Exactas (Argentina)

    1999-11-15

    Investigations of the abnormal magnetic properties of cupric oxide reveal discrepancies between both experimental results and theoretical explanations. Through iron-doping cupric oxide by ball-milling and thermal treatments we have been able to obtain Moessbauer results that are an experimental evidence of semi-disorder. The magnetic hyperfine field of the Cu{sub 0.995}Fe{sub 0.005}O solid solution displays a spin-glass-like thermal dependence that undergoes two transitions, one at about 150 K, that can be assigned to the long-range ordering of the cupric oxide spins, and the second one at some temperature between 4.2 and 15 K, that exposes either the freezing of the Fe{sup 3+} spins into a local canted state or of magnetic clusters in the CuO matrix.

  1. Uptake of iodide by a mixture of metallic copper and cupric compounds

    Energy Technology Data Exchange (ETDEWEB)

    Lefevre, G.; Alnot, M.; Ehrhardt, J.J.; Bessiere, J. [Univ. Henri Poincare Nancy 1, Villers les Nancy (France). Lab. de Chimie Physique pour l`Environnement

    1999-05-15

    Environmental contaminants harmful to the health of present and future generations involve nuclear fission products as iodine radioisotopes. {sup 129}I is potentially one of the more mobile products because of its long half-life and its tendency to go into solution as an anion that is not retarded with silicate minerals. Ability of copper/cupric compound mixtures to remove iodide from solution was investigated to predict sorption of radioactive iodine in the environment and to assess their use in a nuclear reprocessing method. Thermodynamic calculations were performed to study the stability of such mixtures in solution and to obtain equilibrium constants of Cu(0)/Cu(II)/I{sup {minus}} and Cu(0)/Cu(II)/Cl{sup {minus}} systems. Both calculations and experimental results showed that a Cu(0)/Cu{sub 3}(OH){sub 2}(CO{sub 3}){sub 2} (azurite) mixture selectively uptakes iodide ions (initial concentrations: 10{sup {minus}2} and 10{sup {minus}1} M) in the presence of 10{sup {minus}1} M chloride ions. Reaction of iodide with copper powder and azurite crystal or copper plate and azurite powder have also been investigated, leading to precipitation of CuI onto massive copper phase. The different solids were separately analyzed by XPS and MEB-EDX, giving some insight in the uptake mechanism. It is proposed that soluble copper released by the cupric compound is reduced at the surface of metallic copper, leading to a preferential precipitation of CuI on copper surface.

  2. Hip implants - Paper VI - Ion concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Sargeant, A. [Department of Biological Sciences, Ohio Northern University, Ada, OH 45810 (United States); Goswami, T. [Department of Mechanical Engineering, Ohio Northern University, Ada, OH 45810 (United States)]. E-mail: t-goswami@onu.edu

    2007-07-01

    Total hip-joint arthroplasty is performed in increasing numbers where it translates to about 0.16-0.2% of population per year in industrial countries. In most cases, an implant is a metallic component articulating with a metal, ceramic or poly-ethylene liner as seen in the case of hip, knee and spine. The metal implants release ions in vivo. Therefore, there is a need to study metallic implants and ions released as a result. Toxic concentrations of ions can lead to many adverse physiological effects, including cytotoxicity, genotoxicity, carcinogenicity, and metal sensitivity. There is a need to map ion concentrations establishing boundaries between normal and toxic levels; which however, does not exist. Reference levels of ion concentrations in body fluids and tissues determined by many studies are compiled, reviewed, and presented in this paper. The concentrations of ions released from different alloys, including cobalt, chromium, nickel, molybdenum titanium, aluminum, and vanadium, are presented in this paper. This paper reviews the literature pertaining to clinical data on metal ion concentrations in patients with metal joint prostheses, and laboratory data on the physiological effects of the metals.

  3. 氯化铜脱除硫化氢气体制硫磺研究%H2S Removal with Cupric Chloride for Producing Sulfur

    Institute of Scientific and Technical Information of China (English)

    张俊丰; 童志权

    2006-01-01

    A novel technology of removing H2S with cupric chloride solution was developed in this paper. Cupric as the form of CuS deposition, the CuS produced was then oxidized by excessive cupric ion in another reactor meanwhile cupric ion that has been consumed can be recovered by the oxidization of CuCl2- with oxygen in air,and the solution can be circulated. Moreover, the leaching kinetics of CuS by cupric ion was studied. The removal efficiency of H2S is close to 100%, and the required operating condition is mild. Compared with other wet oxidization methods, no raw material is consumed except O2 in air, the process has no secondary pollution and no problem of degradation and scale, and the absorbent is much stable and reliable.

  4. Process of Waste Cupric Ion Water with Activated Peanut Shell Charcoal%花生壳活性炭处理含铜离子废水

    Institute of Scientific and Technical Information of China (English)

    杨莉; 刘毅

    2011-01-01

    Using the microwave method to prepare activated peanut shell charcoal to adsorb Cu2+ . With scaning electron microscope, it was discovered that many thin stripes appeared at the activated charcoal surface, and there were massive pores with average grain diameter of 50μm. In the activated charcoal, the O and C combined and released in the form of CO2, thus caused other elements content to rise relatively, which led the K content to rise most obviously. The adsorptive capacity was the highest when temperature was 30℃, the monolayer adsorption was saturated in 60min and the polymolecular layer adsorption started after 90min. Under the same condition, the activated charcoal adsorption speed and the adsorptive capacity for the highly concentrated Cu2+ solution were more than that of the low concentration solution, and the Cu2+ quantity was more adsorbed obviously in the activated charcoal unit area. Responding speed and the adsorptive capacity were proportional. It showed to be the physical adsorption while the adsorption temperature was between 30 - 50℃, and the adsorption condition transformed to chemical adsorption when the temperature surpassed 60℃.%利用微波法制备花生壳活性炭吸附铜离子,扫描电镜发现活性炭表面出现许多细条纹,有大量微孔,平均粒径为50μm。活性炭中O与C结合,以CO2的形式释放出去,从而使其他元素的含量相对上升,其中以K元素含量上升最为明显。30℃时吸附量最高,在60min内达到单分子层吸附饱和,90min后开始多分子层吸附。在同等条件下,活性炭对高浓度的Cu2+溶液的吸附速率和吸附量比低浓度的溶液大,活性炭单位面积上吸附的铜离子量显然要多;反应速率和吸附量成正比。当吸附温度处于30-50℃之间时,属于物理吸附;温度超过60℃后,吸附状态转变为化学吸附。

  5. Ion-ion Recombination and Chemiion Concentrations In Aircraft Exhaust

    Science.gov (United States)

    Turco, R. P.; Yu, F.

    Jet aircraft emit large quantities of ultrafine volatile aerosols, as well as soot parti- cles, into the environment. To determine the long-term effects of these emissions, a better understanding of the mechanisms that control particle formation and evolution is needed, including the number and size dispersion. A recent explanation for aerosol nucleation in a jet wake involves the condensation of sulfuric acid vapor, and cer- tain organic compounds, onto charged molecular clusters (chemiions) generated in the engine combustors (Yu and Turco, 1997). Massive charged aggregates, along with sulfuric acid and organic precursor vapors, have been detected in jet plumes under cruise conditions. In developing the chemiion nucleation theory, Yu and Turco noted that ion-ion recombination in the engine train and jet core should limit the chemiion emission index to 1017/kg-fuel. This value is consistent with ion-ion recombination coefficients of 1×10-7 cm3/s over time scales of 10-2 s. However, the evolution of the ions through the engine has not been adequately studied. The conditions at the combustor exit are extreme-temperatures approach 1500 K, and pressures can reach 30 atmospheres. In this presentation, we show that as the combustion gases expand and cool, two- and three-body ion-ion recombination processes control the chemiion concentration. The concepts of mutual neutralization and Thomson recombination are first summarized, and appropriate temperature and pressure dependent recombination rate coefficients are derived for the aircraft problem. A model for ion losses in jet exhaust is then formulated using an "invariance" principle discussed by Turco and Yu (1997) in the context of a coagulating aerosol in an expanding plume. This recombina- tion model is applied to estimate chemiion emission indices for a range of operational engine conditions. The predicted ion emission rates are found to be consistent with observations. We discuss the sources of variance in chemiion

  6. Electrolytic regeneration of acid cupric chloride printed circuit board etchant. Final report, August 1, 1995--October 31, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Oxley, J.E.; Smialek, R.J.

    1997-04-18

    The overall objective of this ERIP program was to make substantial progress in further developing a process for electrolytic regeneration of acid cupric chloride etchant - a process which was initially demonstrated in in-house studies and EPA Phase I and Phase II SBIRs. Specific objectives of the work were: (1) to define optimum system operating conditions by conducting a systematic study of process parameters, (2) to develop or find a superior electrolyic cell separator material, (3) to determine an optimum activation procedure for the flow-through carbon/graphite felt electrodes which are so critical to process performance, (4) to demonstrate - on the pre-prototype scale - electrolytic compensation for oxygen ingress - which causes etchant solution growth, and (5) to begin engineering design work on a prototype-scale regeneration unit. Parametric studies looked at the effect that key plating parameters have on copper deposit quality. Parameters tested included (a) velocity past the plating cathodes, (b) copper concentration in the catholyte solution from which the copper is being plated, (c) plating current density, and (d) catholyte cupric ion concentration. The most significant effects were obtained for velocity changes. The work showed that catholyte velocities above 0.5 ft/sec were needed to get adequate plating at 77.5 mA/cm{sup 2} and higher currents, and that even higher flow was better.

  7. Neutral thermospheric temperature from ion concentration measurements

    Science.gov (United States)

    Breig, E. L.; Donaldson, J. S.; Hanson, W. B.; Hoffman, J. H.; Power, R. A.; Kayser, D. C.; Spencer, N. W.; Wharton, L. E.

    1981-01-01

    A technique for extracting information on neutral temperature from in situ F region measurements of O(+) and H(+) ion concentrations is analyzed and evaluated. Advantage is taken of the condition of charge-exchange equilibrium of these species in the neighborhood of 320 km to infer the associated relative abundances of neutral oxygen and hydrogen. Results are shown to be generally consistent with other concurrent in situ measurements.

  8. Hydrolysis of cupric chloride in aqueous ammoniacal ammonium chloride solutions

    Directory of Open Access Journals (Sweden)

    Limpo, J. L.

    1995-06-01

    Full Text Available Cupric solubility in the CuCl2-NH4Cl-NH3-H2O system for chloride concentrations lower than 4 molal in the temperature range 25-60 °C was studied. The experimental results show that for chloride concentration between 3.0 and 1.0 molal the cupric solubility is determined by the solubility of the cupric hydroxychloride Cu(OH1.5Cl0.5. For a chloride concentration value of 4.0 molal, there are two cupric compounds, the hydroxychloride Cu(OH1.5Cl0.5 or the diammine chloride Cu(NH32Cl2, on which the solubility of Cu(II depends, according to the temperature and the value of the ratio [NH3]Total/[Cu]Total.

    Se estudia la solubilidad del Cu(II en el sistema CuCl2-NH4Cl-NH3-H2O para concentraciones de cloruro inferiores a 4 molal en el intervalo de temperaturas 25-60 °C. Los resultados experimentales muestran que, para concentraciones de cloruros comprendidas entre 3,0 y 1,0 molal, la solubilidad cúprica viene determinada por la solubilidad del hidroxicloruro cúprico, Cu(OH1.5Cl0.5. Para concentraciones de cloruro 4,0 molal, existen dos compuestos cúpricos, el hidroxicloruro, Cu(OH1.5Cl0.5 o el cloruro de diamina, Cu(NH32Cl2, de los que, de acuerdo con la temperatura y con el valor de la relación [NH3]Total/[Cu]Total depende la solubilidad del Cu(II.

  9. Direct seawater desalination by ion concentration polarization.

    Science.gov (United States)

    Kim, Sung Jae; Ko, Sung Hee; Kang, Kwan Hyoung; Han, Jongyoon

    2010-04-01

    A shortage of fresh water is one of the acute challenges facing the world today. An energy-efficient approach to converting sea water into fresh water could be of substantial benefit, but current desalination methods require high power consumption and operating costs or large-scale infrastructures, which make them difficult to implement in resource-limited settings or in disaster scenarios. Here, we report a process for converting sea water (salinity approximately 500 mM or approximately 30,000 mg l(-1)) to fresh water (salinity water is divided into desalted and concentrated streams by ion concentration polarization, a phenomenon that occurs when an ion current is passed through ion-selective membranes. During operation, both salts and larger particles (cells, viruses and microorganisms) are pushed away from the membrane (a nanochannel or nanoporous membrane), which significantly reduces the possibility of membrane fouling and salt accumulation, thus avoiding two problems that plague other membrane filtration methods. To implement this approach, a simple microfluidic device was fabricated and shown to be capable of continuous desalination of sea water (approximately 99% salt rejection at 50% recovery rate) at a power consumption of less than 3.5 Wh l(-1), which is comparable to current state-of-the-art systems. Rather than competing with larger desalination plants, the method could be used to make small- or medium-scale systems, with the possibility of battery-powered operation.

  10. Kinetics of coal desulfurization using cupric chloride solution

    Energy Technology Data Exchange (ETDEWEB)

    Ghazali, S.; Muharam, C.; Sani, S.A. [Bandung Inst. of Tech. (Indonesia)

    1995-12-31

    Coal desulfurization prior to combustion can be carried out either by physical or chemical methods. The physical methods, where the elimination of sulfur compounds is based on the difference of physical properties between pyritic sulfur and organic matrix, have progressed significantly and are currently used in commercial practice. These methods are, however, ineffective to remove organic sulfurs where S is attached chemically to carbon in the coal matrix. These compounds, presumed to be mercaptan, thyophene, organic sulfides or organic disulfide, could only be removed by chemical treatments. This paper describes the experimental study of coal beneficiation by chemical methods using cupric chloride solution. The results obtained showed that both organic and pyritic sulfurs were reduced significantly. It was also observed that cupric ions have reacted with in fraction of coal which was assumed to be some oxygenated carbon. The kinetics study has shown that the reaction rate of pyrite pseudo homogenous model and the reaction rates of organic sulfur generated coal fractions follow the power law models. (author). 5 tabs., 4 figs., 10 refs.

  11. Waters of Hydration of Cupric Hydrates: A Comparison between Heating and Absorbance Methods

    Science.gov (United States)

    Barlag, Rebecca; Nyasulu, Frazier

    2011-01-01

    The empirical formulas of four cupric hydrates are determined by measuring the absorbance in aqueous solution. The Beer-Lambert Law is verified by constructing a calibration curve of absorbance versus known Cu[superscript 2+](aq) concentration. A solution of the unknown hydrate is prepared by using 0.2-0.3 g of hydrate, and water is added such…

  12. Ion Concentration Polarization by Bifurcated Current Path.

    Science.gov (United States)

    Kim, Junsuk; Cho, Inhee; Lee, Hyomin; Kim, Sung Jae

    2017-07-11

    Ion concentration polarization (ICP) is a fundamental electrokinetic process that occurs near a perm-selective membrane under dc bias. Overall process highly depends on the current transportation mechanisms such as electro-convection, surface conduction and diffusioosmosis and the fundamental characteristics can be significantly altered by external parameters, once the permselectivity was fixed. In this work, a new ICP device with a bifurcated current path as for the enhancement of the surface conduction was fabricated using a polymeric nanoporous material. It was protruded to the middle of a microchannel, while the material was exactly aligned at the interface between two microchannels in a conventional ICP device. Rigorous experiments revealed out that the propagation of ICP layer was initiated from the different locations of the protruded membrane according to the dominant current path which was determined by a bulk electrolyte concentration. Since the enhancement of surface conduction maintained the stability of ICP process, a strong electrokinetic flow associated with the amplified electric field inside ICP layer was significantly suppressed over the protruded membrane even at condensed limit. As a practical example of utilizing the protruded device, we successfully demonstrated a non-destructive micro/nanofluidic preconcentrator of fragile cellular species (i.e. red blood cells).

  13. Critical concentration of ion-pairs formation in nonpolar media.

    Science.gov (United States)

    Dukhin, Andrei

    2014-07-01

    It is known that nonpolar liquids can be ionized by adding surfactants, either ionic or nonionic. Surfactant molecules serve as solvating agents, building inverse micelles around ions, and preventing their association back into neutral molecules. According to the Bjerrum-Onsager-Fuoss theory, these inverse micelle ions should form "ion pairs." This, in turn, leads to nonlinear dependence of the conductivity on the concentration. Surprisingly, ionic surfactants exhibit linear conductivity dependence, which implies that these inverse micelle ions do not form ion pairs. Theory predicts the existence of two ionic strength ranges, which are separated by a certain critical ion concentration. Ionic strength above the critical one is proportional to the square root of the ion concentration, whereas it becomes linear below the critical concentration. Critical ion concentration lies within the range of 10(-11) -10(-7) mol/L when ion size ranges from 1 to 3 nm. Critical ion concentration is related, but not equal, to a certain surfactant concentration (critical concentration of ion-pairs formation (CIPC)) because only a fraction of the surfactant molecules is incorporated into the micelles ions. The linear conductivity dependence for ionic surfactants indicates that the corresponding CIPC is above the range of studied concentrations, perhaps, due to rather large ion size. The same linearity is a sign that charged inverse micelles structure and fraction are concentration independent due to strong charge-dipole interaction in the charge micelle core. This also proves that CIPC is independent of critical concentration of micelle formation. Nonionic surfactants, on the other hand, exhibit nonlinear conductivity dependence apparently due to smaller ion sizes. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Capillarity ion concentration polarization as spontaneous desalting mechanism

    Science.gov (United States)

    Park, Sungmin; Jung, Yeonsu; Son, Seok Young; Cho, Inhee; Cho, Youngrok; Lee, Hyomin; Kim, Ho-Young; Kim, Sung Jae

    2016-04-01

    To overcome a world-wide water shortage problem, numerous desalination methods have been developed with state-of-the-art power efficiency. Here we propose a spontaneous desalting mechanism referred to as the capillarity ion concentration polarization. An ion-depletion zone is spontaneously formed near a nanoporous material by the permselective ion transportation driven by the capillarity of the material, in contrast to electrokinetic ion concentration polarization which achieves the same ion-depletion zone by an external d.c. bias. This capillarity ion concentration polarization device is shown to be capable of desalting an ambient electrolyte more than 90% without any external electrical power sources. Theoretical analysis for both static and transient conditions are conducted to characterize this phenomenon. These results indicate that the capillarity ion concentration polarization system can offer unique and economical approaches for a power-free water purification system.

  15. Capillarity ion concentration polarization as spontaneous desalting mechanism.

    Science.gov (United States)

    Park, Sungmin; Jung, Yeonsu; Son, Seok Young; Cho, Inhee; Cho, Youngrok; Lee, Hyomin; Kim, Ho-Young; Kim, Sung Jae

    2016-04-01

    To overcome a world-wide water shortage problem, numerous desalination methods have been developed with state-of-the-art power efficiency. Here we propose a spontaneous desalting mechanism referred to as the capillarity ion concentration polarization. An ion-depletion zone is spontaneously formed near a nanoporous material by the permselective ion transportation driven by the capillarity of the material, in contrast to electrokinetic ion concentration polarization which achieves the same ion-depletion zone by an external d.c. bias. This capillarity ion concentration polarization device is shown to be capable of desalting an ambient electrolyte more than 90% without any external electrical power sources. Theoretical analysis for both static and transient conditions are conducted to characterize this phenomenon. These results indicate that the capillarity ion concentration polarization system can offer unique and economical approaches for a power-free water purification system.

  16. Cupric natural zeolites as microbic ides;Zeolitas naturales cupricas como microbicidas

    Energy Technology Data Exchange (ETDEWEB)

    Contreras A, D.; Olguin G, M. T.; Alcantara D, D.; Burrola A, C., E-mail: teresa.olguin@inin.gob.m [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2009-07-01

    The Escherichia coli and the Candida albicans are considered contamination indicators for what these organisms reflect the water quality. The natural zeolites by their characteristics and properties, they could incorporate to a waters treatment system, as ion exchange, adsorbents and/or microbiocid agents, representing an alternative method of low cost. Inside this investigation work was found that depending on the microorganism type, it varies the quantity of cupric zeolite that is required to carry out the water disinfection, being great for the case of yeasts than the bacteria s. In addition to that marked differences are presented in the required time to reach this process. The characterization of the natural zeolite material, sodium and cupric, was realized by means of scanning electron microscopy, determining the elementary composition (Energy Dispersive Spectroscopy) of each one of them, and by X-ray diffraction. (Author)

  17. Edge Vortex Flow Due to Inhomogeneous Ion Concentration

    Science.gov (United States)

    Sugioka, Hideyuki

    2017-04-01

    The ion distribution of an open parallel electrode system is not known even though it is often used to measure the electrical characteristics of an electrolyte. Thus, for an open electrode system, we perform a non-steady direct multiphysics simulation based on the coupled Poisson-Nernst-Planck and Stokes equations and find that inhomogeneous ion concentrations at edges cause vortex flows and suppress the anomalous increase in the ion concentration near the electrodes. A surprising aspect of our findings is that the large vortex flows at the edges approximately maintain the ion-conserving condition, and thus the ion distribution of an open electrode system can be approximated by the solution of a closed electrode system that considers the ion-conserving condition rather than the Gouy-Chapman solution, which neglects the ion-conserving condition. We believe that our findings make a significant contribution to the understanding of surface science.

  18. Detection of arsenic ions with preliminary concentrating on magnetic sorbent

    OpenAIRE

    Kharlyamov, Damir; Dvoryak, Stanislav; Mavrin, Gennady

    2013-01-01

    In represented work a method of arsenic ions concentrating is presented by means of sorption with application of synthetic magnetite, which is successfully used for atomic absorption detection of arsenic in natural waters.

  19. Capillary Ion Concentration Polarization for Power-Free Salt Purification

    Science.gov (United States)

    Park, Sungmin; Jung, Yeonsu; Cho, Inhee; Kim, Ho-Young; Kim, Sung Jae

    2014-11-01

    In this presentation, we experimentally and theoretically demonstrated the capillary based ion concentration polarization for power-free salt purification system. Traditional ion concentration polarization phenomenon has been studied for a decade for both fundamental nanoscale fluid dynamics and novel engineering applications such as desalination, preconcentration and energy harvesting devices. While the conventional system utilizes an external power source, the system based on capillary ion concentration polarization is capable of perm-selective ion transportation only by capillarity so that the same ion depletion zone can be formed without any external power sources. An ion concentration profile near the nanostructure was tracked using fluorescent probes and analyzed by solving the modified Nernst-Planck equation. As a result, the concentration in the vicinity of the nanostructure was at least 10 times lower than that of bulk electrolyte and thus, the liquid absorbed into the nanostructure had the low concentration. This mechanism can be used for the power free salt purification system which would be significantly useful in underdeveloped and remote area. This work was supported by Samsung Research Funding Center of Samsung Electronics under Project Number SRFC-MA1301-02.

  20. The copper recovery from cupric oxide catalysts by plasma reduction process

    Energy Technology Data Exchange (ETDEWEB)

    Imris, I.; Klenovcanova, A. [Technical Univ. of Kosice, Kosice (Slovakia). Dept. of Power Engineering

    2007-07-01

    A plasma reduction process was used to recover copper from cupric oxide catalysts. Two types of plasma reduction smelting tests were conducted to verify the thermodynamic calculations. The plasma reactor consisted of a cylindrical steel shell lined with a castable alumina and a graphite crucible. Cupric oxide catalyst ESM 461 was mixed with stoichiometric amounts of carbon reductant and a 10 per cent addition of calcium oxide flux. Results of the experimental tests and the thermodynamic analysis showed that the copper can be extracted from cupric oxide using the plasma reduction process. Copper recovery was limited by physico-chemical copper losses. Copper oxide solubility was relatively high, so that copper recovery was low in their first series of plasma tests. The addition of calcium oxide flux improved copper recovery rates when dicalcium silicate was formed in the slag. The offgas samples indicated that concentrations of carbon monoxide (CO) in the gas phase was very high. It was concluded that the process is both commercially feasible and does not produce liquid or solid wastes. 7 refs., 2 tabs., 4 figs.

  1. Ion-dipole interactions in concentrated organic electrolytes.

    Science.gov (United States)

    Chagnes, Alexandre; Nicolis, Stamatios; Carré, Bernard; Willmann, Patrick; Lemordant, Daniel

    2003-06-16

    An algorithm is proposed for calculating the energy of ion-dipole interactions in concentrated organic electrolytes. The ion-dipole interactions increase with increasing salt concentration and must be taken into account when the activation energy for the conductivity is calculated. In this case, the contribution of ion-dipole interactions to the activation energy for this transport process is of the same order of magnitude as the contribution of ion-ion interactions. The ion-dipole interaction energy was calculated for a cell of eight ions, alternatingly anions and cations, placed on the vertices of an expanded cubic lattice whose parameter is related to the mean interionic distance (pseudolattice theory). The solvent dipoles were introduced randomly into the cell by assuming a randomness compacity of 0.58. The energy of the dipole assembly in the cell was minimized by using a Newton-Raphson numerical method. The dielectric field gradient around ions was taken into account by a distance parameter and a dielectric constant of epsilon = 3 at the surfaces of the ions. A fair agreement between experimental and calculated activation energy has been found for systems composed of gamma-butyrolactone (BL) as solvent and lithium perchlorate (LiClO4), lithium tetrafluoroborate (LiBF4), lithium hexafluorophosphate (LiPF6), lithium hexafluoroarsenate (LiAsF6), and lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) as salts.

  2. Concentration variations of several ions in stream after a wildfire

    Institute of Scientific and Technical Information of China (English)

    LIU Yang; HU Hai-qing

    2007-01-01

    In May 2006, a high intensity wildfire occurred in Songling forest region in Daxing'an Mountains, China. The concentration changes of eight ions (K+, Na+, Ca2+, Mg2+, Cl-, Br-, NO3- and SO42-) were measured in burned and unburned streams after fire from May to Oct., 2006. Results show that the most ions flux were higher in burned stream than that in unburned stream during the sampling period, and the greatest concentrations of most ions transported from burned stream occurred in July. After fire, the most amplitude chemical ion was Ca2+, whose average concentration was 5.50 mg·L-1 higher than that in unburned stream, and the total concentration of every chemical ion presents a trend Ca2+> SO42- >Na+> Mg2+> NO3- . The average concentrations of Ca2+, SO42-, Na+ Mg2+, NO3- showed an increase trend,but those of K+, Cl-, Br- had a decreased trend. SO42- had the largest loss among these anions, followed by NO3-. Overall, the increase degree of cation was greater than that of anion after burning.

  3. Effect of advection on transient ion concentration-polarization phenomenon

    Science.gov (United States)

    Rosentsvit, Leon; Park, Sinwook; Yossifon, Gilad

    2017-08-01

    Here, we studied the effect of advection on the transient ion concentration-polarization phenomenon in microchannel-membrane systems. Specifically, the temporal evolution of the depletion layer in a system that supports net flow rates with varying Péclet values was examined. Experiments complemented with simplified analytical one-dimensional semi-infinite modeling and numerical simulations demonstrated either suppression or enhancement of the depletion layer propagation against or with the direction of the net flow, respectively. Of particular interest was the third-species fluorescent dye ion concentration-polarization dynamics which was further explained using two-dimensional numerical simulations that accounted for the device complex geometry.

  4. Geochemical factors controlling free Cu ion concentrations in river water

    Science.gov (United States)

    Rozan, Tim F.; Benoit, Gaboury

    1999-10-01

    Copper speciation was determined monthly at seven sites on four rivers in southern New England to understand which geochemical factors control free metal ion concentrations in river water. Samples were conventionally filtered (stripping voltammetry (DPASV) was used to quantify natural organic complexation and cathodic stripping square wave voltammetry (CSSWV) to measure directly both Cu sulfide complexes and total EDTA concentrations. The results showed both dissolved organic matter (DOM) and sulfide complexation dominate Cu speciation and control the concentrations of free ion. Free Cu2+ was calculated to be in the subnanomolar range for the majority of the year. Only in the winter months, when concentrations of DOM and metal sulfides complexes were at a minimum were free metal ions directly measurable by DPASV at low nanomolar concentrations. The extent of sulfide complexation appears to be dominated by the size of headwater marshes (upstream sampling sites) and by the amount of sewage treatment plant effluent (downstream sites). DOM complexation was related to the organic matter composition and followed model organic ligands. Indirect evidence suggests variations in river water pH and Ca2+ (metal competition) has only a minor role in Cu complexation. Measured concentrations of total EDTA suggest this synthetic ligand can control Cu speciation in some highly developed watersheds; however, competition from Ni (and possibly Fe) limits the extent of this complexation.

  5. Undisplayed Bicarbonate ion Concentration in Arterial Blood Gas Analysis

    OpenAIRE

    Sathe, Aditya Balakrishna; Bhalkar, Manjiri Shashank

    2013-01-01

    Blood bicarbonate ion concentration (BcHCO3-) is a vital parameter in the management of acid base disorders. In an arterial blood gas (ABG) analyzer, the BcHCO3- is calculated from the values of pH and pCO2.

  6. Undisplayed Bicarbonate ion Concentration in Arterial Blood Gas Analysis

    OpenAIRE

    2013-01-01

    Blood bicarbonate ion concentration (BcHCO3-) is a vital parameter in the management of acid base disorders. In an arterial blood gas (ABG) analyzer, the BcHCO3- is calculated from the values of pH and pCO2.

  7. Tunable sheathless microfluidic focusing using ion concentration polarization

    Science.gov (United States)

    Yoon, Junghyo; Cho, Youngkyu; Lee, Jeong Hoon; Chung, Seok

    2015-08-01

    In this study, we developed a tunable sheathless focusing method for focusing micrometer- and nanometer-sized particles, using ion concentration polarization (ICP) in an ion-selective, resin-coated channel. The particle movement was regulated using an electric field, and by varying the flow rate and ionic strength of the liquid solution; various phenomena were observed, depending on the particle properties. Here, we provide insights into the physical basis of the ICP-focusing phenomena, and a statistical approach for analyzing the particle movement. This ICP-focusing technology is an approach that could be applied for the separation and sorting of various particles, including cells, proteins, and bacteria.

  8. Ambient sesquiterpene concentration and its link to air ion measurements

    Directory of Open Access Journals (Sweden)

    B. Bonn

    2006-12-01

    Full Text Available Ambient air ion size distributions have been measured continuously at the Finnish boreal forest site in Hyytiälä since spring 2003. In general, these measurements show a maximum of air ions below 1.0 nm in diameter. But this physical characterization does not provide any information about the ion's chemical composition, which is one key question regarding the explanation of nucleation events observed. In this study we propose a link of the observed maximum of negative air ions between 0.56 and 0.75 nm to the so-called stabilised Criegee biradical, formed in the reaction of biogenic sesquiterpenes with ozone and predominantly destroyed by its reaction with ambient water vapour. Calculations of the electron and proton affinities of 120 kJ mol−1 (1.24 eV and of 960 kJ mol−1 support this link. Other possible candidates such as sulphuric acid derived clusters are unable to explain the observations made. By using this approach, we are able to calculate the ambient concentration of sesquiterpenes at the air ion instrument inlet with a high time resolution on the daily and seasonal scale. The estimated concentration is found to reveal the same seasonal pattern as emission measurements conducted at shoot level. As expected for biogenic VOCs, the concentration is obtained highest during summer (maximum values of about 100 pptv and smallest during winter (minimum less than 1 pptv. Because of the sesquiterpenes high reactivity and its low ambient concentrations, this approach can be a first step in understanding their emission and their impact on atmospheric chemistry in more detail. The findings presented are highly relevant for emission budgets too, since boreal forests are extended over large areas of the globe.

  9. Ambient sesquiterpene concentration and its link to air ion measurements

    Directory of Open Access Journals (Sweden)

    B. Bonn

    2007-06-01

    Full Text Available Ambient air ion size distributions have been measured continuously at the Finnish boreal forest site in Hyytiälä since spring 2003. In general, these measurements show a maximum of air ions below 1.0 nm in diameter. But this physical characterization does not provide any information about the ion's chemical composition, which is one key question regarding the explanation of nucleation events observed. In this study we propose a link of the observed maximum of negative air ions between 0.56 and 0.75 nm to the so-called stabilised Criegee biradical, formed in the reaction of biogenic sesquiterpenes with ozone and predominantly destroyed by its reaction with ambient water vapour. Calculations of the electron and proton affinities of 120 kJ mol−1 (1.24 eV and of 960 kJ mol−1 support this link. Other possible candidates such as sulphuric acid derived clusters are unable to explain the observations made. By using this approach, we are able to calculate the ambient concentration of sesquiterpenes at the air ion instrument inlet with a high time resolution on the daily and seasonal scale. The estimated concentration is found to reveal the same seasonal pattern as emission measurements conducted at shoot level. As expected for biogenic VOCs, the concentration is obtained highest during summer (maximum values of about 100 pptv and smallest during winter (minimum less than 1 pptv. Because of the sesquiterpenes high reactivity and its low ambient concentrations, this approach can be a first step in understanding their emission and their impact on atmospheric chemistry in more detail. The findings presented are highly relevant for emission budgets too, since boreal forests are extended over large areas of the globe.

  10. Enhanced Salt Removal by Unipolar Ion Conduction in Ion Concentration Polarization Desalination

    Science.gov (United States)

    Kwak, Rhokyun; Pham, Van Sang; Kim, Bumjoo; Chen, Lan; Han, Jongyoon

    2016-05-01

    Chloride ion, the majority salt in nature, is ˜52% faster than sodium ion (DNa+ = 1.33, DCl- = 2.03[10-9m2s-1]). Yet, current electrochemical desalination technologies (e.g. electrodialysis) rely on bipolar ion conduction, removing one pair of the cation and the anion simultaneously. Here, we demonstrate that novel ion concentration polarization desalination can enhance salt removal under a given current by implementing unipolar ion conduction: conducting only cations (or anions) with the unipolar ion exchange membrane stack. Combining theoretical analysis, experiment, and numerical modeling, we elucidate that this enhanced salt removal can shift current utilization (ratio between desalted ions and ions conducted through electrodes) and corresponding energy efficiency by the factor ˜(D- - D+)/(D- + D+). Specifically for desalting NaCl, this enhancement of unipolar cation conduction saves power consumption by ˜50% in overlimiting regime, compared with conventional electrodialysis. Recognizing and utilizing differences between unipolar and bipolar ion conductions have significant implications not only on electromembrane desalination, but also energy harvesting applications (e.g. reverse electrodialysis).

  11. Enhanced Salt Removal by Unipolar Ion Conduction in Ion Concentration Polarization Desalination.

    Science.gov (United States)

    Kwak, Rhokyun; Pham, Van Sang; Kim, Bumjoo; Chen, Lan; Han, Jongyoon

    2016-05-09

    Chloride ion, the majority salt in nature, is ∼52% faster than sodium ion (DNa+ = 1.33, DCl- = 2.03[10(-9)m(2)s(-1)]). Yet, current electrochemical desalination technologies (e.g. electrodialysis) rely on bipolar ion conduction, removing one pair of the cation and the anion simultaneously. Here, we demonstrate that novel ion concentration polarization desalination can enhance salt removal under a given current by implementing unipolar ion conduction: conducting only cations (or anions) with the unipolar ion exchange membrane stack. Combining theoretical analysis, experiment, and numerical modeling, we elucidate that this enhanced salt removal can shift current utilization (ratio between desalted ions and ions conducted through electrodes) and corresponding energy efficiency by the factor ∼(D- - D+)/(D- + D+). Specifically for desalting NaCl, this enhancement of unipolar cation conduction saves power consumption by ∼50% in overlimiting regime, compared with conventional electrodialysis. Recognizing and utilizing differences between unipolar and bipolar ion conductions have significant implications not only on electromembrane desalination, but also energy harvesting applications (e.g. reverse electrodialysis).

  12. Experimental Study on Surface Reactions of Heavy Metal Ions With Quartz—Aqueous Ion Concentration Dependence

    Institute of Scientific and Technical Information of China (English)

    吴宏海; 吴大清; 等

    1999-01-01

    Adsorption of divalent metal ions,including Cu2+,Pb2+,Zn2+,Cd2+ and Ni2+,on quartz surface was measured as a function of metal ion concentration at 30℃under condi tions of solution pH=6.5 and ion strength I=0.1mol/L.Results of the experimental measuements can be described very well by adsorption isoterm dquations of Freudlich.The correlation coefficients(r)of adsorption isotherm lines are>0.96.Moreover,the exprimental data were interpreted on the basis of surface complexation model.Te experimental results showed that the monodentate-coordinated metal ion surface complex species(SOM+)are predominant over the bidentate-coordinated metal ion surface complex species[(SO)2M]formed only by the ions Cu2+,Zn2+ and Ni2+,And the relevant apparent surface complexation constants are lgKM=2.2-3.3 in order of KCd≥KPb>KZn>KNi≥KCu,and lgβM=5.8-6.8 in oder of βNi>βZn>βCu.Therefore,the reactive ability of the ions onto mineral surface of quartz follows the order of Cd>Pb>Zn>Ni>Cu under the above-mentioned solution conditions.The apparent surface complexation constants,influenced by the surface potential,surface species and hydrolysis of metal ions,depend mainly on the Born solvation coefficeient of the metal ions.

  13. Enhancement of Ag nanoparticles concentration by prior ion implantation

    Science.gov (United States)

    Mu, Xiaoyu; Wang, Jun; Liu, Changlong

    2017-09-01

    Thermally grown SiO2 layer on Si substrates were singly or sequentially implanted with Zn or Cu and Ag ions at the same fluence of 2 × 1016/cm2. The profiles of implanted species, structure, and spatial distribution of the formed nanoparticles (NPs) have been characterized by the cross-sectional transmission electron microscope (XTEM) and Rutherford backscattering spectrometry (RBS). It is found that pre-implantation of Zn or Cu ions could suppress the self sputtering of Ag atoms during post Ag ion implantation, which gives rise to fabrication of Ag NPs with a high density. Moreover, it has also been demonstrated that the suppressing effect strongly depends on the applied energy and mobility of pre-implanted ions. The possible mechanism for the enhanced Ag NPs concentration has been discussed in combination with SRIM simulations. Both vacancy-like defects acting as the increased nucleation sites for Ag NPs and a high diffusivity of prior implanted ions in SiO2 play key roles in enhancing the deposition of Ag implants.

  14. Ion concentration dependent tRNA folding energy landscapes

    Science.gov (United States)

    Li, Rongzhong; Cho, Samuel

    2013-03-01

    The RNA folding is highly dependent on the ionic conditions of its environment in the cell because the surrounding ions electrostatically screen the charged phosphates that line the RNA backbone. Recent studies (Cho, Pincus, and Thirumalai, PNAS, 2007; Biyun, Cho, and Thirumalai, JACS, 2011) demonstrated that the coarse-grained model we use accurately captures the RNA folding mechanisms by incorporating a Debye-Huckel potential to screen the electrostatics. We compare the ion-concentration dependent tRNA folding mechanism to the classical thermodynamic melting profiles of Crothers and co-workers, and we observe excellent agreement. We also supported our findings by performing empirical force field MD simulations with CHARMM and AMBER, and we observe remarkably comparable qualitative similarities between the average base-base distances from simulations and the empirically measured base-stacking potentials from the well-known Turner's Rules.

  15. Dynamics of microvortices induced by ion concentration polarization

    CERN Document Server

    de Valenca, Joeri; Lammertink, Rob G H; Tsai, Peichun Amy

    2015-01-01

    We investigate the coupled dynamics of the local hydrodynamics and global electric response of an electrodialysis system, which consists of an electrolyte solution adjacent to a charge selective membrane under electric forcing. Under a DC electric current, counterions transport through the charged membrane while the passage of co-ions is restricted, thereby developing ion concentration polarization (ICP) or gradients. At sufficiently large currents, simultaneous measurements of voltage drop and flow field reveal several distinct dynamic regimes. Initially, the electrodialysis system displays a steady Ohmic voltage difference ($\\Delta V_{ohm}$), followed by a constant voltage jump ($\\Delta V_c$). Immediately after this voltage increase, micro-vortices set in and grow both in size and speed with time. After this growth, the resultant voltage levels off around a fixed value. The average vortex size and speed stabilize as well, while the individual vortices become unsteady and dynamic. These quantitative results ...

  16. Ions in water: the microscopic structure of concentrated hydroxide solutions.

    Science.gov (United States)

    Imberti, S; Botti, A; Bruni, F; Cappa, G; Ricci, M A; Soper, A K

    2005-05-15

    Neutron-diffraction data on aqueous solutions of hydroxides, at solute concentrations ranging from 1 solute per 12 water molecules to 1 solute per 3 water molecules, are analyzed by means of a Monte Carlo simulation (empirical potential structure refinement), in order to determine the hydration shell of the OH- in the presence of the smaller alkali metal ions. It is demonstrated that the symmetry argument between H+ and OH- cannot be used, at least in the liquid phase at such high concentrations, for determining the hydroxide hydration shell. Water molecules in the hydration shell of K+ orient their dipole moment at about 45 degrees from the K+-water oxygen director, instead of radially as in the case of the Li+ and Na+ hydration shells. The K+-water oxygen radial distribution function shows a shallower first minimum compared to the other cation-water oxygen functions. The influence of the solutes on the water-water radial distribution functions is shown to have an effect on the water structure equivalent to an increase in the pressure of the water, depending on both ion concentration and ionic radius. The changes of the water structure in the presence of charged solutes and the differences among the hydration shells of the different cations are used to present a qualitative explanation of the observed cation mobility.

  17. Theory and experiment on the cuprous-cupric electron transfer rate at a copper electrode.

    Energy Technology Data Exchange (ETDEWEB)

    Halley, J. W.; Smith, B. B.; Walbran, S.; Curtiss, L. A.; Rigney, R. O.; Sutjianto, A.; Hung, N. C.; Yonco, R. M.; Nagy, Z.; Univ. of Minnesota; NREL

    1999-04-01

    We describe results of experiment and theory of the cuprous-cupric electron transfer rate in an aqueous solution at a copper electrode. The methods are similar to those we reported earlier for the ferrous-ferric rate. The comparison strongly suggests that, in marked distinction to the ferrous-ferric case, the electron transfer reaction is adiabatic. The model shows that the activation barrier is dominated by the energy required for the ion to approach the electrode, rather than by the energy required for rearrangement of the solvation shell, also in sharp distinction to the case of the ferric-ferrous electron transfer at a gold electrode. Calculated activation barriers based on this image agree with the experimental results reported here.

  18. Theory and experiment on the cuprous{endash}cupric electron transfer rate at a copper electrode

    Energy Technology Data Exchange (ETDEWEB)

    Halley, J.W. [School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455 (United States); Smith, B.B. [National Renewable Energy Laboratory, Golden, Colorado (United States); Walbran, S. [School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455 (United States); Curtiss, L.A.; Rigney, R.O.; Sutjianto, A.; Hung, N.C.; Yonco, R.M.; Nagy, Z. [Argonne National Laboratory, Divisions of Materials Science, Chemistry and Chemical Technology, Argonne, Illinois 60439-4837 (United States)

    1999-04-01

    We describe results of experiment and theory of the cuprous{endash}cupric electron transfer rate in an aqueous solution at a copper electrode. The methods are similar to those we reported earlier for the ferrous{endash}ferric rate. The comparison strongly suggests that, in marked distinction to the ferrous{endash}ferric case, the electron transfer reaction is adiabatic. The model shows that the activation barrier is dominated by the energy required for the ion to approach the electrode, rather than by the energy required for rearrangement of the solvation shell, also in sharp distinction to the case of the ferric{endash}ferrous electron transfer at a gold electrode. Calculated activation barriers based on this image agree with the experimental results reported here. {copyright} {ital 1999 American Institute of Physics.}

  19. Promotion of hexadecyltrimethyleamine bromide to the damage of Alexandrium sp. LC3 by cupric glutamate

    Institute of Scientific and Technical Information of China (English)

    LI Hao; MIAO Jin-lai; CUI Feng-xia; LI Guang-you

    2006-01-01

    The effect of hexadecyltrimethyleamine bromide (HDTMAB) on the removal of A lexandrium sp. LC3 under cupric glutamate stress was investigated. Toxic effect of cupric glutamate on A lexandrium sp. LC3 was significantly promoted in the presence of HDTMAB, especially at 3.0 cmc of HDTMAB. It was found that the sulfhydryl group content of the cell decreased, while the malonaldehyde content and membrane permeability increased when Alexandrium sp. LC3 was treated with HDTMAB and cupric glutamate complex, compared with cupric glutamate alone. The data suggest that HDTMAB might stimulate the damage of A lexandrium sp. LC3 by enhancing the membrane permeability.

  20. 21 CFR 868.1170 - Indwelling blood hydrogen ion concentration (pH) analyzer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Indwelling blood hydrogen ion concentration (pH... Indwelling blood hydrogen ion concentration (pH) analyzer. (a) Identification. An indwelling blood hydrogen ion concentration (pH) analyzer is a device that consists of a catheter-tip pH electrode and that is...

  1. Micro/nanofluidic Diode using Asymmetric Ion Concentration Polarization Layer

    Science.gov (United States)

    Sohn, Seoyun; Cho, Inhee; Kim, Sung Jae

    2016-11-01

    Recent developments of ion concentration polarization (ICP) theory would suggest that an over-limiting conductance (OLC) of the device is subject to the morphology of ICP layer and a micro-structure is able to alter the morphology. In this study, we demonstrated an ion rectification resulted only from asymmetric microscale structures, while conventional nanofluidic diode applications have usually employed a nanoscale asymmetry which requires sophisticate and expensive fabrication processes. We designed two dead-end microchannels incorporated with the nanoporous membrane. The difference in width of the microchannels was designed to yield asymmetry to the device. Cyclic voltammetry measurement was conducted to investigate the OLC behaviors on both forward and reverse bias. The diodic characteristics on I-V responses were observed at various ratio of the different microchannel width. In addition, we experimentally verified the logarithmical linearity between the ratios and the rectification ratios of OLC. This quantitative analysis would guide the further application utilizing microscale asymmetric diode device that now can be realized with minimum fabrication endeavors.

  2. Hydrogen ions kill brain at concentrations reached in ischemia.

    Science.gov (United States)

    Kraig, R P; Petito, C K; Plum, F; Pulsinelli, W A

    1987-08-01

    Elevation of brain glucose before the onset of nearly complete ischemia leads to increased lactic acid within brain. When excessive, such acidosis may be a necessary factor for converting selective neuronal loss to brain infarction from nearly complete ischemia. To examine the potential neurotoxicity of excessive lactic acid concentrations, we microinjected (0.5 microliter/min) 150 mM sodium lactate solutions (adjusted to 6.50-4.00 pH) for 20 min into parietal cortex of anesthetized rats. Interstitial pH (pH0) was monitored with hydrogen ion-selective microelectrodes. Animals were allowed to recover for 24 h before injection zones were examined with the light microscope. Injectants produced brain necrosis in a histological pattern resembling ischemic infarction only when pH0 was less than or equal to 5.30. Nonlethal injections showed only needle tract injuries. Abrupt deterioration of brain acid-base homeostatic mechanisms correlated with necrosis since pH0 returned to baseline more slowly after lethal tissue injections than after nonlethal ones. The slowed return of pH0 to baseline after the severely acidic injections may reflect altered function of plasma membrane antiport systems for pH regulation and loss of brain hydrogen ion buffers.

  3. Spatial Distribution Characteristics of Negative Air Ion Concentrations in Danqinghe Experimental Forest,Harbin City

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In recent years, air ions, especially of negative air ion has received a universal attention for its health function. The density of negative air ion has become one of the important indexes that measure the air quality grade. With the air ions counter made in Japan, the spatial distribution characteristics of negative air concentrations at specific time in Danqinghe Experimental Forest were measured and studied, Harbin City, and the air quality was assessed by using ion polarity ration (q) and air ion asses...

  4. Microfluidic Paper-Based Sample Concentration Using Ion Concentration Polarization with Smartphone Detection

    Directory of Open Access Journals (Sweden)

    Xue Li

    2016-11-01

    Full Text Available A simple method for microfluidic paper-based sample concentration using ion concentration polarization (ICP with smartphone detection is developed. The concise and low-cost microfluidic paper-based ICP analytical device, which consists of a black backing layer, a nitrocellulose membrane, and two absorbent pads, is fabricated with the simple lamination method which is widely used for lateral flow strips. Sample concentration on the nitrocellulose membrane is monitored in real time by a smartphone whose camera is used to collect the fluorescence images from the ICP device. A custom image processing algorithm running on the smartphone is used to track the concentrated sample and obtain its fluorescence signal intensity for quantitative analysis. Two different methods for Nafion coating are evaluated and their performances are compared. The characteristics of the ICP analytical device especially with intentionally adjusted physical properties are fully evaluated to optimize its performance as well as to extend its potential applications. Experimental results show that significant concentration enhancement with fluorescence dye sample is obtained with the developed ICP device when a fast depletion of fluorescent dye is observed. The platform based on the simply laminated ICP device with smartphone detection is desired for point-of-care testing in settings with poor resources.

  5. Stimulated low frequency Raman scattering in cupric oxide nanoparticles water suspension

    Science.gov (United States)

    Averyushkin, A. S.; Baranov, A. N.; Bulychev, N. A.; Kazaryan, M. A.; Kudryavtseva, A. D.; Strokov, M. A.; Tcherniega, N. V.; Zemskov, K. I.

    2017-04-01

    Cupric oxide nanoparticles with average size of 213.2 nm, were synthesized in acoustoplasma discharge for investigating their vibrational properties. The low-frequency acoustic mode in cupric oxide (CuO) nanoparticles has been studied by stimulated low-frequency Raman scattering (SLFRS). SLFRS conversion efficiency, threshold and frequency shift of the scattered light are measured.

  6. Impact of particle formation on atmospheric ions and particle number concentrations in an urban environment

    Science.gov (United States)

    Cheung, H. C.; Chou, C. C.-K.; Jayaratne, E. R.; Morawska, L.

    2015-04-01

    A measurement campaign was conducted from 3 to 19 December 2012 at an urban site of Brisbane, Australia. Size distribution of ions and particle number concentrations were measured to investigate the influence of particle formation and biomass burning on atmospheric ion and particle concentrations. Overall ion and particle number concentrations during the measurement period were found to be (- 1.2 × 103 cm- 3 | + 1.6 × 103 cm- 3) and 4.4 × 103, respectively. The results of correlation analysis between concentrations of ions and nitrogen oxides indicated that positive and negative ions originated from similar sources, and that vehicle exhaust emissions had a more significant influence on intermediate/large ions, while cluster ions rapidly attached to larger particles once emitted into the atmosphere. Diurnal variations in ion concentration suggested the enrichment of intermediate and large ions on new particle formation event days, indicating that they were involved in the particle formation processes. Elevated total ions, particularly larger ions, and particle number concentrations were found during biomass burning episodes. This could be due to the attachment of cluster ions onto accumulation mode particles or production of charged particles from biomass burning, which were in turn transported to the measurement site. The results of this work enhance scientific understanding of the sources of atmospheric ions in an urban environment, as well as their interactions with particles during particle formation processes.

  7. Fundamental features of copper ion precipitation using sulfide as a precipitant in a wastewater system.

    Science.gov (United States)

    Choi, Jung-Yoon; Kim, Dong-Su; Lim, Joong-Yeon

    2006-01-01

    We have investigated the precipitation features of copper ion using sulfide as a precipitant by varying the mole ratio of sulfide to copper ion, pH, temperature and the kind and concentration of complexing agent. In the precipitation of copper ion by sulfide, sludge is produced as cupric sulfide; thus, there is a possibility for its recycled use in photochemical and ceramic processes. When the ratio of the concentration of copper ion to sulfide was increased to more than 1.0, the extent of precipitation was very high. As the ratio was increased, nucleation time was decreased and crystal growth rate was raised. The higher the pH, the greater the amount of precipitated copper ion due to lowered solubility of cupric sulfide. When temperature changed from 25 degrees C to 55 degrees C, the precipitation of copper ion was increased a little. On the basis of estimated thermodynamic parameters such as Gibbs free energy and enthalpy, the precipitation reaction was spontaneous and endothermic. The precipitation of copper ion was lowered in the presence of complexing agent and it was affected by the stability of the copper complex. The feasibility test for the application of precipitation treatment to actual wastewater containing copper ion showed, although there was a little decrease in the removal of copper, the precipitation extent of copper was higher than 90% compared with that for artificial wastewater.

  8. [The relationship between PMI and concentration of potassium ion and sodium ion in swine aqueous humor after death].

    Science.gov (United States)

    Han, Ju; Yu, Guang-biao; Dong, Ye-qiang; Fang, Chao; Jing, Hua-lan; Luo, Si-min

    2010-04-01

    To explored the relationship between the concentration of potassium ion as well as sodium ion in the aqueous humor and post-mortem interval (PMI). The concentrations of potassium ion and sodium ion in the aqueous humor of swine within 48 h after death at 4 degrees C and 28 degrees C were detected using Z-500 atomic absorption spectrophotometer. The concentrations of potassium ion and sodium ion in aqueous humor of isolated swine eyeballs within 48 h after death when the environmental temperature was 4 degrees C were significantly related to PMI. The relationship between PMI and the concentration of potassium ion was PMI = -0.178[K+]2 + 49.978 (R2 = 0.995). The relationship between PMI and the rate of sodium ion and potassium ion was PMI = 120.987/[Na+/K+]-28.834 (R2 = 0.905). The concentration of potassium in aqueous humor of isolated swine eyeballs may be one of the reference indicators to estimate PMI of the corpses at lower temperatures.

  9. Natural variability in the surface ocean carbonate ion concentration

    Directory of Open Access Journals (Sweden)

    N. S. Lovenduski

    2015-11-01

    Full Text Available We investigate variability in the surface ocean carbonate ion concentration ([CO32−] on the basis of a~long control simulation with an Earth System Model. The simulation is run with a prescribed, pre-industrial atmospheric CO2 concentration for 1000 years, permitting investigation of natural [CO32−] variability on interannual to multi-decadal timescales. We find high interannual variability in surface [CO32−] in the tropical Pacific and at the boundaries between the subtropical and subpolar gyres in the Northern Hemisphere, and relatively low interannual variability in the centers of the subtropical gyres and in the Southern Ocean. Statistical analysis of modeled [CO32−] variance and autocorrelation suggests that significant anthropogenic trends in the saturation state of aragonite (Ωaragonite are already or nearly detectable at the sustained, open-ocean time series sites, whereas several decades of observations are required to detect anthropogenic trends in Ωaragonite in the tropical Pacific, North Pacific, and North Atlantic. The detection timescale for anthropogenic trends in pH is shorter than that for Ωaragonite, due to smaller noise-to-signal ratios and lower autocorrelation in pH. In the tropical Pacific, the leading mode of surface [CO32−] variability is primarily driven by variations in the vertical advection of dissolved inorganic carbon (DIC in association with El Niño–Southern Oscillation. In the North Pacific, surface [CO32−] variability is caused by circulation-driven variations in surface DIC and strongly correlated with the Pacific Decadal Oscillation, with peak spectral power at 20–30-year periods. North Atlantic [CO32−] variability is also driven by variations in surface DIC, and exhibits weak correlations with both the North Atlantic Oscillation and the Atlantic Multidecadal Oscillation. As the scientific community seeks to detect the anthropogenic influence on ocean carbonate chemistry, these results

  10. Mitochondrial dysfunction induced by different concentrations of gadolinium ion.

    Science.gov (United States)

    Zhao, Jie; Zhou, Zhi-Qiang; Jin, Jian-Cheng; Yuan, Lian; He, Huan; Jiang, Feng-Lei; Yang, Xiao-Gang; Dai, Jie; Liu, Yi

    2014-04-01

    Gadolinium-based compounds are the most widely used paramagnetic contrast agents in magnetic resonance imaging on the world. But the tricationic gadolinium ion (Gd(3+)) could induce cell apoptosis probably because of its effects on mitochondria. Until now, the mechanism about how Gd(3+) interacts with mitochondria is not well elucidated. In this work, mitochondrial swelling, collapsed transmembrane potential and decreased membrane fluidity were observed to be important factors for mitochondrial permeability transition pore (mtPTP) opening induced by Gd(3+). The protection effect of CsA (Cyclosporin A) could confirm high concentration of Gd(3+) (500 μM) would trigger mtPTP opening. Moreover, mitochondrial outer membrane breakdown and volume expansion observed clearly by transmission electron microscopy and the release of Cyt c (Cytochrome c) could explain the mtPTP opening from another aspect. In addition, MBM(+) (monobromobimane(+)) and DTT (dithiothreitol) could protect thiol (-SH) groups from oxidation so that the toxicity of Gd(3+) might be resulted from the chelation of -SH of membrane proteins by free Gd(3+). Gd(3+) could inhibit the initiation of mitochondrial membrane lipid peroxidation, so it might interact with anionic lipids too. These findings will highly contribute to the safe applications of Gd-based agents.

  11. Undisplayed Bicarbonate ion Concentration in Arterial Blood Gas Analysis.

    Science.gov (United States)

    Sathe, Aditya Balakrishna; Bhalkar, Manjiri Shashank

    2013-12-01

    Blood bicarbonate ion concentration (BcHCO3 (-)) is a vital parameter in the management of acid base disorders. In an arterial blood gas (ABG) analyzer, the BcHCO3 (-) is calculated from the values of pH and pCO2. We received four samples in a span of one year, from December 2011 to November 2012 for arterial blood gas analysis, in which the BcHCO3 (-) was not displayed by the blood gas analyzer. Based on the information available in literature, the formula for calculating the BcHCO3 (-) from pH and pCO2 was obtained and BcHCO3 (-) was calculated in all four samples mentioned above. An attempt was made to establish a clinical correlation between laboratory and clinical data of these patients. All these values of BcHCO3 (-) were above the maximum display limit of our blood gas analyzer, which was 60 mmol/L and hence, they were not displayed. All four patients had chronic respiratory disease and they were taking furosemide and / or dexamethasone. High values of BcHCO3 (-) , sometimes falling beyond the display range of the ABG analyzer, could be observed in patients of chronic respiratory disease, treated with drugs like furosemide and dexamethasone, that result in bicarbonate retention.

  12. Fractionation of inorganic arsenic by adjusting hydrogen ion concentration.

    Science.gov (United States)

    Oliveira, Andrea; Gonzalez, Mario Henrique; Queiroz, Helena Müller; Cadore, Solange

    2016-12-15

    The inorganic fraction of arsenic species, iAs=∑[As(III)+As(V)] present in fish samples can be quantified in the presence of other arsenic species also found in fishes, such as: monomethylarsonic acid (MMA), dimethylarsinic acid (DMA) and arsenobetaine (AsB). The toxic arsenic fraction was selected taking into account the dissociation constants of these arsenic species in different hydrogen ions concentration leading to the arsine formation from iAs compounds detected as As(III) by HG AAS. For thus, a microwave assisted extraction was carried out using HCl 1molL(-1) in order to maintain the integrity of the arsenic species in this mild extraction media. Recovery experiments were done for iAs fraction, in the presence of other arsenic species. The recovery values obtained for iAs fraction added were quantitative about 87-107% (for N=3, RSD⩽3%). The limit of detection (LOD), and the limit of quantification (LOQ), were 5μgkg(-1) and 16μgkg(-1) respectively.

  13. Direct DNA Analysis with Paper-Based Ion Concentration Polarization.

    Science.gov (United States)

    Gong, Max M; Nosrati, Reza; San Gabriel, Maria C; Zini, Armand; Sinton, David

    2015-11-01

    DNA analysis is essential for diagnosis and monitoring of many diseases. Conventional DNA testing is generally limited to the laboratory. Increasing access to relevant technologies can improve patient care and outcomes in both developed and developing regions. Here, we demonstrate direct DNA analysis in paper-based devices, uniquely enabled by ion concentration polarization at the interface of patterned nanoporous membranes in paper (paper-based ICP). Hepatitis B virus DNA targets in human serum are simultaneously preconcentrated, separated, and detected in a single 10 min operation. A limit of detection of 150 copies/mL is achieved without prior viral load amplification, sufficient for early diagnosis of hepatitis B. We clinically assess the DNA integrity of sperm cells in raw human semen samples. The percent DNA fragmentation results from the paper-based ICP devices strongly correlate (R(2) = 0.98) with the sperm chromatin structure assay. In all cases, agreement was 100% with respect to the clinical decision. Paper-based ICP can provide inexpensive and accessible advanced molecular diagnostics.

  14. Natural variability in the surface ocean carbonate ion concentration

    Directory of Open Access Journals (Sweden)

    N. S. Lovenduski

    2015-08-01

    Full Text Available We investigate variability in the surface ocean carbonate ion concentration ([CO32−] on the basis of a long control simulation with a fully-coupled Earth System Model. The simulation is run with a prescribed, pre-industrial atmospheric CO2 concentration for 1000 years, permitting investigation of natural [CO32−] variability on interannual to multi-decadal timescales. We find high interannual variability in surface [CO32−] in the tropical Pacific and at the boundaries between the subtropical and subpolar gyres in the Northern Hemisphere, and relatively low interannual variability in the centers of the subtropical gyres and in the Southern Ocean. Statistical analysis of modeled [CO32−] variance and autocorrelation suggests that significant anthropogenic trends in the saturation state of aragonite (Ωaragonite are already or nearly detectable at the sustained, open-ocean timeseries sites, whereas several decades of observations are required to detect anthropogenic trends in Ωaragonite in the tropical Pacific, North Pacific, and North Atlantic. The detection timescale for anthropogenic trends in pH is shorter than that for Ωaragonite, due to smaller noise-to-signal ratios and lower autocorrelation in pH. In the tropical Pacific, the leading mode of surface [CO32−] variability is primarily driven by variations in the vertical advection of dissolved inorganic carbon (DIC in association with El Niño–Southern Oscillation. In the North Pacific, surface [CO32−] variability is caused by circulation-driven variations in surface DIC and strongly correlated with the Pacific Decadal Oscillation, with peak spectral power at 20–30 year periods. North Atlantic [CO32−] variability is also driven by variations in surface DIC, and exhibits weak correlations with both the North Atlantic Oscillation and the Atlantic Multidecadal Oscillation. As the scientific community seeks to detect the anthropogenic influence on ocean carbonate chemistry, these

  15. A General Formula for Ion Concentration-Dependent Electrical Conductivities in Polymer Electrolytes

    Directory of Open Access Journals (Sweden)

    Mahardika P. Aji

    2012-01-01

    Full Text Available Problem statement: The aim of this study is to develop a model for describing the effect of ion concentration on the electrical conductivity of polymer electrolytes by considering two mechanisms simultaneously: Enhancements of ion concentration and amorphous phase. Approach: The problems based on new observations in polymer electrolyte when ion concentration in the polymer electrolytes was increased, both the fraction of amorphous phase and the charge carriers increase simultaneously. The model was based on the assumption when ions were inserted into the polymer host, there was an optimum distance between ions at which the ions move easily throughout the polymer. The average distance between ions in the polymer depends on the ion concentration. And we also considered the effect of ion concentration on the amorphous phase in the polymer. Results: We inspected the validity of the model by comparing the model predictions with various experimental data. The new analytical expressions for the electrical conductivity dependent of ion concentration was developed by considering two mechanisms simultaneously in polymer electrolytes, i.e., enhancement of the carries concentration and amorphous phase fraction. Interestingly, most of fitting parameters were not arbitrarily selected, but were derived from the appropriate experimental data. Conclusion: The model can be used to explain the conductivity behavior of other polymer electrolyte systems by selecting appropriately less number of parameters. This model result is fully supported by available experimental data.

  16. Cupric Hexacyanoferrate Nanoparticle Modified Carbon Ceramic Composite Electrodes

    Institute of Scientific and Technical Information of China (English)

    WANG,Peng(王鹏); ZHU,Guo-Yi(朱果逸)

    2002-01-01

    Graphite powder-supported cupric hexacyanoferrate (CuHCF)nanoparticles were dispersed into methyltrimethoxysilane-based gels to produce a conducting carbon ceramic composite, which was used as electrode material to fabricate surface-renewable CuHCF-modified electrodes. Electrochemical behavior of the CuHCF-modified carbon ceramic composite electrodes was characterized using cyclic and square-wave voitammetry.Cyclic voltammograms at various scan rates indicated that peak currents were surface-confined at low scan rates. In the presence of glutathione, a clear electrocatalytic response was observed at the CuHCF-modified composite electrodes. In addition, the electrodes exhibited a distinct advantage of reproducible surface-renewal by simple mechanical polishing on emery paper, as well as ease of preparation, and good chemical and mechanical stability in a flowing stream.

  17. Cupric Hexacyanoferrate Nanoparticle Modified Carbon Ceramic Composite Electrodes

    Institute of Scientific and Technical Information of China (English)

    WANG,Peng; ZHU,Guo-Yi

    2002-01-01

    Graphite powder-supported cupric hexacyanoferrate(CuHCF) nanoparticles were dispersed into methyltrimethoxysilane-based gels to produce a conducting carbon ceramic composite,which was used as electrode materials to fabricate surface-renewable CuHCF-modified electrodes.Electrochemical behavior of the CuHCF-modified carbon ceramic composite electrodes was characterized using cyclic and square-wave voltammetry. Cyclinc voltammograms at various scan rates indicated that peak currents were suface-confined at low scan rates.In the presence of glutathione,a clear electrocatalytic response was observed at the CuHCF-modified composite electrodes.In addition,the electrodes exhibited a distinct advantage of reproducible surface-renewal by simple mechanical polishing on emery paper,as well as ease of preparation,and good chemical and mechanical stability in a flowing stream.

  18. Measuring free metal ion concentrations in multicomponent solutions using Donnan Membrane Technique

    NARCIS (Netherlands)

    Kalis, E.J.J.; Temminghoff, E.J.M.; Weng, L.P.; Riemsdijk, van W.H.

    2007-01-01

    Among speciation techniques that are able to measure free metal ion concentrations, the Donnan membrane technique (DMT) has the advantage that it can measure many different free metal ion concentrations simultaneously in a multicomponent sample. Even though the DMT has been applied to several system

  19. Effects of nitrogen ion implantation on Ca2+ concentration and membrane potential of pollen cell

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The effects of low energy nitrogen ion implantation on Ca2+ concentration and membrane potential of lily (lilium davidii Duch) pollen cell have been studied. The results showed that the Ca2+ concentration was increased when pollen grain was implanted by nitrogen ion with energy 100keV and dose 1013 ions/cra2. However, the increase of Ca2+ concentration was partly inhibited by the addition of Ca2+channel inhibitor depending on dose. And nitrogen ion implantation caused depolarization of pollen cell membrane potential. In other words, membrane potential was increased,but the effect decreased by adding Ca2+ channel inhibitor.However, it was still significantly higher than the membrane potential of control cells. It was indicated that the depolarization of cell membrane potential opened the calcium channel on the membrane that caused the increasing of intraceilular calcium concentration. This might be an earlier step of the effect of low energy nitrogen ion implantation on pollen germination.

  20. Incomplete Ion Dissociation Underlies the Weakened Attraction between DNA Helices at High Spermidine Concentrations

    OpenAIRE

    Yang,Jie; Rau, Donald C

    2005-01-01

    We have investigated the salt sensitivity of the hexagonal-to-cholesteric phase transition of spermidine-condensed DNA. This transition precedes the resolubilization of precipitated DNA that occurs at high spermidine concentration. The sensitivity of the critical spermidine concentration at the transition point to the anion species and the NaCl concentration indicates that ion pairing of this trivalent ion underlies this unusual transition. Osmotic pressure measurements of spermidine salt sol...

  1. Variation and balance of positive air ion concentrations in a boreal forest

    Directory of Open Access Journals (Sweden)

    U. Hõrrak

    2008-02-01

    Full Text Available Air ions are characterized on the basis of measurements carried out in a boreal forest at the Hyytiälä SMEAR station, Finland, during the BIOFOR III campaign in spring 1999. The air ions were discriminated as small ions (charged molecular aggregates of the diameter of less than 2.5 nm, intermediate ions (charged aerosol particles of the diameter of 2.5–8 nm, and large ions (charged aerosol particles of the diameter of 8–20 nm. Statistical characteristics of the ion concentrations and the parameters of ion balance in the atmosphere are presented separately for the nucleation event days and non-event days. In the steady state, the ionization rate is balanced with the loss of small ions, which is expressed as the product of the small ion concentration and the ion sink rate. The widely known sinks of small ions are the recombination with small ions of opposite polarity and attachment to aerosol particles. The dependence of small ion concentration on the concentration of aerosol particles was investigated applying a model of the bipolar diffusion charging of particles by small ions. When the periods of relative humidity above 95% and wind speed less than 0.6 m s−1 were excluded, then the small ion concentration and the theoretically calculated small ion sink rate were closely negatively correlated (correlation coefficient −87%. However, an extra ion loss term of the same magnitude as the ion loss onto aerosol particles is needed for a quantitative explanation of the observations. This term is presumably due to the small ion deposition on coniferous forest. The hygroscopic growth correction of the measured aerosol particle size distributions was also found to be necessary for the proper estimation of the ion sink rate. In the case of nucleation burst events, the concentration of small positive ions followed the general balance equation, no extra ion loss in addition to the deposition on coniferous forest was detected, and the

  2. Ion Induced Changes in Phosphoinositide Monolayers at Phisiological Concentrations

    Science.gov (United States)

    Kazadi Badiambile, Adolphe; Forstner, Martin

    2013-03-01

    Phosphoinositides (PIPs) play a crucial role in many cellular process that occur at the plasma membrane such as calcium release, exocytosis or endocytosis. In order to specifically regulate these functions PIPs must segregate in pools at the plasma membrane. A possible mechanism that could induce and regulate such organization of phosphoinositides is their interaction with bivalent cations. Understanding the physicochemical mechanism that can regulate membrane structure is a crucial step in the development of adaptive biomimetic membrane systems. Using Langmuir monolayers, we investigated the effect of calcium and magnesium on the surface pressure-area/lipid isotherm of monolayer of phosphatidylinositol (PI), phosphatidylinositol bisphosphate (PIP2), dioleoylphosphatidylglycerol (DOPG) and palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC). It is found that the decrease of area per lipid, i.e. the increase in aggregation, is mostly dependent on the lipid's head group charge but ion specific. In addition, we discuss changes in free energy and compressibility of these monolayer-ion systems. NSF

  3. Use of Na clinoptilolite for concentrating silver and nickel ions from wastes

    Energy Technology Data Exchange (ETDEWEB)

    Rustamov, S.M.; Makhmudov, F.T.

    1988-06-20

    The authors report experimental results obtained by concentrating silver ions (Ag/sup +/) and complex nickel ions (Ni(NH/sub 3/)/sub 6/)/sup 2 +/ from actual industrial wastes on Na clinoptilolite. Silver and nickel were concentrated from liquid wastes of photographic processing after electrolytic treatment, and from wastes of multiproduct conversion of serpentine rock after production of magnesium sulfate. The Ag/sup +/ and (Ni(NH/sub 3/)/sub 6/)/sup 2 +/ ions were concentrated from the liquid wastes as follows: the liquid wastes with initial Ag/sup +/ and (Ni(NH/sub 3/)/sub 6/)/sup 2 +/ ion contents c/sub 0/ = 1.14 x 10/sup -4/ and 6.14 x 10/sup -3/ meq/ml respectively were passed at linear velocities v = 0.70 and 0.50 cm/sec through Na clinoptilolite beds in columns (50 g of sorbent in each column) until sorbent was saturated with the ions. The Ag/sup +/ and (Ni(NH/sub 3/)/sub 6/)/sup 2 +/ ions were then desorbed by passing NaNO/sub 3/ and NaCl solutions respectively through the columns at 0.05 cm/sec until these ions were removed completely from the columns. On the average, 14-fold concentrations of Ag/sup +/ and (Ni(NH/sub 3/)/sub 6/)/sup 2 +/ ions from these liquids has been achieved.

  4. Incomplete ion dissociation underlies the weakened attraction between DNA helices at high spermidine concentrations.

    Science.gov (United States)

    Yang, Jie; Rau, Donald C

    2005-09-01

    We have investigated the salt sensitivity of the hexagonal-to-cholesteric phase transition of spermidine-condensed DNA. This transition precedes the resolubilization of precipitated DNA that occurs at high spermidine concentration. The sensitivity of the critical spermidine concentration at the transition point to the anion species and the NaCl concentration indicates that ion pairing of this trivalent ion underlies this unusual transition. Osmotic pressure measurements of spermidine salt solutions are consistent with this interpretation. Spermidine salts are not fully dissociated at higher concentrations. The competition for DNA binding among the fully charged trivalent ion and the lesser charged complex species at higher concentrations significantly weakens attraction between DNA helices in the condensed state. This is contrary to the suggestion that the binding of spermidine at higher concentrations causes DNA overcharging and consequent electrostatic repulsion.

  5. Ion-sensitive field effect transistors for pH and potassium ion concentration sensing: towards detection of myocardial ischemia

    Science.gov (United States)

    Rai, Pratyush; Jung, Soyoun; Ji, Taeksoo; Varadan, Vijay K.

    2008-03-01

    Ion Sensitive Field Effect Transistors (ISFETs) for sensing change in ionic concentration in biological systems can be used for detecting critical conditions like Myocardial Ischemia. Having the ability to yield steady signal characteristics can be used to observe the ionic concentration gradients which mark the onset of ischemia. Two ionic concentrations, pH and [K +], have been considered as the indicator for Myocardial Ischemia in this study. The ISFETs in this study have an organic semi-conductor film as the electronically active component. Poly-3 hexylthiophene was chosen for its compatibility to the solution processing, which is a simple and economical method of thin film fabrication. The gate electrode, which regulates the current in the active layer, has been employed as the sensor element. The devices under study here were fabricated on a flexible substrate PEN. The pH sensor was designed with the Tantalum Oxide gate dielectric as the ion selective component. The charge accumulated on the surface of the metal oxide acts as the source of the effecter electric field. The device was tested for pH values between 6.5 and 7.5, which comprises the variation observed during ischemic attack. The potassium ion sensor has got a floating gate electrode which is functionalized to be selective to potassium ion. The device was tested for potassium ion concentration between 5 and 25 mM, which constitutes the variation in extra cellular potassium ion concentration during ischemic attack. The device incorporated a monolayer of Valinomycin, a potassium specific ionophore, on top of the gate electrode.

  6. EVALUATION OF THE CONCENTRATION OF PHOSPHATE ION IN WATER RESOURCES OF SOME CITIES OF PARANAENSE COAST

    OpenAIRE

    CUNHA, Ellen Joana Nunes Santos; ROCHA, José Roberto Caetano da

    2015-01-01

    This paper presents the results of the concentration of macronutrient phosphorus in the form of phosphate ion. These results were obtained spectrophotometrically by the molybdenum blue method using river water samples from four locations in the coastal cities of Paraná state. The tests showed that the concentration of this particular ion was much higher than the amount recommended in Resolution 357 of the National Envi...

  7. High concentration of calcium ions in Golgi apparatus

    Institute of Scientific and Technical Information of China (English)

    XUESHAOBAI; M.ROBERTNICOUD; 等

    1994-01-01

    The interphase NIH3T3 cells were vitally fluorescentstained with calcium indicator fluo-3 and Glogi probe C6-NBD-ceramide,and then the single cells were examined by laser scanning confocal microscopy(LSCFM) for subcellular distributions of Ca2+ and the location of Golgi apparatus.In these cells,the intracellular Ca2+ were found to be highly concentrated in the Golgi apparatus.The changes of distribution of cytosolic high Ca2+ region and the Golgi apparatus coincided with the cell cycle phase.In calcium free medium,when the plasma membrane of the cells which had been loaded with fluo-3/AM were permeated by digitonin,the fluorescence of the Golgi region decreased far less than that of the cytosol.Our results indicated that the Glogi lumen retained significantly high concentration of free calcium.

  8. Evaluation of Cu Ion Concentration Effects on Cu Etching Rate in Chemical-Mechanical Polishing Slurry

    Science.gov (United States)

    Nishizawa, Hideaki; Sugiura, Osamu; Matsumura, Yoshiyuki; Kinoshita, Masaharu

    2007-04-01

    The effects of Cu ion concentration of the different solutions on Cu etching rate were investigated. From the dipping experiment of Cu substrates in different solutions of malic acid, hydrogen peroxide (H2O2), benzotriazole (BTA), and Cu ions, it was revealed that Cu etching rate is increased if the concentration of Cu(II) ions added in the solution is high. This is considered to be caused by the effect of Cu(II) ions on H2O2 molecules. In the solution of pH 7, the Cu etching rate increased markedly between 1.7× 10-4 and 3.4× 10-4 M Cu(II) ion concentrations. The maximum increase in the etching rate was from 990 to 2200 nm/min at a H2O2 concentration of 2 wt %. In the solution of pH 3, a marked change in the etching rate was not observed. Our results show that the concentration of Cu ions on the polishing pad in chemical-mechanical polishing (CMP) process is very important.

  9. A simple, fast and cost-effective method of synthesis of cupric oxide nanoparticle with promising antibacterial potency: Unraveling the biological and chemical modes of action.

    Science.gov (United States)

    Chakraborty, Ruchira; Sarkar, Raj Kumar; Chatterjee, Arijit Kumar; Manju, Unnikrishnan; Chattopadhyay, Asoke Prasun; Basu, Tarakdas

    2015-04-01

    Gradual attainment of bacterial resistance to antibiotics led us to develop a robust method of synthesis of stable, colloidal cupric oxide nanoparticle of physiological pH with potential antibacterial action. Cu(II) oxide NP was synthesized by reduction-oxidation of CuCl2, using polyvinyl alcohol as stabilizer. Characteristics and antibacterial activity of the particles were investigated by techniques like UV-Vis spectrophotometry, DLS, AFM, TEM, EDS, FTIR, AAS, agar plating, FACS, gel electrophoresis and XPS. The NPs were about 50 nm in size and cubic in shape with two surface plasmon peaks at 266 and 370 nm and had semi-conducting behavior with a band gap of 3.40 and 3.96 eV. About 80% of precursor CuCl2 was converted to NP. The minimum inhibitory and the minimum bactericidal concentrations of CuO-NP were respectively 120 and 160 μg/mL for Escherichia coli and 180 and 195 μg/mL for Staphylococcus aureus in Luria-Bertani medium. In growth media, the NPs got modified by media organics with displacement of the stabilizer PVA molecules. This modified NP (around 240 nm) killed cells by generating ROS, which finally caused membrane lipid per-oxidation and chromosomal DNA degradation in NP-treated cells. Reports indicate that we are among the few who had prepared CuO-NP in colloidal form. The antibacterial potency of our particle in growth media was much promising than other reports. Our findings demonstrated that 'particle-specific' effect, not 'ion-specific' one, was responsible for the NP action. The NP may be used as a sterilizing agent in various bioprocesses and as substituent of antibiotics, after thorough toxicological study. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Concentration Dependent Ion-Protein Interaction Patterns Underlying Protein Oligomerization Behaviours

    Science.gov (United States)

    Batoulis, Helena; Schmidt, Thomas H.; Weber, Pascal; Schloetel, Jan-Gero; Kandt, Christian; Lang, Thorsten

    2016-04-01

    Salts and proteins comprise two of the basic molecular components of biological materials. Kosmotropic/chaotropic co-solvation and matching ion water affinities explain basic ionic effects on protein aggregation observed in simple solutions. However, it is unclear how these theories apply to proteins in complex biological environments and what the underlying ionic binding patterns are. Using the positive ion Ca2+ and the negatively charged membrane protein SNAP25, we studied ion effects on protein oligomerization in solution, in native membranes and in molecular dynamics (MD) simulations. We find that concentration-dependent ion-induced protein oligomerization is a fundamental chemico-physical principle applying not only to soluble but also to membrane-anchored proteins in their native environment. Oligomerization is driven by the interaction of Ca2+ ions with the carboxylate groups of aspartate and glutamate. From low up to middle concentrations, salt bridges between Ca2+ ions and two or more protein residues lead to increasingly larger oligomers, while at high concentrations oligomers disperse due to overcharging effects. The insights provide a conceptual framework at the interface of physics, chemistry and biology to explain binding of ions to charged protein surfaces on an atomistic scale, as occurring during protein solubilisation, aggregation and oligomerization both in simple solutions and membrane systems.

  11. Fluorescence study on the interaction between apoCopC and cupric

    Institute of Scientific and Technical Information of China (English)

    PANG Erguo; ZHAO Yaqin; YANG Binsheng

    2005-01-01

    The interaction between apoCopC and cupric was investigated by fluorescence spectra, in phosphate (20 mmol/L) buffer at pH 6.0. Results suggest that the environment is measured to be hydrophobic completely around tryptophan (83). At the same time, apoCopC fluorescence at 320 nm was significantly quenched with the addition of cupric and the 1:1 stoichiometric ratio of apoCopC to cupric was confirmed by fluorescence. In addition, the conditional binding constants were calculated to be Kcu-Copc = (1.8(0.58)× 1013 mol-1 L on the basis of the results of fluorescence titration curves. The apoCopC has the ability to bind specifically cupricion.

  12. A Concentration-Controllable Microfluidic Droplet Mixer for Mercury Ion Detection

    Directory of Open Access Journals (Sweden)

    Qian-Fang Meng

    2015-07-01

    Full Text Available A microfluidic droplet mixer is developed for rapid detection of Hg(II ions. Reagent concentration and droplets can be precisely controlled by adjusting the flow rates of different fluid phases. By selecting suitable flow rates of the oil phase, probe phase and sample phase, probe droplets and sample droplets can be matched and merged in pairs and subsequently well-mixed in the poly (dimethylsiloxane (PDMS channels. The fluorescence enhancement probe (Rhodamine B mixed with gold nanoparticles encapsulated in droplets can react with Hg(II ions. The Hg(II ion concentration in the sample droplets is adjusted from about 0 to 1000 nM through fluid regulation to simulate possible various contaminative water samples. The intensity of the emission fluorescence is sensitive to Hg(II ions (increases as the Hg(II ion concentration increases. Through the analysis of the acquired fluorescence images, the concentration of Hg(II ions can be precisely detected. With the advantages of less time, cost consumption and easier manipulations, this device would have a great potential in micro-scale sample assays and real-time chemical reaction studies.

  13. Effects of Organic Corrosion Inhibitor and Chloride Ion Concentration on Steel Depassivation and Repassivation in Solution

    Institute of Scientific and Technical Information of China (English)

    WANG Zixiao; YU Lei; LIU Zhiyong; SONG Ning

    2015-01-01

    Effect of an organic corrosion inhibitor (OCI) named PCI-2014 added in chloride solution on the critical chlo-ride concentration of mild steel depassivation and the critical OCI concentrations for repairing the steel in different chlo-ride solution were investigated. The results show that the critical chloride concentration increases exponentially with raises of PCI-2014 concentration in the solution. Within a certain chloride ion concentration range, the critical PCI-2014 concentration for repairing the corroded steel is also increases exponentially with enhancement of chloride content in the solution. Atomic force microscopy images display the molecular particles of inhibitor are adsorbed on the steel surface and formed a protective layer. Analysis of X-ray photoelectron spectroscopy shows the chloride ions at the surface of steel are displaced by atoms or molecules of the inhibitor in chloride condition.

  14. Effects of Organic Corrosion Inhibitor and Chloride Ion Concentration on Steel Depassivation and Repassivation in Solution

    Institute of Scientific and Technical Information of China (English)

    WANG; Zixiao; YU; Lei; LIU; Zhiyong; SONG; Ning

    2015-01-01

    Effect of an organic corrosion inhibitor(OCI) named PCI-2014 added in chloride solution on the critical chloride concentration of mild steel depassivation and the critical OCI concentrations for repairing the steel in different chloride solution were investigated.The results show that the critical chloride concentration increases exponentially with raises of PCI-2014 concentration in the solution.Within a certain chloride ion concentration range,the critical PCI-2014 concentration for repairing the corroded steel is also increases exponentially with enhancement of chloride content in the solution.Atomic force microscopy images display the molecular particles of inhibitor are adsorbed on the steel surface and formed a protective layer.Analysis of X-ray photoelectron spectroscopy shows the chloride ions at the surface of steel are displaced by atoms or molecules of the inhibitor in chloride condition.

  15. Knowledge Representation of Ion-Sensitive Field-Effect Transistor Voltage Response for Potassium Ion Concentration Detection in Mixed Potassium/Ammonium Ion Solutions

    Directory of Open Access Journals (Sweden)

    Wan F.H. Abdullah

    2010-01-01

    Full Text Available Problem statement: The Ion-Sensitive Field-Effect Transistor (ISFET is a metal-oxide field-effect transistor-based sensor that reacts to ionic activity at the electrolye/membrane/gate interface. The ionic sensor faces issue of selectivity from interfering ions that contribute to the sensor electrical response in mixed solutions. Approach: We present the training data collection of ISFET voltage response for the purpose of post-processing stage neural network supervised learning. The role of the neural network is to estimate the main ionic activity from the interfering ion contribution in mixed solutions given time-independent input voltages. In this work, potassium ion (K+ and ammonium ion (NH4+ ISFET response data are collected with readout interface circuit that maintains constant voltage and current bias levels to the ISFET drain-source terminals. Sample solutions are prepared by keeping the main ion concentration fixed while the activity of an interfering ion varied based on the fixed interference method. Results: Sensor demonstrates linear relationship to the ion concentration within detection limit but has low repeatability of 0.52 regression factor and 0.16 mean squared error between similarly repeated measurements. We find that referencing the voltage response to the sensor response in DIW prior to measurement significantly improves the repeatability by 15.5% for correlation and 98.3% for MSE. Demonstration of multilayer perceptron feed-forward neural network estimation of ionic concentration from the data collection shows a recognition of >0.8 regression factor. Conclusion: Time-independent DC voltage response of ISFET of the proposed setup can be used as training data for neural network supervised learning for the estimation of K+ in mixed K+/NH4+ solutions.

  16. [Development of conductometric biosensor based on alkaline phosphatase for determining concentration of cadmium ions].

    Science.gov (United States)

    Sosovs'ka, O F; Berezhets'kyĭ, A L

    2007-01-01

    The paper describes a novel conductometric biosensor sensitive to cadmium ions based on alkaline phosphatase immobilized on gold planar microelectrodes used as transducers. Assays have been carried out with paranitrophenyl phosphate as substrate for the immobilized enzyme. Various parameters such as reticulation time, along with pH, ionic strength and buffer concentration of the measuring solution were studied. The optimized biosensor was stable, reproducible and it exhibited a detection limit of 4.45 microM for cadmium ions.

  17. Potentiometric Sensor for Real-Time Monitoring of Multivalent Ion Concentrations in Molten Salt

    Energy Technology Data Exchange (ETDEWEB)

    Peter A. Zink; Jan-Fong Jue; Brenda E. Serrano; Guy L. Fredrickson; Ben F. Cowan; Steven D. Herrmann; Shelly X. Li

    2010-07-01

    Electrorefining of spent metallic nuclear fuel in high temperature molten salt systems is a core technology in pyroprocessing, which in turn plays a critical role in the development of advanced fuel cycle technologies. In electrorefining, spent nuclear fuel is treated electrochemically in order to effect separations between uranium, noble metals, and active metals, which include the transuranics. The accumulation of active metals in a lithium chloride-potassium chloride (LiCl-KCl) eutectic molten salt electrolyte occurs at the expense of the UCl3-oxidant concentration in the electrolyte, which must be periodically replenished. Our interests lie with the accumulation of active metals in the molten salt electrolyte. The real-time monitoring of actinide concentrations in the molten salt electrolyte is highly desirable for controlling electrochemical operations and assuring materials control and accountancy. However, real-time monitoring is not possible with current methods for sampling and chemical analysis. A new solid-state electrochemical sensor is being developed for real-time monitoring of actinide ion concentrations in a molten salt electrorefiner. The ultimate function of the sensor is to monitor plutonium concentrations during electrorefining operations, but in this work gadolinium was employed as a surrogate material for plutonium. In a parametric study, polycrystalline sodium beta double-prime alumina (Na-ß?-alumina) discs and tubes were subject to vapor-phase exchange with gadolinium ions (Gd3+) using a gadolinium chloride salt (GdCl3) as a precursor to produce gadolinium beta double-prime alumina (Gd-ß?-alumina) samples. Electrochemical impedance spectroscopy and microstructural analysis were performed on the ion-exchanged discs to determine the relationship between ion exchange and Gd3+ ion conductivity. The ion-exchanged tubes were configured as potentiometric sensors in order to monitor real-time Gd3+ ion concentrations in mixtures of gadolinium

  18. Potentiometric Sensor for Real-Time Monitoring of Multivalent Ion Concentrations in Molten Salt

    Energy Technology Data Exchange (ETDEWEB)

    Peter A. Zink; Jan-Fong Jue; Brenda E. Serrano; Guy L. Fredrickson; Ben F. Cowan; Steven D. Herrmann; Shelly X. Li

    2010-07-01

    Electrorefining of spent metallic nuclear fuel in high temperature molten salt systems is a core technology in pyroprocessing, which in turn plays a critical role in the development of advanced fuel cycle technologies. In electrorefining, spent nuclear fuel is treated electrochemically in order to effect separations between uranium, noble metals, and active metals, which include the transuranics. The accumulation of active metals in a lithium chloride-potassium chloride (LiCl-KCl) eutectic molten salt electrolyte occurs at the expense of the UCl3-oxidant concentration in the electrolyte, which must be periodically replenished. Our interests lie with the accumulation of active metals in the molten salt electrolyte. The real-time monitoring of actinide concentrations in the molten salt electrolyte is highly desirable for controlling electrochemical operations and assuring materials control and accountancy. However, real-time monitoring is not possible with current methods for sampling and chemical analysis. A new solid-state electrochemical sensor is being developed for real-time monitoring of actinide ion concentrations in a molten salt electrorefiner. The ultimate function of the sensor is to monitor plutonium concentrations during electrorefining operations, but in this work gadolinium was employed as a surrogate material for plutonium. In a parametric study, polycrystalline sodium beta double-prime alumina (Na-ß?-alumina) discs and tubes were subject to vapor-phase exchange with gadolinium ions (Gd3+) using a gadolinium chloride salt (GdCl3) as a precursor to produce gadolinium beta double-prime alumina (Gd-ß?-alumina) samples. Electrochemical impedance spectroscopy and microstructural analysis were performed on the ion-exchanged discs to determine the relationship between ion exchange and Gd3+ ion conductivity. The ion-exchanged tubes were configured as potentiometric sensors in order to monitor real-time Gd3+ ion concentrations in mixtures of gadolinium

  19. Analyzing free zinc(II) ion concentrations in cell biology with fluorescent chelating molecules.

    Science.gov (United States)

    Maret, Wolfgang

    2015-02-01

    Essential metal ions are tightly controlled in biological systems. An understanding of metal metabolism and homeostasis is being developed from quantitative information of the sizes, concentrations, and dynamics of cellular and subcellular metal ion pools. In the case of human zinc metabolism, minimally 24 proteins of two zinc transporter families and a dozen metallothioneins participate in cellular uptake, extrusion, and re-distribution among cellular compartments. Significantly, zinc(ii) ions are now considered signaling ions in intra- and intercellular communication. Such functions require transients of free zinc ions. It is experimentally quite challenging to distinguish zinc that is protein-bound from zinc that is not bound to proteins. Measurement of total zinc is relatively straightforward with analytical techniques such as atomic absorption/emission spectroscopy or inductively coupled plasma mass spectrometry. Total zinc concentrations of human cells are 200-300 μM. In contrast, the pool of non-protein bound zinc is mostly examined with fluorescence microscopy/spectroscopy. There are two widely applied fluorescence approaches, one employing low molecular weight chelating agents ("probes") and the other metal-binding proteins ("sensors"). The protein sensors, such as the CALWY, Zap/ZifCY, and carbonic anhydrase-based sensors, can be genetically encoded and have certain advantages in terms of controlling intracellular concentration, localization, and calibration. When employed correctly, both probes and sensors can establish qualitative differences in free zinc ion concentrations. However, when quantitative information is sought, the assumptions underlying the applications of probes and sensors must be carefully examined and even then measured pools of free zinc ions remain methodologically defined. A consensus is building that the steady-state free zinc ion concentrations in the cytosol are in the picomolar range but there is no consensus on their

  20. Dopant concentration dependence of the response of SiC Schottky diodes to light ions

    Energy Technology Data Exchange (ETDEWEB)

    De Napoli, M. [Dipartimento di Fisica e Astronomia, Universita degli Studi di Catania, Via S. Sofia 64, I-95123 Catania (Italy); Laboratori Nazionali del Sud, Via S. Sofia 62, I-95123 Catania (Italy); Giacoppo, F. [Laboratori Nazionali del Sud, Via S. Sofia 62, I-95123 Catania (Italy); Dipartimento di Fisica, Universita degli Studi di Messina, Via Salita Sperone 31, I-98166 Messina (Italy); Raciti, G. [Dipartimento di Fisica e Astronomia, Universita degli Studi di Catania, Via S. Sofia 64, I-95123 Catania (Italy); Isituto Nazionale di Fisica Nucleare, Sezione di Catania, Via S. Sofia 64, I-95123 Catania (Italy)], E-mail: raciti@lns.infn.it; Rapisarda, E. [Dipartimento di Fisica e Astronomia, Universita degli Studi di Catania, Via S. Sofia 64, I-95123 Catania (Italy); Isituto Nazionale di Fisica Nucleare, Sezione di Catania, Via S. Sofia 64, I-95123 Catania (Italy)

    2009-03-11

    The responses of Silicon Carbide (SiC) Schottky diodes of different dopant concentration to {sup 12}C ions at 14.2, 28.1 and 37.6 MeV incident energies are compared. The relation between the applied reverse bias and the thickness of the depleted epitaxial region is studied for different dopant concentrations. The experimental data show that SiC diodes with lower dopant concentration need lower reverse bias to be depleted. Moreover it has been observed that the energy resolution, measured as a function of the applied reverse bias and of the ions incident energies, does not depend on the dopant concentration. The radiation damage, produced by irradiating SiC diodes of different dopant concentration with {sup 16}O ions at 35.2 MeV, was evaluated by measuring the degradation of both the signal pulse-height and the energy resolution as a function of the {sup 16}O fluence. Diodes having a factor 20 lower dopant concentration exhibit a radiation hardness reduced by 60%. No inversion in the signal at the breakdown fluence was observed for {sup 16}O ions stopped inside the diode epitaxial region.

  1. Types and concentrations of metal ions affect local structure and dynamics of RNA

    Science.gov (United States)

    Wang, Jun; Xiao, Yi

    2016-10-01

    The roles that metal ions play in the structure and dynamics of RNA molecules are long-standing problems that have been studied extensively but are still not well understood. Here we show that metal ions have distributions around RNA molecules that strongly depend on the types and concentrations of the metal ions and also the electrostatic surface of the molecule. In particular, the ion distributions may not balance all the local electronegativity of the molecule. These ion distributions do not only greatly affect local structures but also lead to different local dynamics of RNA. We studied the effects of different ion solutions on the structure and dynamics of RNA by taking the pre Q1 riboswitch aptamer domain as an illustrative example and using molecular dynamics simulations. Since the local structures and dynamics of RNAs are important to their functions, our results also indicate that the selection of proper ion conditions is necessary to model them correctly, in contrast to the use of diverse ion solutions in current molecular dynamics simulations.

  2. Measurement of free heavy metal ion concentrations in soils using Donnan membrane technique

    Institute of Scientific and Technical Information of China (English)

    YI Li; HONG Yetang; WENG Liping; ZHU Yongxuan

    2005-01-01

    In natural systems heavy metals are present in very low concentrations (less than micro-molar), so precise measurement of the free metal ions is difficult. Recently, a new method has been developed called the Donnan membrane technique (DMT). Several heavy metals could be measured simultaneously using this method. Furthermore, all the metals did not interfere with each other, and the balance between the measured system and the surrounding condition could not be disturbed. Improvements were made according to the internal condition. The free heavy metal ion concentrations were measured in different systems using the improved method, and satisfied results have been obtained.

  3. Dependence of ion concentration in simulated body fluid on apatite precipitation on titania surface

    Science.gov (United States)

    Sakaguchi, Akira; Nakano, Masayuki; Hieda, Junko; Ohtake, Naoto; Akasaka, Hiroki

    2015-08-01

    Titanium and its alloys are used as biomaterials, because of their high biocompatibility. Apatite precipitates on a titania surface in vivo, and living bone and titanium alloy are coupled through the thin apatite layer. The initial precipitation behavior of apatite on titania in simulated body fluid (SBF) solutions was evaluated and the effect of inorganic ions in the SBF was investigated. Measurement using the SPR phenomenon was used to evaluate the initial apatite precipitation. An SBF containing approximately equal ion concentrations to those in blood plasma was added to a titania surface and the SPR profile was obtained, from which the initial apatite precipitation rate was found to be 1.14 nm/h. Furthermore, the relationship between the inorganic concentration and the precipitation rate was determined for SBFs with different Na+ and Ca2+ concentrations. Apatite precipitation did not occur in the SBF with a low Na+ concentration, whereas the initial apatite precipitation rate in the SBF that did not contain Ca2+ was 0.32 nm/h. According to these results, Ca2+ has little effect on the initial apatite precipitation. In the initial reaction of apatite precipitation, sodium titanate is formed by the absorption of Na+. Next, calcium titanate precipitates upon the substitution of Na+ with Ca2+. Finally, Na+, phosphate ions and hydroxyl ions are attracted to the surface and apatite is formed. Thus, the rate-limiting factor in the initial nucleation of apatite is the Na+ concentration.

  4. Influence of ion sterics on diffusiophoresis and electrophoresis in concentrated electrolytes

    Science.gov (United States)

    Stout, Robert F.; Khair, Aditya S.

    2017-01-01

    We quantify the diffusiophoresis and electrophoresis of a uniformly charged, spherical colloid in a binary electrolyte using modified Poisson-Nernst-Planck equations that account for steric repulsion between finite sized ions. Specifically, we utilize the Bikerman (Bik) lattice gas model and the Carnahan-Starling (CS) and Boublik-Mansoori-Carnahan-Starling-Leland (BMCSL) equations of state for monodisperse and polydisperse, respectively, hard spheres. We compute the phoretic mobility for weak applied fields using an asymptotic approach for thin diffuse layers, where ion steric effects are expected to be most prevalent. The thin diffuse layer limit requires λD/R →0 , where λD is the Debye screening length and R is the particle radius; this limit is readily attained for micron-sized colloids in concentrated electrolytic solutions. It is well known that the classic Poisson-Boltzmann (PB) model for pointlike, noninteracting ions leads to a prediction of a maximum in both the diffusiophoretic and electrophoretic mobilities with increasing particle zeta potential (at fixed λD/R ). In contrast, we find that ion sterics essentially eliminate this maximum (for reasonably attainable zeta potentials) and increase the mobility relative to PB. Next, we consider the more experimentally relevant case of a particle with a constant surface charge density and vary the electrolyte concentration, neglecting charge regulation on surface active sites. Rather surprisingly, there is little difference between the predictions of the four models (PB, Bik, CS, and BMCSL) for electrophoretic mobility in concentrated solutions, at reasonable surface charge densities (˜1 -10 μ C /cm2 ). This is because as the concentration increases, the zeta potential is reduced (to below the thermal voltage for concentrations above about 1 M) and therefore the diffuse layer structure is largely unaffected by ion sterics. For gradients of symmetric electrolytes (equal diffusivities, charge, and size

  5. Variations of ion concentrations in the deep ice core and surface snow at NEEM, Greenland

    Science.gov (United States)

    Goto-Azuma, K.; Wegner, A.; Hansson, M.; Hirabayashi, M.; Kuramoto, T.; Miyake, T.; Motoyama, H.; NEEM Aerosol Consortium members

    2012-04-01

    Discrete samples were collected from the CFA (Continuous Flow Analysis) melt fractions during the field campaign carried out at NEEM, Greenland in 2009-2011, and were distributed to different laboratories. Ionic species were analyzed at National Institute of Polar Research (Japan) and Alfred Wegener Institute for Polar and Marine Research (Germany). Here we present and compare the ion concentration data obtained by both institutes. Most of the ions show good agreement between the two institutes. As is indicated with the CFA data (Bigler and the NEEM Aerosol Consortium members, EGU 2012), ion chromatograph data also display that calcium and sodium, mainly originated from terrestrial dust and sea-salt, respectively, show large variations associated with Dansgaard-Oeschger (DO) events. Chloride, fluoride, sulfate, sodium, potassium and magnesium also show such variations, as has been already reported for other Greenland ice cores. New ion data obtained from the NEEM deep core also show large variability of oxalate and phosphate concentrations during DO events. Acetate, which is thought to be mainly derived from biomass burning, as is oxalate, appears to show variability associated with DO events, but to a lesser extent. On the other hand, nitrate, ammonium and methanesulfonate do not show such variations. Together with ion data from the deep ice core, we present those from the pits dug during the NEEM field campaign to discuss seasonal variations of ionic species. The seasonal and millennial scale variations of ions are thought to be caused by changes in atmospheric circulation and source strength.

  6. Nanostructured cupric oxide electrode: An alternative to amperometric detection of carbohydrates in anion-exchange chromatography.

    Science.gov (United States)

    Barragan, José T C; Kubota, Lauro T

    2016-02-01

    In this paper, a new and low cost copper/cupric oxide nanostructured electrode is presented as an alternative to the amperometric detection of carbohydrates in high-performance anion exchange chromatography. The modified copper electrodes were prepared by a simple and fast method which resulted in the obtainment of homogeneously distributed nanostructures adhered to the surface with controlled chemical nature. The results, when compared to conventional copper electrodes, exhibited considerable improvements in analytical results, including: 1) Better repeatability in consecutive glucose detections, in which the percent relative standard deviation improved from 15.1% to 0.279%. 2) Significant improvements in the stability of the baseline and a decrease of the stabilization time, going from several hours to approximately 15 min. 3) Considerable increase in the sensitivity towards glucose, from 5.02 nA min mg L(-1) to 25.5 nA min mg L(-1). 4) Improvements in the detectability with limits as low as 1.09 pmol. 5) Wide working range of concentrations (1 × 10(-2) to 1 × 10(4) mg L(-1)). 6) Good linearity with correlation coefficients greater than 0.998. 7) Possibility of detecting different molecules of carbohydrates (lactose, maltose, sucrose cellobiose, sorbitol, fructose, glucose, galactose, manose, arabitol, xylose, ribose and arabnose). In comparison to the electrode that is more employed for this type of application (gold electrode), the low cost, the possibility of detection at constant potential and the equivalent detection limits presented by the new electrode material introduced in this work emerge as characteristics that make this material a powerful alternative considering the detection of carbohydrates in anion exchange chromatography.

  7. A synthetic ion transporter that disrupts autophagy and induces apoptosis by perturbing cellular chloride concentrations

    Science.gov (United States)

    Busschaert, Nathalie; Park, Seong-Hyun; Baek, Kyung-Hwa; Choi, Yoon Pyo; Park, Jinhong; Howe, Ethan N. W.; Hiscock, Jennifer R.; Karagiannidis, Louise E.; Marques, Igor; Félix, Vítor; Namkung, Wan; Sessler, Jonathan L.; Gale, Philip A.; Shin, Injae

    2017-07-01

    Perturbations in cellular chloride concentrations can affect cellular pH and autophagy and lead to the onset of apoptosis. With this in mind, synthetic ion transporters have been used to disturb cellular ion homeostasis and thereby induce cell death; however, it is not clear whether synthetic ion transporters can also be used to disrupt autophagy. Here, we show that squaramide-based ion transporters enhance the transport of chloride anions in liposomal models and promote sodium chloride influx into the cytosol. Liposomal and cellular transport activity of the squaramides is shown to correlate with cell death activity, which is attributed to caspase-dependent apoptosis. One ion transporter was also shown to cause additional changes in lysosomal pH, which leads to impairment of lysosomal enzyme activity and disruption of autophagic processes. This disruption is independent of the initiation of apoptosis by the ion transporter. This study provides the first experimental evidence that synthetic ion transporters can disrupt both autophagy and induce apoptosis.

  8. Calculation of multicomponent ionic diffusion from zero to high concentration: II. Inclusion of associated ion species

    Science.gov (United States)

    Felmy, Andrew R.; Weare, John H.

    1991-01-01

    This paper presents a theoretical model of multicomponent ionic diffusion which is valid to high concentration for systems which show ion association. The development is completely general for species which do not react with the solvent. It is demonstrated that the Onsager phenomenological coefficients for associated ion species can be unambiguously determined only in solutions where the concentration of these species can be independently measured. In all other instances, only combinations of the Onsager coefficients for the bare ions and the ion pairs can be experimentally determined. The results of our formulations are contrasted with those of more simplified models for systems containing Na 2SO 4 and MgSO 4, as well as for multicomponent natural seawater. The differences between our model and simplified models are significant, especially at high concentration. Inconsistencies which may develop with the use of the simplified approaches are demonstrated. Our approach requires considerable data which are not available at temperatures other than 25°C. Therefore, other approaches which are based only on data at infinite dilution are of great interest. We show here that, if chemical potential derivatives are included in the infinite dilution model of Nernst and Hartley which uses only infinite dilution mobilities, the model can be extended to slightly concentrated solutions. This extended Nernst-Hartley model gives good agreement with all of the existing experimental mutual diffusion coefficient data at concentrations below about 0.2 M in the six component system Na-K-Ca-Mg-Cl-SO 4-H 2O. This may be the most reliable way to extend infinite dilution data into more concentrated regions. In the systems we have studied, the inclusion of ion-association species for weakly interacting species does not appear to provide significant improvement over our generalized Nernst-Hartley model.

  9. Nonlinear Dynamics of Ion Concentration Polarization in Porous Media: The Leaky Membrane Model

    CERN Document Server

    Dydek, E Victoria

    2013-01-01

    The conductivity of highly charged membranes is nearly constant, due to counter-ions screening pore surfaces. Weakly charged porous media, or "leaky membranes", also contain a significant concentration of co-ions, whose depletion at high current leads to ion concentration polarization and conductivity shock waves. To describe these nonlinear phenomena the absence of electro-osmotic flow, a simple Leaky Membrane Model is formulated, based on macroscopic electroneutrality and Nernst-Planck ionic fluxes. The model is solved in cases of unsupported binary electrolytes: steady conduction from a reservoir to a cation-selective surface, transient response to a current step, steady conduction to a flow-through porous electrode, and steady conduction between cation-selective surfaces in cross flow. The last problem is motivated by separations in leaky membranes, such as shock electrodialysis. The article begins with a tribute to Neal Amundson, whose pioneering work on shock waves in chromatography involved similar mat...

  10. A new approach to endocochlear potential and potassium ion concentration measures in mini pig models

    Institute of Scientific and Technical Information of China (English)

    Lili Ren a; Ling Zhang b; Weiwei Guo a; Wei Sun c; Shiming Yang a

    2014-01-01

    Mini pig models are large mammals and their ears are more similar with human beings in structure and development than other animals. However, the study on porcine ears is still in the initial stage and there is no description of an ideal operation approach to endocochlear potential and potassium ion concentration measurements. In this article, we describe a pre-auricular surgical approach to access the middle and inner ear for endocochlear potential and potassium ion concentration measures in mini pig models. Ten one-week old normal mini pigs were used in the study. The bulla of the temporal bone was accessed via a pre-auricular approach for endocochlear potential and potassium ion concentration measurements. The condition of the animals during the first posteexperiment 24 h was observed. One animal died during surgery. The pre-auricular approach improved protection and preservation of relevant nervous and vascular elements including the facial nerve and carotid ar-tery. So, the pre-auricular approach can be used for endocochlear potential and potassium ion concentration measurements with improved nerve and artery preservation mini pigs.

  11. Combined effects of water temperature and copper ion concentration on catalase activity in Crassostrea ariakensis

    Science.gov (United States)

    Wang, Hui; Yang, Hongshuai; Liu, Jiahui; Li, Yanhong; Liu, Zhigang

    2015-07-01

    A central composite experimental design and response surface method were used to investigate the combined effects of water temperature (18-34°C) and copper ion concentration (0.1-1.5 mg/L) on the catalase (CAT) activity in the digestive gland of Crassostrea ariakensis. The results showed that the linear effects of temperature were significant ( P0.05), and the quadratic effects of copper ion concentration were significant ( P0.05), and the effect of temperature was greater than that of copper ion concentration. A model equation of CAT enzyme activity in the digestive gland of C. ariakensis toward the two factors of interest was established, with R 2, Adj. R 2 and Pred. R 2 values as high as 0.943 7, 0.887 3 and 0.838 5, respectively. These findings suggested that the goodness of fit to experimental data and predictive capability of the model were satisfactory, and could be practically applied for prediction under the conditions of the study. Overall, the results suggest that the simultaneous variation of temperature and copper ion concentration alters the activity of the antioxidant enzyme CAT by modulating active oxygen species metabolism, which may be utilized as a biomarker to detect the effects of copper pollution.

  12. OPTIMIZATION OF TIME REACTION AND HYDROXIDE ION CONCENTRATION ON FLAVONOID SYNTHESIS FROM BENZALDEHYDE AND ITS DERIVATIVES

    Directory of Open Access Journals (Sweden)

    Sri Handayani

    2010-06-01

    Full Text Available The aim of this research is to determine the optimum time of reaction and concentration of hydroxide ion on chalcone, 4-methoxychalcone and 3,4-dimethoxychalcone synthesis. Chalcone and its derivatives were synthesized by dissolving KOH in ethanol followed by dropwise addition of acetophenone and benzaldehyde. Then, the mixture was stirred for several hours. Three benzaldehydes has been used, i.e : benzaldehyde, p-anysaldehyde and veratraldehyde. The time of reaction was varied for, 12, 18, 24, 30 and 36 hours. Furthermore, on the optimum reaction time for each benzaldehyde the hydroxyl ion concentration was varied from 5,7,9,11 and 13%(w/v. The results of this research suggested that the optimum time of chalchone synthesis was 12 hours, while, 4-methoxychalcone and 3,4-dimethoxychalcone were 30 hours. The optimum concentration of hydroxide ion of chalcone synthesis was 13% and for 4-methoxychalcone and 3,4-dimethoxychalcone were 11%. Keywords: Chalcone synthesis, time of reaction, hydroxide ion concentration.

  13. Ion concentrations in seagrass: A comparison of results from field and controlled-environment studies

    Science.gov (United States)

    Garrote-Moreno, Aurora; Cambridge, Marion; Sánchez-Lizaso, Jose Luis

    2016-11-01

    Osmoregulation is essential for the survival of seagrasses in marine and hypersaline environments. The aim of this study was to examine ion concentrations of four seagrass species (Posidonia australis, P. sinuosa, Amphibolis antarctica and A. griffithii) after exposure to salinity changes. Plant fragments were placed in a series of aquaria at marine salinity (35) and, after one week of acclimation, exposed for 7 days to salinities between 20 and 70. Cl-, Na+ and total ion concentration increased with salinity in leaf tissue of the four seagrasses species. These results were compared with those of P. australis and A. antarctica samples collected at three locations at Shark Bay, Western Australia where higher salinities occurred, ranging from 46 to 51. Concentrations of K+ and Ca+2 were higher in seagrass tissues from Shark Bay than in those in aquarium trials. Cl-, Na+ and total ions in P. australis and A. antarctica from Shark Bay were lowest at the highest salinity location. The K+/Na+ ratio in the aquarium trials (under ambient conditions) was in the following order: A. antarctica = A. griffithii > P. australis > P. sinuosa and Ca+2/Na+ ratio was: A. antarctica = A. griffithii > P. sinuosa > P. australis. This species order indicates a physiological capacity to tolerate variation in salinity. Furthermore, these ratios were higher in the locality with highest salinity in Shark Bay, indicating acclimation and adaptation of ion concentrations to the salinity regime in the environment.

  14. Electrochemical activation and inhibition of neuromuscular systems through modulation of ion concentrations with ion-selective membranes

    Science.gov (United States)

    Song, Yong-Ak; Melik, Rohat; Rabie, Amr N.; Ibrahim, Ahmed M. S.; Moses, David; Tan, Ara; Han, Jongyoon; Lin, Samuel J.

    2011-12-01

    Conventional functional electrical stimulation aims to restore functional motor activity of patients with disabilities resulting from spinal cord injury or neurological disorders. However, intervention with functional electrical stimulation in neurological diseases lacks an effective implantable method that suppresses unwanted nerve signals. We have developed an electrochemical method to activate and inhibit a nerve by electrically modulating ion concentrations in situ along the nerve. Using ion-selective membranes to achieve different excitability states of the nerve, we observe either a reduction of the electrical threshold for stimulation by up to approximately 40%, or voluntary, reversible inhibition of nerve signal propagation. This low-threshold electrochemical stimulation method is applicable in current implantable neuroprosthetic devices, whereas the on-demand nerve-blocking mechanism could offer effective clinical intervention in disease states caused by uncontrolled nerve activation, such as epilepsy and chronic pain syndromes.

  15. Chromium and cobalt ion concentrations in blood and serum following various types of metal-on-metal hip arthroplasties

    DEFF Research Database (Denmark)

    Jantzen, Christopher; Jørgensen, Henrik L; Duus, Benn R

    2013-01-01

    Widely different metal ion concentrations in blood and serum have been reported with metal-on-metal (MoM) implants. We reviewed the literature on blood and serum ion concentrations of chromium (Cr) and cobalt (Co) following various MoM hip arthroplasties.......Widely different metal ion concentrations in blood and serum have been reported with metal-on-metal (MoM) implants. We reviewed the literature on blood and serum ion concentrations of chromium (Cr) and cobalt (Co) following various MoM hip arthroplasties....

  16. A Simplified Model to Estimate the Concentration of Inorganic Ions and Heavy Metals in Rivers

    Directory of Open Access Journals (Sweden)

    Clemêncio Nhantumbo

    2016-10-01

    Full Text Available This paper presents a model that uses only pH, alkalinity, and temperature to estimate the concentrations of major ions in rivers (Na+, K+, Mg2+, Ca2+, HCO3−, SO42−, Cl−, and NO3− together with the equilibrium concentrations of minor ions and heavy metals (Fe3+, Mn2+, Cd2+, Cu2+, Al3+, Pb2+, and Zn2+. Mining operations have been increasing, which has led to changes in the pollution loads to receiving water systems, meanwhile most developing countries cannot afford water quality monitoring. A possible solution is to implement less resource-demanding monitoring programs, supported by mathematical models that minimize the required sampling and analysis, while still being able to detect water quality changes, thereby allowing implementation of measures to protect the water resources. The present model was developed using existing theories for: (i carbonate equilibrium; (ii total alkalinity; (iii statistics of major ions; (iv solubility of minerals; and (v conductivity of salts in water. The model includes two options to estimate the concentrations of major ions: (1 a generalized method, which employs standard values from a world-wide data base; and (2 a customized method, which requires specific baseline data for the river of interest. The model was tested using data from four monitoring stations in Swedish rivers with satisfactory results.

  17. Relationship between ion concentration of ferrofluid and response signals of magnetic nanoparticles against ac magnetic fields

    Science.gov (United States)

    Oda, Shoya; Kitamoto, Yoshitaka

    2017-05-01

    Harmonic components of magnetic signals from ferrofluids excited by alternating magnetic fields are studied in view of applications to liquid sensing. The harmonic signals from ferrofluids of iron-oxide magnetic nanoparticles excited at the field strength of 100 mTp-p and the frequency range from 1510-6500 Hz are detected by a pickup coil and are processed with a lock-in amplifier. The harmonic signal exhibits a minimum in the frequency dependence at a frequency, which is correlated to the magnetic relaxation. The minimum frequency is decreased and the minimum value is increased with the increase of the ion concentration; the frequency dependence around the minimum frequency exhibits characteristic features depending on the ion concentration. The features are originated from polydispersity in the aggregation formed in the ferrofluids at higher ion concentration, and are different from the frequency characteristics depending on the viscosity. This magnetic relaxometry using the harmonic signals is useful for ion sensing in liquids without the influence of viscosity.

  18. Relationship between ion concentration of ferrofluid and response signals of magnetic nanoparticles against ac magnetic fields

    Directory of Open Access Journals (Sweden)

    Shoya Oda

    2017-05-01

    Full Text Available Harmonic components of magnetic signals from ferrofluids excited by alternating magnetic fields are studied in view of applications to liquid sensing. The harmonic signals from ferrofluids of iron-oxide magnetic nanoparticles excited at the field strength of 100 mTp-p and the frequency range from 1510−6500 Hz are detected by a pickup coil and are processed with a lock-in amplifier. The harmonic signal exhibits a minimum in the frequency dependence at a frequency, which is correlated to the magnetic relaxation. The minimum frequency is decreased and the minimum value is increased with the increase of the ion concentration; the frequency dependence around the minimum frequency exhibits characteristic features depending on the ion concentration. The features are originated from polydispersity in the aggregation formed in the ferrofluids at higher ion concentration, and are different from the frequency characteristics depending on the viscosity. This magnetic relaxometry using the harmonic signals is useful for ion sensing in liquids without the influence of viscosity.

  19. Separation and Concentration of Indium from Leaching Solution Containing Indium, Antimony and Iron Ions

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Processing conditions of effectively separating indium from the leaching solution of a smelting antimony slag were studied. For the leaching solution containing indium and antimony and iron ions, indium was separated by extracting with HDEHP-kerosine solution, washing antimony and iron ions with oxalic acid solution and stripping indium with a dilute solution of hydrochloric acid. InCl3 solution with purity above 90% is obtained. Indium can be enriched through a circulation of stripping with a dilute HCl solution. The concentration of InCl3 solution is about 25~30 g/L.

  20. Niobium-gallium oxide with a high concentration of Cr3+ ions: Photoluminescence and structural characteristics

    Science.gov (United States)

    Costa, G. K. B.; Pedro, S. S.; López, A.; Carvalho, I. C. S.; Cella, N.; Sosman, L. P.

    2016-10-01

    This work presents photoluminescence data for gallium-niobium oxide with chromium ion as an impurity. The samples were obtained by the solid-state method (SSM) and the wet-chemical method (WCM) and investigated by X-ray diffraction, photoluminescence, excitation, and photoacoustic and X-ray fluorescence. The color of the sample obtained by the SSM was pink, while the color of the sample prepared by the WCM was green. This dramatic difference was associated with Cr3+ concentration and with the neighborhood of the doping ions, obtained from crystallographic data, which is strongly dependent on the preparation method. The difference between the samples was also verified in the photoacoustic and excitation spectra, in which the energy bands were located at different energy levels; on the other hand, in the photoluminescence spectra, no band shift was observed. All spectra were assigned to chromium ions at nonequivalent octahedral sites.

  1. Influence of concentration of zinc ions on electrocrystallization process of zinc

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhao

    2005-01-01

    Cyclic voltammetry, chronoamperometry and scanning electron microscopy were employed to study the influence of Zn2+ ion concentration in electrolyte solutions on zinc electroplating process. The results show that, at high overpotentials, the nucleation of zinc is instantaneous, and nuclear density increases with the overpotentials increasing. While at low overpotentials, the zinc may be preferentially electrodeposited on surface inhomogeneities such as emergence points of edge, screw dislocations, atomic disorder, kink sites, or monoatomic steps, and no distinguished nucleation current can be observed. The major dissolution peak in cyclic voltammogram drifts positively due to the change of the rate-determining step of zinc electroplating processes from diffusion to the electrochemical reaction with the increase of Zn2+ ion concentration.

  2. Concrete Durability. Influence of chloride ions concentrations in mixing water and dissolution

    Directory of Open Access Journals (Sweden)

    López Villarino, Begoña

    1995-03-01

    Full Text Available The most aggressive situation which is responsible for most of the cases of steel reinforcement corrosion in concrete, takes place when chlorides are present in the environment. These chlorides destroy the passivating film of steel and promote the denominated pitting corrosion. In order to study the demonstrated corrosive action of chloride ions on concrete structures, a number of experiments have been designed, to quantify the effect of different amounts of this ion in concrete. Several mixes have been prepared with portland cement type II-C-35 to which it has been added, as an additive in mixing water, NaCl in increasing concentrations. The samples obtained were submerged in different dissolutions of NaCl. From the results obtained it is clear that the chloride content in mixing water does not affect the flux of calcium ions; however, its influence on the flux of chloride ions is significant. Likewise, it is confirmed that the existence of chloride ions in dissolution influences the migration of calcium and chloride ions.

    La situación más agresiva, y la responsable del mayor número de casos de corrosión de armaduras en el hormigón, se da cuando en el ambiente hay presencia de cloruros, pues éstos destruyen de forma puntual la capa pasivante del acero, lo que provoca la denominada corrosión por picaduras. Con objeto de estudiar la demostrada acción perniciosa de los cloruros sobre las estructuras de hormigón, se ha diseñado un conjunto de ensayos con el fin de cuantificar el efecto de las distintas cantidades de este ion en la masa de hormigón. Se han realizado diversas amasadas con cemento tipo II-C-35 a las que se añadió, como aditivo en el agua de amasado, NaCl en concentraciones crecientes. Las probetas obtenidas se sumergieron en disoluciones de NaCl de distintas concentraciones. De los resultados obtenidos se deduce que la presencia de cloruros en el agua de amasado no afecta al flujo de iones cálcicos, mientras

  3. The Synthesis of Highly Aligned Cupric Oxide Nanowires by Heating Copper Foil

    Directory of Open Access Journals (Sweden)

    Jianbo Liang

    2011-01-01

    Full Text Available We have investigated the effects of grain size and orientation of copper substrates for the growth of cupric oxide nanowires by thermal oxidation method. Long, less-roughness, high-density, and aligned cupric oxide nanowires have been synthesized by heating (200 oriented copper foils with small grain size in air gas. Long and aligned nanowires of diameter around 80 nm can only be formed within a short temperature range from 400 to 700°C. On the other hand, uniform, smooth-surface, and aligned nanowires were not formed in the case of larger crystallite size of copper foils with (111 and (200 orientation. Smaller grain size of copper foil with (200 orientation is favorable for the growth of highly aligned, smooth surface, and larger-diameter nanowires by thermal oxidation method.

  4. Thermodynamics of interface formation between Hexa-Peri Hexabenzocoronene and Cupric oxide

    Energy Technology Data Exchange (ETDEWEB)

    Manwani, Krishna; Panda, Emila, E-mail: emila@iitgn.ac.in

    2015-02-27

    A thermodynamic formalism has been developed to predict the formation of an ultra-thin interfacial layer at a solid–solid interface. To derive the thermodynamic expressions at crystalline–crystalline as well as crystalline–amorphous interfaces, as used in this study, Miedema's semi-empirical approach is used. This formalism is then applied to understand the interfacial layer formation between the organic Hexa-Peri Hexabenzocoronene and inorganic Cupric oxide layers at room temperature. It is found that, graphene interfacial layer formation is thermodynamically favorable. This prediction is in agreement with the experimental observations from literature. - Highlights: • Formalism was developed to predict ultra-thin interfacial layer between solids. • This is unique to similar and dissimilar systems with scarce thermodynamic data. • Applicability was tested to Hexa-Peri Hexabenzocoronene–Cupric oxide interface. • Model predicted graphene interfacial layer is concurrent with experimental results.

  5. High gradient magnetic filtration of cupric oxide and fly ash particles

    Energy Technology Data Exchange (ETDEWEB)

    Lua, A.C. [Nanyang Technological University (Singapore). School of Mechanical and Production Engineering

    1996-12-31

    High gradient magnetic filtration (HGMF) tests have been carried out on cupric oxide particles and power plant fly ash which were dispersed in air streams. An experimental test rig was set up to conduct these tests. Results showed that for cupric oxide particles, filtration efficiencies of up to 95% were obtained for submicron sizes with dust loadings of up to 0.36 time the matrix volume. For fly ash, filtration efficiencies of up to 65% were obtained for submicron particles. However, all particle sizes showed progressive deterioration in efficiencies with loading. At the end of the test, the matrix had collected 0.52 times its own mass of fly ash. 2 refs., 7 figs.

  6. Relationship between the concentration of spermatozoa and alkali ions in the semen

    Directory of Open Access Journals (Sweden)

    H. V. Maksymjuk

    2012-03-01

    Full Text Available It was found that destabilization of the low, medium and high concentrations of К+ in seminal fluid, spermatozoa and sperm is related to the hypo- and hyperfunctions of genitals’ generative tissues. The unmatched К+ concentrations and constant ratios of Са2+, К+ and Na+ under presence of normofunction and destabilization of their contents and ratios in seminal plasma and spermatozoa under hypo- and hyperfunction indicate that the features of ion homeostasis in sperm are programmed at the genetic level.

  7. Entanglement concentration and teleportation of multipartite entangled states in an ion trap

    Institute of Scientific and Technical Information of China (English)

    Pan Chang-Ning; Fang Mao-Fa

    2007-01-01

    We propose an effective scheme for the entanglement concentration of a four-particle state via entanglement swapping in an ion trap. Taking the maximally entangled state after concentration as a quantum channel, we can faithfully and determinatively teleport quantum entangled states from Alice to Bob without the joint Bell-state measurement. In the process of constructing the quantum channel, we adopt entanglement swapping to avoid the decrease of entanglement during the distribution of particles. Thus our scheme provides a new prospect for quantum teleportation over a longer distance. Furthermore, the success probability of our scheme is 1.0.

  8. Serum Metal Ion Concentrations in Paediatric Patients following Total Knee Arthroplasty Using Megaprostheses

    Directory of Open Access Journals (Sweden)

    Jörg Friesenbichler

    2014-01-01

    Full Text Available The purpose of this study was to determine the concentrations of cobalt, chromium, and molybdenum in the serum of paediatric tumour patients after fixed hinge total knee arthroplasty. Further, these metal ion levels were compared with serum metal ion levels of patients with other orthopaedic devices such as hip and knee prostheses with metal-on-metal or metal-on-polyethylene articulation to find differences between anatomical locations, abrasion characteristics, and bearing surfaces. After an average follow-up of 108 months (range: 67 to 163 of 11 paediatric patients with fixed hinge total knee arthroplasty, the mean concentrations for Co and Cr were significantly increased while Mo was within the limits compared to the upper values from the reference laboratory. Furthermore, these serum concentrations were significantly higher compared to patients with a standard rotating hinge device (P=0.002 and P<0.001 and preoperative controls (P<0.001. On the other hand, the serum levels of patients following MoM THA or rotating hinge arthroplasty using megaprostheses were higher. Therefore, periodic long-term follow-ups are recommended due to the rising concerns about systemic metal ion exposure in the literature. Upon the occurrence of adverse reactions to metal debris the revision of the fixed hinge implant should be considered.

  9. Highly Efficient and Versatile Acetalization of Glycol Catalyzed by Cupric p-Toluenesulfonate

    Institute of Scientific and Technical Information of China (English)

    LIU,Cai-Hua; YU,Xin-Yu; LIANG,Xue-Zheng; WANG,Wen-Juan; YANG,Jian-Guo; HE,Ming-Yuan

    2007-01-01

    Acetalization of glycol with carbonyl compounds was carried out catalyzed by cupric p-toluenesulfonate. These carbonyl compounds included cyclohexanone, propionoaldehyde, n-butyraldehyde, iso-butyraldehyde, n-valeraldehyde, benzaldehyde and butanone. Satisfactory results were obtained: the conversions of these carbonyl compounds were more than 90%, the selectivities were higher than 99.1%, only 0.1% mole ratio of catalyst to substrate and 90 min were sufficient in most cases. The catalyst and products were separated easily by phase separation.

  10. NTP technical report on the toxicity studies of Cupric Sulfate (CAS No. 7758-99-8) Administered in Drinking Water and Feed to F344/N Rats and B6C3F1 Mice.

    Science.gov (United States)

    Hebert, Charles

    1993-07-01

    Cupric sulfate is an inorganic salt which is widely used in industry, agriculture, and veterinary medicine. Its applications include use as an algicide in potable waters and as a feed additive and therapeutic agent in swine, sheep, and cattle. Because copper salts are found in human water supplies, toxicity studies of cupric sulfate pentahydrate were conducted in male and female F344/N rats and B6C3F1 mice by the drinking water (2-week studies only) and dosed feed routes (2-week and 13-week studies). Animals were evaluated for hematology, clinical chemistry, urinalysis, reproductive toxicity, tissue metal accumulation, and histopathology. In the 2-week drinking water studies, groups of five rats and five mice per sex received cupric sulfate at concentrations of 300 to 30,000 ppm for 15 days. One female rat, one male mouse, and three female mice in the 3000 ppm groups and all rats and mice in the 10,000 and 30,000 ppm groups died before the end of the studies. The remaining mice and rats in the 3000 ppm groups gained little or lost weight. Water consumption in the three highest dose groups of both species was reduced by more than 65%. Clinical signs observed in these groups were typical of those seen in moribund animals and were attributed to dehydration. The only gross or microscopic change specifically related to cupric sulfate toxicity was an increase in the size and number of cytoplasmic protein droplets in the epithelium of the renal proximal convoluted tubule in male rats from the 300 and 1000-ppm groups. In the 2-week feed studies, groups of five rats and five mice per sex were fed diets containing 1000 to 16,000 ppm cupric sulfate. No chemical-related deaths occurred in any dose group. Compared to the controls, rats and mice in the two highest dose groups had reduced body weight gains which were attributed to decreased feed consumption. Hyperplasia with hyperkeratosis of the squamous epithelium on the limiting ridge of the forestomach was seen in rats and

  11. The effect of Cu (II) on the electro-olfactogram (EOG) of the Atlantic salmon (Salmo salar L) in artificial freshwater of varying inorganic carbon concentrations

    DEFF Research Database (Denmark)

    Winberg, S; Bjerselius, R; Baatrup, E;

    1993-01-01

    The effect of inorganic copper species was studied by recording the receptor potential, electro-olfactogram (EOG), from the olfactory epithelium of Atlantic salmon (Salmo salar L). In a series of experiments, the olfactory organ was irrigated with aqueous copper solutions with concentrations...... of the free cupric ion (Cu2+) ranging from 0.2 to 9.7 microM. The diverse copper species were created by varying the amount of bicarbonate (NaHCO3) in artificial freshwater solutions of equal total copper concentrations. In general, these copper solutions induced a slow depolarization of the baseline followed...... by a hyperpolarization. The amplitudes of these variations in baseline potentials increased with increasing concentrations of Cu2+ ion, i.e., decreasing concentrations of NaHCO3. Stimulating the olfactory epithelium with L-alanine during the copper exposure evoked atypical EOG responses. The amplitudes and form...

  12. Estimation of free copper ion concentrations in blood serum using T1 relaxation rates

    Science.gov (United States)

    Blicharska, Barbara; Witek, Magdalena; Fornal, Maria; MacKay, Alex L.

    2008-09-01

    The water proton relaxation rate constant R1 = 1/ T1 (at 60 MHz) of blood serum is substantially increased by the presence of free Cu 2+ ions at concentrations above normal physiological levels. Addition of chelating agents to serum containing paramagnetic Cu 2+ nulls this effect. This was demonstrated by looking at the effect of adding a chelating agent—D-penicillamine (D-PEN) to CuSO 4 and CuCl 2 aqueous solutions as well as to rabbit blood serum. We propose that the measurement of water proton spin-lattice relaxation rate constants before and after chelation may be used as an alternative approach for monitoring the presence of free copper ions in blood serum. This method may be used in the diagnosis of some diseases (leukaemia, liver diseases and particularly Wilson's disease) because, in contrast to conventional methods like spectrophotometry which records the total number of both bound and free ions, the proton relaxation technique is sensitive solely to free paramagnetic ions dissolved in blood serum. The change in R1 upon chelation was found to be less than 0.06 s -1 for serum from healthy subjects but greater than 0.06 s -1 for serum from untreated Wilson's patients.

  13. [Spatiotemporal distribution of negative air ion concentration in urban area and related affecting factors: a review].

    Science.gov (United States)

    Huang, Xiang-Hua; Wang, Jian; Zeng, Hong-Da; Chen, Guang-Shui; Zhong, Xian-Fang

    2013-06-01

    Negative air ion (NAI) concentration is an important indicator comprehensively reflecting air quality, and has significance to human beings living environment. This paper summarized the spatiotemporal distribution features of urban NAI concentration, and discussed the causes of these features based on the characteristics of the environmental factors in urban area and their effects on the physical and chemical processes of NAI. The temporal distribution of NAI concentration is mainly controlled by the periodic variation of solar radiation, while the spatial distribution of NAI concentration along the urban-rural gradient is mainly affected by the urban aerosol distribution, underlying surface characters, and urban heat island effect. The high NAI concentration in urban green area is related to the vegetation life activities and soil radiation, while the higher NAI concentration near the water environment is attributed to the water molecules that participate in the generation of NAI through a variety of ways. The other environmental factors can also affect the generation, life span, component, translocation, and distribution of NAI to some extent. To increase the urban green space and atmospheric humidity and to maintain the soil natural attributes of underlying surface could be the effective ways to increase the urban NAI concentration and improve the urban air quality.

  14. Research of the Temperature and Humidity Processes in the Air Conditioning Apparatus Varying Air Ion Concentration

    Directory of Open Access Journals (Sweden)

    Marchenko V. G.

    2015-12-01

    Full Text Available To create comfortable conveniences for people in the room, we have to process the indoor air in the AC apparatus. Depending on given air parameters in the room, the air processing comprises the next steps: heating, cooling, wetting, drying. Except the compliance of the temperature and humidity parameters of air, we must control its ionic composition. Thereby, the experimental analysis of the air preparing in the AC apparatus is given in this article. Thank to that analysis, we can estimate the ionic and deionic impact on the air space in the specific processes of the air preparing. According to the results of experiments, we have identified, that the air temperature varying does not have significant effect on the ionic concentration. The ionic increasing after electric heater is not associated with air temperature. It is the consequence of the electron extrication from the surface of the heating element. Reducing ion moving the high air humidity decreases the concentration of the lightweight ions. The increasing of the ions in the spray-type air washers is explained by ballo-electric effect of spraying water drops, but not the air humidity rising.

  15. A Microfluidic Long-Period Fiber Grating Sensor Platform for Chloride Ion Concentration Measurement

    Directory of Open Access Journals (Sweden)

    Jian-Neng Wang

    2011-09-01

    Full Text Available Optical fiber sensors based on waveguide technology are promising and attractive in chemical, biotechnological, agronomy, and civil engineering applications. A microfluidic system equipped with a long-period fiber grating (LPFG capable of measuring chloride ion concentrations of several sample materials is presented. The LPFG-based microfluidic platform was shown to be effective in sensing very small quantities of samples and its transmitted light signal could easily be used as a measurand. The investigated sample materials included reverse osmosis (RO water, tap water, dilute aqueous sample of sea sand soaked in RO water, aqueous sample of sea sand soaked in RO water, dilute seawater, and seawater. By employing additionally a chloride ion-selective electrode sensor for the calibration of chloride-ion concentration, a useful correlation (R2 = 0.975 was found between the separately-measured chloride concentration and the light intensity transmitted through the LPFG at a wavelength of 1,550 nm. Experimental results show that the sensitivity of the LPFG sensor by light intensity interrogation was determined to be 5.0 × 10−6 mW/mg/L for chloride ion concentrations below 2,400 mg/L. The results obtained from the analysis of data variations in time-series measurements for all sample materials show that standard deviations of output power were relatively small and found in the range of 7.413 × 10−5–2.769 × 10−3 mW. In addition, a fairly small coefficients of variations were also obtained, which were in the range of 0.03%–1.29% and decreased with the decrease of chloride ion concentrations of sample materials. Moreover, the analysis of stability performance of the LPFG sensor indicated that the random walk coefficient decreased with the increase of the chloride ion concentration, illustrating that measurement stability using the microfluidic platform was capable of measuring transmitted optical power with accuracy in the range of −0

  16. Ability of freshwater fish to extract oxygen at different hydrogen-ion concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Wiebe, A.H.; McGavock, A.M.; Fuller, A.C.; Markus, H.C.

    1934-01-01

    Pruthi's observations on the stickleback at pH 3.1 have been confirmed for the stickleback as well as several other species of fresh-water fish. Pruthi's criticism of the work of Powers is invalid within the pH range to which the fish are acclimated. The initial oxygen has either no effect on the lethal oxygen or the effect is in the opposite direction from that suggested by Pruthi. Outside of the pH range normal to the species in question the lethal oxygen is dependent in a large measure on the initial oxygen. Several species of freshwater fish--largemouth blackbass, smallmouth blackbass, white crappie, yellow perch, rainbow trout, as well as the goldfish and green sunfish--have the ability to extract oxygen from the water at low oxygen tensions equally well over a fairly wide range of hydrogen-ion concentration. The bluegill has a somewhat narrower range of toleration. The two species of minnow--steel-colored and bluntnose--tolerate a markedly narrower range of difference in hydrogen-ion concentration as shown by the lethal oxygen. The ability of fish to extract oxygen from the water at low pressure depends more or less on the hydrogen-ion concentration of water. The results obtained in this investigation confirm the studies on pH tolerance of fish previously published. These results also confirm the observations that in highly alkaline water fish require a higher concentration of oxygen to survive.

  17. Analysis of drifting electron concentration in a self-magnetically insulated ion diode

    Science.gov (United States)

    Pushkarev, A. I.; Pak, V. G.

    2015-02-01

    The drifting electron concentration in a self-magnetically insulated ion diode is analyzed using a TEMP-4M accelerator operating in a double bipolar pulse regime with the first pulse (300-600 ns and 150-200 kV) being negative and the second (120 ns and 250-300 kV) being positive. The electron concentration in the drift region is shown to be 1013-1014 cm-3. It is established that the Lorentz force acting on electrons in crossed electric and magnetic fields is 150-200 times greater than the Coulomb repulsion force, which ensures a higher electron concentration in the drift region as compared with the space charge region.

  18. Effects of size and concentration on diffusion-induced stress in lithium-ion batteries

    Science.gov (United States)

    Ma, Zengsheng; Gao, Xiang; Wang, Yan; Lu, Chunsheng

    2016-07-01

    Capacity fade of lithium-ion batteries induced by chemo-mechanical degradation during charge-discharge cycles is the bottleneck in design of high-performance batteries, especially high-capacity electrode materials. Stress generated due to diffusion-mechanical coupling in lithium-ion intercalation and deintercalation is accompanied by swelling, shrinking, and even micro-cracking. In this paper, we propose a theoretical model for a cylindrical nanowire electrode by combining the bond-order-length-strength and diffusion theories. It is shown that size and concentration have a significant influence on the stress fields in radial, hoop, and axial directions. This can explain why a smaller electrode with a huge volume change survives in the lithiation/delithiation process.

  19. Effects of ion concentration on the hydrogen bonded structure of water in the vicinity of ions in aqueous NaCl solutions

    Indian Academy of Sciences (India)

    A Nag; D Chakraborty; A Chandra

    2008-01-01

    Molecular dynamics simulations of dilute and concentrated aqueous NaCl solutions are carried out to investigate the changes of the hydrogen bonded structures in the vicinity of ions for different ion concentrations. An analysis of the hydrogen bond population in the first and second solvation shells of the ions and in the bulk water is done. Although essentially no effect of ions on the hydrogen bonding is observed beyond the first solvation shell of the ions for the dilute solutions, for the concentrated solutions a noticeable change in the average number of water-water hydrogen bonds is observed in the second solvation shells of the ions and even beyond. However, the changes in the average number of hydrogen bonds are found to be relatively less when both water-water and ion-water hydrogen bonds are counted. Thus, the changes in the total number of hydrogen bonds per water are not very dramatic beyond the first solvation shell even for concentrated solutions.

  20. Concentration effect on the spectroscopic behavior of Tb{sup 3+} ions in zinc phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Kesavulu, C.R., E-mail: crkesavulu2005@gmail.com [Instituto de Fisica de São Carlos, Universidade de São Paulo, Avenida Trabalhador Sãocarlense 400, São Carlos, SP (Brazil); Almeida Silva, Anielle Christine [Laboratorio de Novos Materials Isolantes e Semicondutores (LNMIS), Instituto de Física, Universidade Federal de Uberândia, MG (Brazil); Dousti, M.R. [Instituto de Fisica de São Carlos, Universidade de São Paulo, Avenida Trabalhador Sãocarlense 400, São Carlos, SP (Brazil); Dantas, Noelio Oliveira [Laboratorio de Novos Materials Isolantes e Semicondutores (LNMIS), Instituto de Física, Universidade Federal de Uberândia, MG (Brazil); Camargo, A.S.S. de; Catunda, Tomaz [Instituto de Fisica de São Carlos, Universidade de São Paulo, Avenida Trabalhador Sãocarlense 400, São Carlos, SP (Brazil)

    2015-09-15

    Zinc phosphate glasses (PZABPTb) in the compositional system: P{sub 2}O{sub 5}–ZnO–Al{sub 2}O{sub 3}–BaO–PbO doped with variable Tb{sup 3+} concentrations (1–5 wt% Tb{sub 2}O{sub 3}) were prepared and characterized through absorption, excitation, emission and intensity decay rate measurements. The Judd–Ofelt model has been adopted to evaluate the radiative properties of the {sup 5}D{sub 4}→{sup 7}F{sub 6–3} emission transitions. The effect of Tb{sup 3+} ion concentration on the emissions from the {sup 5}D{sub 3,4} excited levels is discussed in detail. Analysis of the intensity decay curves corresponding to blue and green emissions from levels {sup 5}D{sub 3} and {sup 5}D{sub 4}, respectively, allowed determination of effective lifetimes, which confirmed the Tb{sup 3+} ion concentration quenching of the blue emission in these glasses. The decay curves for the {sup 5}D{sub 3} level are found to be non-exponential in nature for all the studied concentrations due to ion–ion energy transfer through cross-relaxation. In an attempt to identify the origin of the energy transfer mechanism, the decay curves were well fitted to the Inokuti–Hirayama model for S=6, which indicates that the energy transfer process is of dipole–dipole type. The optical band gap energy (E{sub opt}) has been evaluated taking into account the ultraviolet edge of absorption spectra. - Highlights: • Tb{sup 3+}-doped zinc phosphate glasses have been prepared by melt quenching technique. • Spectroscopic parameters were evaluated using the Judd–Ofelt theory. • Effects of Tb{sup 3+} concentration on luminescence of the glasses were studied. • Strong intense laser transition for Tb{sup 3+} ion in PZABPTb glasses is {sup 5}D{sub 4}→{sup 7}F{sub 5} (0.54 μm). • PZABPTb glasses could be used in the development of green color display devices and solid state visible lasers.

  1. Role of carrier concentration in swift heavy ion irradiation induced surface modifications

    Science.gov (United States)

    Gupta, Sushant; Ganesan, V.; Sulania, Indra; Das, B.

    2017-10-01

    Highly conducting SnO2 thin films were prepared by chemical spray pyrolysis technique. One set of as-deposited films were annealed in air for 2 h at 850 °C. These as-deposited and annealed SnO2 thin films were irradiated using gold ions with energy of 120 MeV at different fluences ranging from 1 × 1011 to 3 × 1013 ions/cm2. Electrical measurement shows that as-deposited SnO2 films are in conducting state with n = 3.164 ×1020cm-3 and annealed SnO2 films are in insulating state. The amorphized latent tracks are created only above a certain threshold value of Se, which directly depends on the free electron concentration (n). The electronic energy loss (Se) of 120 MeV Au9+ ions in SnO2 is greater than the threshold energy loss (Seth) required for the latent track/molten zone formation in annealed SnO2 thin film, but is less than Seth required for as-deposited SnO2 film. Therefore, the latent tracks/molten zones are formed in the annealed SnO2 film and not in the as-deposited SnO2 film. Thermal spike model is used for the calculation of threshold energy loss and radius of melted zone. The possible mechanism of the structural changes and surface microstructure evolutions is briefly discussed in the light of ion's energy relaxation processes and target's conductivity. The atomic force microscopy (AFM) study of films shows that the morphologies of irradiated films are linked with carrier concentration of target materials.

  2. Selective removal of arsenic and monovalent ions from brackish water reverse osmosis concentrate.

    Science.gov (United States)

    Xu, Pei; Capito, Marissa; Cath, Tzahi Y

    2013-09-15

    Concentrate disposal and management is a considerable challenge for the implementation of desalination technologies, especially for inland applications where concentrate disposal options are limited. This study has focused on selective removal of arsenic and monovalent ions from brackish groundwater reverse osmosis (RO) concentrate for beneficial use and safe environmental disposal using in situ and pre-formed hydrous ferric oxides/hydroxides adsorption, and electrodialysis (ED) with monovalent permselective membranes. Coagulation with ferric salts is highly efficient at removing arsenic from RO concentrate to meet a drinking water standard of 10 μg/L. The chemical demand for ferric chloride however is much lower than ferric sulfate as coagulant. An alternative method using ferric sludge from surface water treatment plant is demonstrated as an efficient adsorbent to remove arsenic from RO concentrate, providing a promising low cost, "waste treat waste" approach. The monovalent permselective anion exchange membranes exhibit high selectivity in removing monovalent anions over di- and multi-valent anions. The transport of sulfate and phosphate through the anion exchange membranes was negligible over a broad range of electrical current density. However, the transport of divalent cations such as calcium and magnesium increases through monovalent permselective cation exchange membranes with increasing current density. Higher overall salt concentration reduction is achieved around limiting current density while higher normalized salt removal rate in terms of mass of salt per membrane area and applied energy is attained at lower current density because the energy unitization efficiency decreases at higher current density.

  3. Mineral dust and major ion concentrations in snowpit samples from the NEEM site, Greenland

    Science.gov (United States)

    Kang, Jung-Ho; Hwang, Heejin; Hong, Sang Bum; Hur, Soon Do; Choi, Sung-Deuk; Lee, Jeonghoon; Hong, Sungmin

    2015-11-01

    Polar ice sheets conserve atmospheric aerosols at the time of snowfall, which can be used to reconstruct past climate and environmental conditions. We investigated mineral dust and major ion records in snowpit samples obtained from the northwestern Greenland ice sheet near the North Greenland Eemian Ice Drilling (NEEM) camp in June 2009. We analyzed the samples for mineral dust concentrations as well as stable water isotopes (δ18O, δD, and deuterium excess) and major ions (Cl-, SO42-, methanesulfonic acid (MSA), Na+, and Ca2+). Seasonal δ18O and δD cycles indicate that the snowpit samples covered a six-year period from spring 2003 to early summer 2009. Concentrations of mineral dust, nss-Ca2+, and nss-SO42- showed seasonal deposition events with maxima in the winter-spring layers. On the other hand, the Cl-/Na+ ratio and the concentrations of MSA exhibited maxima in the summer layers, making them useful indicators for the summer season. Moreover, an anomalous atmospheric mineral dust event was recorded at a depth of 165-170 cm corresponding to late winter 2005 to spring 2006. A back trajectory analysis suggests that a major contributor to the Greenland aerosol was an air mass passing over the Canadian Arctic and North America. Several trajectories point to Asian regions as a dust source. The mineral dust deposited at NEEM was strongly influenced by long-range atmospheric transport and dust input from arid source areas in northern China and Mongolia.

  4. Non-Negligible Diffusio-Osmosis Inside an Ion Concentration Polarization Layer

    Science.gov (United States)

    Cho, Inhee; Kim, Wonseok; Kim, Junsuk; Kim, Ho-Young; Lee, Hyomin; Kim, Sung Jae

    2016-06-01

    The first experimental and theoretical evidence was provided for the non-negligible role of a diffusio-osmosis in the ion concentration polarization (ICP) layer, which had been reported to be in a high Peclet number regime. Under the assumption that the hydrated shells of cations were stripped out with the amplified electric field inside the ICP layer, its concentration profile possessed a steep concentration gradient at the stripped location. Since the concentration gradient drove a strong diffusio-osmosis, the combination of electro-osmotic and diffusio-osmotic slip velocity had a form of an anomalous nonmonotonic function with both a single- and multiple-cationic solution. A direct measurement of electrolytic concentrations around the layer quantitatively validated our new investigations. This non-negligible diffusio-osmotic contribution in a micro- and nanofluidic platform or porous medium would be essential for clarifying the fundamental insight of nanoscale electrokinetics as well as guiding the engineering of ICP-based electrochemical systems.

  5. Dynamics of micro-vortices induced by ion concentration polarization in electrodialysis

    Science.gov (United States)

    de Valenca, Joeri; Wagterveld, R. M.; Lammertink, Rob; Tsai, Peichun Amy; Soft Matter, Fluidics; Interfaces Group, University of Twente Team; Wetsus Team

    2014-11-01

    We experimentally investigate the coupled dynamics of global ion transport and local electroconvective flow of an electrolyte solution close to a charge selective membrane under an electric forcing. At small dc electric currents, due to the membrane permselectivity counterions (cations) transport diffusively through the cation exchange membrane (CEM) whereas the passage of co-ions (anions) is inhibited, thereby forming ion concentration polarization or gradients. At large currents, our simultaneous measurements of voltage drop and flow filed reveal several distinct dynamical regimes. Initially, the electrodialysis system exhibits a linear Ohmic electric resistance and then a rate-limiting regime with a voltage jump. Subsequently, electro-osmotic micro-vortices set in and grow linearly both in size and speed with time. After this linearly growing electroconvective regime, the measured voltage drop levels off around a fixed value. The average vortex size and speed saturate as well, however the individual vortices are unsteady and dynamical. Furthermore, the influence of micro-patterned CEM on the couple dynamics will be presented and discussed.

  6. The influence of ion concentrations on the dynamic behavior of the Hodgkin-Huxley model-based cortical network.

    Science.gov (United States)

    Tagluk, M Emin; Tekin, Ramazan

    2014-08-01

    Action potentials (APs) in the form of very short pulses arise when the cell is excited by any internal or external stimulus exceeding the critical threshold of the membrane. During AP generation, the membrane potential completes its natural cycle through typical phases that can be formatted by ion channels, gates and ion concentrations, as well as the synaptic excitation rate. On the basis of the Hodgkin-Huxley cell model, a cortical network consistent with the real anatomic structure is realized with randomly interrelated small population of neurons to simulate a cerebral cortex segment. Using this model, we investigated the effects of Na(+) and K(+) ion concentrations on the outcome of this network in terms of regularity, phase locking, and synchronization. The results suggested that Na(+) concentration does slightly affect the amplitude but not considerably affects the other parameters specified by depolarization and repolarization. K(+) concentration significantly influences the form, regularity, and synchrony of the network-generated APs. No previous study dealing directly with the effects of both Na(+) and K(+) ion concentrations on regularity and synchronization of the simulated cortical network-generated APs, allowing for the comparison of results obtained using our methods, was encountered in the literature. The results, however, were consistent with those obtained through studies concerning resonance and synchronization from another perspective and with the information revealed through physiological and pharmacological experiments concerning changing ion concentrations or blocking ion channels. Our results demonstrated that the regularity and reliability of brain functions have a strong relationship with cellular ion concentrations, and suggested the management of the dynamic behavior of the cellular network with ion concentrations.

  7. Effect of Alginate Concentration on Alginate-TiO{sub 2} Hydrogel for Lead Ion Removal

    Energy Technology Data Exchange (ETDEWEB)

    Teoh, W T; Sato, K [Department of Environmental Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka 940-2188 (Japan); Saito, N, E-mail: teoh@vos.nagaokaut.ac.jp [Department of Materials Science and Technology, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka 940-2188 (Japan)

    2011-03-15

    Alginate-TiO{sub 2} hydrogel was investigated for lead ion (Pb(II)) removal. By immobilizing TiO{sub 2} powder onto an alginate biopolymer, it is possible to utilize the ion exchange properties of the alginate and the photoreducibility of TiO{sub 2} to recover Pb(II). However, these photocatalytic activities degrade the alginate biopolymer in addition to removing Pb(II). This study examines photolytic degradation of alginate-TiO{sub 2} hydrogels prepared with alginate concentrations of 1, 1.5, 2, and 2.5%w/v; the same amount (0.4%w/v) of TiO{sub 2} was added to each alginate solution. The alginate-TiO{sub 2} hydrogels were formed by dripping the alginate-TiO{sub 2} suspension into a 0.2 M calcium chloride solution. The samples were washed and dried and then photoirradiated. The samples with alginate concentrations of 1 and 1.5%w/v were depolymerized, whereas the surface morphology of the sample that prepared from the 2%w/v alginate solution remained unchanged. The samples prepared from 1.5, 2, and 2.5%w/v alginate solutions had Pb(II) uptakes of 24.0, 39.8, and 39.7 mg/g, respectively.

  8. Determination of Ion Concentrations and Heavy Metals in the Air Particulates of an Industrial Area

    Directory of Open Access Journals (Sweden)

    Ömer Işıldak

    2011-12-01

    Full Text Available This study deals with the determination of heavy metals, anions and cations in atmospheric aerosols at four heavily polluted sites in Samsun city, Turkey. The anions (Cl-, Br-, NO3- and NO2- and cations (Na+, K+ and NH4+ in the samples were determined by ion chromatography using a potentiometric detector with ion selective electrodes. Flame and graphite-furnace Atomic Absorption Spectrometer was used for the determination of Pb, Cu, Zn and Fe. The average values of Cl-, NO3-, NO2-, Br-, Na+, K+ and NH4+ concentrations in the samples were 4.58±1.30, 7.42±1.32, 0.86±0.10, 0.28±0.05, 0.77±0.13, 0.72±0.06, and 1.08±0.09 µg/m3 respectively. The average values of Zn, Cu, Fe and Pb concentrations in the samples were 2.32±0.21, 1.71±0.14, 2.29±0.18, and 2.46±0.22 µg/m3 respectively.

  9. Development of ion-exchange properties of bamboo charcoal modified with concentrated nitric acid

    Science.gov (United States)

    Khandaker, S.; Kuba, T.; Toyohara, Y.; Kamida, S.; Uchikawa, Y.

    2017-08-01

    The surface chemistry and the structural properties of activated carbon can be altered by the acidic modification. The objective of this study is to investigate the changes occurring in bamboo charcoal (BC) during activation with concentrated nitric acid. Low temperature (500°C) carbonized BC has been prepared and oxidized with 70% concentrated boiling nitric acid (BC-AC). The porous properties of the BC are analyzed with nitrogen adsorption isotherm at 77 K. The surface structure is observed by Field emission scanning electronic microscope (FESEM) and the surface functional groups are examined by Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and the pH of the point of zero charge (pHPZC). The results reveal that severe oxidation with HNO3 considerably decreases the surface area of BC with enhanced pore widening and FESEM observation demonstrates the erosive effect of oxidation. The FTIR analysis detects that some absorption bands are assigned for carboxyl, aldehyde and ketone groups on BC-AC. The XPS analysis also clearly shows that the ratio of oxygen and acidic functional groups has been enriched significantly on the BC-AC. The low pHPZC value of BC-AC confirms that the surface is highly acidic for the fixation of acidic functional groups on surface. In general, the existence of the abundant amount of acidic functional groups on adsorbents enhances the sorption of heavy metals ions in aqueous solution. Therefore, it is strongly expected that the modified BC, activated under the proposed conditions would be a promising ion exchanger in aqueous solution and can be applied for the adsorption of different heavy metal ions and radioactive materials from effluent.

  10. Enrichment and isolation of Flavobacterium strains with tolerance to high concentrations of cesium ion.

    Science.gov (United States)

    Kato, Souichiro; Goya, Eri; Tanaka, Michiko; Kitagawa, Wataru; Kikuchi, Yoshitomo; Asano, Kozo; Kamagata, Yoichi

    2016-02-17

    Interest in the interaction of microorganisms with cesium ions (Cs(+)) has arisen, especially in terms of their potent ability for radiocesium bioaccumulation and their important roles in biogeochemical cycling. Although high concentrations of Cs(+) display toxic effects on microorganisms, there have been only limited reports for Cs(+)-tolerant microorganisms. Here we report enrichment and isolation of Cs(+)-tolerant microorganisms from soil microbiota. Microbial community analysis revealed that bacteria within the phylum Bacteroidetes, especially Flavobacterium spp., dominated in enrichment cultures in the medium supplemented with 50 or 200 mM Cs(+), while Gammaproteobacteria was dominant in the control enrichment cultures (in the presence of 50 and 200 mM K(+) instead of Cs(+)). The dominant Flavobacterium sp. was successfully isolated from the enrichment culture and was closely related to Flavobacterium chungbukense with 99.5% identity. Growth experiments clearly demonstrated that the isolate has significantly higher tolerance to Cs(+) compared to its close relatives, suggesting the Cs(+)-tolerance is a specific trait of this strain, but not a universal trait in the genus Flavobacterium. Measurement of intracellular K(+) and Cs(+) concentrations of the Cs(+)-tolerant isolate and its close relatives suggested that the ability to maintain low intracellular Cs(+) concentration confers the tolerance against high concentrations of external Cs(+).

  11. In-vacuum scattered light reduction with cupric oxide surfaces for sensitive fluorescence detection

    CERN Document Server

    Norrgard, Eric B; Barry, John F; McCarron, Daniel J; Steinecker, Matthew H; DeMille, David

    2016-01-01

    We demonstrate a simple and easy method for producing low-reflectivity surfaces that are ultra-high vacuum compatible, may be baked to high temperatures, and are easily applied even on complex surface geometries. Black cupric oxide (CuO) surfaces are chemically grown in minutes on any copper surface, allowing for low-cost, rapid prototyping and production. The reflective properties are measured to be comparable to commercially available products for creating optically black surfaces. We describe a vacuum apparatus which uses multiple blackened copper surfaces for sensitive, low-background detection of molecules using laser-induced fluorescence.

  12. Photoelectrochemical water splitting for hydrogen production with metal oxide (hematite and cupric oxide) based photocatalysts

    Science.gov (United States)

    Tang, Houwen

    Solar hydrogen is one ideal energy source to replace fossil fuel, as it is sustainable and environmentally friendly. Solar hydrogen can be generated in a number of ways. Photoelectrochemical (PEC) water splitting is one of the most promising methods for solar-to-chemical energy conversion. In this research project, metal oxide-based photocatalysts, especially hematite (α-Fe 2O3) and cupric oxide (CuO), were investigated for use as electrodes in PEC water splitting for solar hydrogen production. In our research project of hematite-based electrodes, we started with the incorporation of transition metal, particularly titanium (Ti), in hematite thin films to modify the valence and conduction band edges of hematite. We found that Ti impurities improve the electron conductivity of hematite and consequently lead to significantly enhanced photocurrents. We further investigated the Ti and Mg co-alloyed hematite. In this case, Ti is the donor and Mg is the acceptor in hematite. The co-alloying approach enhanced the solubility of Mg and Ti, which led to reduced electron effective mass and therefore increased electron mobility. Also, co-alloying tunes the carrier density and therefore allows the optimization of electrical conductivity. The densities of charged defects were found to be reduced, and therefore carrier recombinations were reduced. As a result, the Ti and Mg co-alloyed hematite thin films exhibited much improved performance in PEC water splitting as compared to pure hematite thin films. For the study of cupric oxide-based electrodes, we first investigated the possibility of reducing the electrode corrosion of cupric oxide in aqueous solutions by incorporating Ti as an electrode corrosion inhibitor. We found that Ti alloying can enhance the stability of cupric oxide in base solutions at the cost of reducing its crystallinity and optical absorption, and consequently lowering its photon-to-electron conversion efficiency. In order to balance the stability and the

  13. Spectrophotometric total reducing sugars assay based on cupric reduction.

    Science.gov (United States)

    Başkan, Kevser Sözgen; Tütem, Esma; Akyüz, Esin; Özen, Seda; Apak, Reşat

    2016-01-15

    As the concentration of reducing sugars (RS) is controlled by European legislation for certain specific food and beverages, a simple and sensitive spectrophotometric method for the determination of RS in various food products is proposed. The method is based on the reduction of Cu(II) to Cu(I) with reducing sugars in alkaline medium in the presence of 2,9-dimethyl-1,10-phenanthroline (neocuproine: Nc), followed by the formation of a colored Cu(I)-Nc charge-transfer complex. All simple sugars tested had the linear regression equations with almost equal slope values. The proposed method was successfully applied to fresh apple juice, commercial fruit juices, milk, honey and onion juice. Interference effect of phenolic compounds in plant samples was eliminated by a solid phase extraction (SPE) clean-up process. The method was proven to have higher sensitivity and precision than the widely used dinitrosalicylic acid (DNS) colorimetric method.

  14. Synthesis and application of ion-imprinted polymer for extraction and pre-concentration of iron ions in environmental water and food samples.

    Science.gov (United States)

    Roushani, Mahmoud; Beygi, Tahereh Musa; Saedi, Zahra

    2016-01-15

    In this work, a novel Fe(III) ion imprinted polymer as a sorbent for extraction of iron ions from different samples was synthesized. Precipitation of thermal copolymerization was used for preparation of polymeric sorbent. In this technique, methacrylic acid, ethylene glycoldimethacrylate, 2,2'-azobisisobutyronitrile and (DHBPT)2 {(DHBPT)2=3,6-bis (3,5-dimethyl-1-H-pyrzol-1-yl)-1,2-dihydro-1,2,4,5-tetrazine)} were used as monomer, cross-linker, initiator and ligand, respectively, in the presence of Fe(III) ions and ethanol as a porogenic solvent. Moreover, control polymer (NIP) particles were similarly prepared without the Fe(III) ions. XRD, FT-IR, SEM and nitrogen adsorption-desorption techniques have been used to characterization of these prepared polymeric samples. Iron ion imprinted polymer particles, abbreviated as Fe(III)-IIP, were leached with 50 mL of HCl (50% (v/v)). Absorption capacity for ion imprinted polymer was calculated about 40.41 mg·g(-1). Per-concentration of iron ion was investigated as a function of pH, weight of IIP, adsorption and desorption times, and volumes of sample. FAAS technique was used to determination of Fe(III) ion in the foods and waters samples.

  15. Vacancies driven magnetic ordering in ZnO nanoparticles due to low concentrated Co ions

    Science.gov (United States)

    Verma, Kuldeep Chand; Bhatia, Ravi; Kumar, Sanjeev; Kotnala, R. K.

    2016-07-01

    The lattice defects due to oxygen vacancies in ZnO nanoparticles with low doping of Co ions are investigated. The low concentrated Co ions in ZnO are responsible to the free charge carriers and oxygen vacancies to induce long-range ferromagnetic ordering. We have synthesized Zn1-x Co x O [x = 0.002, 0.004, 0.006 and 0.008] nanoparticles by a sol-gel process. X-ray fluorescence analysis detects the chemical composition of Zn, Co and O atoms. Rietveld refinement of x-ray diffraction pattern could confirm the wurtzite ZnO structure and the lattice constants with Co doping. The nanoparticles dimensions as well lattice spacing of ZnO are enhanced with Co substitution. Fourier transform infrared vibrational modes involve some organic groups to induce lattice defects and the ionic coordination among Zn, Co and O atoms. The room temperature Raman active mode E2 indicates frequency shifting with Co to induce stress in the wurtzite lattice. Photoluminescence spectra have a strong near-band-edge emission due to band gap energy and defects related to oxygen vacancies. X-ray photoelectron spectra confirm that the low dopant Co ions in ZnO lattice occupied Zn atoms by introducing oxygen vacancies and the valance states Zn2+, Co2,3+. The zero-field and field cooling magnetic measurement at 500 Oe in Co:ZnO samples indicate long-range ferromagnetism that is enhanced at 10 K due to antiferromagnetic-ferromagnetic ordering. The lattice defects/vacancies due to oxygen act as the medium of magnetic interactions which is explained by the bound magnetic polaron model.

  16. Biodegradation of high concentration phenol containing heavy metal ions by functional biofilm in bioelectro-reactor

    Institute of Scientific and Technical Information of China (English)

    LI Xin-gang; WANG Tao; SUN Jin-sheng; HUANG Xin; KONG Xiao-song

    2006-01-01

    Functional microorganisms to high concentration phenol containing Cr6+ and Pb2+ were cultured and biofilm was formed on polypropylene packings in bioelectro-reactor. It was found that the biodegradation capability of such biofilm to phenol changed with the applied voltage. Under the optimal electric field conditions (voltage of 3.0 V, electric field of strength 17.7 V/m and current density of 1.98 A/m2), biodegradation efficiency of phenol aof concentration of 1200 mg/L increased 33% compared to the instance without applying electric field. However, voltage had inverse effect on biodegradation, as microorganisms were killed under strong electric field. Voltage had little effect on heavy ions elimination. Higher absorption rate of Cr6+ and Pb2+ was observed when changing pH from acidic to neutral. The experiment results indicated that, after treatment, 10 L phenol of 2400 mg/L was biodegraded completely within 55 h and concentrations of Cr6+ and Pb2+ dropped to less than 1 mg/L within 12 h and 6 h, from initial values of 50 mg/L and 30 mg/L, respectively.

  17. Sulfur in foraminiferal calcite as a potential proxy for seawater carbonate ion concentration

    Science.gov (United States)

    van Dijk, I.; de Nooijer, L. J.; Boer, W.; Reichart, G.-J.

    2017-07-01

    Sulfur (S) incorporation in foraminiferal shells is hypothesized to change with carbonate ion concentration [CO32-], due to substitution of sulfate for carbonate ions in the calcite crystal lattice. Hence S/Ca values of foraminiferal carbonate shells are expected to reflect sea water carbonate chemistry. To generate a proxy calibration linking the incorporation of S into foraminiferal calcite to carbonate chemistry, we cultured juvenile clones of the larger benthic species Amphistegina gibbosa and Sorites marginalis over a 350-1200 ppm range of pCO2 values, corresponding to a range in [CO32-] of 93 to 211 μmol/kg. We also investigated the potential effect of salinity on S incorporation by culturing juvenile Amphistegina lessonii over a large salinity gradient (25-45). Results show S/CaCALCITE is not impacted by salinity, but increases with increasing pCO2 (and thus decreasing [CO32-] and pH), indicating S incorporation may be used as a proxy for [CO32-]. Higher S incorporation in high-Mg species S. marginalis suggests a superimposed biomineralization effect on the incorporation of S. Microprobe imaging reveals co-occurring banding of Mg and S in Amphistegina lessonii, which is in line with a strong biological control and might explain higher S incorporation in high Mg species. Provided a species-specific calibration is available, foraminiferal S/Ca values might add a valuable new tool for reconstructing past ocean carbonate chemistry.

  18. Transport-limited water splitting at ion-selective interfaces during concentration polarization

    DEFF Research Database (Denmark)

    Nielsen, Christoffer Peder; Bruus, Henrik

    2014-01-01

    We present an analytical model of salt- and water-ion transport across an ion-selective interface based on an assumption of local equilibrium of the water-dissociation reaction. The model yields current-voltage characteristics and curves of water-ion current versus salt-ion current, which are in ...

  19. The hemodynamic effect of calcium ion concentration in the infusate during predilution hemofiltration in chronic renal failure

    DEFF Research Database (Denmark)

    Karamperis, N.; Sloth, E.; Jensen, Jens Dam

    2005-01-01

    BACKGROUND: It is the prevailing view that convective dialysis techniques stabilize blood pressure. Calcium concentration in the substitution fluid may be important in this respect. The aim of this study is to investigate the influence of calcium ion concentration in the substitution fluid...... on hemodynamic stability during predilution hemofiltration (HF). METHODS: We conducted a randomized, crossover, blinded, controlled trial with 12 stable long-term hemodialysis patients without diabetes. Each patient was randomly assigned to substitution fluid with a calcium ion (iCa) concentration of 2.5 m...

  20. Survey of Nitrate Ion Concentrations in Vegetables Cultivated in Plant Factories: Comparison with Open-Culture Vegetables.

    Science.gov (United States)

    Oka, Yuka; Hirayama, Izumi; Yoshikawa, Mitsuhide; Yokoyama, Tomoko; Iida, Kenji; Iwakoshi, Katsushi; Suzuki, Ayana; Yanagihara, Midori; Segawa, Yukino; Kukimoto, Sonomi; Hamada, Humika; Matsuzawa, Satomi; Tabata, Setsuko; Sasamoto, Takeo

    2017-01-01

    A survey of nitrate-ion concentrations in plant-factory-cultured leafy vegetables was conducted. 344 samples of twenty-one varieties of raw leafy vegetables were examined using HPLC. The nitrate-ion concentrations in plant-factory-cultured leafy vegetables were found to be LOD-6,800 mg/kg. Furthermore, the average concentration values varied among different leafy vegetables. The average values for plant-factory-cultured leafy vegetables were higher than those of open-cultured leafy vegetables reported in previous studies, such as the values listed in the Standard Tables of Food Composition in Japan- 2015 - (Seventh revised edition). For some plant-factory-cultured leafy vegetables, such as salad spinach, the average values were above the maximum permissible levels of nitrate concentration in EC No 1258/2011; however, even when these plant-factory-cultured vegetables were routinely eaten, the intake of nitrate ions in humans did not exceed the ADI.

  1. Thermal stimulated current response in cupric oxide single crystal thin films over a wide temperature range

    Science.gov (United States)

    Yang, Kungan; Wu, Shuxiang; Yu, Fengmei; Zhou, Wenqi; Wang, Yunjia; Meng, Meng; Wang, Gaili; Zhang, Yueli; Li, Shuwei

    2017-01-01

    Cupric oxide single crystal thin films (~26 nm) were grown by plasma-assisted molecular beam epitaxy. X-ray diffraction, Raman spectra and in situ reflection high-energy electron diffraction show that the thin films are 2  ×  2 reconstructed with an in-plane compression and out-of-plane stretching. A thermal stimulated current measurement indicates that the electric polarization response is shown in the special 2D cupric oxide single crystal thin film over a wide temperature range from 130 K to near-room temperature. We infer that the abnormal electric response involves the changing of phase transition temperature induced by structure distortion, the spin frustration and the magnetic fluctuation effect of a short-range magnetic order, or the combined action of both of the two factors mentioned above. This work suggests a promising clue for finding new room temperature single phase multiferroics or tuning phase transition temperatures.

  2. Effectiveness of orally administered cupric oxide needles in alleviating hypocupraemia in sheep and cattle.

    Science.gov (United States)

    Suttle, N F

    1981-05-09

    The oral administration of a small dose of cupric oxide "needles" (CuOn), providing 0.5 g copper, to hypocupraemic ewes maintained on a copper-deficient diet alleviated hypocupraemia for 111 days when the diet was supplemented with molybdenum and sulphate and for 301 days when the diet was not supplemented. The same amount of copper given as cupric sulphate was approximately half as effective. The administration of a large dose of CuOn, providing 40 g copper, to hypocupraemic steers and heifers alleviated hypocupraemia for not less than 41 days, at which time a substantial reserve of copper (428 mg) remained in the liver. The absorbability of copper in CuOn was estimated to be 8.3 per cent and 3.8 per cent (depending on diet) for sheep. It was calculated that enough absorbable copper could be provided in a single dose to meet the net copper requirements of ewes for several years. This new form of copper therapy demands a totally different approach from that associated with parenteral copper usage.

  3. Purification of High Salinity Brine by Multi-Stage Ion Concentration Polarization Desalination

    Science.gov (United States)

    Kim, Bumjoo; Kwak, Rhokyun; Kwon, Hyukjin J.; Pham, Van Sang; Kim, Minseok; Al-Anzi, Bader; Lim, Geunbae; Han, Jongyoon

    2016-01-01

    There is an increasing need for the desalination of high concentration brine (>TDS 35,000 ppm) efficiently and economically, either for the treatment of produced water from shale gas/oil development, or minimizing the environmental impact of brine from existing desalination plants. Yet, reverse osmosis (RO), which is the most widely used for desalination currently, is not practical for brine desalination. This paper demonstrates technical and economic feasibility of ICP (Ion Concentration Polarization) electrical desalination for the high saline water treatment, by adopting multi-stage operation with better energy efficiency. Optimized multi-staging configurations, dependent on the brine salinity values, can be designed based on experimental and numerical analysis. Such an optimization aims at achieving not just the energy efficiency but also (membrane) area efficiency, lowering the true cost of brine treatment. ICP electrical desalination is shown here to treat brine salinity up to 100,000 ppm of Total Dissolved Solids (TDS) with flexible salt rejection rate up to 70% which is promising in a various application treating brine waste. We also demonstrate that ICP desalination has advantage of removing both salts and diverse suspended solids simultaneously, and less susceptibility to membrane fouling/scaling, which is a significant challenge in the membrane processes. PMID:27545955

  4. Microfluidic paper-based biomolecule preconcentrator based on ion concentration polarization.

    Science.gov (United States)

    Han, Sung Il; Hwang, Kyo Seon; Kwak, Rhokyun; Lee, Jeong Hoon

    2016-06-21

    Microfluidic paper-based analytical devices (μPADs) for molecular detection have great potential in the field of point-of-care diagnostics. Currently, a critical problem being faced by μPADs is improving their detection sensitivity. Various preconcentration processes have been developed, but they still have complicated structures and fabrication processes to integrate into μPADs. To address this issue, we have developed a novel paper-based preconcentrator utilizing ion concentration polarization (ICP) with minimal addition on lateral-flow paper. The cation selective membrane (i.e., Nafion) is patterned on adhesive tape, and this tape is then attached to paper-based channels. When an electric field is applied across the Nafion, ICP is initiated to preconcentrate the biomolecules in the paper channel. Departing from previous paper-based preconcentrators, we maintain steady lateral fluid flow with the separated Nafion layer; as a result, fluorescent dyes and proteins (FITC-albumin and bovine serum albumin) are continuously delivered to the preconcentration zone, achieving high preconcentration performance up to 1000-fold. In addition, we demonstrate that the Nafion-patterned tape can be integrated with various geometries (multiplexed preconcentrator) and platforms (string and polymer microfluidic channel). This work would facilitate integration of various ICP devices, including preconcentrators, pH/concentration modulators, and micro mixers, with steady lateral flows in paper-based platforms.

  5. Purification of High Salinity Brine by Multi-Stage Ion Concentration Polarization Desalination

    Science.gov (United States)

    Kim, Bumjoo; Kwak, Rhokyun; Kwon, Hyukjin J.; Pham, Van Sang; Kim, Minseok; Al-Anzi, Bader; Lim, Geunbae; Han, Jongyoon

    2016-08-01

    There is an increasing need for the desalination of high concentration brine (>TDS 35,000 ppm) efficiently and economically, either for the treatment of produced water from shale gas/oil development, or minimizing the environmental impact of brine from existing desalination plants. Yet, reverse osmosis (RO), which is the most widely used for desalination currently, is not practical for brine desalination. This paper demonstrates technical and economic feasibility of ICP (Ion Concentration Polarization) electrical desalination for the high saline water treatment, by adopting multi-stage operation with better energy efficiency. Optimized multi-staging configurations, dependent on the brine salinity values, can be designed based on experimental and numerical analysis. Such an optimization aims at achieving not just the energy efficiency but also (membrane) area efficiency, lowering the true cost of brine treatment. ICP electrical desalination is shown here to treat brine salinity up to 100,000 ppm of Total Dissolved Solids (TDS) with flexible salt rejection rate up to 70% which is promising in a various application treating brine waste. We also demonstrate that ICP desalination has advantage of removing both salts and diverse suspended solids simultaneously, and less susceptibility to membrane fouling/scaling, which is a significant challenge in the membrane processes.

  6. Purification of High Salinity Brine by Multi-Stage Ion Concentration Polarization Desalination.

    Science.gov (United States)

    Kim, Bumjoo; Kwak, Rhokyun; Kwon, Hyukjin J; Pham, Van Sang; Kim, Minseok; Al-Anzi, Bader; Lim, Geunbae; Han, Jongyoon

    2016-08-22

    There is an increasing need for the desalination of high concentration brine (>TDS 35,000 ppm) efficiently and economically, either for the treatment of produced water from shale gas/oil development, or minimizing the environmental impact of brine from existing desalination plants. Yet, reverse osmosis (RO), which is the most widely used for desalination currently, is not practical for brine desalination. This paper demonstrates technical and economic feasibility of ICP (Ion Concentration Polarization) electrical desalination for the high saline water treatment, by adopting multi-stage operation with better energy efficiency. Optimized multi-staging configurations, dependent on the brine salinity values, can be designed based on experimental and numerical analysis. Such an optimization aims at achieving not just the energy efficiency but also (membrane) area efficiency, lowering the true cost of brine treatment. ICP electrical desalination is shown here to treat brine salinity up to 100,000 ppm of Total Dissolved Solids (TDS) with flexible salt rejection rate up to 70% which is promising in a various application treating brine waste. We also demonstrate that ICP desalination has advantage of removing both salts and diverse suspended solids simultaneously, and less susceptibility to membrane fouling/scaling, which is a significant challenge in the membrane processes.

  7. Detection of lead ions in picomolar concentration range using underpotential deposition on silver nanoparticles-deposited glassy carbon electrodes.

    Science.gov (United States)

    Sivasubramanian, R; Sangaranarayanan, M V

    2011-09-30

    The efficacy of silver-deposited glassy carbon electrode for the determination of lead ions at the sub-nanomolar concentration ranges is investigated. The silver nanoparticles are electrodeposited on glassy carbon electrode using chronoamperometry and the electrode surface is characterized using SEM. Lead ions are detected in the region of underpotential deposition. The analysis is performed in square wave mode in the stripping voltammetry without the removal of oxygen. The detection limit of 10 pM has been obtained with a constant potential of -0.7 V during the electrodeposition step for a period of 50s. The interference of surfactants in the detection of lead ions is also studied.

  8. Characteristics of High Time-Resolved Concentrations of Particulate Inorganic Ions and Black Carbon Downwind of Seoul, Korea

    Science.gov (United States)

    Lee, Y.; Choi, Y.; Kim, C.; Ghim, Y.

    2012-12-01

    Concentrations of inorganic ions and black carbon (BC) in PM2.5 were continuously measured using PILS (particle-into-liquid sampler, ADI 2081, Applikon) and MAAP (Multiangle Absorption Photometer, Model 5012, Thermo), respectively, for three and half months from mid-February to May, at intervals of 20-30 minutes. The measurements were made at the Global Campus of Hankuk University of Foreign Studies, about 35 km southeast of downtown Seoul, the general area of which is affected by prevailing northwesterlies. The site is considered to be an ideal place for exploring transport of air pollutants and formation of secondary ions by photochemical reactions since there are no major emission sources nearby except a 4-lane road running about 1.4 km to the west. Analyses were made by two stages. In the first stage, typical types of diurnal variations in inorganic ions and BC concentrations were identified using cluster analysis. Diurnal variations in concentrations of each cluster were compared with the mean diurnal variations during the measurement period. Factors causing the differences in diurnal variations were discussed by cluster and by species. In the second stage, high and low concentration episodes were determined based on three-day moving averages of the sum of concentrations of particulate inorganic ions and BC. Mean concentrations and compositions in each episode were compared with those during the measurement period.

  9. Correlation between Copper Ion Concentration in Cervical Mucus and Fllbrinolytic Activity in Menstrual Blood in Copper-releasiag IUD Users

    Institute of Scientific and Technical Information of China (English)

    林建华; 潘家骧; 严隽鸿

    1993-01-01

    In the present study, 44 women using TCu220c-IUD or inert-IUD were asked to make follow-ups before insertion and at the 1st., 3rd., 6th, 9th and 12th month after insertion The mean menstrual blood loss, the fibrinalytic activity including the activation of tissue-plasminogen activator (t-PA) and the amount of plasminogen PIG) and fibrinogen-fibrin degradation products (FDP) in menstrual blood and the copper ion concentration in cervical mucus were determined. The correlation between the copper ion concentration and the fibrinalytic activity was considered. It was found that the change of the copper ion concentration was positively correlated with that of the activition of t-PA and the amount of FDP. On the contrary, the change ofthe copper ion concentration was inversely related to the change of PLG value. It is concluded that the high copper ion level can enhance the activation of fibrinolytic system in human endometrium and induce the increase of menorrhagia.

  10. Transport-limited water splitting at ion-selective interfaces during concentration polarization

    OpenAIRE

    Nielsen, Christoffer Peder; Bruus, Henrik

    2013-01-01

    We present an analytical model of salt- and water-ion transport across an ion-selective interface based on an assumption of local equilibrium of the water-dissociation reaction. The model yields current-voltage characteristics and curves of water-ion current versus salt-ion current, which are in qualitative agreement with experimental results published in the literature. The analytical results are furthermore in agreement with direct numerical simulations. As part of the analysis, we find app...

  11. Phosphate glass core/silica clad fibres with a high concentration of active rare-earth ions

    Science.gov (United States)

    Egorova, O. N.; Galagan, B. I.; Denker, B. I.; Sverchkov, S. E.; Semjonov, S. L.

    2016-12-01

    We report a study of silica-clad composite optical fibres having a phosphate glass core doped with active rare-earth elements. The phosphate glass core allows a high concentration of active rare-earth ions to be obtained, and the silica cladding ensures high mechanical strength and facilitates fusion splicing of such fibres to silica fibres. Owing to the high concentration of active rare-earth ions, this type of fibre is potentially attractive for applications where a small cavity length and high lasing efficiency are needed.

  12. Multisite ion model in concentrated solutions of divalent cations (MgCl2 and CaCl2): osmotic pressure calculations.

    Science.gov (United States)

    Saxena, Akansha; García, Angel E

    2015-01-08

    Accurate force field parameters for ions are essential for meaningful simulation studies of proteins and nucleic acids. Currently accepted models of ions, especially for divalent ions, do not necessarily reproduce the right physiological behavior of Ca(2+) and Mg(2+) ions. Saxena and Sept (J. Chem. Theor. Comput. 2013, 9, 3538-3542) described a model, called the multisite-ion model, where instead of treating the ions as an isolated sphere, the charge was split into multiple sites with partial charge. This model provided accurate inner shell coordination of the ion with biomolecules and predicted better free energies for proteins and nucleic acids. Here, we expand and refine the multisite model to describe the behavior of divalent ions in concentrated MgCl2 and CaCl2 electrolyte solutions, eliminating the unusual ion-ion pairing and clustering of ions which occurred in the original model. We calibrate and improve the parameters of the multisite model by matching the osmotic pressure of concentrated solutions of MgCl2 to the experimental values and then use these parameters to test the behavior of CaCl2 solutions. We find that the concentrated solutions of both divalent ions exhibit the experimentally observed behavior with correct osmotic pressure, the presence of solvent separated ion pairs instead of direct ion pairs, and no aggregation of ions. The improved multisite model for (Mg(2+) and Ca(2+)) can be used in classical simulations of biomolecules at physiologically relevant salt concentrations.

  13. Luminescence properties of europium ions-doped yttrium silicate (Y2SiO5:Eu3+) nanocrystalline phosphors: effect of Eu3+ ion concentration and thermal annealing.

    Science.gov (United States)

    Ko, Yeong Hwan; Lee, Soo Hyun; Yu, Jae Su

    2013-05-01

    The trivalent europium ions-doped yttrium silicate (Y2SiO5:Eu3+) nanocrystalline phosphors were synthesized via a sol-gel method, followed by post thermal annealing. The effects of thermal annealing temperature and doping concentration on the structural and luminescent properties of Y2SiO5:Eu3+ nanocrystalline phosphors were systematically investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and photoluminescence measurements. The nanocrystalline phosphors with a high crystallinity were obtained at an annealing temperature of 1300 degrees C. The luminescent spectra were affected strongly by the Eu3+ ion concentration and annealing temperature. The Eu3+ ion concentration was optimized at 5 mol%, exhibiting excellent red emission (-612 nm) corresponding to the 5D0 --> 7F2 transition of Eu3+ ions at the excitation wavelengths of 262 and 396 nm. For the optimized Y2SiO5:Eu3+ nanocrystalline phosphors, the lifetimes were also estimated from the decay curves under the ultraviolet excitations.

  14. The nonmonotonic concentration dependence of the mean activity coefficient of electrolytes is a result of a balance between solvation and ion-ion correlations.

    Science.gov (United States)

    Vincze, Julianna; Valiskó, Mónika; Boda, Dezso

    2010-10-21

    We propose a simple model to explain the nonmonotonic concentration dependence of the mean activity coefficient of simple electrolytes without using any adjustable parameters. The primitive model of electrolytes is used to describe the interaction between ions computed by the adaptive grand canonical Monte Carlo method. For the dielectric constant of the electrolyte, we use experimental concentration dependent values. This is included through a solvation term in our treatment to describe the interaction between ions and water that changes as the dielectric constant changes with concentration. This term is computed by a Born-treatment fitted to experimental hydration energies. Our results for LiCl, NaCl, KCl, CsCl, NaBr, NaI, MgCl(2), CaCl(2), SrCl(2), and BaCl(2) demonstrate that the principal reason of the nonmonotonic behavior of the activity coefficient is a balance between the solvation and ion-ion correlation terms. This conclusion differs from previous studies that assumed that it is the balance of hard sphere repulsion and electrostatic attraction that produces the nonmonotonic behavior. Our results indicate that the earlier assumption that solvation can be taken into account by a larger, "solvated" ionic radius should be reconsidered. To explain second order effects (such as dependence on ionic size), we conclude that explicit water models are needed.

  15. The general description of major ion concentrations in groundwater of Latvia

    Science.gov (United States)

    Kalvāns, A.; Delina, A.

    2012-04-01

    Latvia is situated at the North central part of the Baltic sedimentary basin where the crystalline basement is found in depth between 0.6 to 2 km. Three large aquifer complexes with distinct chemical composition of groundwater are identified: the stagnant water exchange zone where Na-Ca-Cl brine is found; the slow water exchange zone where Na-Ca-Cl-SO4 brackish water is found and active water exchange zone where the freshwater resides. These are separated by distinct regional aquicludes. The composition of the Cl- dominated brines at the base of sedimentary basin is characterised by shift from Na+ towards Ca++ as dominant cation, partially associated with depth of the aquifer and the strength of the brine. The concentration of SO4-- here is inversely linked to the concentration of Ca++ and, according to geochemical modelling, often is close to the solubility limit of the gypsum. The major ion concentrations in the E and W part of the territory are rather different. Therefore two different initial sources of the formation brine were suggested. Alternatively the observations can be explained by different thermal histories of different parts of the basin, affecting the rate of albitization - exchange of the Na for Ca in the solution due to water-rock interaction. The groundwater composition in the slow exchange zone can be nicely explained by the mixing of freshwater and brine residing deeper in the presence of gypsum during some but no all stages of mixing. In some shallow parts of the zone still bound by the Narva regional aquiclude freshwater is found. The question is posted - could this be a paleogroundwater originating from the extensive continental glaciations that override the territory several times during the Pleistocene? Initial isotope studies presented elsewhere seems to give negative answer to this question. The active water exchange zone is characterised by fresh Ca-Mg-HCO3 water with exceptions in cases where gypsum are abundant in sedimentary rocks and

  16. ELECTROCHEMICAL NOISE ANALYSIS OF THE INFLUENCE OF THE Zn2+ IONS CONCENTRATION ON ZINC ELECTROPLATING

    Institute of Scientific and Technical Information of China (English)

    Z. Zhang; C.S. Wu; Q.Y. Cai; F.H. Cao; J.Q. Zhang

    2005-01-01

    The influence of the concentration of Zn2+ ions on zinc electroplating process was investigated by means of electrochemical noise (EN) and cyclic voltammetry methods in conjunction with the scanning electron microscopy (SEM) technique. It was found that the EN generated during the electroplating of dentritic or large polymeric zinc deposit has large potential oscillation amplitude and positive potential drift while the compact zinc deposit possesses small noise amplitude and little potential drifi. With the change of rate determining step from diffusion-control through mixed-control to activation-control, the maximum relative energy obtained from wavelet analysis defined from the region with larger scales to those with smaller scales, and the EDP (relative energy distribution plot) can be us, as 'fingerprints" of EN to characterize the electroplating process and the deposit structure. The results also showed that electrochemical noise technique can give more information about the electrodeposit structure than other normal electrochemical measurements, such as linear potential sweep method and cyclic voltammetry technique.

  17. Determination of haloacetic acids concentrations in hospital effluent after chlorination by ion chromatography

    Institute of Scientific and Technical Information of China (English)

    SUN Ying-xue; GU Ping

    2007-01-01

    The ion chromatography combined solid phase extraction (SPE) method was developed for the analysis of low concentration haloacetic acids(HAAs),a calss of disinfection by-products formed as a result of chlorination of hospital wastewater. The monitored HAAs included monochloroacetic acid, monobromoacetic acid, dichloroacetic acid, dibromoacetic acid and trichloroacetic acid. The method employed a sodium hydroxide eluent at a flow rate of 0.8 ml/min, electrolytically generated gradients, and suppressed conductivity detection. To analyze the HAAs in real hospital wastewater samples, C18 pretreatment cartridge was utilized to reduce samples' turbidity. Preconcentration with SPE and matrix elimination with treatment cartridges were investigated and were found to be able to obtain acceptable detection limits. Linearity, repeatability and detection limits of the above method were evaluated. The detection limits of monobromoacetic acid and dibromoacetic acid were 2.61 μg/L and 1.30 μg/L respectively, and the other three are ranging from 0.48 to 0.82 μg/L under 25-fold preconcentration. When the above optimization procedure was applied to three hospital wastewater samples with different treatment processes in Tianjin, it was found that the dichloroacetic acid is the major compound, and the growth ratios of the HAAs after disinfection by sodium hypochlorite were 91.28%, 63.61% and 79.50%, respectively.

  18. Fast computation of the electrolyte-concentration transfer function of a lithium-ion cell model

    Science.gov (United States)

    Rodríguez, Albert; Plett, Gregory L.; Trimboli, M. Scott

    2017-08-01

    One approach to creating physics-based reduced-order models (ROMs) of battery-cell dynamics requires first generating linearized Laplace-domain transfer functions of all cell internal electrochemical variables of interest. Then, the resulting infinite-dimensional transfer functions can be reduced by various means in order to find an approximate low-dimensional model. These methods include Padé approximation or the Discrete-Time Realization algorithm. In a previous article, Lee and colleagues developed a transfer function of the electrolyte concentration for a porous-electrode pseudo-two-dimensional lithium-ion cell model. Their approach used separation of variables and Sturm-Liouville theory to compute an infinite-series solution to the transfer function, which they then truncated to a finite number of terms for reasons of practicality. Here, we instead use a variation-of-parameters approach to arrive at a different representation of the identical solution that does not require a series expansion. The primary benefits of the new approach are speed of computation of the transfer function and the removal of the requirement to approximate the transfer function by truncating the number of terms evaluated. Results show that the speedup of the new method can be more than 3800.

  19. High-temperature electromagnons in the magnetically induced multiferroic cupric oxide driven by intersublattice exchange.

    Science.gov (United States)

    Jones, S P P; Gaw, S M; Doig, K I; Prabhakaran, D; Hétroy Wheeler, E M; Boothroyd, A T; Lloyd-Hughes, J

    2014-04-29

    Magnetically induced ferroelectric multiferroics present an exciting new paradigm in the design of multifunctional materials, by intimately coupling magnetic and polar order. Magnetoelectricity creates a novel quasiparticle excitation--the electromagnon--at terahertz frequencies, with spectral signatures that unveil important spin interactions. To date, electromagnons have been discovered at low temperature (domain spectroscopy that intersublattice exchange in the improper multiferroic cupric oxide (CuO) creates electromagnons at substantially elevated temperatures (213-230 K). Dynamic magnetoelectric coupling can therefore be achieved in materials, such as CuO, that exhibit minimal static cross-coupling. The electromagnon strength and energy track the static polarization, highlighting the importance of the underlying cycloidal spin structure. Polarized neutron scattering and terahertz spectroscopy identify a magnon in the antiferromagnetic ground state, with a temperature dependence that suggests a significant role for biquadratic exchange.

  20. Modelisation of the contribution of the Na/Ca exchanger to cell membrane potential and intracellular ion concentrations.

    Science.gov (United States)

    Bahlouli, S; Hamdache, F; Riane, H

    2008-09-01

    Modelisation plays a significant role in the study of ion transfer through the cell membrane and in the comprehension of cellular excitability. We were interested in the selective ion transfers through the K(Ca), Na(v), Ca(v) channels and the Na/Ca exchanger (NCX). The membrane behaves like an electric circuit because of the existence of ion gradients maintained by the cell. The non-linearity of this circuit gives rise to complex oscillations of the membrane potential. By application of the finite difference method (FDM) and the concept of percolation we studied the role of the NCX in the regulation of the intracellular Ca(2+) concentration and the oscillations of the membrane potential. The fractal representation of the distribution of active channels allows us to follow the diffusion of intracellular Ca(2+) ions. These calculations show that the hyperpolarization and the change in the burst duration of the membrane potential are primarily due to the NCX.

  1. μPIXE for a μBrain: The vinegar fly's brain, antenna, sensilla hairs and eye ion concentrations

    Science.gov (United States)

    Reinert, Anja; Barapatre, Nirav; Sachse, Silke; Reinert, Tilo

    2011-10-01

    The vinegar fly Drosophila melanogaster is used as model organism to study a variety of different scientific purposes. Thus, our laboratory studies the olfactory system by neurobiological experiments. These techniques are often disruptive and need to compensate or exchange the body fluid, the lymph, with an artificial Ringer's solution in defined compartments of the fly. The solution mainly contains Na, Cl, K and Ca and is to keep physiological conditions. Therefore, the knowledge about the ion concentrations in the respective Drosophila lymph is required for a correct mixture of the ions. This paper presents the spatially resolved concentrations of P, S, Cl, K, Ca, Fe, Cu and Zn in lyophilised head cryosections of Drosophila by using quantitative μPIXE at the ion beam facility LIPSION in Leipzig. The PIXE maps enable a detailed analysis of particular regions of interest down to a spatial resolution of 0.5 μm. We quantified the ion concentrations especially in the brain, the antenna and its sensilla hairs acting as the olfactory organ of the fly, in the compound eye and in the mouthparts. The averaged element concentrations of these main compartments are (in descending order): P: 90 mM, K: 81 mM, S: 38 mM, Cl: 18 mM, Ca: 4.9 mM, Fe: 1.4 mM, Zn: 1.2 mM, Cu: 0.06 mM. Certain structures or cavities possess a remarkably high concentration of particular elements and might reflect the different functions of the compartments. An example presented in more detail is the composition of the compound eye. Conclusively, our findings on the ion concentrations might be useful for the mixture of the Drosophila Ringer's solution to ensure physiological conditions in experiments.

  2. Seasonal dynamics of nitrate and ammonium ion concentrations in soil solutions collected using MacroRhizon suction cups.

    Science.gov (United States)

    Kabala, Cezary; Karczewska, Anna; Gałka, Bernard; Cuske, Mateusz; Sowiński, Józef

    2017-07-01

    The aims of the study were to analyse the concentration of nitrate and ammonium ions in soil solutions obtained using MacroRhizon miniaturized composite suction cups under field conditions and to determine potential nitrogen leaching from soil fertilized with three types of fertilizers (standard urea, slow-release urea, and ammonium nitrate) at the doses of 90 and 180 kg ha(-1), applied once or divided into two rates. During a 3-year growing experiment with sugar sorghum, the concentration of nitrate and ammonium ions in soil solutions was the highest with standard urea fertilization and the lowest in variants fertilized with slow-release urea for most of the months of the growing season. Higher concentrations of both nitrogen forms were noted at the fertilizer dose of 180 kg ha(-1). One-time fertilization, at both doses, resulted in higher nitrate concentrations in June and July, while dividing the dose into two rates resulted in higher nitrate concentrations between August and November. The highest potential for nitrate leaching during the growing season was in July. The tests confirmed that the miniaturized suction cups MacroRhizon are highly useful for routine monitoring the concentration of nitrate and ammonium ions in soil solutions under field conditions.

  3. Analyzing freely dissolved concentrations of cationic surfactant utilizing ion-exchange capability of polyacrylate coated solid-phase microextraction fibers

    NARCIS (Netherlands)

    Chen, Y.; Droge, S.T.J.; Hermens, J.L.M.

    2012-01-01

    A 7-μm polyacrylate (PA) coated fiber was successfully employed to determine freely dissolved concentrations of cationic surfactants by solid-phase microextraction (SPME) and utilizing the capability of the PA-coating to sorb organic cations via ion-exchange at carboxylic groups. Measured fiber-wate

  4. Hydroxide ion concentration at an interface between concrete and a self-levelling flooring compound

    OpenAIRE

    Anderberg, Anders; Wadsö, Lars

    2007-01-01

    This article presents results from measurements of hydroxide ion transport between a concrete and a floor screed of a lower alkalinity than the concrete. As many floor coverings and floor adhesives are sensitive to high alkaline conditions it is important to know how hydroxide ions are transported to be able to evaluate the long-term function of floor constructions. It was found that only minor transport of hydroxide ions occurs in the hygroscopic moisture range. One conclusion is therefore t...

  5. REE concentration processes in ion adsorption deposits: Evidence from Madagascar and China.

    Science.gov (United States)

    Smith, Martin; Estrade, Guillaume; Marquis, Eva; Goodenough, Kathryn; Nasun, Peter; Cheng, Xu; Kynicky, Jindrich

    2017-04-01

    Lateritic clay deposits, where the rare earth elements (REE) occur adsorbed to clay mineral surfaces, are the world's dominant supply of heavy REE (Gd-Lu). These deposits are currently only mined in China where there is a reported heavy REE enrichment, but other deposits are currently under exploration in Brazil, the Philippines and Madagascar. Concentration of REE within IADs has been proposed to be a dominantly supergene process, where easily degradable REE-minerals (e.g. REE-fluorcarbonates) break down and release REE that are then adsorbed to clay minerals resulting in HREE enrichment. Here we present data from the Ambohimirahavavy Complex, Madagascar, and compare them to data from mineralised profiles in China, with the aim of further constraining the formation and REE enrichment processes in ion adsorption deposits. Bulk rock total REE contents from Madagascar vary from 400-5000ppm, with the HREE varying from 10 to 20% of the TREE. Ammonium Sulphate leaches (designed to remove clay-adsorbed REE) of laterite show leachable TREE from 130-500ppm, with no preferential HREE adsorption. Within the sequential extraction procedure the reducible fraction (hydroxylammonium chloride leach) showed the highest REE, but this is largely attributable to Ce4+ in oxide layers. Analysis of laterite profiles show that the REE distribution is heterogeneous, with control from both bedrock heterogeneity, and the hydrological variation between pedolith and saprolith. Similar patterns are seen in Chinese profiles from Jiangxi province. X-ray diffraction shows the clay fraction in all sites is dominated by kaolinite and halloysite. These data are consistent with experimental data which show that kaolinite is only HREE selective in high ionic strength solutions (Coppin et al., 2002), and suggest that HREE enrichment in lateritic deposits may be a function of exceptional bed rock conditions. Petrographic investigation of the Zhaibei granite, immediately underlying HREE enriched

  6. Influence of Gd3+ concentration on luminescence properties of Eu3+ ions in sol-gel materials

    Science.gov (United States)

    Szpikowska-Sroka, Barbara; Pawlik, Natalia; Pisarski, Wojciech A.

    2016-12-01

    The sol-gel powders doubly-doped with Gd3+/Eu3+ ions with different concentration of Gd3+ have been successfully obtained. The spectroscopic characterization of prepared samples was conducted based on excitation and emission spectra as well as luminescence decay analysis. Upon direct excitation of Eu3+ active ions, the characteristic 5D0 → 7F1 (orange) and 5D0 → 7F2 (red) emission bands were observed. The energy transfer from Gd3+ to Eu3+ ions was registered upon λexc = 273 nm excitation. An efficient conversion of ultraviolet radiation (UV) into visible luminescence was successfully observed. The energy transfer process from Gd3+ to Eu3+ led to longer luminescence decay from the 5D0 state in comparison to that obtained under direct excitation of Eu3+ ions (λexc = 393 nm). Generally, obtained results clearly indicated the beneficial influence of increasing concentration of Gd3+ ions on luminescence properties of Eu3+ in studied silica sol-gel phosphors.

  7. Concentration Effects and Ion Properties Controlling the Fractionation of Halides during Aerosol Formation

    Science.gov (United States)

    Guzman, Marcelo I.; Athalye, Richa R.; Rodriguez, Jose M.

    2012-01-01

    During the aerosolization process at the sea surface, halides are incorporated into aerosol droplets, where they may play an important role in tropospheric ozone chemistry. Although this process may significantly contribute to the formation of reactive gas phase molecular halogens, little is known about the environmental factors that control how halides selectively accumulate at the air-water interface. In this study, the production of sea spray aerosol is simulated using electrospray ionization (ESI) of 100 nM equimolar solutions of NaCl, NaBr, NaI, NaNO2, NaNO3, NaClO4, and NaIO4. The microdroplets generated are analyzed by mass spectrometry to study the comparative enrichment of anions (f (Isub x-)) and their correlation with ion properties. Although no correlation exists between f (sub x-) and the limiting equivalent ionic conductivity, the correlation coefficient of the linear fit with the size of the anions R(sub x-), dehydration free-energy ?Gdehyd, and polarizability alpha, follows the order: (R(sub x-)(exp -2)) > (R(sub x-)(exp -1)) >(R(sub x-) > delta G(sub dehyd) > alpha. The same pure physical process is observed in H2O and D2O. The factor f (sub x-) does not change with pH (6.8-8.6), counterion (Li+, Na+, K+, and Cs+) substitution effects, or solvent polarity changes in methanol - and ethanol-water mixtures (0 surfactant is used to modify the structure of the interface. Despite the observed enrichment of I- on the air-water interface of equimolar solutions, our results of seawater mimic samples agree with a model in which the interfacial composition is increasingly enriched in I- < Br- < Cl- over the oceanic boundary layer due to concentration effects in sea spray aerosol formation.

  8. NIRS-Derived Tissue Oxygen Saturation and Hydrogen Ion Concentration Following Bed Rest

    Science.gov (United States)

    Lee, S. M. C.; Everett, M. E.; Crowell, J. B.; Westby, C. M.; Soller, B. R.

    2010-01-01

    Long-term bed rest (BR), a model of spaceflight, results in a decrease in aerobic capacity and altered submaximal exercise responses. The strongest BR-induced effects on exercise appear to be centrally-mediated, but longer BR durations may result in peripheral adaptations (e.g., decreased mitochondrial and capillary density) which are likely to influence exercise responses. PURPOSE: To measure tissue oxygen saturation (SO2) and hydrogen ion concentration ([H+]) in the vastus lateralis (VL) using near infrared spectroscopy (NIRS) during cycle ergometry before and after . 30 d of BR. METHODS: Eight subjects performed a graded exercise test on a cycle ergometer to volitional fatigue 7 d before (pre-BR) and at the end or 1 day after BR (post-BR). NIRS spectra were collected from a sensor adhered to the skin overlying the VL. Oxygen consumption (VO2) was measured by open circuit spirometry. Blood volume (BV) was measured before and after BR using the carbon monoxide rebreathing technique. Changes in pre- and post-BR SO2 and [H+] data were compared using mixed model analyses. BV and peak exercise data were compared using paired t-tests. RESULTS: BV (pre-BR: 4.3+/-0.3, post-BR: 3.7+/-0.2 L, mean+/-SE, p=.01) and peak VO2 (pre-BR: 1.98+/-0.24, post-BR: 1.48 +/-0.21 L/min, padaptations which contribute to cardiovascular and muscular deconditioning as measured by NIRS-derived SO2 and [H+] in the VL and may contribute to lower post-BR exercise tolerance. Supported by the National Space Biomedical Research Institute through NASA NCC 9-58

  9. Transport-limited water splitting at ion-selective interfaces during concentration polarization

    CERN Document Server

    Nielsen, Christoffer P

    2013-01-01

    We present an analytical model of salt- and water-ion transport across an ion-selective interface based on an assumption of local equilibrium of the water-dissociation reaction. The model yields current-voltage characteristics and curves of water-ion current versus salt-ion current, which are in qualitative agreement with experimental results published in the literature. The analytical results are furthermore in agreement with direct numerical simulations. As part of the analysis, we find approximate solutions to the classical problem of pure salt transport across an ion-selective interface. These solutions provide closed-form expressions for the current-voltage characteristics, which include the overlimiting current due to the development of an extended space charge region. Finally, we discuss how the addition of an acid or a base affects the transport properties of the system and thus provide predictions accessible to further experimental tests of the model.

  10. Influence of chloride ion concentration on immersion corrosion behaviour of plasma sprayed alumina coatings on AZ31B magnesium alloy

    Directory of Open Access Journals (Sweden)

    D. Thirumalaikumarasamy

    2014-12-01

    Full Text Available Corrosion attack of aluminium and magnesium based alloys is a major issue worldwide. The corrosion degradation of an uncoated and atmospheric plasma sprayed alumina (APS coatings on AZ31B magnesium alloy was investigated using immersion corrosion test in NaCl solutions of different chloride ion concentrations viz., 0.01 M, 0.2 M, 0.6 M and 1 M. The corroded surface was characterized by an optical microscope and X-ray diffraction. The results showed that the corrosion deterioration of uncoated and coated samples were significantly influenced by chloride ion concentration. The uncoated magnesium and alumina coatings were found to offer a superior corrosion resistance in lower chloride ion concentration NaCl solutions (0.01 M and 0.2 M NaCl. On the other hand the coatings and Mg alloy substrate were found to be highly susceptible to localized damage, and could not provide an effective corrosion protection in solutions containing higher chloride concentrations (0.6 M and 1 M. It was found that the corrosion resistance of the ceramic coatings and base metal gets deteriorated with the increase in the chloride concentrations.

  11. Electron energy distribution functions and negative ion concentrations in tandem and hybrid multicusp negative hydrogen ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Hopkins, M.B. (Dublin City Univ. (Ireland). Dept. of Physics); Bacal, M. (Ecole Polytechnique, 91 - Palaiseau (France). Lab. de Physique des Milieux Ionises); Graham, W.G. (Queen' s Univ., Belfast, Northern Ireland (UK). School of Mathematics and Physics)

    1991-03-14

    The second derivative of a Langmuir probe characteristic is used to establish the electron energy distribution function (EEDF) in both a tandem and hybrid multicusp H{sup -} ion source. Moveable probes are used to establish the spatial variation of the EEDF. The negative ion density is measured by laser induced photo-detachment. In the case of the hybrid source the EEDF consists of a cold Maxwellian in the central region of the source; the electron temperature increases with increasing discharge current (rising from 0.3 eV at 1 A to 1.2 eV at 50 A when the pressure is 0.4 Pa). A hot electron tail exists in the EEDF of the driver region adjacent to each filament which is shown to consist of a distinct group of primary electrons at low pressure (0.08 Pa) but becomes degraded mainly through inelastic collisions at higher pressures (0.27 Pa). The tandem source, on the other hand, has a single driver region which extends throughout the central region. The primary electron confinement times are much longer so that even at the lowest pressure considered (0.07 Pa) the primaries are degraded. In both cases the measured EEDF at specific locations and values of discharge operating parameters are used to establish the rate coefficients for the processes of importance in H{sup -} production and destruction. (author).

  12. Investigating the effect of electro-active ion concentration on spectral induced polarization signatures arising from biomineralization pathways

    Science.gov (United States)

    Ntarlagiannis, D.; Slater, L. D.; Williams, K. H.; Hubbard, S. S.; Wu, Y.

    2010-12-01

    Spectral induced polarization (SIP) is a proven geophysical method for detecting biomineral formation with promising applications for monitoring biogeochemical products during microbial induced sequestration of heavy metals and radionuclides in soils. SIP has been used to monitor the evolution of bioremediation-induced end-products at the uranium-contaminated U.S. Department of Energy Rifle Integrated Field Research Challenge site in Colorado. Although a significant SIP response was detected, the quantitative interpretation is non-trivial as the polarization of metallic minerals depends both on the mineral surface properties and the electrolyte chemistry. In previous experiments SIP mechanisms were studied under complex environments and individual source mechanisms could not be evaluated. Here we examine the role of electrolyte chemistry by comparing the effect of redox active / inactive ions on metallic polarization. In these abiotic experiments magnetite was used as a proxy biomineral and dispersed within columns packed with sand. Parallel columns were saturated with solutions of different concentrations of active (Fe2+) and inactive (Ca2+) ions (0.01mM-10mM) and SIP measurements made (0.1-1000 Hz). Experimental results show small, but detectable, differences in the effect of active ion and inactive ion concentration on the SIP response. To better characterize the effect of electro-active ions on metallic minerals we used a Cole - Cole type relaxation model, to describe the SIP responses. In order to better resolve the relaxation model parameters, we followed a two-step approach whereby we started with a Bayesian based inversion to resolve for the initial parameter estimates, and subsequently used these estimates as a starting model for a deterministic solution. Our results suggest that changes in the active ion concentration, in the presence of magnetite, alone are unlikely to fully explain recent SIP monitoring data from the Rifle site.

  13. Concentration Polarization and Nonequilibrium Electro-osmotic Instability at an Ion-Selective Surface Admitting Normal Flow

    Science.gov (United States)

    Khair, Aditya

    2011-11-01

    We revisit and build upon on the prototypical problem of ion transport across a flat ideal ion-selective surface. Specifically, we examine the influence of imposed fluid flows on concentration polarization (CP) and electrokinetic instability at over-limiting currents. We consider an ion-selective surface, or membrane, that admits a uniform flow across itself. The membrane contacts an electrolyte, whose concentration is uniform in a well-mixed region at a prescribed distance from the membrane. A voltage across the system drives an ionic current, leading to CP in the ``unstirred layer'' between the membrane and well-mixed bulk. The CP reflects a balance between advection of ions with the ``normal flow'' and diffusion. A Peclet number, Pe, parameterizes their relative importance; note, Pe is signed, as the flow can be toward or away from the membrane. An asymptotic analysis for thin Debye layers reveals a nonlinear CP profile, in contrast to the familiar linear profile at Pe=0. Next, we consider over-limiting currents, wherein a non-equilibrium space-charge layer emerges near the membrane surface. Finally, we examine the instability of the quiescent concentration polarization due to second-kind electro-osmosis in the space-charge layer. A stability analysis shows that the imposed normal flow can enhance or retard the instability, depending on its direction.

  14. Hydronium-dominated ion transport in carbon-dioxide-saturated electrolytes at low salt concentrations in nanochannels

    DEFF Research Database (Denmark)

    Pennathur, Sumita; Kristensen, Jesper; Crumrine, Andrew

    2011-01-01

    Nanochannel ion transport is known to be governed by surface charge at low ionic concentrations. In this talk, we show that this surface charge is dominated by hydronium ions arising from dissolution of ambient atmospheric carbon dioxide. By refining the electrokinetic model of the nanochannel...... the surface reaction equilibrium constant for silica/hydronium reactions. The model describes our experimental data with aqueous potassium chloride solutions in 165-nm-high silica nanochannels well, and furthermore, by comparing model predictions with measurements in bulk and in nanochannels with hydrochloric...

  15. Handheld Device Adapted to Smartphone Cameras for the Measurement of Sodium Ion Concentrations at Saliva-Relevant Levels via Fluorescence

    Directory of Open Access Journals (Sweden)

    Michelle Lipowicz

    2015-06-01

    Full Text Available The use of saliva sampling as a minimally-invasive means for drug testing and monitoring physiology is a subject of great interest to researchers and clinicians. This study describes a new optical method based on non-axially symmetric focusing of light using an oblate spheroid sample chamber. The device is simple, lightweight, low cost and is easily attached to several different brands/models of smartphones (Apple, Samsung, HTC and Nokia for the measurement of sodium ion levels at physiologically-relevant saliva concentrations. The sample and fluorescent reagent solutions are placed in a specially-designed, lightweight device that excludes ambient light and concentrates 470-nm excitation light, from a low-power photodiode, within the sample through non-axially-symmetric refraction. The study found that smartphone cameras and post-image processing quantitated sodium ion concentration in water over the range of 0.5–10 mM, yielding best-fit regressions of the data that agree well with a data regression of microplate luminometer results. The data suggest that fluorescence can be used for the measurement of salivary sodium ion concentrations in low-resource or point-of-care settings. With further fluorescent assay testing, the device may find application in a variety of enzymatic or chemical assays.

  16. Trace anion determination in concentrated hydrofluoric acid solutions by two-dimensional ion chromatography I. Matrix elimination by ion-exclusion chromatography.

    Science.gov (United States)

    Vermeiren, Koen

    2005-08-26

    Since years, ion exclusion chromatography (ICE) has been the standard method to separate strong acid analyte anions from concentrated weak acid matrices such as hydrofluoric acid (HF). In this work, the commercially available IonPac ICE-AS 1 column was used to separate trace levels of chloride, nitrate, sulfate and phosphate from HF solutions at 20% (w/w). The efficiency of the separation was studied in more detail using techniques such as ion chromatography (IC), inductively coupled plasma optical emission spectrometry (ICP-OES) and ICP-mass spectrometry (ICP-MS). For 20% (w/w) HF solutions and at a water carrier flow-rate of 0.50 ml/min, the cut window was set from 8.5 to 14.5 min. Under these conditions, analyte recoveries of better than 90% were obtained for chloride, nitrate and sulfate, but only about 75% for phosphate. The HF rejection efficiency was better than 99.9%. It was found that the ICP techniques, measuring total element levels and not species, yielded significantly higher recoveries for phosphorus and sulfur compared to IC. Evidence will be given that part of the added phosphorus (approximately 15% for an addition of 10 mg PO4/kg) is present as mono-fluorophosphoric acid (H2FPO3). In the case of sulfate, the difference between IC and ICP-MS could be attributed to an important matrix effect from the residual HF concentration.

  17. A Liquid Chromatography Detector for Transition and Rare-Earth Metal Ions Based on a Cupric Ion-Selective Electrode

    Science.gov (United States)

    1981-05-01

    both comparators are at negative saturation. Consequentially, the bases of Ql and Q2 (3140SK PNP transistors , RCA) are negative with respect to their...Devices). Ql, Q2 - 3140 SK PNP transistor (RCA). 196 conduct. The input to ICA from QI is then +5V, or "high." IC2 is a 555 timer configured to strobe...emitters, and the transistors are switched "on." Their collectors are thus poised at 0 volts. This potential is fed into an input of ICA and ICIB (both

  18. The differentiation inducer, dimethyl sulfoxide, transiently increases the intracellular calcium ion concentration in various cell types.

    Science.gov (United States)

    Morley, P; Whitfield, J F

    1993-08-01

    Dimethyl sulfoxide (DMSO) initiates a coordinated differentiation program in various cell types but the mechanism(s) by which DMSO does this is not understood. In this study, the effect of DMSO on intracellular calcium ion concentration ([Ca2+]i) was determined in primary cultures of chicken ovarian granulosa cells from the two largest preovulatory follicles of laying hens, and in three cell lines: undifferentiated P19 embryonal carcinoma cells, 3T3-L1 fibroblasts, and Friend murine erythroleukemia (MEL) cells. [Ca2+]i was measured in cells loaded with the Ca(2+)-specific fluoroprobe Fura-2. There was an immediate (i.e., within 5 sec), transient, two to sixfold increase in [Ca2+]i after exposing all cell types to 1% DMSO. DMSO was effective between 0.2 and 1%. The prompt DMSO-induced [Ca2+]i spike in all of the cell types was not prevented by incubating the cells in Ca(2+)-free medium containing 2 mM EGTA or by pretreating them with the Ca(2+)-channel blockers methoxyverapamil (D600; 100 microM), nifedipine (20 microM), or cobalt (5 mM). However, when granulosa cells, 3T3-L1 cells, or MEL cells were pretreated with lanthanum (La3+; 1 mM), which blocks both Ca2+ channels and membrane Ca2+ pumps, there was a sustained increase in [Ca2+]i in response to 1% DMSO. By contrast, pretreating P19 cells with La3+ (1 mM) did not prolong the DMSO-triggered [Ca2+]i transient. In all cases, the DMSO-induced [Ca2+]i surge was unaffected by pretreating the cells with the inhibitors of inositol phospholipid hydrolysis, neomycin (1.5 mM) or U-73, 122 (2.5 microM). These results suggest that DMSO almost instantaneously triggers the release of Ca2+ from intracellular stores through a common mechanism in cells in primary cultures and in cells of a variety of established lines, but this release is not mediated through phosphoinositide breakdown. This large, DMSO-induced Ca2+ spike may play a role in the induction of cell differentiation by DMSO.

  19. Hydrogen-ion titrations of amino acids and proteins in solutions containing concentrated electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Fergg, F. [Technische Universitaet Muenchen (Germany); Kuehner, D.E.; Blanch, H.W.; Prausnitz, J.M. [Lawrence Berkeley Lab., CA (United States)

    1994-12-01

    This report describes a first attempt to quantify the net charge as a function of solution pH for lysozyme and {alpha}-chymotrypsin at 0.1 M, 1.0 M and 3.0 M ionic strength, (IS). The calculations are based on the residue (titratable group) pK{sub a}`s in the amino-acid sequence of the protein. To determine these pK{sub a}`s, a simple theory was used which assumes that the pK{sub a}`s are independent from each other in the protein and are equal to their pK{sub a} values in free amino-acid solution (Independent-Site Theory, IST). Residue pK{sub a}`s were obtained from amino-acid hydrogen-ion titrations at three different KCl concentrations corresponding to 0.1M, 1.0M and 3.0M ionic strength. After construction of a suitable apparatus, the experimental procedure and data reduction were computerized to perform a large number of titrations. Most measured pK{sub a}`s showed high reproducibility (the difference of pK{sub a} values observed between two experiments was less than 0.05). For IS = 0.1M, observed pK{sub a}`s agreed with literature values to within a few hundredths of a pH unit. Furthermore, the ionic-strength dependence of the pK{sub a}`s followed the trends reported in the literature, viz. pK{sub a} values decrease with increasing ionic strength until they reach a minimum at about IS = 0.5M. At still higher IS, pK{sub a}`s increase as the ionic strength rises to 3M. The known pK{sub a}`s of all titratable groups in a protein were used with the IST to give a first approximation of how the protein net charge varies with pH at high ionic strength. A comparison of the titration curves based on the IST with experimental lysozyme and {alpha}-chymotrypsin titration data indicates acceptable agreement at IS = 0.1M. However, comparison of measured and calculated titration curves at IS = 1M and IS = 3M indicates only quantitative agreement.

  20. Spatial distribution of the electrical potential and ion concentration in the downstream area of atmospheric pressure remote plasma

    Directory of Open Access Journals (Sweden)

    M. V. Mishin

    2014-10-01

    Full Text Available This paper presents the results from an experimental study of the ion flux characteristics behind the remote plasma zone in a vertical tube reaction chamber for atmospheric pressure plasma enhanced chemical vapor deposition. Capacitively coupled radio frequency plasma was generated in pure He and gas mixtures: He–Ar, He–O2, He–TEOS. We previously used the reaction system He–TEOS for the synthesis of self-assembled structures of silicon dioxide nanoparticles. It is likely that the electrical parameters of the area, where nanoparticles have been transported from the synthesis zone to the substrate, play a significant role in the self-organization processes both in the vapor phase and on the substrate surface. The results from the spatial distribution of the electrical potential and ion concentration in the discharge downstream area measured by means of the external probe of original design and the special data processing method are demonstrated in this work. Positive and negatives ions with maximum concentrations of 106–107 cm−3 have been found at 10–80 mm distance behind the plasma zone. On the basis of the revealed distributions for different gas mixtures, the physical model of the observed phenomena is proposed. The model illustrates the capability of the virtual ion emitter formation behind the discharge gap and the presence of an extremum of the electrical potential at the distance of approximately 10−2–10−1 mm from the grounded electrode.

  1. The use of Na+ and K+ ion concentrations as potential diagnostic indicators of subclinical mastitis in dairy cows

    OpenAIRE

    Abdul Wahid Haron; Faez Firdaus Jesse Abdullah; Abdulnasir Tijjani; Yusuf Abba; Lawan Adamu; Konto Mohammed; Aisyah Munira Mohammed Amir; Mohammad Abubakar Sadiq; Mohd Azmi Mohd Lila

    2014-01-01

    Aim: This study was conducted to evaluate the concentrations of sodium (Na+) and potassium (K+) ions in milk of lactating dairy cows with and without subclinical mastitis as putative indicators for detecting subclinical mastitis in dairy cows. Materials and Methods: Thirty seven lactating dairy cows were screened for the evidence of subclinical mastitis using California mastitis test (CMT). The lactating dairy cows were categorized as CMT-Positive (CMT-P; n=20) and CMT-Negative (CMT-N; n=1...

  2. Effects of increasing nitrogen concentration on the structure of carbon nitride films deposited by ion beam assisted deposition

    OpenAIRE

    Hammer, P.; Victoria, NM; F Alvarez

    2000-01-01

    Amorphous carbon nitride films containing increasing concentrations of nitrogen were deposited by ion beam assisted deposition at a substrate temperature of 150 degrees C. The relationship between the deposition conditions and the chemical bonding structure was investigated by x-ray photoelectron, ultraviolet photoelectron, infrared, and Raman spectroscopies. Film properties were examined by ultraviolet-vis spectroscopy, conductivity, hardness, density, and internal stress measurements. The e...

  3. Effects of ion concentration and natural organic matter on arsenic(V) removal by nanofiltration under different transmembrane pressures

    Institute of Scientific and Technical Information of China (English)

    Yang Yu; Changwei Zhao; Yangui Wang; Weihong Fan; Zhaokun Luan

    2013-01-01

    The removal of As(V) from synthetic water was studied using four different nanofiltradon (NF) membranes (ESNA-1-K1,NF270,ESNA-1-LF,and HODRA-CORE).The influences of ion concentration,transmembrane pressure (TMP),and the presence of natural organic matter (humic acid,HA) on the arsenic removal efficiency and permeate flux were investigated.The arsenic rejection of ESNA-1-LP was higher than those of the other membranes in all experiments (> 94%),and the HODRA-CORE membrane gave the lowest removal of arsenic (< 47%).An increase in the ion concentration in the feed solution and addition of HA decreased the arsenic rejection of the HODRA-CORE membrane.However,both increasing of the ion concentration and addition of HA made the rejection increased for the other membranes (ESNA-1-K1,NF270,and ESNA-1-LF).With increasing TMP,for all four NF membranes,increases in both arsenic rejection and permeate flux were observed.The permeate fluxes of the four NF membranes decreased to some extent after addition of HA to the solutions for operating time of 6 hr.

  4. Combined effects of temperature and copper ion concentration on the superoxide dismutase activity inCrassostrea ariakensis

    Institute of Scientific and Technical Information of China (English)

    WANG Hui; YANG Hongshuai; LIU Jiahui; LI Yanhong; LIU Zhigang

    2016-01-01

    Superoxide dismutase (SOD) is a crucial antioxidant enzyme playing the first defense line in antioxidant pathways against reactive oxygen species in various organisms including marine invertebrates. There exist mainly two specific forms, Cu/Zn-SOD (SOD1) and Mn-SOD (SOD2), in eukaryotes. SODs are known to be concurrently modulated by a variety of environmental stressors. By using central composite experimental design and response surface method, the joint effects of water temperature (18–34°C) and copper ion concentration (0.1–1.5 mg/L) on the total SOD activity in the digestive gland ofCrassostrea ariakensis were studied. The results showed that the linear effect of temperature was highly significant (P0.05), while the quadratic effect of copper ion concentration was highly significant (P0.05); the effect of temperature was greater than that of copper ion concentration. The model equation of digestive gland SOD enzyme activity towards the two factors of interest was established, withR2 and predictiveR2 as high as 0.961 6 and 0.820 7, respectively, suggesting that the goodness-of-fit to experimental data be very satisfactory, and could be applied to prediction of digestive gland SOD activity in C. ariakensis under the conditions of the experiment. Our results would be conducive to addressing the health of aquatic animals and/or to detecting environmental problems by taking SOD as a potential bioindicator.

  5. Depth concentrations of deuterium ions implanted into some pure metals and alloys

    Science.gov (United States)

    Didyk, A. Yu.; Wiśniewski, R.; Kitowski, K.; Kulikauskas, V.; Wilczynska, T.; Hofman, A.; Shiryaev, A. A.; Zubavichus, Ya. V.

    2012-01-01

    Pure metals (Cu, Ti, Zr, V, Pd) and diluted Pd alloys (Pd-Ag, Pd-Pt, Pd-Ru, Pd-Rh) were implanted by 25-keV deuterium ions at fluences in the range (1.2-2.3) × 1022 m-2. The post-treatment depth distributions of deuterium ions were measured 10 days and three months after the implantation by using Elastic Recoil Detection Analysis (ERDA) and Rutherford Backscattering (RBS). Comparison of the obtained results allowed us to make conclusions about relative stability of deuterium and hydrogen gases in pure metals and diluted Pd alloys. Very high diffusion rates of implanted deuterium ions in V and Pd pure metals and Pd alloys were observed. Small-angle X-ray scattering revealed formation of nanosized defects in implanted corundum and titanium.

  6. Analyzing freely dissolved concentrations of cationic surfactant utilizing ion-exchange capability of polyacrylate coated solid-phase microextraction fibers.

    Science.gov (United States)

    Chen, Yi; Droge, Steven T J; Hermens, Joop L M

    2012-08-24

    A 7-μm polyacrylate (PA) coated fiber was successfully employed to determine freely dissolved concentrations of cationic surfactants by solid-phase microextraction (SPME) and utilizing the capability of the PA-coating to sorb organic cations via ion-exchange at carboxylic groups. Measured fiber-water partitioning coefficients (K(fw)) were constant below a fiber loading of 2mmol per liter polyacrylate, allowing for simple and accurate analysis in a concentration range that is relevant from a risk assessment point of view. Ion-exchange was confirmed to be the main sorption mechanism because of a decreasing K(fw) with either higher CaCl(2) concentrations or lower pH, and maximum fiber uptake at the polyacrylate cation-exchange capacity (CEC, at 30mmol/L PA). Fiber-water sorption isotherms were established in various aqueous media in toxicological relevant concentrations. The developed SPME method has a high potential for application in ecotoxicological studies, as demonstrated in sorption studies with humic acid in different electrolyte solutions at aqueous concentrations down to the sub nM range. Cationic surfactant sorption affinities for humic acid also depend on medium composition but are orders of magnitude higher than to the PA fiber on a sorbent weight basis.

  7. Orbital driven impurity spin effect on the magnetic order of quasi-3D cupric oxide

    Science.gov (United States)

    Ganga, B. G.; Santhosh, P. N.; Nanda, B. R. K.

    2017-04-01

    Density functional calculations are performed to study the magnetic order of the severely distorted square planar cupric oxide (CuO) and local spin disorder in it in the presence of the transition metal impurities M (=Cr, Mn, Fe, Co and Ni). The distortion in the crystal structure, arisen to reduce the band energy by minimizing the covalent interaction, creates two crisscrossing zigzag spin-1/2 chains. From the spin dimer analysis we find that while the spin chain along ≤ft[1 0 \\bar{1}\\right] has strong Heisenberg type antiferromagnetic coupling (J ~ 127 meV), along ≤ft[1 0 1\\right] it exhibits weak, but robust, ferromagnetic coupling (J ~ 9 meV) mediated by reminiscent p-d covalent interactions. The impurity effect on the magnetic ordering is independent of M and purely orbital driven. If the given spin-state of M is such that the {{d}{{x2}-{{y}2}}} orbital is spin-polarized, then the original long-range ordering is maintained. However, if {{d}{{x2}-{{y}2}}} orbital is unoccupied, the absence of corresponding covalent interaction breaks the weak ferromagnetic coupling and a spin-flip takes place at the impurity site leading to breakdown of the long range magnetic ordering.

  8. Monitoring changes in membrane polarity, membrane integrity, and intracellular ion concentrations in Streptococcus pneumoniae using fluorescent dyes.

    Science.gov (United States)

    Clementi, Emily A; Marks, Laura R; Roche-Håkansson, Hazeline; Håkansson, Anders P

    2014-02-17

    Membrane depolarization and ion fluxes are events that have been studied extensively in biological systems due to their ability to profoundly impact cellular functions, including energetics and signal transductions. While both fluorescent and electrophysiological methods, including electrode usage and patch-clamping, have been well developed for measuring these events in eukaryotic cells, methodology for measuring similar events in microorganisms have proven more challenging to develop given their small size in combination with the more complex outer surface of bacteria shielding the membrane. During our studies of death-initiation in Streptococcus pneumoniae (pneumococcus), we wanted to elucidate the role of membrane events, including changes in polarity, integrity, and intracellular ion concentrations. Searching the literature, we found that very few studies exist. Other investigators had monitored radioisotope uptake or equilibrium to measure ion fluxes and membrane potential and a limited number of studies, mostly in Gram-negative organisms, had seen some success using carbocyanine or oxonol fluorescent dyes to measure membrane potential, or loading bacteria with cell-permeant acetoxymethyl (AM) ester versions of ion-sensitive fluorescent indicator dyes. We therefore established and optimized protocols for measuring membrane potential, rupture, and ion-transport in the Gram-positive organism S. pneumoniae. We developed protocols using the bis-oxonol dye DiBAC4(3) and the cell-impermeant dye propidium iodide to measure membrane depolarization and rupture, respectively, as well as methods to optimally load the pneumococci with the AM esters of the ratiometric dyes Fura-2, PBFI, and BCECF to detect changes in intracellular concentrations of Ca(2+), K(+), and H(+), respectively, using a fluorescence-detection plate reader. These protocols are the first of their kind for the pneumococcus and the majority of these dyes have not been used in any other bacterial

  9. Synthesis of Polyacrylaminothiourea Chelating Fiber and Properties of Concentration and Separation of Trace Noble Metal Ions from Samples

    Institute of Scientific and Technical Information of China (English)

    GONG,Bo-Lin(龚波林); WANG,Yan(王彦); SUN,Yan-Pu(孙彦璞); Zhao,Jian-Guo(赵建国)

    2002-01-01

    A novel polyacrylaminothiourea chelating fiber was synthesized simply and rapidly from nitrilon ( an acrylonitrile-based synthetic fiber), which was applied to preconcentrate and separate of trace amount of Au(Ⅲ), Pt(Ⅳ), Pd(Ⅳ) and Ir (Ⅳ) ions from solution of samples. The analyzed ions can be quantitatively concentrated by the fiber up to a flow rate of 20.0 mL/min at pH 2, and can also be desorbed with 15 mL of 4 mol/L HCl + 3% thiourea from the fiber column with recoveries of 96.5%-100%. The chelating fiber can be reused for ten times, the recoveries of these ions are still over 92%,and hundred to thousand times of excess of Fe(Ⅲ), Al(Ⅲ),Ca(Ⅱ), Mg(Ⅱ), Ni(Ⅱ), Mn(Ⅱ), Cu(Ⅱ), Zn(Ⅱ), and Cd (Ⅱ) cause no interference on the determination of the analyzed ions by inductively-coupled plasma atomic emission spectrometry (ICP-AES). The static saturation adsorption capacities of the fiber for the analytes are in the range of 1.15-2.80 mmol/g. The relative standard deviations for the determination of 20.0 ng/mL each of Au(Ⅲ), Pt(Ⅳ), Pd(Ⅳ) and Ir (Ⅳ) are in the range of 0.7%-3.0%. The recoveries for test from standard additions to real solution sammples are between 96% and 100%. The concentration of each ion in powder sample detected by the method is in good agreement with the certified value.

  10. Concentration dependence of luminescence efficiency of Dy(3)(+) ions in strontium zinc phosphate glasses mixed with Pb3 O4.

    Science.gov (United States)

    Kumar, Valluri Ravi; Giridhar, G; Veeraiah, N

    2017-02-01

    In this work we synthesized SrO-ZnO-P2 O5 glasses mixed with Pb3 O4 (heavy metal oxide) and doped with different amounts of Dy2 O3 (0.1 to 1.0 mol%). Subsequently their emission and decay characteristics were investigated as a function of Dy2 O3 concentration. The emission spectra exhibited three principal emission bands in the visible region corresponding to (4) F9/2  → (6) H15/2 (482 nm), (6) H13/2 (574 nm) and (6) H11/2 (663 nm) transitions. With increase in the concentration of Dy2 O3 (upto 0.8 mol%) a considerable increase in the intensity of these bands was observed and, for further increase, quenching of photoluminescence (PL) output was observed. Using emission spectra, various radiative parameters were evaluated and all these parameters were found to increase with increase in Dy2 O3 concentration. The Y/B integral emission intensity ratio of Dy(3)(+) ions evaluated from these spectra exhibited a decreasing trend with increase in the Dy2 O3 concentration up to 0.8 mol%. Quenching of luminescence observed in the case of the glasses doped with 1.0 mol% is attributed to clustering of Dy(3)(+) ions. The quantitative analysis of these results together with infra-red (IR) spectral studies indicated that 0.8 mol% is the optimum concentration of Dy(3)(+) ions needed to achieve maximum luminescence efficiency. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  11. Ion association in concentrated NaCl brines from ambient to supercritical conditions: results from classical molecular dynamics simulations

    Directory of Open Access Journals (Sweden)

    Collings Matthew D

    2002-11-01

    Full Text Available Highly concentrated NaCl brines are important geothermal fluids; chloride complexation of metals in such brines increases the solubility of minerals and plays a fundamental role in the genesis of hydrothermal ore deposits. There is experimental evidence that the molecular nature of the NaCl–water system changes over the pressure–temperature range of the Earth's crust. A transition of concentrated NaCl–H2O brines to a "hydrous molten salt" at high P and T has been argued to stabilize an aqueous fluid phase in the deep crust. In this work, we have done molecular dynamic simulations using classical potentials to determine the nature of concentrated (0.5–16 m NaCl–water mixtures under ambient (25°C, 1 bar, hydrothermal (325°C, 1 kbar and deep crustal (625°C, 15 kbar conditions. We used the well-established SPCE model for water together with the Smith and Dang Lennard-Jones potentials for the ions (J. Chem. Phys., 1994, 100, 3757. With increasing temperature at 1 kbar, the dielectric constant of water decreases to give extensive ion-association and the formation of polyatomic (NanClmn-m clusters in addition to simple NaCl ion pairs. Large polyatomic (NanClmn-m clusters resemble what would be expected in a hydrous NaCl melt in which water and NaCl were completely miscible. Although ion association decreases with pressure, temperatures of 625°C are not enough to overcome pressures of 15 kbar; consequently, there is still enhanced Na–Cl association in brines under deep crustal conditions.

  12. Comparative Salt Stress Study on Intracellular Ion Concentration in Marine and Salt-adapted Freshwater Strains of Microalgae

    Directory of Open Access Journals (Sweden)

    Ahmad Farhad TALEBI

    2013-08-01

    Full Text Available Salinity imposes significant stresses in various living organisms including microalgae. High extracellular concentration of Na+ directly influences ionic balance inside the cell and subsequently the cellular activities. In the present study, the effect of such stress on growth and intracellular ions concentration (IIC of Dunaliella salina and Chlorella Spp. was investigated. IIC was analyzed using Ion chromatography technique. D. salina showed the highest degree of resistance to increase in salinity as little changes occurred both in IIC and in growth parameters. D. salina could maintain the balance of K+ inside the cell and eject the excess Na+ even at NaCl concentrations above 1M. Moreover, D. salina accumulated β-carotene in order to protect its photosynthetic apparatus. Among Chlorella species, C. vulgaris showed signs of adaptation to high content of salinity, though it is a fresh water species by nature. Moreover, the response shown by C. vulgaris to rise in salinity was even stronger than that of C. salina, which is presumably a salt-water resistant species. In fact, C. vulgaris could maintain intracellular K+ better than C. salina in response to increasing salinity, and as a result, it could survive at NaCl concentrations as high as 0.75 M. Marine strains such as D. salina well cope with the fluctuations in salinity through the existing adaptation mechanisms i.e. maintaining the K+/N+ balance inside the cell, K+ accumulation and Na+ ejection, accumulation of photosynthetic pigments like β-carotene.

  13. Ion size effects on the electric double layer of a spherical particle in a realistic salt-free concentrated suspension.

    Science.gov (United States)

    Roa, Rafael; Carrique, Félix; Ruiz-Reina, Emilio

    2011-05-28

    A new modified Poisson-Boltzmann equation accounting for the finite size of the ions valid for realistic salt-free concentrated suspensions has been derived, extending the formalism developed for pure salt-free suspensions [Roa et al., Phys. Chem. Chem. Phys., 2011, 13, 3960-3968] to real experimental conditions. These realistic suspensions include water dissociation ions and those generated by atmospheric carbon dioxide contamination, in addition to the added counterions released by the particles to the solution. The electric potential at the particle surface will be calculated for different ion sizes and compared with classical Poisson-Boltzmann predictions for point-like ions, as a function of particle charge and volume fraction. The realistic predictions turn out to be essential to achieve a closer picture of real salt-free suspensions, and even more important when ionic size effects are incorporated to the electric double layer description. We think that both corrections have to be taken into account when developing new realistic electrokinetic models, and surely will help in the comparison with experiments for low-salt or realistic salt-free systems. This journal is © the Owner Societies 2011

  14. Effect of rare earth oxides and La{sup 3+} ion concentration on some properties of Ni–Zn ferrites

    Energy Technology Data Exchange (ETDEWEB)

    Ateia, Ebtesam E., E-mail: ebtesam@sci.cu.edu.eg; Ahmed, M.A.; Salah, L.M.; El-Gamal, A.A.

    2014-07-15

    The effect of both the rare earth ions and the La{sup 3+} ion concentration on the dielectric properties of Ni{sub 0.5}Zn{sub 0.5}R{sub y}Fe{sub 2−y}O{sub 4}; 0.0≤y≤0.9, R=La, Yb, Dy and Ce is studied. All the samples are sintered at 1250 °C with heating rate of 4 °C/min and sintering time of 35 h. The ionic radii of the used rare earth (Yb{sup 3+}, Dy{sup 3+}, Ce{sup 3+} and La{sup 3+}) are too large to occupy the octahedral site. They form a secondary phases on the grain boundaries. The X-ray data shows that the lattice parameter for the un- substituted ferrite sample is larger than the substituted one, which is the main feature for all rare earth elements. The dielectric properties show that the pure sample has a larger dielectric constant as well as a larger valence exchange with respect to substituted one. This means that introducing rare earth ions into the samples decreases ε′ owing to the decreasing Fe–Fe interaction. The lowest conduction for La substituted sample is attributed to the nature of La{sup 3+} ions which is insoluble in the spinel lattice so it hindered Fe–R (3d–4f) coupling. This feature can help to obtain well applicable ferrites.

  15. Spectrofluorometric determination and chemical speciation of trace concentrations of tungsten species in water using the ion pairing reagent procaine hydrochloride.

    Science.gov (United States)

    El-Shahawi, M S; Al Khateeb, L A

    2012-01-15

    A highly selective and low cost extractive spectrofluorimetric method was developed for determination of trace concentrations of tungsten (VI) in water. The method was based upon solvent extraction of the developed ion associate [(PQH(+))(2)·WO(4)(2-)] of the fluorescent ion-pairing reagent [2-(diethylamino)ethyl 4 aminobenzoate] hydrochloride namely procaine hydrochloride, PQH(+)·Cl(-) and tungstate (WO(4)(2-)) in aqueous solution of pH 6-7 followed by measuring the resulting fluorescence enhancement in n-hexane at λ(ex/em)=270/320nm. The fluorescence intensity of PQH(+)·Cl(-) increased linearly on increasing tungstate concentration in the range 25-250μgL(-1). The limits of detection (LOD) and quantification (LOQ) of tungsten (VI) were found 7.51 and 24.75μgL(-1), respectively. Chemical composition of the developed ion associate and the molar absorptivity at 270nm were found to be [(PQH(+))(2)·WO(4)(2-)] and 2.7×10(4)Lmol(-1)cm(-1), respectively. Other oxidation states (III, IV, V) of tungsten species could also be determined after oxidation with H(2)O(2) in aqueous solution to tungsten (VI). The method was applied for analysis of tungsten in certified reference material (IAEA Soil-7) and wastewater samples. The results were compared successfully (>95%) with the data of inductively coupled plasma-mass spectrometry (ICP-MS).

  16. Concentration dependent spectroscopic properties of Dy3+ ions doped boro-phosphate glasses

    Science.gov (United States)

    Mariyappan, M.; Marimuthu, K.

    2016-05-01

    Dy3+ ions doped boro-phosphate glasses have been synthesized by melt quenching method and characterized through FTIR, absorption and luminescence spectral measurements. The presence of various stretching and bending vibrations of different borate and phosphate groups were identified from the FTIR spectra. In order to examine the electronic band structure of the studied glasses, Optical energy gap (Eopt) and Urbach energy (ΔE) values were estimated from the absorption spectra. The Judd-Ofelt (JO) intensity parameters were calculated to examine the symmetry of the ligand environment around the Dy3+ ions site. The emission spectra exhibit two intense emission bands at around 482 nm (blue) and 574 nm (yellow) corresponding to the 4F9/2→6H15/2 and 4F9/2→6H13/2 transitions respectively. The emission spectra were characterized through Commission International d'Eclairage (CIE) 1931 chromaticity diagram to explore its suitability for WLED applications.

  17. Zero-Gap Alkaline Water Electrolysis Using Ion-Solvating Polymer Electrolyte Membranes at Reduced KOH Concentrations

    DEFF Research Database (Denmark)

    Kraglund, Mikkel Rykær; Aili, David; Jankova Atanasova, Katja;

    2016-01-01

    Membranes based on poly(2,2'-(m-phenylene)-5,5-bibenzimidazole) (m-PBI) can dissolve large amounts of aqueous KOH to give electrolyte systems with ion conductivity in a practically useful range. The conductivity of the membrane strongly depends on the concentration of the aqueous KOH phase......, reaching about 10-1 S cm-1 or higher in 15-25 wt% KOH. Herein, m-PBI membranes are systematically characterized with respect to performance and short-term stability as electrolyte in a zero-gap alkaline water electrolyzer at different KOH concentrations. Using plain uncatalyzed nickel foam electrodes...... exclusion chromatography and spectroscopy reveal evidence of oxidative degradation of the base polymer at KOH concentrations of 15 wt% and higher....

  18. Long-term effects of cupric oxide nanoparticles (CuO NPs) on the performance, microbial community and enzymatic activity of activated sludge in a sequencing batch reactor.

    Science.gov (United States)

    Wang, Sen; Li, Zhiwei; Gao, Mengchun; She, Zonglian; Ma, Bingrui; Guo, Liang; Zheng, Dong; Zhao, Yangguo; Jin, Chunji; Wang, Xuejiao; Gao, Feng

    2017-02-01

    The long-term effects of cupric oxide nanoparticles (CuO NPs) on the performance, microbial activity and microbial community of activated sludge were investigated in a sequencing batch reactor (SBR). The SBR performance had no evident change at 0-10 mg/L CuO NPs, whereas the CuO NPs concentration at 30-60 mg/L affected the COD, NH4(+)-N and soluble orthophosphate (SOP) removal, nitrogen and phosphorus removal rate and microbial enzymatic activity of activated sludge. Some CuO NPs might be absorbed on the surface of activated sludge or penetrate the microbial cytomembrane into the microbial cell interior of activated sludge. Compared to 0 mg/L CuO NPs, the reactive oxygen species (ROS) production and lactate dehydrogenase (LDH) release increased by 43.6% and 56.4% at 60 mg/L CuO NPs, respectively. The variations of ROS production and LDH release demonstrated that CuO NPs could induce the toxicity towards the microorganisms and destroy the integrity of microbial cytomembrane in the activated sludge. High throughput sequencing of 16S rDNA indicated that CuO NPs could evidently impact on the microbial richness, diversity and composition of activated sludge in the SBR.

  19. One-Step Synthesis of Copper and Cupric Oxide Particles from the Liquid Phase by X-Ray Radiolysis Using Synchrotron Radiation

    Directory of Open Access Journals (Sweden)

    Akinobu Yamaguchi

    2016-01-01

    Full Text Available The deposition of copper (Cu and cupric oxide (Cu4O3, Cu2O, and CuO particles in an aqueous copper sulfate (CuSO4 solution with additive alcohol such as methanol, ethanol, 2-propanol, and ethylene glycol has been studied by X-ray exposure from synchrotron radiation. An attenuated X-ray radiation time of 5 min allows for the synthesis of Cu, Cu4O3, Cu2O, and CuO nano/microscale particles and their aggregation into clusters. The morphology and composition of the synthesized Cu/cupric oxide particle clusters were characterized by scanning electron microscopy, scanning transmission electron microscopy, and high-resolution transmission electron microscopy with energy dispersive X-ray spectroscopy. Micro-Raman spectroscopy revealed that the clusters comprised cupric oxide core particles covered with Cu particles. Neither Cu/cupric oxide particles nor their clusters were formed without any alcohol additives. The effect of alcohol additives is attributed to the following sequential steps: photochemical reaction due to X-ray irradiation induces nucleation of the particles accompanying redox reaction and forms a cluster or aggregates by LaMer process and DLVO interactions. The procedure offers a novel route to synthesize the Cu/cupric oxide particles and aggregates. It also provides a novel additive manufacturing process or lithography of composite materials such as metal, oxide, and resin.

  20. Stimulation of TRPC5 cationic channels by low micromolar concentrations of lead ions (Pb{sup 2+})

    Energy Technology Data Exchange (ETDEWEB)

    Sukumar, Piruthivi [Multidisciplinary Cardiovascular Research Centre and Institute of Membrane and Systems Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT (United Kingdom); Beech, David J., E-mail: d.j.beech@leeds.ac.uk [Multidisciplinary Cardiovascular Research Centre and Institute of Membrane and Systems Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT (United Kingdom)

    2010-02-26

    Lead toxicity is long-recognised but continues to be a major public health problem. Its effects are wide-ranging and include induction of hyper-anxiety states. In general it is thought to act by interfering with Ca{sup 2+} signalling but specific targets are not clearly identified. Transient receptor potential canonical 5 (TRPC5) is a Ca{sup 2+}-permeable ion channel that is linked positively to innate fear responses and unusual amongst ion channels in being stimulated by trivalent lanthanides, which include gadolinium. Here we show investigation of the effect of lead, which is a divalent ion (Pb{sup 2+}). Intracellular Ca{sup 2+} and whole-cell patch-clamp recordings were performed on HEK 293 cells conditionally over-expressing TRPC5 or other TRP channels. Extracellular application of Pb{sup 2+} stimulated TRPC5 at concentrations greater than 1 {mu}M. Control cells without TRPC5 showed little or no response to Pb{sup 2+} and expression of other TRP channels (TRPM2 or TRPM3) revealed partial inhibition by 10 {mu}M Pb{sup 2+}. The stimulatory effect on TRPC5 depended on an extracellular residue (E543) near the ion pore: similar to gadolinium action, E543Q TRPC5 was resistant to Pb{sup 2+} but showed normal stimulation by the receptor agonist sphingosine-1-phosphate. The study shows that Pb{sup 2+} is a relatively potent stimulator of the TRPC5 channel, generating the hypothesis that a function of the channel is to sense metal ion poisoning.

  1. Strong Relationships in Acid-Base Chemistry - Modeling Protons Based on Predictable Concentrations of Strong Ions, Total Weak Acid Concentrations, and pCO2

    DEFF Research Database (Denmark)

    Ring, Troels; Kellum, John A

    2016-01-01

    confirmed the relationship between charged species we then examine some of the classical and recent literature concerning the importance of charge balance. We conclude that focusing on the charges which are predictable such as strong ions and total concentrations of weak acids leads to new insights......Understanding acid-base regulation is often reduced to pigeonholing clinical states into categories of disorders based on arterial blood sampling. An earlier ambition to quantitatively explain disorders by measuring production and elimination of acid has not become standard clinical practice....... Seeking back to classical physical chemistry we propose that in any compartment, the requirement of electroneutrality leads to a strong relationship between charged moieties. This relationship is derived in the form of a general equation stating charge balance, making it possible to calculate [H+] and p...

  2. Determination of Metal Ion Concentrations in Components of Household Solid Waste in the Akwapim South Municipality of Ghana

    Directory of Open Access Journals (Sweden)

    M. Ackah

    2011-08-01

    Full Text Available The potential of household solid waste to supply micro-nutrients is studied. The study aimed at finding the levels of metal ion concentrations in domestic refuse typically the organic, paper and plastic waste stream components which constituted the highest waste stream fractions generated by residents in the Nsawam- Adoadjiri townships. INAA was used to determine metal ions concentrations in household solid organic, paper and plastic components of wastes generated by sampled households of Nsawam and Adoagyiri townships of the Akwapim South Municipality of Ghana. The analysis covered (Ca, K, Mg, Na, Cu, Mn, Al, Cl, and V. Standard reference materials were also analysed in the same manner as the waste samples to ensure good quality control/quality assurance procedures. Higher mean concentrations of 5.59 μg/g and 13.27 mg/g were recorded for Mn and Cl, respectively in organic waste stream component as compared to 1.13 μg/g and 0.19 mg/g in paper/cardboard waste stream and 2.67 μg/g and 13.27 mg/g in rubber/plastic waste stream components respectively. These values are comparable to literature values.

  3. Influence of OH− Ion Concentration on the Surface Morphology of ZnO-SiO2 Nanostructure

    Directory of Open Access Journals (Sweden)

    Jessica Ven G. Tinio

    2015-01-01

    Full Text Available The influence of varying OH− ion concentration on the surface morphology of chemically deposited ZnO-SiO2 nanostructures on glass substrate was investigated. The morphological features, phase structure, and infrared characteristics were examined by scanning electron microscopy (SEM, X-ray diffraction (XRD, and Fourier transform infrared spectroscopy (FTIR, respectively. Results revealed that silica significantly changes the hexagonal morphology of bare ZnO rod to “pointed tips” when using low initial OH− precursor concentration. Increasing OH− ion concentration resulted in a “flower-like” formation of ZnO-SiO2 and a remarkable change from “pointed tips” to “hemispherical tips” at the top surface of the rods. The surface capping of SiO2 to ZnO leads to the formation of these “hemispherical tips.” The infrared spectroscopic analysis showed the characteristics peaks of ZnO and SiO2 as well as the Si-O-Zn band which confirms the formation of ZnO-SiO2. Phase analysis manifested that the formed ZnO-SiO2 is of wurtzite structure. Furthermore, a possible growth mechanism is proposed based on the obtained results.

  4. Relationship between Salivary Alkaline Phosphatase Enzyme Activity and The Concentrations of Salivary Calcium and Phosphate Ions

    Directory of Open Access Journals (Sweden)

    Mina Jazaeri

    2015-04-01

    Full Text Available Although salivary alkaline phosphatase (ALP can balance de- and remineralization processes of enamel, there is no evidence regarding its effects on the concentrations of calcium and phosphate in saliva. The present study aims to determine the relationship between salivary ALP activity and the concentrations of calcium and phosphate in saliva. In this cross-sectional study, we evaluated salivary markers in 120 males, ages 19 to 44 years. All participants provided 5 mL of unstimulated whole saliva and the level of enzyme activity as well as calcium and phosphate concentrations were measured using a colorimetric method. Data were gathered and analyzed by statistical package for social sciences (SPSS 13.00 using Pearson correlation test. A p value of 0.05. According to the results of the present study, there was no significant relation between salivary ALP activity and calcium and phosphate concentrations in saliva. However, further research is highly recommended.

  5. Effects of low-dose carbon ion irradiation on the proliferation of splenocytes and the concentration of interferon in mice

    Science.gov (United States)

    Li, Ning

    AIM: To investigate the changes in the proliferation response of splenic lymphocytes and the concentration of serum interferon (IFN-γ) in mice induced by low doses carbon ion irradiation. METHODS: The experiment was carried out in the laboratory of physical medicine, Institute of Modern Physics, Chinese Academy of Sciences in November 2006. 1. Thirty Kunming mice were randomly divided into five groups with six animals in each group and irradiated with 0, 0.01, 0.03, 0.05 and 0.10 Gy carbon ion at Heavy Ion Research Facility Laboratory of Lanzhou. Twenty-four hours after irradiation, the eyeballs of mice were taken out under anesthesia and blood was harvested. 2. The concentration of IFN-γ in serum was detected by ELISA kit. After the mice were executed, the spleen was harvested under sterile condition to prepare spleen mononuclear cell suspension. The effects of concanavalin A(ConA) and lipopolysaccharide(LPS) on the proliferations of mononuclear cells was tested by MTT assay. RESULTS: All thirty mice were involved in the result analysis. 1. The concentration of IFN-γ in serum remarkably increased after irradiation with 0.01 Gy and 0.03 Gy compared with that in controls (p<0.05). However, the concentration of IFN-γ decreased after irradiation with 0.05 Gy and 0.1 Gy. 2. Compared with control group, the proliferation of T lymphocytes induced by ConA and B lymphocytes induced by LPS remarkably increased after irradiation with 0.01 Gy (p<0.001) and the effect was of significant difference compared with that of 0.03 Gy (p<0.01). The irradiation with 0.05 Gy presented an inhibition to the proliferation of splenic lymphocytes. This inhibition was also obvious when irradiated with 0.10 Gy. CONCLUSION: 0.01 Gy and 0.03 Gy carbon ion irradiation can stimulate the proliferation of splenocytes, induce the secretion of IFN-γ and, in consequence, enhance the immune function.

  6. Measurements of lithium-ion concentration equilibration processes inside graphite electrodes

    Science.gov (United States)

    Kindermann, Frank M.; Osswald, Patrick J.; Klink, Stefan; Ehlert, Günter; Schuster, Jörg; Noel, Andreas; Erhard, Simon V.; Schuhmann, Wolfgang; Jossen, Andreas

    2017-02-01

    Methods for estimating inner states in a lithium-ion cell require steady state conditions or accurate models of the dynamic processes. Besides often used inner states such as state-of-charge, state-of-health or state-of-function, relaxation processes strongly influence the mentioned states. Inhomogeneous utilization of electrodes and consequent limitations in the operating conditions have recently been brought to attention. Relaxation measurements after an inhomogeneous current distribution through the thickness of an electrode have not been addressed so far. By using a previously developed laboratory cell, we are able to show an inhomogeneous retrieval of lithium-ions from a graphite electrode through the layer with spatial resolution. After this inhomogeneity caused by a constant current operation, equilibration processes are recorded and can be assigned to two different effects. One effect is an equilibration inside the particles (intra-particle) from surface to bulk and vice versa. The other effect is an assimilation between the particles (inter-particle) to reach a homogeneous state-of-charge in each particle throughout the electrode layer. While intra-particle relaxation is observed to be finished within 4 h, inter-particle relaxation through the layer takes more than 40 h. The overall time for both equilibration processes shows to be in the order of 48 h.

  7. Effects of lead on Na+, K+-ATPase and hemolymph ion concentrations in the freshwater mussel Elliptio complanata

    Science.gov (United States)

    Mosher, Shad; Cope, W. Gregory; Weber, Frank X.; Shea, Damian; Kwak, Thomas J.

    2012-01-01

    Freshwater mussels are an imperiled fauna exposed to a variety of environmental toxicants such as lead (Pb) and studies are urgently needed to assess their health and condition to guide conservation efforts. A 28-day laboratory toxicity test with Pb and adult Eastern elliptio mussels (Elliptio complanata) was conducted to determine uptake kinetics and to assess the toxicological effects of Pb exposure. Test mussels were collected from a relatively uncontaminated reference site and exposed to a water-only control and five concentrations of Pb (as lead nitrate) ranging from 1 to 245 mu g/L in a static renewal test with a water hardness of 42 mg/L. Endpoints included tissue Pb concentrations, hemolymph Pb and ion (Na+, K+, Cl-, Ca2+) concentrations, and Na+, K+-ATPase enzyme activity in gill tissue. Mussels accumulated Pb rapidly, with tissue concentrations increasing at an exposure-dependent rate for the first 2 weeks, but with no significant increase from 2 to 4 weeks. Mussel tissue Pb concentrations ranged from 0.34 to 898 mu g/g dry weight, were strongly related to Pb in test water at every time interval (7, 14, 21, and 28 days), and did not significantly increase after day 14. Hemolymph Pb concentration was variable, dependent on exposure concentration, and showed no appreciable change with time beyond day 7, except for mussels in the greatest exposure concentration (245 mu g/L), which showed a significant reduction in Pb by 28 days, suggesting a threshold for Pb binding or elimination in hemolymph at concentrations near 1000 mu g/g. The Na+, K+-ATPase activity in the gill tissue of mussels was significantly reduced by Pb on day 28 and was highly correlated with tissue Pb concentration (R2 = 0.92; P = 0.013). The Na+, K+-ATPase activity was correlated with reduced hemolymph Na+ concentration at the greatest Pb exposure when enzyme activity was at 30% of controls. Hemolymph Ca2+ concentration increased significantly in mussels from the greatest Pb exposure and may

  8. Particulate sulfate ion concentration and SO2 emission trends in the United States from the early 1990s through 2010

    Directory of Open Access Journals (Sweden)

    W. C. Malm

    2012-11-01

    Full Text Available We examined particulate sulfate ion concentrations across the United States from the early 1990s through 2010 using remote/rural data from the Interagency Monitoring of Protected Visual Environments (IMPROVE network and from early 2000 through 2010 using data from the Environmental Protection Agency's (EPA urban Chemical Speciation Network (CSN. We also examined measured sulfur dioxide (SO2 emissions from power plants from 1995 through 2010 from the EPA's Acid Rain Program. The 1992–2010 annual mean sulfate concentrations at long-term rural sites in the United States have decreased significantly and fairly consistently across the United States at a rate of −2.7% yr−1 (p −1 (p −1 (p 2 emissions from power plants across the United States have decreased at a similar rate as sulfate concentrations from 2001 to 2010 (−6.2% yr−1, p 2 emissions and average sulfate concentrations. This linearity was strongest in the eastern United States and weakest in the West where power plant SO2 emissions were lowest and sulfate concentrations were more influenced by non-power-plant and perhaps international SO2 emissions. In addition, annual mean, short-term sulfate concentrations decreased more rapidly in the East relative to the West due to differences in seasonal trends at certain regions in the West. Specifically, increased wintertime concentrations in the central and northern Great Plains and increased springtime concentrations in the western United States were observed. These seasonal and regional positive trends could not be explained by changes in known local and regional SO2 emissions, suggesting other contributing influences. This work implies that on an annual mean basis across the United States, air quality mitigation strategies have been successful in reducing the particulate loading of sulfate in the atmosphere; however, for certain seasons and regions, especially in the West, current mitigation strategies appear insufficient.

  9. Ion mobility spectrometry as a simple and rapid method to measure the plasma propofol concentrations for intravenous anaesthesia monitoring

    Science.gov (United States)

    Wang, Xin; Zhou, Qinghua; Jiang, Dandan; Gong, Yulei; Li, Enyou; Li, Haiyang

    2016-11-01

    The plasma propofol concentration is important information for anaesthetists to monitor and adjust the anaesthesia depth for patients during a surgery operation. In this paper, a stand-alone ion mobility spectrometer (IMS) was constructed for the rapid measurement of the plasma propofol concentrations. Without any sample pre-treatment, the plasma samples were dropped on a piece of glass microfiber paper and then introduced into the IMS cell by the thermal desorption directly. Each individual measurement could be accomplished within 1 min. For the plasma propofol concentrations from 1 to 12 μg mL-1, the IMS response was linear with a correlation coefficient R2 of 0.998, while the limit of detection was evaluated to be 0.1 μg mL-1. These measurement results did meet the clinical application requirements. Furthermore, other clinically-often-used drugs, including remifentanil, flurbiprofen and atracurium, were found no significant interference with the qualitative and quantitative analysis of the plasma propofol. The plasma propofol concentrations measured by IMS were correlated well with those measured by the high performance liquid chromatography (HPLC). The results confirmed an excellent agreement between these two methods. Finally, this method was applied to monitor the plasma propofol concentrations for a patient undergoing surgery, demonstrating its capability of anaesthesia monitoring in real clinical environments.

  10. Iontophoretic transdermal delivery of glycyrrhizin: effects of pH, drug concentration, co-ions, current intensity, and chemical enhancers.

    Science.gov (United States)

    Yamamoto, Rie; Takasuga, Shinri; Kominami, Katsuya; Sutoh, Chiyo; Kinoshita, Mine; Kanamura, Kiyoshi; Takayama, Kozo

    2013-01-01

    The aim of the present study was to evaluate the feasibility of transdermal delivery of glycyrrhizin, an agent used in the treatment of chronic hepatitis C, by cathodal iontophoresis using Ag/AgCl electrodes in vitro. The effects of donor pH (pH 4-7), concentration of drug (0.025-0.2% (w/v)), concentration of external chloride ions (Cl(-)) (0-133 mM), current strength (0-0.5 mA/cm(2)), and permeation enhancers (urea and Tween 80) on the skin permeability of glycyrrhizin were examined in in vitro skin permeation studies using porcine ear skin as the membrane. The cumulative amount of permeated glycyrrhizin and the steady-state skin permeation flux of glycyrrhizin across porcine skin increased in a pH-dependent manner. The skin permeability of glycyrrhizin was independent of the concentration of drug and competed only with a high external Cl(-) concentration. The skin permeation flux of glycyrrhizin increased with the current (R(2)=0.8955). The combination of iontophoresis and enhancers provided an additive or synergistic effect, and a skin permeation flux of about 60 µg/h/cm(2) was achieved. The plasma concentration of glycyrrhizin in humans, extrapolated from the in vitro steady-state permeation flux across porcine skin, was within the therapeutic level. These results suggest that cathodal iontophoresis can be used as a transdermal drug delivery system for glycyrrhizin using reasonable patch sizes and acceptable levels of current intensity.

  11. High extracellular potassium ion concentration attenuates the blockade action of ketanserin on Kvl.3 channels expressed in xenopus oocytes

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Background Ketanserin (KT), a selective serotonin (5-HT) 2-receptor antagonist, reduces peripheral blood pressure by blocking the activation of peripheral 5-HT receptors. In this study electrophysiological method was used to investigate the effect of KT and potassium ion on Kv1.3 potassium channels and explore the role of blocker KT in the alteration of channel kinetics contributing to the potassium ion imbalances. Methods Kvl.3 channels were expressed in xenopus oocytes, and currents were measured using the two-microelectrode voltage-clamp technique. Results KCI made a left shift of activation and an inactivation curve of Kv1.3 current and accelerated the activation and inactivation time constant. High extracellular [K+] attenuated the blockade effect of KT on Kv1.3 channels. In the presence of KT and KCI the activation and inactivation time constants were not influenced significantly no matter what was administered first. KT did not significantly inhibit Kv1.3 current induced by tetraethylammonium (TEA). Conclusions KT is a weak blocker of Kv1.3 channels at different concentrations of extracellular potassium and binds to the intracellular side of the channel pore. The inhibitor KT of ion channels is not fully effective in clinical use because of high [K+]o and other electrolyte disorders.

  12. In-Plane Electrical Connectivity and Near-Field Concentration of Isolated Graphene Resonators Realized by Ion Beams.

    Science.gov (United States)

    Luo, Weiwei; Cai, Wei; Xiang, Yinxiao; Wu, Wei; Shi, Bin; Jiang, Xiaojie; Zhang, Ni; Ren, Mengxin; Zhang, Xinzheng; Xu, Jingjun

    2017-08-01

    Graphene plasmons provide great opportunities in light-matter interactions benefiting from the extreme confinement and electrical tunability. Structured graphene cavities possess enhanced confinements in 3D and steerable plasmon resonances, potential in applications for sensing and emission control at the nanoscale. Besides graphene boundaries obtained by mask lithography, graphene defects engineered by ion beams have shown efficient plasmon reflections. In this paper, near-field responses of structured graphene achieved by ion beam direct-writing are investigated. Graphene nanoresonators are fabricated easily and precisely with a spatial resolution better than 30 nm. Breathing modes are observed in graphene disks. The amorphous carbons around weaken the response of edge modes in the resonators, but meanwhile render the isolated resonators in-plane electrical connections, where near-fields are proved gate-tunable. The realization of gate-tunable near-fields of graphene 2D resonators opens up tunable near-field couplings with matters. Moreover, graphene nonconcentric rings with engineered near-field confinement distributions are demonstrated, where the quadrupole plasmon modes are excited. Near-field mappings reveal concentrations at the scale of 3.8×10-4λ02 within certain zones which can be engineered. The realization of electrically tunable graphene nanoresonators by ion beam direct-writing is promising for active manipulation of emission and sensing at the nanoscale. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Effect of solution concentration and composition on the electrochemical properties of ion exchange membranes for energy conversion

    Science.gov (United States)

    Fontananova, E.; Messana, D.; Tufa, R. A.; Nicotera, I.; Kosma, V.; Curcio, E.; van Baak, W.; Drioli, E.; Di Profio, G.

    2017-02-01

    The electrochemical properties of ion exchange membranes (IEMs) applied for salinity-gradient power (SGP) harvesting, are usually measured using diluited NaCl aqueous solutions because of the prevalence of its constituents ions in natural solutions (e.g. seawater). However, in real applications, the IEMs come in contact with other ionic species than Na+ and Cl- that can have a relevant effect on their properties. As a consequence, the obtained results in many cases are not really representative. The aim of the present study was to investigate the effect of solution concentration and compositions on permselectivity, membrane and interface resistance, for both anion and cation exchange membranes (AEMs and CEMs). Special attention was paid to the influence of the most common multivalent ions in seawater (Mg2+, Ca2+ and SO42-) on the electrochemical properties of the AEM and the CEM. It was possible to discriminate the impact on the AEM from that on the CEM. The results highlighted a strong negative effect of Mg2+ on the CEM (relevant increase of ionic resistance and permselectivity) and, at minor extent, on the AEM (moderate reduction of permselectivity).

  14. Effect of Cr(VI) concentration on gas and particle production during iron oxidation in aqueous solutions containing Cl(-) ions.

    Science.gov (United States)

    Ahn, Hyangsig; Jo, Ho Young; Ryu, Ji-Hun; Koh, Yong-Kwon

    2017-02-01

    Zero-valent iron (ZVI) is commonly used as a medium in permeable reactive barriers (PRBs) because of its high reducing ability. The generation of H2 gas in PRBs, however, can decrease the permeability of PRBs and reduce the contact area between the PRB and contaminated groundwater. This study investigated the effect of the initial Cr(VI) concentration ([Cr(VI)init]) in aqueous solutions containing Cl(-) ions on the generation of H2 gas. ZVI chips were reacted in reactors with 0.5-M NaCl solutions with [Cr(VI)init] ranging between 51 and 303 mg/L. The initial pH was set at 3. The oxidation of ZVI chips by Cr(VI) in aqueous solutions containing Cl(-) ions produced H2 gas and particles (Fe(III)-Cr(III)(oxy)hydroxides). The Cr(VI) removal from aqueous solutions increased as the [Cr(VI)init] increased, as did H2 gas generation. The positive effect of [Cr(VI)init] on H2 gas generation might be due to an increase in the redox potential gradient as [Cr(VI)init] increases. This increased gradient would enhance H(+) ion penetration through the passive film (Fe(III)-Cr(III)(oxy)hydroxides), which formed on the ZVI surface, by diffusion from the solution to pits beneath the passive film.

  15. Nanomolar concentrations of inorganic lead increase Ca2+ efflux and decrease intracellular free Ca2+ ion concentrations in cultured rat hippocampal neurons by a calmodulin-dependent mechanism.

    Science.gov (United States)

    Ferguson, C; Kern, M; Audesirk, G

    2000-06-01

    Inorganic lead (Pb2+) activates calmodulin, which in turn may stimulate many other cellular processes. The plasma membrane Ca2+ ATPase is a calmodulin-stimulated enzyme that plays the major role in regulating the "resting" intracellular free Ca2+ ion concentration, [Ca2+]i. We hypothesized that exposing neurons to low levels of Pb2+ would cause Pb2+ to enter the cytoplasm, and that intracellular Pb2+, by activating calmodulin, would stimulate plasma membrane Ca2+ ATPase activity, thereby increasing Ca2+ extrusion and reducing [Ca2+]i. We used the ratiometric Ca2+ indicator fura-2 to estimate changes in [Ca2+]i. In vitro calibrations of fura-2 with solutions of defined free Ca2+ and free Pb2+ concentrations showed that, at free Ca2+ concentrations from 10 nM to 1000 nM, adding Pb2+ caused either no significant change in the F340/F380 ratio (free Pb2+ concentrations from 100 fM to 1 pM) or increased the F340/F380 ratio (free Pb2+ concentrations from 5 to 50 pM). Therefore, fura-2 should be suitable for estimating Pb2+-induced decreases in [Ca2+]i, but not increases in [Ca2+]i. We exposed cultured embryonic rat hippocampal neurons to 100 nM Pb2+ for periods from 1 hour to 2 days and measured the F340/F380 ratio; the ratio decreased significantly by 9 to 16% at all time points, indicating that Pb2+ exposure decreased [Ca2+]i. In neurons loaded with 45Ca, Pb2+ exposure increased Ca2+ efflux for at least two hours; by 24 hours, Ca2+ efflux returned to control levels. Influx of 45Ca was not altered by Pb2+ exposure. Low concentrations (250 nM) of the calmodulin inhibitor calmidazolium had no effect on either 45Ca efflux or on the F340/F380 ratio in fura-loaded control neurons, but completely eliminated the increase in 45Ca efflux and decrease in F340/F380 ratio in Pb2+-exposed neurons. Zaldoride, another calmodulin inhibitor, also eliminated the decrease in F340/F380 ratio in Pb2+-exposed neurons. We conclude that Pb2+ exposure decreases [Ca2+]i and increases Ca2+ efflux

  16. Toxic Effects of Cupric Acetate and Avermectins on Orange Spotted Grouper Epinephelus coioides%乙酸铜和阿维菌素对斜带石斑幼鱼毒性效应的研究

    Institute of Scientific and Technical Information of China (English)

    程敏红; 杨小立; 庞强; 黄建荣; 黎祖福

    2014-01-01

    In this study ,the activities of acetylcholinesterase (AChE) ,superoxide dismutase (SOD) ,and aspartate transaminase (GOT ) and glutathione (GSH ) content were studied in liver of orange spotted grouper Epinephelus coioides exposed to cupric acetate and Avermectins at various concentrations to evaluate acute toxicity of cupric acetate and Avermectins .The results showed that the 24 h LC50 and 48 h LC50 were 103 .51 mg/L and 50 .86 mg/L in cupric acetate and 0 .02543 mg/L and 0 .01726 mg/L in Avermectins , with safe concentration of 3 .684 mg/L for cupric acetate and 0 .00239 mg/L for Avermectins .Cupric acetate and Avermectins stress resulted in significant changes in AChE ,SOD ,and GOT activities in liver (P0 .05) ,but higher than that in the control group in 96 h cupric acetate exposure (P< 0 .05) .There were significantly lower liver GSH contents in 2 .5μg/L ,4 .25μg/L ,7 .25 μg/L and 12 .25 μg/L Avermectins groups than that in the control group . The findings indicate that cupric acetate and Avermectins stress affect AChE , SOD and GOT activities and GSH content ,and that biological effects of pesticides on orange spotted grouper are reflected in changes in activities of AChE ,SOD and GOT and GSH content .%采用静水生物法,研究了乙酸铜和阿维菌素对斜带石斑鱼的急性毒性并进行安全评价;依据急性试验结果,设计一系列质量浓度梯度进行暴露试验,探讨了乙酸铜和阿维菌素暴露对斜带石斑鱼肝脏中乙酰胆碱酯酶、超氧化物歧化酶、谷草转氨酶活性和谷胱甘肽含量的毒性影响。试验结果表明,乙酸铜和阿维菌素对斜带石斑鱼的24 h半致死质量浓度、48 h半致死质量浓度分别为103.51、50.86 mg/L和0.02543、0.01726 mg/L ,安全质量浓度分别为3.684 mg/L和0.00239 mg/L ;除阿维菌素对谷草转氨酶作用不明显外,乙酸铜和阿维菌素胁迫均引起肝脏乙酰胆碱酯酶、超氧化物歧化酶和谷草转

  17. Effect of Fe ion concentration on corrosion of carbon steel in CO2 environment

    DEFF Research Database (Denmark)

    Rogowska, Magdalena; Gudme, J.; Rubin, A.

    2016-01-01

    In this work, the corrosion behaviour of steel wires in solutions containing different concentrations of Fe2+ was investigated by the linear polarisation resistance method, while the evolution of pH was monitored in situ and changes of the Fe2+ concentration were monitored ex situ. Characterisation...... of the corrosion scales was performed using microscopic and diffraction techniques. Scale analysis revealed that the passivation of samples, exposed to initially highly Fe2+ supersaturated solution, occurred when a formation of a double layer took place, resulting in 30 times lower corrosion rate compared...

  18. Study of electron-vibrational interaction and concentration quenching effect of Cu+ ions in lithium based sulphate phosphors

    Science.gov (United States)

    Bhoyar, Priyanka D.; Choithrani, Renu; Dhoble, S. J.

    2016-07-01

    The objective of this work is to study electron-vibrational interaction (EVI) and concentration quenching and their manifestation in experimental photoluminescence spectra of Cu+ ion in various lithium based phosphors namely, Li2SO4, LiNaSO4 and LiKSO4. The main parameters of EVI, such as the Stokes shift, Huang-Rhys factor and zero-phonon line positions, were estimated. The studied systems shows strong electron lattice coupling. The validity of results was established by modeling the shape of the emission spectra, which was found to be in good agreement with experimental photoluminescence spectra. The concentration quenching study is also carried out for these compounds. The studied systems correspond to the nearest neighbor energy transfer mechanism.

  19. Concentration polarization with monopolar ion exchange membranes: current-voltage curves and water dissociation

    NARCIS (Netherlands)

    Krol, J.J.; Wessling, M.; Strathmann, H.

    1999-01-01

    Concentration polarization is studied using a commercial anion and cation exchange membrane. Current¿voltage curves show the occurrence of an overlimiting current. The nature of this overlimiting current is investigated in more detail, especially with respect to the contribution of water dissociatio

  20. Effects of calcium ion concentration on starch hydrolysis of barley α-amylase isozymes

    DEFF Research Database (Denmark)

    Yuk, Jeong-Bin; Choi, Seung-Ho; Lee, Tae-Hee

    2008-01-01

    in glucose, maltose, or maltotriose. Against insoluble blue starch, AMY1 showed the highest activity at 0.1-5 mM calcium concentration, whereas 15-20 mM was optimal for AMY2. On the hydrolysis of soluble starch, unexpectedly, there was no significant difference between AMYs with increase of calcium. However...

  1. Incorporation of uranium in benthic foraminiferal calcite reflects seawater carbonate ion concentration

    NARCIS (Netherlands)

    Keul, N.; Langer, G.; de Nooijer, L.J.; Nehrke, G.; Reichart, G.-J.; Bijma, J.

    2013-01-01

    The chemical and isotopic composition of foraminiferal shells (so-called proxies) reflects the physicochemical properties of the seawater. In current day paleoclimate research, the reconstruction of past seawater carbonate system to infer atmospheric CO2 concentrations is one of the most

  2. Incorporation of uranium in benthic foraminiferal calcite reflects seawater carbonate ion concentration

    NARCIS (Netherlands)

    Keul, N.; Langer, G.; de Nooijer, L.J.; Nehrke, G.; Reichart, G.-J.; Bijma, J.

    2013-01-01

    The chemical and isotopic composition of foraminiferal shells (so-called proxies) reflects the physicochemical properties of the seawater. In current day paleoclimate research, the reconstruction of past seawater carbonate system to infer atmospheric CO2 concentrations is one of the most pressing

  3. Optimization of an electrolyte conductivity detector for measuring low ion concentrations

    NARCIS (Netherlands)

    Timmer, B.H.; Sparreboom, Wouter; Olthuis, Wouter; Bergveld, Piet; van den Berg, Albert

    2002-01-01

    The optimization process of a planar interdigitated conductivity detector for measuring very low electrolyte concentrations for use in a lab-on-chip gas detection system is described. An electrical equivalent of the sensor is given, which includes the double layer capacitance dependency on the elect

  4. Incorporation of uranium in benthic foraminiferal calcite reflects seawater carbonate ion concentration

    NARCIS (Netherlands)

    Keul, N.; Langer, G.; de Nooijer, L.J.; Nehrke, G.; Reichart, G.-J.; Bijma, J.

    2013-01-01

    The chemical and isotopic composition of foraminiferal shells (so-called proxies) reflects the physicochemical properties of the seawater. In current day paleoclimate research, the reconstruction of past seawater carbonate system to infer atmospheric CO2 concentrations is one of the most pressing ch

  5. Incorporation of uranium in benthic foraminiferal calcite reflects seawater carbonate ion concentration

    NARCIS (Netherlands)

    Keul, N.; Langer, G.; de Nooijer, L.J.; Nehrke, G.; Reichart, G.-J.; Bijma, J.

    2013-01-01

    The chemical and isotopic composition of foraminiferal shells (so-called proxies) reflects the physicochemical properties of the seawater. In current day paleoclimate research, the reconstruction of past seawater carbonate system to infer atmospheric CO2 concentrations is one of the most pressing ch

  6. The involvement of intracellular calcium ion concentration and calmodulin in the 25-hydroxylation of cholecalciferol in ovine and rat liver.

    Science.gov (United States)

    Corlett, S C; Chaudhary, M S; Tomlinson, S; Care, A D

    1987-08-01

    The effect of Ca2+ ion concentration on the 25 hydroxylation of tritiated cholecalciferol (3HD3) was investigated using homogenates of ovine liver from vitamin D replete sheep. A significant decrease in the production of 25 hydroxycholecalciferol (25OHD3) was observed when the concentration of Ca2+ in the homogenate was raised above 0.68 mmol/l by the addition of calcium gluconate. Similarly, a final concentration of 37 mumol EGTA/1 (equivalent to a Ca2+ concentration of 26.5 nmol/l) was associated with a 50% reduction of 25OHD3 production. That is, a broad bell-shaped relationship was observed between the production of 25OHD3 and the Ca2+ concentration in the homogenate. These changes in the rate of production of 25OHD3 were reproduced with hepatocytes from vitamin D replete rats, prepared by collagenase perfusion, using the drugs dantrolene sodium (DaNa) to reduce (ED50 = 57 mmol/l) and veratridine to increase (ED50 = 550 mmol/l) the intracellular Ca2+ concentration. Hepatocytes from vitamin D replete rats also showed a reduction in 25 hydroxylation of D3 (ED50 = 6 ng/ml) in response to the addition of 1-25 dihydroxycholecalciferol (1-25 (OH)2D3). The calmodulin antagonists; W7, compound 48/80, trifluoperazine (TFP) and calmidazolium (R24571) were all found to effect a dose response inhibition of the 25 hydroxylation of cholecalciferol by homogenates of ovine liver. R24571 had a similar inhibitory effect (ED50 = 70 mumol/l) upon the 25 hydroxylase enzyme of rat hepatocytes. It is concluded that the 25 hydroxylation of cholecalciferol in liver of vitamin D replete rats and sheep is calcium sensitive and is reduced in the presence of increased concentrations of 1,25(OH)2D3. Calmodulin may also be involved in the regulation of hepatocyte 25-hydroxylase activity by Ca2+.

  7. Multiphysics simulation of ion concentration polarization induced by a surface-patterned nanoporous membrane in single channel devices.

    Science.gov (United States)

    Jia, Mingjie; Kim, Taesung

    2014-10-21

    Microfluidic devices utilize ion concentration polarization (ICP) phenomena for a variety of applications, but a comprehensive understanding of the generation of ICP is still necessary. Recently, the emergence of a novel single channel ICP (SC-ICP) device has stimulated further research on the mechanism of ICP generation, so that we developed a 2-D model of an SC-ICP device that integrates a nanoporous membrane on the bottom surface of the channel, allowing bulk flow over the membrane. We solved a set of coupled governing equations with appropriate boundary conditions to explore ICP numerically. As a result, we not only showed that the simulation results held a strong qualitative agreement with experimental results, but also found the distribution of ion concentrations in the SC-ICP device that has never been reported in previous studies. We confirmed again that the electrophoretic mobility (EPM) of counterions in the membrane is the most dominant factor determining the generation and strength of ICP, whereas the charge density of the membrane was dominant to the ICP strength only when a high EPM value was assumed. From the viewpoint of practical applications, an SC-ICP device with a long membrane under low buffer strength showed enhanced performance in the preconcentration of charged molecules. Therefore, we believe that the simulation results could not only provide sharp insight into ICP phenomena but also predict and optimize the performance of SC-ICP devices in various microfluidic applications.

  8. The influence of extraction procedure on ion concentrations in sediment pore water

    Science.gov (United States)

    Winger, P.V.; Lasier, P.J.; Jackson, B.P.

    1998-01-01

    Sediment pore water has the potential to yield important information on sediment quality, but the influence of isolation procedures on the chemistry and toxicity are not completely known and consensus on methods used for the isolation from sediment has not been reached. To provide additional insight into the influence of collection procedures on pore water chemistry, anion (filtered only) and cation concentrations were measured in filtered and unfiltered pore water isolated from four sediments using three different procedures: dialysis, centrifugation and vacuum. Peepers were constructed using 24-cell culture plates and cellulose membranes, and vacuum extractors consisted of fused-glass air stones attached with airline tubing to 60cc syringes. Centrifugation was accomplished at two speeds (2,500 and 10,000 x g) for 30 min in a refrigerated centrifuge maintained at 4?C. Only minor differences in chemical characteristics and cation and anion concentrations were found among the different collecting methods with differences being sediment specific. Filtering of the pore water did not appreciably reduce major cation concentrations, but trace metals (Cu and Pb) were markedly reduced. Although the extraction methods evaluated produced pore waters of similar chemistries, the vacuum extractor provided the following advantages over the other methods: (1) ease of extraction, (2) volumes of pore water isolated, (3) minimal preparation time and (4) least time required for extraction of pore water from multiple samples at one time.

  9. Size and dopant-concentration dependence of photoluminescence properties of ion-implanted phosphorus- and boron-codoped Si nanocrystals

    Science.gov (United States)

    Nakamura, Toshihiro; Adachi, Sadao; Fujii, Minoru; Sugimoto, Hiroshi; Miura, Kenta; Yamamoto, Shunya

    2015-04-01

    We investigate the nanocrystallite-size and dopant-concentration dependence of the photoluminescence (PL) properties of heavily phosphorus- (P) and boron- (B) codoped Si nanocrystals (Si NCs), prepared using a combination of sputtering and ion implantation techniques. We find that the heavily doped Si NC exhibits three exotic luminescence bands, A, B, and C. The peak energy of band A redshifts with increasing dopant concentration. This band is due to the band-to-band transition at the reduced Si-NC band gap caused by the formation of impurity bands together with band-tailing effects. The PL redshift becomes large when the nanocrystallite size decreases, suggesting the occurrence of the quantum-confinement-induced carrier doping effect. The peak energies of bands B and C are independent of both the concentration and size, indicating that these bands are due to transitions between defect- and/or impurity-related localized states. Band A shows stronger thermal quenching than the PL band in pure (undoped) Si NCs, the magnitude of which depends on the dopant concentration. The stronger thermal quenching in band A is probably due to the thermally induced migration of electrons in the impurity band.

  10. Evaluation of Metal Ion Concentration in Hard Tissues of Teeth in Residents of Central Poland

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    Piotr Wychowanski

    2017-01-01

    Full Text Available Objectives. The aim of the study was an assessment of the content of trace elements in enamel and dentin of teeth extracted in patients residing in urban and agricultural areas of Poland. Methods. The study included 30 generally healthy patients with retained third molars. 65 samples of enamel and dentin from individuals living in urban areas and 85 samples of enamel and dentin from individuals living in agricultural areas were prepared. The content of manganese, lead, cadmium, and chromium in the studied enamel and dentin samples from retained teeth was determined by Graphite Furnace Atomic Absorption Spectrometry. In the process of statistical hypothesis testing, the level of significance was assumed at α=0.05. Results. A comparative analysis of the data showed that enamel and dentin of inhabitants of industrialized areas contain significantly higher amounts of lead and cadmium than hard tissues of teeth in residents of agricultural areas and comparable amounts of manganese and chromium. Significance. It appears that hard tissues of retained teeth may constitute valuable material for assessment of long-term environmental exposure to metal ions. The study confirms that the risk of exposure to heavy metals depends on the place of residence and environmental pollution.

  11. Evaluation of Metal Ion Concentration in Hard Tissues of Teeth in Residents of Central Poland

    Science.gov (United States)

    Wychowanski, Piotr

    2017-01-01

    Objectives. The aim of the study was an assessment of the content of trace elements in enamel and dentin of teeth extracted in patients residing in urban and agricultural areas of Poland. Methods. The study included 30 generally healthy patients with retained third molars. 65 samples of enamel and dentin from individuals living in urban areas and 85 samples of enamel and dentin from individuals living in agricultural areas were prepared. The content of manganese, lead, cadmium, and chromium in the studied enamel and dentin samples from retained teeth was determined by Graphite Furnace Atomic Absorption Spectrometry. In the process of statistical hypothesis testing, the level of significance was assumed at α = 0.05. Results. A comparative analysis of the data showed that enamel and dentin of inhabitants of industrialized areas contain significantly higher amounts of lead and cadmium than hard tissues of teeth in residents of agricultural areas and comparable amounts of manganese and chromium. Significance. It appears that hard tissues of retained teeth may constitute valuable material for assessment of long-term environmental exposure to metal ions. The study confirms that the risk of exposure to heavy metals depends on the place of residence and environmental pollution. PMID:28197416

  12. Evaluation of Metal Ion Concentration in Hard Tissues of Teeth in Residents of Central Poland.

    Science.gov (United States)

    Wychowanski, Piotr; Malkiewicz, Konrad

    2017-01-01

    Objectives. The aim of the study was an assessment of the content of trace elements in enamel and dentin of teeth extracted in patients residing in urban and agricultural areas of Poland. Methods. The study included 30 generally healthy patients with retained third molars. 65 samples of enamel and dentin from individuals living in urban areas and 85 samples of enamel and dentin from individuals living in agricultural areas were prepared. The content of manganese, lead, cadmium, and chromium in the studied enamel and dentin samples from retained teeth was determined by Graphite Furnace Atomic Absorption Spectrometry. In the process of statistical hypothesis testing, the level of significance was assumed at α = 0.05. Results. A comparative analysis of the data showed that enamel and dentin of inhabitants of industrialized areas contain significantly higher amounts of lead and cadmium than hard tissues of teeth in residents of agricultural areas and comparable amounts of manganese and chromium. Significance. It appears that hard tissues of retained teeth may constitute valuable material for assessment of long-term environmental exposure to metal ions. The study confirms that the risk of exposure to heavy metals depends on the place of residence and environmental pollution.

  13. The use of Na+ and K+ ion concentrations as potential diagnostic indicators of subclinical mastitis in dairy cows

    Directory of Open Access Journals (Sweden)

    Abdul Wahid Haron

    2014-11-01

    Full Text Available Aim: This study was conducted to evaluate the concentrations of sodium (Na+ and potassium (K+ ions in milk of lactating dairy cows with and without subclinical mastitis as putative indicators for detecting subclinical mastitis in dairy cows. Materials and Methods: Thirty seven lactating dairy cows were screened for the evidence of subclinical mastitis using California mastitis test (CMT. The lactating dairy cows were categorized as CMT-Positive (CMT-P; n=20 and CMT-Negative (CMT-N; n=17 based on whether they were positive or negative for CMT using a standard kit. The CMT-P lactating dairy cows were further sub divided into subclinical 1+ (S1+; n=6, subclinical 2+ (S2+; n=9, and subclinical 3+(S3+; n=5. Direct microscopy somatic cell count (SCC was used to determine the SCC using Wright’s stain. The samples were filtered and diluted at 1:100 dilutions before being measured for the concentrations of Na+ and K+ using atomic absorption spectrophotometer. Results: There was a significant increase (p<0.05 in SCCs and Na+ concentration in the milk of CMT-P dairy cows, with a mean Log10 SCC score of 5.35±0.06 cells/ml and mean Na+ concentration of 232±19.1 mg/dL. However, there was a significant reduction (p<0.05 in the concentration of K+ (123±7.6 mg/dL in the milk samples of the CMT-P cows. There were significant differences (p<0.05 in SCC, Na+ and K+ concentrations between milk samples from the CMT-N dairy cows and CMT-P subgroups; S1+, S2+, and S3+ respectively. Potassium (K+ concentration had a significant strong negative correlation with sodium (Na+ concentration (r=−0.688; p<0.01 and weak positive correlation with SCC (r=−0.436; p<0.01. The sensitivity of using Na+ and K+ concentrations as detection indices for sub-clinical mastitis is 40% and 90%, respectively, while the specificity of each was 100%. Conclusion: This study thus shows that evaluation of Na+ and K+ concentrations from milk samples of dairy cows with sub clinical mastitis

  14. Sodium concentration measurement during hemodialysis through ion-exchange resin and conductivity measure approach: in vitro experiments.

    Directory of Open Access Journals (Sweden)

    Andrea Tura

    Full Text Available Sodium measurement during hemodialysis treatment is important to preserve the patient from clinical events related to hypo- or hyper-natremia Usually, sodium measurement is performed through laboratory equipment which is typically expensive, and requires manual intervention. We propose a new method, based on conductivity measurement after treatment of dialysate solution through ion-exchange resin. To test this method, we performed in vitro experiments. We prepared 40 ml sodium chloride (NaCl samples at 280, 140, 70, 35, 17.5, 8.75, 4.375 mEq/l, and some "mixed samples", i.e., with added potassium chloride (KCl at different concentrations (4.375-17.5 mEq/l, to simulate the confounding factors in a conductivity-based sodium measurement. We measured the conductivity of all samples. Afterwards, each sample was treated for 1 min with 1 g of Dowex G-26 resin, and conductivity was measured again. On average, the difference in the conductivity between mixed samples and corresponding pure NaCl samples (at the same NaCl concentration was 20.9%. After treatment with the exchange resin, it was 14.7%, i.e., 42% lower. Similar experiments were performed with calcium chloride and magnesium chloride as confounding factors, with similar results. We also performed some experiments on actual dialysate solution during hemodialysis sessions in 15 patients, and found that the correlation between conductivity measures and sodium concentration improved after resin treatment (R=0.839 before treatment, R=0.924 after treatment, P<0.0001. We conclude that ion-exchange resin treatment coupled with conductivity measures may improve the measurement of sodium compared to conductivity measures alone, and may become a possible simple approach for continuous and automatic sodium measurement during hemodialysis.

  15. Effect of Fe ion concentration on fatigue life of carbon steel in aqueous CO2 environment

    DEFF Research Database (Denmark)

    Rogowska, Magdalena; Gudme, J.; Rubin, A.

    2016-01-01

    In this work, the corrosion fatigue behaviour of steel armours used in the flexible pipes, in aqueous solutions initially containing different concentrations of Fe2+, was investigated by four-point bending testing under saturated 1 bar CO2 condition. Corrosion fatigue results were supported with ex...... of Fe2+ marginally above the solubility limit of FeCO3 compared to the samples tested in highly supersaturated solution of Fe2+. Results revealed that the impact of the alternating stresses on the corrosion behaviour of samples reduces with lowering the applied stresses. At the stress range of 100 MPa...

  16. In Vitro Sensitivity Research Concerning Some Microorganisms at Hydroxyquinoline and Cupric Derivatives Deposited onto Hydroxyapatite

    Directory of Open Access Journals (Sweden)

    Sorin Rapuntean

    2016-11-01

    Full Text Available ABSTRACT Introduction: The preparations based on hydroxyquinoline, in various combinations, are used in medicine, being shown to have an inhibitory effect against bacteria, molds, fungi, parasites, and viruses, but also having other beneficial effects mentioned in other medical conditions (anti-cancer, anti-degenerative, anti-inflammatory. Aims: In vitro susceptibility testing of microorganisms: bacteria (Gram positive and Gram negative, yeast (Candida spp., and unicellular algae (Prototheca spp. at the preparations based on hydroxyquinoline (HQ and its cupric derivatives deposited on hydroxyapatite (HAP. Materials and methods: There were tested microbial strains of the following genera: Escherichia, Staphylococcus, Micrococcus, Bacillus, Candida, and Prototheca. The tested products (developed in the Laboratory for Nanobiomaterials Synthesis, Center of Physical Chemistry, Faculty of Chemistry and Chemical Engineering, UBB Cluj-Napoca were developed in three versions: 1 HQ–Cu2+–HAP1; 2 HQ–Cu2+–HAP2; and 3 NHQ–Cu2+–HAP2, where NHQ stands for nitro hydroxyquinoline. Determination of the inhibitory effect was conducted by diffusion technique in nutrient agar, according to CLSI 2013 standards, with necessary adaptations for testing of products made in the form of suspensions. Results: Following interpretation, it was found that the inhibition zones, arising from the antimicrobial effect of the tested products showed variability in size, depending on the test product and the microbial strain: Escherichia coli (8-10 mm, Staphylococcus sp. (17.6 - 23.2 mm, Micrococcus spp. (24.4 - 27.6 mm, Bacillus spp. (14.0 - 16.0 mm, Candida spp. (20.4 - 25.2 mm, Prototheca spp. (20.8 - 30.0 mm. From the three tested products, the best efficacy was found at the product no. 3 (NHQ – Cu2+ – HAP2, followed by no. 1 (HQ– Cu2+–HAP1 and no. 2 (HQ–Cu2+–HAP2. Conclusions: The inhibitory effect was bactericidal, manifested more intensively against Gram

  17. Ultra-high performance supercritical fluid chromatography of lignin-derived phenols from alkaline cupric oxide oxidation.

    Science.gov (United States)

    Sun, Mingzhe; Lidén, Gunnar; Sandahl, Margareta; Turner, Charlotta

    2016-08-01

    Traditional chromatographic methods for the analysis of lignin-derived phenolic compounds in environmental samples are generally time consuming. In this work, an ultra-high performance supercritical fluid chromatography method with a diode array detector for the analysis of major lignin-derived phenolic compounds produced by alkaline cupric oxide oxidation was developed. In an analysis of a collection of 11 representative monomeric lignin phenolic compounds, all compounds were clearly separated within 6 min with excellent peak shapes, with a limit of detection of 0.5-2.5 μM, a limit of quantification of 2.5-5.0 μM, and a dynamic range of 5.0-2.0 mM (R(2) > 0.997). The new ultra-high performance supercritical fluid chromatography method was also applied for the qualitative and quantitative analysis of lignin-derived phenolic compounds obtained upon alkaline cupric oxide oxidation of a commercial humic acid. Ten out of the previous eleven model compounds could be quantified in the oxidized humic acid sample. The high separation power and short analysis time obtained demonstrate for the first time that supercritical fluid chromatography is a fast and reliable technique for the analysis of lignin-derived phenols in complex environmental samples.

  18. Characteristics of concentrations and water-soluble inorganic ions in PM2.5 in Handan City, Hebei province, China

    Science.gov (United States)

    Meng, C. C.; Wang, L. T.; Zhang, F. F.; Wei, Z.; Ma, S. M.; Ma, X.; Yang, J.

    2016-05-01

    In order to explore the spatial, temporal, and chemical characteristics of fine particulate matter (PM2.5) pollution in Handan city, China, a comprehensive dataset including continuous online observations at four air quality monitoring stations in 2013 and 2014, and the concentrations of water-soluble inorganic ions (WSII) (NO3-, SO42 -, NH4+, Cl-, Na+, Mg2 +, K+, Ca2 +) in PM2.5 samples collected in four representative seasons in 2013 and 2014 are analyzed in this study. And the principal component analysis (PCA) method is applied to identify the source of WSII in Handan. Our results indicate that PM2.5 concentration decreased from 139.4 μg/m3 in 2013 to 116.0 μg/m3 in 2014 on annual average. Spatial variations of PM2.5 mass are not pronounced, indicating that PM2.5 is nearly evenly spread over the study area. The seasonal variations of PM2.5 concentration are significant, normally with 1.7 to 2.4 times higher in winter than in summer. The concentrations of TWSII (total water-soluble inorganic ions) remain relatively stable in two years, with annual averages of 63.1 μg/m3 in 2013 and 57.2 μg/m3 in 2014. SNA (SO42 -, NO3-, NH4+) dominates in the TWSII, accounting for ~ 87% of the TWSII. Similar to PM2.5, WSII exhibits obvious seasonal variations with higher concentrations in autumn and winter, lower in spring and summer. PM2.5 samples are acidic in spring, summer and autumn of 2013, while in winter of 2013 and all seasons of 2014, they are alkaline. SO42 -, NO3- are formed mainly through homogeneous reactions, heterogeneous reactions also exist in winter. Finally, the major sources of WSII in Handan are identified as the mixture of secondary origin, coal combustion, biomass burning (46.1%), dust sources (25.8%), and motor vehicle (12.3%).

  19. Effects of calcium ion concentration on starch hydrolysis of barley alpha-amylase isozymes.

    Science.gov (United States)

    Yuk, Jeong-Bin; Choi, Seung-Ho; Lee, Tae-Hee; Jang, Myoung-Uoon; Park, Jung-Mi; Yi, Ah-Rum; Svensson, Birte; Kim, Tae-Jip

    2008-04-01

    Barley alpha-amylase genes, amy1 and amy2, were separately cloned into the expression vector of pPICZalphaA and recombinant Pichia strains were established by homologous recombination. Both AMYs from Pichia shared almost identical hydrolysis patterns on short maltooligosaccharides to result in glucose, maltose, or maltotriose. Against insoluble blue starch, AMY1 showed the highest activity at 0.1-5 mM calcium concentration, whereas 15-20 mM was optimal for AMY2. On the hydrolysis of soluble starch, unexpectedly, there was no significant difference between AMYs with increase of calcium. However, the relative activity on various starch substrates was significantly different between AMYs, which supports that the isozymes are clearly distinguished from each other on the basis of their unique preferences for substrates.

  20. Effects of calcium ion concentration on starch hydrolysis of barley α-amylase isozymes

    DEFF Research Database (Denmark)

    Yuk, Jeong-Bin; Choi, Seung-Ho; Lee, Tae-Hee;

    2008-01-01

    Barley (x-amylase genes, amyl and amy2, were separately cloned into the expression vector of pPICZ alpha A and recombinant Pichia strains were established by homologous recombination. Both AMYs from Pichia shared almost identical hydrolysis patterns on short maltooligosaccharides to result...... in glucose, maltose, or maltotriose. Against insoluble blue starch, AMY1 showed the highest activity at 0.1-5 mM calcium concentration, whereas 15-20 mM was optimal for AMY2. On the hydrolysis of soluble starch, unexpectedly, there was no significant difference between AMYs with increase of calcium. However......, the relative activity on various starch substrates was significantly different between AMYs, which supports that the isozymes are clearly distinguished from each other on the basis of their unique preferences for substrates....

  1. Determination of benzene, toluene and xylene concentration in humid air using differential ion mobility spectrometry and partial least squares regression.

    Science.gov (United States)

    Maziejuk, M; Szczurek, A; Maciejewska, M; Pietrucha, T; Szyposzyńska, M

    2016-05-15

    Benzene, toluene and xylene (BTX compounds) are chemicals of greatest concern due to their impact on humans and the environment. In many cases, quantitative information about each of these compounds is required. Continuous, fast-response analysis, performed on site would be desired for this purpose. Several methods have been developed to detect and quantify these compounds in this way. Methods vary considerably in sensitivity, accuracy, ease of use and cost-effectiveness. The aim of this work is to show that differential ion mobility spectrometry (DMS) may be applied for determining concentration of BTX compounds in humid air. We demonstrate, this goal is achievable by applying multivariate analysis of the measurement data using partial least squares (PLS) regression. The approach was tested at low concentrations of these compounds in the range of 5-20 ppm and for air humidity in a range 0-12 g/kg. These conditions correspond to the foreseeable application of the developed approach in occupational health and safety measurements. The average concentration assessment error was about 1 ppm for each: benzene, toluene and xylene. We also successfully determined water vapor content in air. The error achieved was 0.2 g/kg. The obtained results are very promising regarding further development of DMS technique as well as its application.

  2. Long-term observations of positive cluster ion concentration, sources and sinks at the high altitude site of the Puy de Dôme

    Science.gov (United States)

    Rose, C.; Boulon, J.; Hervo, M.; Holmgren, H.; Asmi, E.; Ramonet, M.; Laj, P.; Sellegri, K.

    2013-06-01

    Cluster particles (0.8-1.9 nm) are key entities involved in nucleation and new particle formation processes in the atmosphere. Cluster ions were characterized in clear sky conditions at the Puy de Dôme station (1465 m a.s.l). The studied dataset spread over five years (February 2007-February 2012), which provided a unique chance to catch seasonal variations of cluster ion properties at high altitude. Statistical values of the cluster ion concentration and diameter are reported for both positive and negative polarities. Cluster ions were found to be ubiquitous at the Puy de Dôme and displayed an annual variation with lower concentrations in spring. Positive cluster ions were less numerous than negative ones but were larger in diameters. Negative cluster ion properties seemed insensitive to the occurrence of a new particle formation (NPF) event while positive cluster ions appeared to be significantly more numerous and larger on event days. The parameters of the balance equation for the positive cluster concentration are reported, separately for the different seasons and for the NPF event days and non-event days. The steady state assumption suggests that the ionization rate is balanced with two sinks which are the ion recombination and the attachment on aerosol particles, referred as "aerosol ion sink". The aerosol ion sink was found to be higher during the warm season and dominated the loss of ions. The positive ionization rates derived from the balance equation were well correlated with the ionization rates obtained from radon measurement, and they were on average higher in summer and fall compared to winter and spring. Neither the aerosol ion sink nor the ionization rate were found to be significantly different on event days compared to non-event days, and thus they were not able to explain the different positive cluster concentrations between event and non-event days. Hence, the excess of positive small ions on event days may derive from an additional source of

  3. Salivary-free fluoride ion concentration measured using a flow-injection analysis device and oral environment in 4-6-year-old children.

    Science.gov (United States)

    Iwasaki, Terumi; Uchikawa, Yoshimori; Shirase, Toshiomi

    2016-09-01

    Although fluoride (F) products are widely used for caries prevention, the safest and most effective modes of application, in particular for young children, remain to be elucidated. The limitations associated with the detection of ultra-low F ion concentrations are the major obstacles in accurately assessing the salivary F ion concentrations in children. This study aimed to measure accurate salivary-free F ion concentrations in children using a flow-injection analysis device and highlight the conditions or substances that influence changes in salivary content. Subjects were 4-6-year-old children, and we statistically compared the data involving the number of decayed, missing, or filled surfaces (dmfs), the levels of Mutans streptococci (MS) and Lactobacilli (LB) cariogenic bacteria, and oral hygiene habits. The information on the latter was obtained using a parent/guardian questionnaire. The average free F ion concentration measured was 0.421 ± 0.158 μmol/L (0.008 ± 0.003 ppm), which was considerably lower than that obtained in previous studies using the conventional F electrode method. No significantly different correlations were seen between salivary-free F ion concentrations and dmfs, MS and LB levels. With regard to salivary-free F ion concentrations and oral hygiene habits, only finishing brush of subjects' teeth by guardians showed a significant difference. In summary, the frequency of brushing was shown to correlate with free F ion concentration in saliva of children. Further studies are needed to circumstantially evaluate some other substances in saliva and oral hygiene habits.

  4. Protein-ion binding process on finite macromolecular concentration. A Poisson-Boltzmann and Monte Carlo study.

    Science.gov (United States)

    de Carvalho, Sidney Jurado; Fenley, Márcia O; da Silva, Fernando Luís Barroso

    2008-12-25

    Electrostatic interactions are one of the key driving forces for protein-ligands complexation. Different levels for the theoretical modeling of such processes are available on the literature. Most of the studies on the Molecular Biology field are performed within numerical solutions of the Poisson-Boltzmann Equation and the dielectric continuum models framework. In such dielectric continuum models, there are two pivotal questions: (a) how the protein dielectric medium should be modeled, and (b) what protocol should be used when solving this effective Hamiltonian. By means of Monte Carlo (MC) and Poisson-Boltzmann (PB) calculations, we define the applicability of the PB approach with linear and nonlinear responses for macromolecular electrostatic interactions in electrolyte solution, revealing some physical mechanisms and limitations behind it especially due the raise of both macromolecular charge and concentration out of the strong coupling regime. A discrepancy between PB and MC for binding constant shifts is shown and explained in terms of the manner PB approximates the excess chemical potentials of the ligand, and not as a consequence of the nonlinear thermal treatment and/or explicit ion-ion interactions as it could be argued. Our findings also show that the nonlinear PB predictions with a low dielectric response well reproduce the pK shifts calculations carried out with an uniform dielectric model. This confirms and completes previous results obtained by both MC and linear PB calculations.

  5. [Obtaining of bacterial bioluminescent strain Protobacterium phosphoreum B7071 (lux+) for the determination of zinc ion concentration].

    Science.gov (United States)

    Gruzina, T G; Dybkova, S N; Chekhovskaia, T P; Vember, V V; Zadorozhniaia, A M; Ul'berg, Z R

    2006-01-01

    The transconjugate containing hybrid plasmid (Te(R)Zn(R)lux+) was obtained using the conjugation method on Pseudomonasfragi T2(5) (Te(R)ZnR) strain and bioluminescent strain Protobacterium phosphoreum B7071 (lux+). The expression regulation of lux-genes on the obtained plasmid is carried out by promotor-operational area conjointly with zinc resistance genes. The cells of the obtained genetically modified bacteria have the ability to specific induced luminescence, which is a respond to zinc ions' presence in the measuring medium. It was shown that the cells' bioluminescence intensity of trans-conjugate is linearly dependent on zinc ions' concentration within the range of 1-100 microM, that provides the opportunity of using biosensor as a strain for qualitative and quantitative detection of the metal. The low sensitivity limit of this method is 0.5 microM for the metal. Besides having high sensitivity, the developed lux-biosensor is highly specified.

  6. Effect of ocean acidification on the benthic foraminifera Ammonia sp. is caused by a decrease in carbonate ion concentration

    Directory of Open Access Journals (Sweden)

    J. Bijma

    2013-01-01

    Full Text Available About 30% of the anthropogenically released CO2 is taken up by the oceans, which causes surface ocean pH to decrease and is commonly referred to as Ocean Acidification (OA. Foraminifera are one of the most abundant groups of marine calcifiers, estimated to precipitate ca. 50% of biogenic calcium carbonate in the open oceans. We have compiled the state of the art of OA effects on foraminifera, because the majority of OA research on this group was published within the last 3 yr. Disparate responses of this important group of marine calcifiers to OA were reported, highlighting the importance of a process based understanding of OA effects on foraminifera. The benthic foraminifer Ammonia sp. was cultured using two carbonate chemistry manipulation approaches: While pH and carbonate ions where varied in one, pH was kept constant in the other while carbonate ion concentration varied. This allows the identification of teh parameter of the parameter of the carbonate system causing observed effects. This parameter identification is the first step towards a process based understanding. We argue that [CO32−] is the parameter affecting foraminiferal size normalized weights (SNW and growth rates and based on the presented data we can confirm the strong potential of foraminiferal SNW as a [CO32−] proxy.

  7. [Quantitative monitoring the concentration changes of organic acids in fermentation process of Clostridium acetobutylicum using capillary ion electrophoresis].

    Science.gov (United States)

    Cheng, Jiayi; Wang, Tongdan; Kang, Jingwu

    2008-11-01

    A method for monitoring the concentration changes of organic acids in the fermentation process of Clostridium acetobutylicum by capillary ion electrophoresis has been developed. In this study, 4-methoxybenzoic acid was used as the background electrolyte for the indirect ultraviolet detection, and cetyltrimethylammonium chloride (CTAC) was employed as the electroosmotic flow modifier. The sample of fermentation was simply treated by centrifugation and dilution. The optimal conditions for the separation were established as 10 mmol/L of 4-methoxybenzoic acid solution (pH 5. 8) and 0. 15 mmol/L of CTAC solution. The limits of quantification for lactate, acetate and n-butyrate were 1.22, 0.38 and 0.58 mg/L, respectively. The method can be successfully used for the metabolic flux analysis of Clostridium acetobutylicum.

  8. Intracellular ion concentrations and cell volume during cholinergic stimulation of eccrine secretory coil cells

    Energy Technology Data Exchange (ETDEWEB)

    Takemura, T.; Sato, F.; Saga, K.; Suzuki, Y.; Sato, K. (Univ. of Iowa College of Medicine, Iowa City (USA))

    1991-02-01

    Methacholine (MCh)-induced changes in intracellular concentrations of Na, K, and Cl (( Na)i, (K)i, and (Cl)i, respectively) and in cellular dry mass (a measure of cell shrinkage) were examined in isolated monkey eccrine sweat secretory coils by electron probe X-ray microanalysis using the peripheral standard method. To further confirm the occurrence of cell shrinkage during MCh stimulation, the change in cell volume of dissociated clear and dark cells were directly determined under a light microscope equipped with differential interference contrast (DIC) optics. X-ray microanalysis revealed a biphasic increase in cellular dry mass in clear cells during continuous MCh stimulation; an initial increase of dry mass to 158% (of control) followed by a plateau at 140%, which correspond to the decrease in cell volume of 37 and 29%, respectively. The latter agrees with the MCh-induced cell shrinkage of 29% in dissociated clear cells. The MCh-induced increase in dry mass in myoepithelial cells was less than half that of clear cells. During the steady state of MCh stimulation, both (K+)i and (Cl)i of clear cells decreased by about 45%, whereas (Na)i increased in such a way to maintain the sum of (Na) i + (K)i constant. There was a small (12-15 mM) increase in (Na)i and a decrease in (K)i in myoepithelial cells during stimulation with MCh. Dissociated dark cells failed to significantly shrink during MCh stimulation. The decrease in (Cl)i in the face of constant (Na)i + (K)i suggests the accumulation of unknown anion(s) inside the clear cell during MCh stimulation.

  9. Strong Relationships in Acid-Base Chemistry – Modeling Protons Based on Predictable Concentrations of Strong Ions, Total Weak Acid Concentrations, and pCO2

    Science.gov (United States)

    Kellum, John A.

    2016-01-01

    Understanding acid-base regulation is often reduced to pigeonholing clinical states into categories of disorders based on arterial blood sampling. An earlier ambition to quantitatively explain disorders by measuring production and elimination of acid has not become standard clinical practice. Seeking back to classical physical chemistry we propose that in any compartment, the requirement of electroneutrality leads to a strong relationship between charged moieties. This relationship is derived in the form of a general equation stating charge balance, making it possible to calculate [H+] and pH based on all other charged moieties. Therefore, to validate this construct we investigated a large number of blood samples from intensive care patients, where both data and pathology is plentiful, by comparing the measured pH to the modeled pH. We were able to predict both the mean pattern and the individual fluctuation in pH based on all other measured charges with a correlation of approximately 90% in individual patient series. However, there was a shift in pH so that fitted pH in general is overestimated (95% confidence interval -0.072–0.210) and we examine some explanations for this shift. Having confirmed the relationship between charged species we then examine some of the classical and recent literature concerning the importance of charge balance. We conclude that focusing on the charges which are predictable such as strong ions and total concentrations of weak acids leads to new insights with important implications for medicine and physiology. Importantly this construct should pave the way for quantitative acid-base models looking into the underlying mechanisms of disorders rather than just classifying them. PMID:27631369

  10. Calcification of the planktonic foraminifera Globigerina bulloides and carbonate ion concentration: Results from the Santa Barbara Basin

    Science.gov (United States)

    Osborne, Emily B.; Thunell, Robert C.; Marshall, Brittney J.; Holm, Jessica A.; Tappa, Eric J.; Benitez-Nelson, Claudia; Cai, Wei-Jun; Chen, Baoshan

    2016-08-01

    Planktonic foraminiferal calcification intensity, reflected by shell wall thickness, has been hypothesized to covary with the carbonate chemistry of seawater. Here we use both sediment trap and box core samples from the Santa Barbara Basin to evaluate the relationship between the calcification intensity of the planktonic foraminifera species Globigerina bulloides, measured by area density (µg/µm2), and the carbonate ion concentration of seawater ([CO32-]). We also evaluate the influence of both temperature and nutrient concentration ([PO43-]) on foraminiferal calcification and growth. The presence of two G. bulloides morphospecies with systematically different calcification properties and offset stable isotopic compositions was identified within sampling populations using distinguishing morphometric characteristics. The calcification temperature and by extension calcification depth of the more abundant "normal" G. bulloides morphospecies was determined using δ18O temperature estimates. Calcification depths vary seasonally with upwelling and were used to select the appropriate [CO32-], temperature, and [PO43-] depth measurements for comparison with area density. Seasonal upwelling in the study region also results in collinearity between independent variables complicating a straightforward statistical analysis. To address this issue, we use additional statistical diagnostics and a down core record to disentangle the respective roles of each parameter on G. bulloides calcification. Our results indicate that [CO32-] is the primary variable controlling calcification intensity while temperature influences shell size. We report a modern calibration for the normal G. bulloides morphospecies that can be used in down core studies of well-preserved sediments to estimate past [CO32-].

  11. The influence of ion binding and ion specific potentials on the double layer pressure between charged bilayers at low salt concentrations

    Science.gov (United States)

    Bostrom, M.; Lima, E. R. A.; Tavares, F. W.; Ninham, B. W.

    2008-04-01

    Measurements of surface forces between double-chained cationic bilayers adsorbed onto molecularly smooth mica surfaces across different millimolar salt solutions have revealed a large degree of ion specificity [Pashley et al., J. Phys. Chem. 90, 1637 (1986)]. This has been interpreted in terms of highly specific anion binding to the adsorbed bilayers. We show here that inclusion in the double layer theory of nonspecific ion binding and ion specific nonelectrostatic potentials acting between ions and the two surfaces can account for the phenomenon. It also gives the right Hofmeister series for the double layer pressure.

  12. Characteristics of Lipoprotein Peak x Eluted from a Column with the Eluent of High-magnesium Ion Concentration in Lipoprotein Analysis Using the Cation-exchange Chromatography

    OpenAIRE

    Yuji Hirowatari; Hiroshi Yoshida; Yutaka Ogura; Hidekastu Yanai; Hideo Kurosawa; Norio Tada

    2005-01-01

    The new lipoprotein analysis method using a cation-exchange chromatography, which contains a sulfopropyl-ligand column and two magnesium ion-containing eluents was previously reported. This method can separate serum lipoproteins on the column gel with a magnesium ion concentration gradient and high-density lipoprotein (HDL), low-density lipoprotein (LDL), very-low-density lipoprotein (VLDL) and an unspecified lipoprotein peak are eluted in order from the column. We have now characterize...

  13. Effect of concentration of lithium ions on the voltammetric responses of nitro-substituted aromatic sulfides in dimethylformamide on glassy carbon electrodes

    Science.gov (United States)

    Chellammal, S.; Noel, M.; Anantharaman, P. N.

    Lithium salts are used as supporting electrolytes and ion-pair forming reagents during voltammetric investigations in aprotic solvents. In the present work, these ions are found to have a significant influence on the voltammetric responses of aromatic sulfides in dimethylformamide given their concentration and the cathodic potential limits applied. At very low concentrations (reduction of nitro groups on the electrode surface. This is the conventional lithium ion-pair formation effect reported in the literature. With increasing lithium ion concentration and increasing cathodic limit, the ion-pairs tend to form an insoluble salt film on the electrode surface. This leads to inhibition of further electron transfer. The inhibiting effect does not seem to correlate with the size of the reactant organic molecule involved. At cathodic potential limits exceeding - 2 V, lithium ions appear to undergo direct reduction and subsequent reaction with trace levels of water in the solvent to produce a passive LiOH layer. This inhibits all further electron transfer.

  14. Sodium concentration measurement during hemodialysis through ion-exchange resin and conductivity measure approach: in vitro experiments.

    Science.gov (United States)

    Tura, Andrea; Sbrignadello, Stefano; Mambelli, Emanuele; Ravazzani, Paolo; Santoro, Antonio; Pacini, Giovanni

    2013-01-01

    Sodium measurement during hemodialysis treatment is important to preserve the patient from clinical events related to hypo- or hyper-natremia Usually, sodium measurement is performed through laboratory equipment which is typically expensive, and requires manual intervention. We propose a new method, based on conductivity measurement after treatment of dialysate solution through ion-exchange resin. To test this method, we performed in vitro experiments. We prepared 40 ml sodium chloride (NaCl) samples at 280, 140, 70, 35, 17.5, 8.75, 4.375 mEq/l, and some "mixed samples", i.e., with added potassium chloride (KCl) at different concentrations (4.375-17.5 mEq/l), to simulate the confounding factors in a conductivity-based sodium measurement. We measured the conductivity of all samples. Afterwards, each sample was treated for 1 min with 1 g of Dowex G-26 resin, and conductivity was measured again. On average, the difference in the conductivity between mixed samples and corresponding pure NaCl samples (at the same NaCl concentration) was 20.9%. After treatment with the exchange resin, it was 14.7%, i.e., 42% lower. Similar experiments were performed with calcium chloride and magnesium chloride as confounding factors, with similar results. We also performed some experiments on actual dialysate solution during hemodialysis sessions in 15 patients, and found that the correlation between conductivity measures and sodium concentration improved after resin treatment (R=0.839 before treatment, R=0.924 after treatment, Pconductivity measures may improve the measurement of sodium compared to conductivity measures alone, and may become a possible simple approach for continuous and automatic sodium measurement during hemodialysis.

  15. Metal ion concentrations in body fluids after implantation of hip replacements with metal-on-metal bearing--systematic review of clinical and epidemiological studies.

    Directory of Open Access Journals (Sweden)

    Albrecht Hartmann

    Full Text Available INTRODUCTION: The use of metal-on-metal (MoM total hip arthroplasty (THA increased in the last decades. A release of metal products (i.e. particles, ions, metallo-organic compounds in these implants may cause local and/or systemic adverse reactions. Metal ion concentrations in body fluids are surrogate measures of metal exposure. OBJECTIVE: To systematically summarize and critically appraise published studies concerning metal ion concentrations after MoM THA. METHODS: Systematic review of clinical trials (RCTs and epidemiological studies with assessment of metal ion levels (cobalt, chromium, titanium, nickel, molybdenum in body fluids after implantation of metalliferous hip replacements. Systematic search in PubMed and Embase in January 2012 supplemented by hand search. Standardized abstraction of pre- and postoperative metal ion concentrations stratified by type of bearing (primary explanatory factor, patient characteristics as well as study quality characteristics (secondary explanatory factors. RESULTS: Overall, 104 studies (11 RCTs, 93 epidemiological studies totaling 9.957 patients with measurement of metal ions in body fluids were identified and analyzed. Consistently, median metal ion concentrations were persistently elevated after implantation of MoM-bearings in all investigated mediums (whole blood, serum, plasma, erythrocytes, urine irrespective of patient characteristics and study characteristics. In several studies very high serum cobalt concentrations above 50 µg/L were measured (detection limit typically 0.3 µg/L. Highest metal ion concentrations were observed after treatment with stemmed large-head MoM-implants and hip resurfacing arthroplasty. DISCUSSION: Due to the risk of local and systemic accumulation of metallic products after treatment with MoM-bearing, risk and benefits should be carefully balanced preoperatively. The authors support a proposed "time out" for stemmed large-head MoM-THA and recommend a restricted

  16. The impact of seawater saturation state and bicarbonate ion concentration on calcification by new recruits of two Atlantic corals

    Science.gov (United States)

    de Putron, S. J.; McCorkle, D. C.; Cohen, A. L.; Dillon, A. B.

    2011-06-01

    Rising concentrations of atmospheric CO2 are changing the carbonate chemistry of the oceans, a process known as ocean acidification (OA). Absorption of this CO2 by the surface oceans is increasing the amount of total dissolved inorganic carbon (DIC) and bicarbonate ion (HCO3 -) available for marine calcification yet is simultaneously lowering the seawater pH and carbonate ion concentration ([CO3 2-]), and thus the saturation state of seawater with respect to aragonite (Ωar). We investigated the relative importance of [HCO3 -] versus [CO3 2-] for early calcification by new recruits (primary polyps settled from zooxanthellate larvae) of two tropical coral species, Favia fragum and Porites astreoides. The polyps were reared over a range of Ωar values, which were manipulated by both acid-addition at constant pCO2 (decreased total [HCO3 -] and [CO3 2-]) and by pCO2 elevation at constant alkalinity (increased [HCO3 -], decreased [CO3 2-]). Calcification after 2 weeks was quantified by weighing the complete skeleton (corallite) accreted by each polyp over the course of the experiment. Both species exhibited the same negative response to decreasing [CO3 2-] whether Ωar was lowered by acid-addition or by pCO2 elevation—calcification did not follow total DIC or [HCO3 -]. Nevertheless, the calcification response to decreasing [CO3 2-] was nonlinear. A statistically significant decrease in calcification was only detected between Ωar = <2.5 and Ωar = 1.1-1.5, where calcification of new recruits was reduced by 22-37% per 1.0 decrease in Ωar. Our results differ from many previous studies that report a linear coral calcification response to OA, and from those showing that calcification increases with increasing [HCO3 -]. Clearly, the coral calcification response to OA is variable and complex. A deeper understanding of the biomineralization mechanisms and environmental conditions underlying these variable responses is needed to support informed predictions about future OA

  17. Study rationale and protocol: prospective randomized comparison of metal ion concentrations in the patient's plasma after implantation of coated and uncoated total knee prostheses

    Directory of Open Access Journals (Sweden)

    Günther Klaus-Peter

    2009-10-01

    Full Text Available Abstract Background Any metal placed in a biological environment undergoes corrosion. Thus, with their large metallic surfaces, TKA implants are particularly prone to corrosion with subsequent release of metal ions into the human body which may cause local and systemic toxic effects and hypersensitivity reactions, and increase cancer risk. To address this problem, a new 7-layer zirconium coating developed especially for cobalt-chrome orthopaedic implants was tested biomechanically and found to lower metal ion release. The purpose of the proposed clinical trial is to compare the metal ion concentration in patients' plasma before and after implantation of a coated or uncoated TKA implant. Methods/Design In this randomised controlled trial, 120 patients undergoing primary TKA will be recruited at the Department of Orthopaedic Surgery of the University Hospital in Dresden, Germany, and randomised to either the coated or uncoated prosthesis. Outcome assessments will be conducted preoperatively and at 3 months, 12 months and 5 years postoperatively. The primary clinical endpoint will be the chromium ion concentration in the patient's plasma after 1 and 5 years. Secondary outcomes include cobalt, molybdenum and nickel ion concentrations after 1 and 5 years, allergy testing for hypersensitivity against one of these metals, the Knee Society Score to assess clinical and physical function of the knee joint, the self-assessment Oxford Score and the Short Form 36 quality of live questionnaire. Discussion The metal ion concentration in the patient's plasma has been shown to increase after TKA, its eventual adverse effects being widely debated. In the light of this discussion, ways to reduce metal ion release from orthopaedic implants should be studied in detail. The results of this investigation may lead to a new method to achieve this goal. Trials register Clinicaltrials registry NCT00862511

  18. Study rationale and protocol: prospective randomized comparison of metal ion concentrations in the patient's plasma after implantation of coated and uncoated total knee prostheses

    Science.gov (United States)

    Lützner, Jörg; Dinnebier, Gerd; Hartmann, Albrecht; Günther, Klaus-Peter; Kirschner, Stephan

    2009-01-01

    Background Any metal placed in a biological environment undergoes corrosion. Thus, with their large metallic surfaces, TKA implants are particularly prone to corrosion with subsequent release of metal ions into the human body which may cause local and systemic toxic effects and hypersensitivity reactions, and increase cancer risk. To address this problem, a new 7-layer zirconium coating developed especially for cobalt-chrome orthopaedic implants was tested biomechanically and found to lower metal ion release. The purpose of the proposed clinical trial is to compare the metal ion concentration in patients' plasma before and after implantation of a coated or uncoated TKA implant. Methods/Design In this randomised controlled trial, 120 patients undergoing primary TKA will be recruited at the Department of Orthopaedic Surgery of the University Hospital in Dresden, Germany, and randomised to either the coated or uncoated prosthesis. Outcome assessments will be conducted preoperatively and at 3 months, 12 months and 5 years postoperatively. The primary clinical endpoint will be the chromium ion concentration in the patient's plasma after 1 and 5 years. Secondary outcomes include cobalt, molybdenum and nickel ion concentrations after 1 and 5 years, allergy testing for hypersensitivity against one of these metals, the Knee Society Score to assess clinical and physical function of the knee joint, the self-assessment Oxford Score and the Short Form 36 quality of live questionnaire. Discussion The metal ion concentration in the patient's plasma has been shown to increase after TKA, its eventual adverse effects being widely debated. In the light of this discussion, ways to reduce metal ion release from orthopaedic implants should be studied in detail. The results of this investigation may lead to a new method to achieve this goal. Trials register Clinicaltrials registry NCT00862511 PMID:19828019

  19. The Equivalent Electrokinetic Circuit Model of Ion Concentration Polarization Layer: Electrical Double Layer, Extended Space Charge and Electro-convection

    Science.gov (United States)

    Cho, Inhee; Huh, Keon; Kwak, Rhokyun; Lee, Hyomin; Kim, Sung Jae

    2016-11-01

    The first direct chronopotentiometric measurement was provided to distinguish the potential difference through the extended space charge (ESC) layer which is formed with the electrical double layer (EDL) near a perm-selective membrane. From this experimental result, the linear relationship was obtained between the resistance of ESC and the applied current density. Furthermore, we observed the step-wise distributions of relaxation time at the limiting current regime, confirming the existence of ESC capacitance other than EDL's. In addition, we proposed the equivalent electrokinetic circuit model inside ion concentration polarization (ICP) layer under rigorous consideration of EDL, ESC and electro-convection (EC). In order to elucidate the voltage configuration in chronopotentiometric measurement, the EC component was considered as the "dependent voltage source" which is serially connected to the ESC layer. This model successfully described the charging behavior of the ESC layer with or without EC, where both cases determined each relaxation time, respectively. Finally, we quantitatively verified their values utilizing the Poisson-Nernst-Planck equations. Therefore, this unified circuit model would provide a key insight of ICP system and potential energy-efficient applications.

  20. {mu}PIXE for a {mu}Brain: The vinegar fly's brain, antenna, sensilla hairs and eye ion concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Reinert, Anja, E-mail: areinert@ice.mpg.de [Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knoell-Strasse 8, 07745 Jena (Germany); Barapatre, Nirav [Institute for Experimental Physics II, University of Leipzig, Linnestrasse 5, 04103 Leipzig (Germany); Sachse, Silke [Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knoell-Strasse 8, 07745 Jena (Germany); Reinert, Tilo [Department of Physics, University of North Texas, 1155 Union Circle, 76203 Denton, TX (United States)

    2011-10-15

    The vinegar fly Drosophila melanogaster is used as model organism to study a variety of different scientific purposes. Thus, our laboratory studies the olfactory system by neurobiological experiments. These techniques are often disruptive and need to compensate or exchange the body fluid, the lymph, with an artificial Ringer's solution in defined compartments of the fly. The solution mainly contains Na, Cl, K and Ca and is to keep physiological conditions. Therefore, the knowledge about the ion concentrations in the respective Drosophila lymph is required for a correct mixture of the ions. This paper presents the spatially resolved concentrations of P, S, Cl, K, Ca, Fe, Cu and Zn in lyophilised head cryosections of Drosophila by using quantitative {mu}PIXE at the ion beam facility LIPSION in Leipzig. The PIXE maps enable a detailed analysis of particular regions of interest down to a spatial resolution of 0.5 {mu}m. We quantified the ion concentrations especially in the brain, the antenna and its sensilla hairs acting as the olfactory organ of the fly, in the compound eye and in the mouthparts. The averaged element concentrations of these main compartments are (in descending order): P: 90 mM, K: 81 mM, S: 38 mM, Cl: 18 mM, Ca: 4.9 mM, Fe: 1.4 mM, Zn: 1.2 mM, Cu: 0.06 mM. Certain structures or cavities possess a remarkably high concentration of particular elements and might reflect the different functions of the compartments. An example presented in more detail is the composition of the compound eye. Conclusively, our findings on the ion concentrations might be useful for the mixture of the Drosophila Ringer's solution to ensure physiological conditions in experiments.

  1. Immobilised metal-ion affinity chromatography purification of histidine-tagged recombinant proteins : a wash step with a low concentration of EDTA

    NARCIS (Netherlands)

    Westra, DF; Welling, GW; Koedijk, DGAM; Scheffer, AJ; The, TH; Welling-Wester, S

    2001-01-01

    Immobilised metal-ion affinity chromatography (IMAC) is widely used for the purification of recombinant proteins in which a poly-histidine tag is introduced. However, other proteins may also bind to IMAC columns. We describe the use of a washing buffer with a low concentration of EDTA (0.5 mM) for t

  2. Simultaneous determination of free calcium, magnesium, sodium and potassium ion concentrations in simulated milk ultrafiltrate and reconstituted skim milk using the Donnan Membrane Technique

    NARCIS (Netherlands)

    Gao, R.; Temminghoff, E.J.M.; Leeuwen, van H.P.; Valenberg, van H.J.F.; Eisner, M.D.; Boekel, van M.A.J.S.

    2009-01-01

    This study focused on determination of free Ca2+, Mg2+, Na+ and K+ concentrations in a series of CaCl2 solutions, simulated milk ultrafiltrate and reconstituted skim milk using a recently developed Donnan Membrane Technique (DMT). A calcium ion selective electrode was used to compare the DMT results

  3. Oscillatory and ion-correlation forces observed in direct force measurements between silica surfaces in concentrated CaCl2 solutions

    NARCIS (Netherlands)

    Fielden, ML; Hayes, RA; Ralston, J

    2000-01-01

    The force between silica spheres and naturally oxidised silicon wafer has been measured in calcium chloride solutions at concentrations between 1 and 5 M using an atomic force microscope. An oscillatory force, consistent in periodicity with the expulsion of layers of ions, was found to overlay the e

  4. Cloud water composition during HCCT-2010: Scavenging efficiencies, solute concentrations, and droplet size dependence of inorganic ions and dissolved organic carbon

    Directory of Open Access Journals (Sweden)

    D. van Pinxteren

    2015-09-01

    Full Text Available Cloud water samples were taken in September/October 2010 at Mt. Schmücke in a rural, forested area in Germany during the Lagrange-type Hill Cap Cloud Thuringia 2010 (HCCT-2010 cloud experiment. Besides bulk collectors, a 3-stage and a 5-stage collector were applied and samples were analysed for inorganic ions (SO42−, NO3−, NH4+, Cl−, Na+, Mg2+, Ca2+, K+, H2O2 (aq, S(IV, and dissolved organic carbon (DOC. Campaign volume-weighted mean concentrations were 191, 142, and 39 μmol L−1 for ammonium, nitrate, and sulfate, respectively, between 4 and 27 μmol L−1 for minor ions, 5.4 μmol L−1 for H2O2 (aq, 1.9 μmol L−1 for S(IV, and 3.9 mgC L−1 for DOC. The concentrations compare well to more recent European cloud water data from similar sites. On a mass basis, organic material (as DOC · 1.8 contributed 20–40 % (event means to total solute concentrations and was found to have non-negligible impact on cloud water acidity. Relative standard deviations of major ions were 60–66 % for solute concentrations and 52–80 % for cloud water loadings (CWLs. Contrary to some earlier suggestions, the similar variability of solute concentrations and CWLs together with the results of back trajectory analysis and principal component analysis, suggests that concentrations in incoming air masses (i.e. air mass history, rather than cloud liquid water content (LWC was the main factor controlling bulk solute concentrations at Mt. Schmücke. Droplet effective radius was found to be a somewhat better predictor for cloud water total ionic content (TIC than LWC, even though no single explanatory variable can fully describe TIC (or solute concentration variations in a simple functional relation due to the complex processes involved. Bulk concentrations typically agreed within a factor of 2 with co-located measurements of residual particle concentrations sampled by a counterflow virtual impactor (CV and analysed by an aerosol mass spectrometer (AMS, with

  5. Effect of concentration of Er3+ ions on ultra-large index of refraction via atomic coherence in Er3+: YAG crystal

    Institute of Scientific and Technical Information of China (English)

    张惠芳; 戴振文; 张冰; 吴金辉; 高锦岳

    2003-01-01

    A four-level system is proposed to produce large index of refraction accompanied by vanishing absorption in the Er3+-doped yttrium aluminium garnet(YAG)crystal.It is found that the high index of refraction with zero absorption can be provided by adjusting the incoherent pumping,the coherent field,as well as the concentration of Er3+ ions in the crystal.Furthermore,the value of the incoherent pump to achieve the high index of refraction with zero absorption is greatly changed with increasing the concentration of Er3+ ions in the crystal.This indicates that the effect of concentration on the high index of refraction with zero absorption cannot be neglected.

  6. Production of a fluorescence probe in ion-beam radiolysis of aqueous coumarin-3-carboxylic acid solution-1: Beam quality and concentration dependences

    Science.gov (United States)

    Maeyama, Takuya; Yamashita, Shinichi; Baldacchino, Gérard; Taguchi, Mitsumasa; Kimura, Atsushi; Murakami, Takeshi; Katsumura, Yosuke

    2011-04-01

    Aqueous coumarin-3-carboxylic acid (3-CCA) solutions were irradiated with seven different ion beams covering LET range from 0.5 to above 2000 eV/nm. G-values of 7OH-CCA, one of hydroxylated products in radiolysis of the solutions, have been determined by fluorescence-HPLC technique in 3-CCA concentration range from 0.1 to 26 mM. The formation yield of 7OH-CCA increased with increase in concentration of 3-CCA while it decreased with increase in LET value of ion beam. Compared with our previous reports on G(•OH) at a scavenging capacity of 107 s-1 with absorption spectroscopy, it was found that G(7OH-CCA) is about (4.7±0.6)% of G(•OH), which is consistent for all of the ion beams used in the present study. However, 7OH-CCA yields in high 3-CCA concentration region, especially by using extremely high LET ions, were much higher than expected values based on the above conversion factor and G(•OH) value predicted in theoretical work.

  7. High-flux ionic diodes, ionic transistors and ionic amplifiers based on external ion concentration polarization by an ion exchange membrane: a new scalable ionic circuit platform.

    Science.gov (United States)

    Sun, Gongchen; Senapati, Satyajyoti; Chang, Hsueh-Chia

    2016-04-07

    A microfluidic ion exchange membrane hybrid chip is fabricated using polymer-based, lithography-free methods to achieve ionic diode, transistor and amplifier functionalities with the same four-terminal design. The high ionic flux (>100 μA) feature of the chip can enable a scalable integrated ionic circuit platform for micro-total-analytical systems.

  8. Data on recovery of 21 amino acids, 9 biogenic amines and ammonium ions after spiking four different beers with five concentrations of these analytes

    Directory of Open Access Journals (Sweden)

    Begoña Redruello

    2016-12-01

    Full Text Available A novel chromatographic method for the simultaneous analysis of nine biogenic amines, 21 amino acids and ammonium ions in beer has been recently described in “A UHPLC method for the simultaneous analysis of biogenic amines, amino acids and ammonium ions in beer” (Redruello et al., 2017 [1]. The present article provides recovery data of the 31 analytes after spiking four different beers with five concentrations of each analyte (15, 30, 60, 120 and 240 µM.

  9. Anodic performance in lithium-ion batteries of graphite-like materials prepared from anthracites and unburned carbon concentrates from coal combustion fly ashes

    Directory of Open Access Journals (Sweden)

    I. Cameán

    2013-01-01

    Full Text Available The electrochemical performance as anodes for lithium-ion batteries of graphite-like materials that were prepared from anthracites and unburned carbon concentrates from coal combustion fly ashes by high temperature treatment was investigated by galvanostatic cycling of lithium test cells. Some of the materials prepared have provided reversible capacities up to ~ 310 mA h g-1 after 50 discharge/ charge cycles. These values are similar to those of oil-derived graphite (petroleum coke being the main precursor which is currently used as anodic material in commercial lithium-ion batteries.

  10. Simulated spatial and temporal dependence of chromium concentration in pure Fe and Fesbnd 14%Cr under high dpa ion irradiation

    Science.gov (United States)

    Vörtler, K.; Mamivand, M.; Barnard, L.; Szlufarska, I.; Garner, F. A.; Morgan, D.

    2016-10-01

    In this work we develop an ab initio informed rate theory model to track the spatial and temporal evolution of implanted ions (Cr+) in Fe and Fesbnd 14%Cr during high dose irradiation. We focus on the influence of the specimen surface, the depth dependence of ion-induced damage, the damage rate, and the consequences of ion implantation, all of which influence the depth dependence of alloy composition evolving with continued irradiation. We investigate chemical segregation effects in the material by considering the diffusion of the irradiation-induced defects. Moreover, we explore how temperature, grain size, grain boundary sink strength, and defect production bias modify the resulting distribution of alloy composition. Our results show that the implanted ion profile can be quite different than the predicted SRIM implantation profile due to radiation enhanced transport and segregation.

  11. Multi-element pre-concentration of heavy metal ions by solid phase extraction on Chromosorb 108

    Energy Technology Data Exchange (ETDEWEB)

    Tuzen, Mustafa [Gaziosmanpasa University, Faculty of Science and Arts, Chemistry Department, 60250 Tokat (Turkey); Soylak, Mustafa [Erciyes University, Faculty of Art and Science, Department of Chemistry, 38039 Kayseri (Turkey)]. E-mail: soylak@erciyes.edu.tr; Elci, Latif [Pamukkale University, Faculty of Art and Science, Department of Chemistry, 20020 Denizli (Turkey)

    2005-08-29

    A multi-element preconcentration procedure for solid phase extraction on Chromosorb 108 as bathocuproinedisulfonic acid chelates and flame atomic absorption spectrometric determinations of some heavy metal ions in environmental samples is proposed in the present work. The influences of analytical parameters including pH of the aqueous solution, amounts of reagents, flow rates of sample and eluent solutions, sample volume etc. on the quantitative recoveries of copper, cadmium, lead, zinc, manganese, iron, chromium, nickel and cobalt ions were investigated. The effects of concomitant ions on the retentions of the analytes were also examined. The presented preconcentration procedure was applied to the determination of metal ions in reference standard materials (NRCC-SLRS 4 Riverine Water, SRM 1515 Apple leaves and GBW 07605 Tea) and some real samples including tap and river water, red wine, rice, black tea and honey.

  12. Concentrations and behavior of oxygen and oxide ion in melts of composition CaO.MgO.xSiO2

    Science.gov (United States)

    Semkow, K. W.; Haskin, L. A.

    1985-01-01

    The behavior of oxygen and oxide ion in silicate melts was investigated through their electrochemical reactions at a platinum electrode. Values are given for the diffusion coefficient for molecular oxygen in diopside melt and the activation energy of diffusion. It is shown that molecular oxygen dissociates prior to undergoing reduction and that oxide ion reacts quickly with silicate polymers when it is produced. The concentration of oxide ion is kept low by a buffering effect of the silicate, the exact level being dependent on the silicate composition. Data on the kinetics of reaction of the dissociation of molecular oxygen and on the buffering reactions are provided. It is demonstrated that the data on oxygen in these silicate melts are consistent with those for solid buffers.

  13. Determination of hexavalent chromium concentration in industrial waste incinerator stack gas by using a modified ion chromatography with post-column derivatization method.

    Science.gov (United States)

    Miyake, Yuichi; Tokumura, Masahiro; Iwazaki, Yuta; Wang, Qi; Amagai, Takashi; Horii, Yuichi; Otsuka, Hideyuki; Tanikawa, Noboru; Kobayashi, Takeshi; Oguchi, Masahiro

    2017-06-16

    An ion chromatography with post-column derivatization with 1,5-diphenylcarbazide (IC-DPC) analytical method was modified to enable measurement of trace-level hexavalent chromium (Cr(VI)) in air. One of the difficulties in determining trace levels of Cr(VI) in air with conventional IC-DPC methods is co-elution of the solvent and ion peaks due to high concentrations of ionic compounds in the extract. However, by using gradient elution rather than isocratic elution we were able to fully resolve the Cr(VI) ion peak from the solvent peak without the need for diluting the extract, which would have reduced the minimum quantifiable level of the method. With this method, we were able to detect Cr(VI) in air at concentrations of 5.3ng/m(3) (assuming a sampling volume of 1m(3) and a final solution volume of 10mL). Recovery tests at three different concentrations of Cr(VI) (50, 250, 1000ng) were performed with or without fly ash; recovery rates at all the concentrations of Cr(VI), with or without fly ash, ranged from 68% to 110% (mean±relative standard deviation, 96%±11%), and there were no differences in recovery rates with respect to the presence or absence of fly ash. Finally, we used the developed method to determine the concentration of Cr(VI) in stack gases collected from eight industrial waste incinerators located in Japan. The concentration of Cr(VI) in the stack gases ranged from below the method quantification limit to 3100ng/m(3). The highest concentrations of Cr(VI) detected in the stack gases were two to three orders of magnitude higher than that in ambient air in Japan. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Cloud water composition during HCCT-2010: Scavenging efficiencies, solute concentrations, and droplet size dependence of inorganic ions and dissolved organic carbon

    Science.gov (United States)

    van Pinxteren, Dominik; Wadinga Fomba, Khanneh; Mertes, Stephan; Müller, Konrad; Spindler, Gerald; Schneider, Johannes; Lee, Taehyoung; Collett, Jeffrey L.; Herrmann, Hartmut

    2016-03-01

    Cloud water samples were taken in September/October 2010 at Mt. Schmücke in a rural, forested area in Germany during the Lagrange-type Hill Cap Cloud Thuringia 2010 (HCCT-2010) cloud experiment. Besides bulk collectors, a three-stage and a five-stage collector were applied and samples were analysed for inorganic ions (SO42-,NO3-, NH4+, Cl-, Na+, Mg2+, Ca2+, K+), H2O2 (aq), S(IV), and dissolved organic carbon (DOC). Campaign volume-weighted mean concentrations were 191, 142, and 39 µmol L-1 for ammonium, nitrate, and sulfate respectively, between 4 and 27 µmol L-1 for minor ions, 5.4 µmol L-1 for H2O2 (aq), 1.9 µmol L-1 for S(IV), and 3.9 mgC L-1 for DOC. The concentrations compare well to more recent European cloud water data from similar sites. On a mass basis, organic material (as DOC × 1.8) contributed 20-40 % (event means) to total solute concentrations and was found to have non-negligible impact on cloud water acidity. Relative standard deviations of major ions were 60-66 % for solute concentrations and 52-80 % for cloud water loadings (CWLs). The similar variability of solute concentrations and CWLs together with the results of back-trajectory analysis and principal component analysis, suggests that concentrations in incoming air masses (i.e. air mass history), rather than cloud liquid water content (LWC), were the main factor controlling bulk solute concentrations for the cloud studied. Droplet effective radius was found to be a somewhat better predictor for cloud water total ionic content (TIC) than LWC, even though no single explanatory variable can fully describe TIC (or solute concentration) variations in a simple functional relation due to the complex processes involved. Bulk concentrations typically agreed within a factor of 2 with co-located measurements of residual particle concentrations sampled by a counterflow virtual impactor (CVI) and analysed by an aerosol mass spectrometer (AMS), with the deviations being mainly caused by systematic

  15. Structural, morphological, electrical, and optical properties of silver thin films of varying thickness deposited on cupric oxide

    Science.gov (United States)

    Hajakbari, Fatemeh; Shafieinejad, Farzaneh

    2016-03-01

    In this investigation, silver (Ag) films of varying thickness (25-100 nm) were grown on cupric oxide (CuO) on silicon and quartz. The CuO preparation was carried out by the thermal oxidation annealing of copper (Cu) thin films deposited by DC magnetron sputtering. The physical properties of the prepared films were studied by different techniques. Rutherford backscattering spectroscopy (RBS) analysis indicated that the Ag film thickness was about 25-100 nm. X-ray diffraction (XRD) results showed that by increasing Ag thickness, the film crystallinity was improved. Also, atomic force microscopy (AFM) and scanning electron microscopy (SEM) results demonstrated that the surface morphology and the grain size were affected by the Ag film thickness. Furthermore, the electrical resistivity of films determined by four-point probe measurements versus the Ag film thickness was discussed. A reduction in the optical band gap energy of CuO is observed from 1.51 to 1.42 eV with an increase in Ag film thickness to 40 nm in Ag/CuO films.

  16. In Situ Raman Spectroscopic Studies on Concentration of Electrolyte Salt in Lithium-Ion Batteries by Using Ultrafine Multifiber Probes.

    Science.gov (United States)

    Yamanaka, Toshiro; Nakagawa, Hiroe; Tsubouchi, Shigetaka; Domi, Yasuhiro; Doi, Takayuki; Abe, Takeshi; Ogumi, Zempachi

    2017-03-09

    Lithium-ion batteries have attracted considerable attention due to their high power density. The change in concentration of salt in the electrolyte solution in lithium-ion batteries during operation causes serious degradation of battery performance. Herein, a new method of in situ Raman spectroscopy with ultrafine multifiber probes was developed to simultaneously study the concentrations of ions at several different positions in the electrolyte solution in deep narrow spaces between the electrodes in batteries. The total amount of ions in the electrolyte solution clearly changed during operation due to the low permeability of the solid-electrolyte interphase (SEI) at the anode for Li(+) permeation. The permeability, which is a key factor to achieve high battery performance, was improved (enhanced) by adding film-forming additives to the electrolyte solution to modify the properties of the SEI. The results provide important information for understanding and predicting phenomena occurring in a battery and for designing a superior battery. The present method is useful for analysis in deep narrow spaces in other electrochemical devices, such as capacitors. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. The Influence of Lead Concentration on Photocatalytic Reduction of Pb(II Ions Assisted by Cu-TiO2 Nanotubes

    Directory of Open Access Journals (Sweden)

    Srimala Sreekantan

    2014-01-01

    Full Text Available Cu2+ ions were successfully loaded into TiO2 nanotubes using wet impregnation technique in 0.6 M Cu(NO32·3H2O solution. The effect of reaction temperatures on the nanotube’s morphology, crystal structure, and their photocatalytic reduction of Pb(II ions were investigated. The high reaction temperature could improve the crystallinity of anatase phase. However, irregular and corrugated nanotubular surface covered with Cu precipitates was observed. In the present study, incorporation of an optimum content of Cu element (1.3 at% into TiO2 nanotubes at room temperature has an important function in enhancing the photocatalytic reduction of Pb(II ions in alkaline condition (pH 11 due to the higher synergistic effects of photocatalytic reaction under UV illumination. The optimum concentration of Pb(II ions for effective Pb(II ions removal performance was found in between 20 and 60 ppm.

  18. Development of novel processes for Cu concentrates without producing sulfuric acid; Hiryusan hasseigata no atarashii doshigen shori gijutsu no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Awakura, Y.; Hirato, T. [Kyoto University, Kyoto (Japan)

    1997-02-01

    Studies are conducted to develop a new wet method for copper concentrates to replace the conventional dry smelting method for the settlement of problems involving the processing of impurities for environmental protection. A specimen of pyrites polycrystals is subjected to leaching at 80 {degree}C in a strongly acidic cupric solution. Findings are that the element sulfur generated in this process does not impede leaching and only approximately 4% of the sulfur is oxidized into sulfur ions; that the presence of more than 2g/liter of bromide ions produced during bromine-aid leaching of gold changes the structure of sulfur for the inhibition of leaching; that circulation of a bromine-containing leaching liquid is not desired since even a small amount of approximately 0.02mol/liter inhibits the leaching rate. Controlled potential electrolysis is performed for the anode in an acid solution containing CuCl, NaCl, and NaBr, for the observation of oxidation/reduction potentials predicted by Nernst`s equation. It is then disclosed that bromine is more effective than chlorine in gold leaching and that the solution potential during leaching agent regeneration enables the monitoring of solution constitution. 2 refs.

  19. Energy recovery from effluents of sugar processing industries in the UASB reactors seeded with granular sludge developed under low and high concentrations of calcium ion

    Energy Technology Data Exchange (ETDEWEB)

    Raphael, D.M.; Rubindamayugi, M.S.T. [Univ. of Dar es Salaam, Dept. of Botany, Applied Microbiology Unit (Tanzania, United Republic of)

    1997-12-31

    The digestion of wastewater from sugar processing industries in a single phase UASB reactor was evaluated by a step wise increase in organic loading rate. This study was conducted to compare the treatability of effluents from sugar processing industries in a single phase UASB reactors inoculated with granular sludge developed under low and high concentrations of calcium ions. At OLR of 11.34 g COD/l/day and HRT of 16 hours, UASB reactor R2 attained a COD removal efficiency of 90% with a maximum methane production rate of 3 l/l/day. From the results, the digestion of the wastewater from sugar industries in the UASB reactor inoculated with granular sludge developed under high calcium ion concentration seem feasible with regard to COD removal efficiency and methane production rate. (au) 24 refs.

  20. High concentrations of Na+ and Cl– ions in soil solution have simultaneous detrimental effects on growth of faba bean under salinity stress

    OpenAIRE

    Tavakkoli, Ehsan; Rengasamy, Pichu; McDonald, Glenn K

    2010-01-01

    Despite the fact that most plants accumulate both sodium (Na+) and chloride (Cl–) ions to high concentration in their shoot tissues when grown in saline soils, most research on salt tolerance in annual plants has focused on the toxic effects of Na+ accumulation. There have also been some recent concerns about the ability of hydroponic systems to predict the responses of plants to salinity in soil. To address these two issues, an experiment was conducted to compare the responses to Na+ and to ...

  1. Changes in the Concentration of Ions in Saliva and Dental Plaque after Application of CPP-ACP with and without Fluoride among 6-9 Year Old Children

    Directory of Open Access Journals (Sweden)

    Poureslami H

    2017-03-01

    Full Text Available Statement of Problem: The casein phospho peptide-amorphous calcium phosphate with or without fluoride (CPP-ACPF and CPP-ACP respectively are of considerably new materials which are highly recommended for prevention of dental caries. However, there is a shortage in literature on how they affect the ion concentration of saliva or dental plaque. Objectives: The aim of this study was to evaluate the concentration of calcium, phosphate and fluoride in the plaque and saliva of children with Early Childhood Caries (ECC after applying the CPP-ACP paste in comparison with the use of CPP- ACPF paste. Materials and Methods: One ml of un-stimulated saliva of 25 preschool children was collected and then 1 mg of the plaque sample was collected from the buccal surfaces of the two first primary molars on the upper jaw. CPP-ACP as well as CPP- ACPF pastes were applied on the tooth surfaces in two separate steps. In steps, plaque and saliva sampling was performed after 60 minutes. The amount of calcium ions was measured by Atomic Absorption Device and the amount of phosphate and fluoride ions was measured by Ion Chromatography instrument. Data were analyzed using Repeated Measurements ANOVA at a p < 0.05 level of significance. Results: Application of both CPP-ACPF and CPP-ACP significantly increased the concentration of calcium, phosphate, and fluoride in both saliva and dental plaque. Moreover, significantly higher salivary fluoride concentration was seen after application of CPP-ACPF compared to CPP-ACP. No other significant difference was observed between these two materials. Conclusions: CPP-ACPF can be more useful than CPP-ACP in protecting the primary teeth against caries process, especially when there is poor hygiene.

  2. Effects of Different Greenbelt Structure on Air Negative Ions Concentration%不同结构绿地对空气负离子水平的影响

    Institute of Scientific and Technical Information of China (English)

    于志会; 杨波

    2011-01-01

    以吉林农业科技学院校园内具有代表性的绿地结构为研究对象,对不同结构绿地的空气负离子水平进行测定.结果表明:不同结构绿地的空气负离子水平差异极显著,其中乔灌草复层结构绿地空气负离子水平最高,空气质量最佳.城市不同结构绿地空气负离子浓度大小、空气质量优劣的排序为乔灌草结构>乔草结构>灌草结构>草坪>裸地.%Taking representative greenbelts in Jilin Agricultural Science and Technology College as the objectives,the effects of different green-belt structures on the air negative ions concentration were determined. The results indicated that air negative ions concentration differed significantly with greenbelt structure. Multilayer structure tree-shrub-grass had the highest air negative ions concentration and the best air quality,followed by tree-grass,shrub-grass,grass,and bare land.

  3. Cytological comparison of gill chloride cells and blood serum ion concentrations in kutum (Rutilus frisii kutum spawners from brackish (Caspian Sea and fresh water (Khoshkrood River environments

    Directory of Open Access Journals (Sweden)

    Ghahremanzadeh Zahra

    2014-09-01

    Full Text Available The size and number of chloride cells and serum ion concentrations in kutum, Rutillus frisii kutum Nordman, from brackish (Caspian Sea and fresh water (Khoshkrood River environments were studied to gain a better understanding of osmoregulation in this species. Twenty mature kutum specimens were collected from the Caspian Sea (Anzali coasts, 8.49 ppt salinity and 12.4°C temperature and 20 specimens from Khoshkrood River (0.18 ppt salinity and 18°C temperature. Gill samples were analyzed histologically and concentrations of Na+, Cl- , K+, and Mg2+ ions were determined in the blood serum. Concentrations of Na+, Cl- , K+, and Mg2+ ions and osmotic pressure in mature kutum from brackish water were significantly higher than in specimens from fresh water. The average size and number of chloride cells in the fish from seawater were considerably larger than those from fresh water. The mean size of chloride cells was 6.89 ± 1.16 μm in brackish water samples and 5.1 ± 0.81 μm in river samples. The average number of chloride cells in brackish and river water samples were 16.92 and 6.57, respectively. The density and size of chloride cells increased with increases in salinity

  4. Dopant-assisted negative photoionization Ion mobility spectrometry coupled with on-line cooling inlet for real-time monitoring H2S concentration in sewer gas.

    Science.gov (United States)

    Peng, Liying; Jiang, Dandan; Wang, Zhenxin; Hua, Lei; Li, Haiyang

    2016-06-01

    Malodorous hydrogen sulfide (H2S) gas often exists in the sewer system and associates with the problems of releasing the dangerous odor to the atmosphere and causing sewer pipe to be corroded. A simple method is in demand for real-time measuring H2S level in the sewer gas. In this paper, an innovated method based on dopant-assisted negative photoionization ion mobility spectrometry (DANP-IMS) with on-line semiconductor cooling inlet was put forward and successfully applied for the real-time measurement of H2S in sewer gas. The influence of moisture was effectively reduced via an on-line cooling method and a non-equilibrium dilution with drift gas. The limits of quantitation for the H2S in ≥60% relative humidity air could be obtained at ≤79.0ng L(-1) with linear ranges of 129-2064ng L(-1). The H2S concentration in a sewer manhole was successfully determined while its product ions were identified by an ion-mobility time-of-fight mass spectrometry. Finally, the correlation between sewer H2S concentration and the daily routines and habits of residents was investigated through hourly or real-time monitoring the variation of sewer H2S in manholes, indicating the power of this DANP-IMS method in assessing the H2S concentration in sewer system. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Effect of impurities on the transition concentration of helium-3 ions in (3He)-H tokamak plasmas heated with ICRH

    CERN Document Server

    Kazakov, Ye O; Van Eester, D

    2013-01-01

    Hydrogen majority plasmas will be used in the initial non-activated phase of ITER operation. Optimizing ion cyclotron resonance heating (ICRH) in such scenarios will help in achieving H-mode in these plasmas. Past JET experiments with the carbon wall revealed a significant impact of intrinsic impurities on the ICRH performance in (3He)-H plasmas. High plasma contamination with carbon impurities resulted in the appearance of a supplementary mode conversion layer and significant reduction in the transition concentration of 3He minority ions, defined as the concentration at which the change from minority heating to mode conversion regime occurs. In view of the installation of the new ITER-like wall at JET, it is important to evaluate the effect of Be and W impurities on ICRH scenarios in (3He)-H plasmas. In this paper, an approximate analytical expression for the transition concentration of 3He minority ions is derived as a function of plasma and ICRH parameters, and accounting for typical impurity species at JE...

  6. Modeling of the TL response of K{sub 2}YF{sub 5} for different concentrations of Tb{sup 3+} ions

    Energy Technology Data Exchange (ETDEWEB)

    Kadari, Ahmed, E-mail: kadariahmed_14@yahoo.fr [Department of Sciences of the Matter, Faculty of Science and Technology and Sciences of the Matter, Ibn Khaldoun University, Tiaret (Algeria); Department of Physics, Electronic Microscopy and Materials Sciences Laboratory (EMMSL), B.P.1505 El M' Naouar, Oran (Algeria); Faria, Luiz O. [Centro de Desenvolvimento da Tecnologia Nuclear, Av. Antonio Carlos 6627, C.P. 941, 30161-970, Belo Horizonte, MG (Brazil); Kadri, Dahane [Institute of General and Inorganic Chemistry, Leninskii Prospect 31, 119991 Moscow (Russian Federation); Khaidukov, Nicholas M. [Department of Physics, Electronic Microscopy and Materials Sciences Laboratory (EMMSL), B.P.1505 El M' Naouar, Oran (Algeria)

    2013-11-15

    In this work we simulated the concentration quenching (CQ) of the thermoluminescence glow peaks of K{sub 2}YF{sub 5} single crystals doped with different concentrations of Tb{sup 3+} ions, for samples irradiated with a {sup 137}Cs gamma source. A physical model used in this study, consisting of three trapping states and one kind of recombination center, has been assumed and the set of differential equations have been integrated without additional approximations. The parameters employed in the simulation have been estimated by previous glow curve deconvolution employing the general order kinetic (GOK) model. The model succeeds to predict the behavior of the areas under glow peaks as function of Tb{sup 3+} ions concentrations, confirming that the proposed model provides a good explanation of the concentration quenching phenomena. -- Highlights: • Thermoluminescence mechanisms in K{sub 2}YF{sub 5}:Tb{sup 3+} have been studied. • Modeling of the concentration quenching of TL in K{sub 2}YF{sub 5}:Tb{sup 3+}. • Thermoluminescence response after several irradiation gamma doses was investigated. • Glow curves simulated using our numerical models compared to experimental results.

  7. Deriving concentrations of oxygen and carbon in human tissues using single- and dual-energy CT for ion therapy applications

    Science.gov (United States)

    Landry, Guillaume; Parodi, Katia; Wildberger, Joachim E.; Verhaegen, Frank

    2013-08-01

    Dedicated methods of in-vivo verification of ion treatment based on the detection of secondary emitted radiation, such as positron-emission-tomography and prompt gamma detection require high accuracy in the assignment of the elemental composition. This especially concerns the content in carbon and oxygen, which are the most abundant elements of human tissue. The standard single-energy computed tomography (SECT) approach to carbon and oxygen concentration determination has been shown to introduce significant discrepancies in the carbon and oxygen content of tissues. We propose a dual-energy CT (DECT)-based approach for carbon and oxygen content assignment and investigate the accuracy gains of the method. SECT and DECT Hounsfield units (HU) were calculated using the stoichiometric calibration procedure for a comprehensive set of human tissues. Fit parameters for the stoichiometric calibration were obtained from phantom scans. Gaussian distributions with standard deviations equal to those derived from phantom scans were subsequently generated for each tissue for several values of the computed tomography dose index (CTDIvol). The assignment of %weight carbon and oxygen (%wC,%wO) was performed based on SECT and DECT. The SECT scheme employed a HU versus %wC,O approach while for DECT we explored a Zeff versus %wC,O approach and a (Zeff, ρe) space approach. The accuracy of each scheme was estimated by calculating the root mean square (RMS) error on %wC,O derived from the input Gaussian distribution of HU for each tissue and also for the noiseless case as a limiting case. The (Zeff, ρe) space approach was also compared to SECT by comparing RMS error for hydrogen and nitrogen (%wH,%wN). Systematic shifts were applied to the tissue HU distributions to assess the robustness of the method against systematic uncertainties in the stoichiometric calibration procedure. In the absence of noise the (Zeff, ρe) space approach showed more accurate %wC,O assignment (largest error of

  8. A novel ion-exclusion chromatography-mass spectrometry method to measure concentrations and cycling rates of carbohydrates and amino sugars in freshwaters.

    Science.gov (United States)

    Horňák, Karel; Pernthaler, Jakob

    2014-10-24

    The concentrations of free neutral carbohydrates and amino sugars were determined in freshwater samples of distinct matrix complexity, including meso-, eu- and dystrophic lakes and ponds, using high-performance ion-exclusion chromatography (HPIEC) coupled to mass spectrometry (MS). In contrast to other methods, our approach allowed the quantification of free neutral carbohydrates and amino sugars at low nM concentrations without derivatization, de-salting or pre-concentration. New sample preparation procedures were applied prior to injection employing syringe and hollow fiber filtration. Analytes were separated on a strong cation exchange resin under 100% aqueous conditions using 0.1% formic acid as a mobile phase. To minimize background noise in MS, analytes were detected in a multiple reaction monitoring scan mode with double ion filtering. Detection limits of carbohydrates and amino sugars ranged between 0.2 and 2nM at a signal-to-noise ratio >5. Error ranged between 1 and 12% at 0.5-500nM levels. Using a stable isotope dilution approach, both the utilization and recycling of glucose in Lake Zurich was observed. In contrast, N-acetyl-glucosamine was equally rapidly consumed but there was no visible de novo production. The simple and rapid sample preparation makes our protocol suitable for routine analyses of organic compounds in freshwater samples. Application of stable isotope tracers along with accurate measures of carbohydrate and amino sugar concentrations enables novel insights into the compound in situ dynamics.

  9. A Liquid Inorganic Electrolyte Showing an Unusually High Lithium Ion Transference Number: A Concentrated Solution of LiAlCl4 in Sulfur Dioxide

    Directory of Open Access Journals (Sweden)

    Martin Winter

    2013-08-01

    Full Text Available We report on studies of an inorganic electrolyte: LiAlCl4 in liquid sulfur dioxide. Concentrated solutions show a very high conductivity when compared with typical electrolytes for lithium ion batteries that are based on organic solvents. Our investigations include conductivity measurements and measurements of transference numbers via nuclear magnetic resonance (NMR and by a classical direct method, Hittorf’s method. For the use of Hittorf’s method, it is necessary to measure the concentration of the electrolyte in a selected cell compartment before and after electrochemical polarization very precisely. This task was finally performed by potentiometric titration after hydrolysis of the salt. The Haven ratio was determined to estimate the association behavior of this very concentrated electrolyte solution. The measured unusually high transference number of the lithium cation of the studied most concentrated solution, a molten solvate LiAlCl4 × 1.6SO2, makes this electrolyte a promising alternative for lithium ion cells with high power ability.

  10. Characteristics of Lipoprotein Peak x Eluted from a Column with the Eluent of High-magnesium Ion Concentration in Lipoprotein Analysis Using the Cation-exchange Chromatography

    Directory of Open Access Journals (Sweden)

    Yuji Hirowatari

    2005-01-01

    Full Text Available The new lipoprotein analysis method using a cation-exchange chromatography, which contains a sulfopropyl-ligand column and two magnesium ion-containing eluents was previously reported. This method can separate serum lipoproteins on the column gel with a magnesium ion concentration gradient and high-density lipoprotein (HDL, low-density lipoprotein (LDL, very-low-density lipoprotein (VLDL and an unspecified lipoprotein peak are eluted in order from the column. We have now characterized the unspecified lipoproteins, designated peak x, which is last eluted from the column with the eluent of high-magnesium ion concentration. The peak x was small size chylomicron fraction with a part of VLDL. Furthermore, the cholesterol values in the peak x were significantly correlated with remnant-like particle (RLP-cholesterol values. The peak x separated from a hyperlipidemic patient included apolipoprotein B-100, B-48, E, A-1 and Cs (C-I, C-II, C-III and its composition of free cholesterol, cholesteryl esters, triglyceride (TG and phospholipids in total lipids were 6, 15, 66 and 13%, respectively. These results suggest that a major part of the lipoprotein peak X may be composed of remnants of chylomicron and VLDL, but it remains to be elucidated.

  11. Mechanistic insights into the oxidation of substituted phenols via hydrogen atom abstraction by a cupric-superoxo complex.

    Science.gov (United States)

    Lee, Jung Yoon; Peterson, Ryan L; Ohkubo, Kei; Garcia-Bosch, Isaac; Himes, Richard A; Woertink, Julia; Moore, Cathy D; Solomon, Edward I; Fukuzumi, Shunichi; Karlin, Kenneth D

    2014-07-16

    To obtain mechanistic insights into the inherent reactivity patterns for copper(I)-O2 adducts, a new cupric-superoxo complex [(DMM-tmpa)Cu(II)(O2(•-))](+) (2) [DMM-tmpa = tris((4-methoxy-3,5-dimethylpyridin-2-yl)methyl)amine] has been synthesized and studied in phenol oxidation-oxygenation reactions. Compound 2 is characterized by UV-vis, resonance Raman, and EPR spectroscopies. Its reactions with a series of para-substituted 2,6-di-tert-butylphenols (p-X-DTBPs) afford 2,6-di-tert-butyl-1,4-benzoquinone (DTBQ) in up to 50% yields. Significant deuterium kinetic isotope effects and a positive correlation of second-order rate constants (k2) compared to rate constants for p-X-DTBPs plus cumylperoxyl radical reactions indicate a mechanism that involves rate-limiting hydrogen atom transfer (HAT). A weak correlation of (k(B)T/e) ln k2 versus E(ox) of p-X-DTBP indicates that the HAT reactions proceed via a partial transfer of charge rather than a complete transfer of charge in the electron transfer/proton transfer pathway. Product analyses, (18)O-labeling experiments, and separate reactivity employing the 2,4,6-tri-tert-butylphenoxyl radical provide further mechanistic insights. After initial HAT, a second molar equiv of 2 couples to the phenoxyl radical initially formed, giving a Cu(II)-OO-(ArO') intermediate, which proceeds in the case of p-OR-DTBP substrates via a two-electron oxidation reaction involving hydrolysis steps which liberate H2O2 and the corresponding alcohol. By contrast, four-electron oxygenation (O-O cleavage) mainly occurs for p-R-DTBP which gives (18)O-labeled DTBQ and elimination of the R group.

  12. Comparison of metal toxic impacts between aquatic and terrestrial organisms: is the free ion concentration a sufficient descriptor?

    DEFF Research Database (Denmark)

    Owsianiak, Mikolaj; Rosenbaum, Ralph K.; Larsen, Henrik Fred

    2011-01-01

    Characterization of metal toxic impacts in comparative risk assessment and life cycle impact assessment (LCIA) should take into account metal speciation and interactions with soil/water organic constituents, because these mechanisms control metal bioavailability and may influence their toxic...... to be a sufficient indicator of metal toxicity for both aquatic and terrestrial species. With the aim of deriving extrapolations to predict terrestrial toxic impacts of metals from aquatic effect data, we compared copper toxicity of aquatic organisms with that of terrestrial organisms, testing the hypothesis...... that the free metal ion is an appropriate “general”descriptor of metal toxicity. Results for 128 laboratory tests on Daphnia magna exposed to copper ions (Cu2+) in water show that variation of several orders of magnitude are observed between the toxicity tests. These variations may be a result of the inability...

  13. Hydronium-dominated ion transport in carbon-dioxide-saturated electrolytes at low salt concentrations in nanochannels

    DEFF Research Database (Denmark)

    Pennathur, Sumita; Kristensen, Jesper; Crumrine, Andrew

    2011-01-01

    conductance for low salt concentrations, we identify a minimum conductance value before saturation at a value independent of salt concentration in the dilute limit. Our model self-consistently couples chemical equilibrium models of the silica wall and the electrolyte bulk, and is parameterized by only...

  14. Hydronium-dominated ion transport in carbon-dioxide-saturated electrolytes at low salt concentrations in nanochannels

    DEFF Research Database (Denmark)

    Lund Jensen, Kristian; Kristensen, Jesper Toft; Crumrine, Andrew Michael

    2011-01-01

    the nanochannel conductance at low salt concentrations and identify a conductance minimum before saturation at a value independent of salt concentration in the dilute limit. Via the Poisson-Boltzmann equation, our model self-consistently couples chemical-equilibrium dissociation models of the silica wall...

  15. Observations for Sharp Changes of Ionospheric Ion Concentration and Electromagnetic Field Measurements at Altitude 900 km on Equatorial Latitudes by INTERKOSMOS - Bulgaria-1300 Satellite Data

    Science.gov (United States)

    Gdalevich, G. L.; Bankov, N.; Chapkanov, S.; Todorieva, L.

    Three-axis stabilization of the satellite orientation ensured success for convenient measurements both of electric and magnetic field vectors. X axis was directed along the satellite orbital velocity vector. Z axis was directed upwards, perpendicular to the Earth's surface. Fast flows of electrons and ions were measured in the directions along both +z and -z axes and also perpendicular to z axis. Ionospheric ion concentration meters registered sharp changes of the plasma density. Taking into account the totality meter set data we can conclude that the physical phenomena observed in these measurements are caused by damping both of electrostatic oscillations and plasma vortices. Also it is shown that large-scale irregularity rise and disintegration into small-scale irregular structures can be connected with magnetospheric and ionospheric sources.

  16. High concentrations of Na+ and Cl- ions in soil solution have simultaneous detrimental effects on growth of faba bean under salinity stress.

    Science.gov (United States)

    Tavakkoli, Ehsan; Rengasamy, Pichu; McDonald, Glenn K

    2010-10-01

    Despite the fact that most plants accumulate both sodium (Na(+)) and chloride (Cl(-)) ions to high concentration in their shoot tissues when grown in saline soils, most research on salt tolerance in annual plants has focused on the toxic effects of Na(+) accumulation. There have also been some recent concerns about the ability of hydroponic systems to predict the responses of plants to salinity in soil. To address these two issues, an experiment was conducted to compare the responses to Na(+) and to Cl(-) separately in comparison with the response to NaCl in a soil-based system using two varieties of faba bean (Vicia faba), that differed in salinity tolerance. The variety Nura is a salt-sensitive variety that accumulates Na(+) and Cl(-) to high concentrations while the line 1487/7 is salt tolerant which accumulates lower concentrations of Na(+) and Cl(-). Soils were prepared which were treated with Na(+) or Cl(-) by using a combination of different Na(+) salts and Cl(-) salts, respectively, or with NaCl. While this method produced Na(+)-dominant and Cl(-)-dominant soils, it unavoidably led to changes in the availability of other anions and cations, but tissue analysis of the plants did not indicate any nutritional deficiencies or toxicities other than those targeted by the salt treatments. The growth, water use, ionic composition, photosynthesis, and chlorophyll fluorescence were measured. Both high Na(+) and high Cl(-) reduced growth of faba bean but plants were more sensitive to Cl(-) than to Na(+). The reductions in growth and photosynthesis were greater under NaCl stress and the effect was mainly additive. An important difference to previous hydroponic studies was that increasing the concentrations of NaCl in the soil increased the concentration of Cl(-) more than the concentration of Na(+). The data showed that salinity caused by high concentrations of NaCl can reduce growth by the accumulation of high concentrations of both Na(+) and Cl(-) simultaneously, but

  17. Effect of Initial nitrite concentration on growth of spirulina platensis; Supirurina no zoshoku ni oyobosu ashosan ion shonodo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Ohira, Y.; Obata, E.; Kuga, Y.; Ando, K. [Muroran Inst. of Tech., Hokkaido (Japan). Dept. of Applied Chemistry; Yamada, S.

    2000-09-10

    The effect of the initial nitrite concentration on the growth of S. platensis was experimentally investigated using the medium added to the sodium nitrite of 0.0-1.6 kg{center_dot}m{sup -3}. When the initial nitrite concentration is smaller than 0.8 kg{center_dot}m{sup -3}, the growth rate is greater than that without nitrite. The specific growth rate had the maximum value and is approximately 1.3 times that of a standard medium when the range of the initial nitrite concentration is 0.3-0.4 kg{center_dot}m{sup -3}. When the initial nitrite concentration is greater than 0.8 kg{center_dot}m{sup -3}, the growth rate was smaller than that of a standard medium due to nitrite inhibition. (author)

  18. Influences of hydrological regime on heavy metal and salt ion concentrations in intertidal sediment from Chongming Dongtan, Changjiang River estuary, China

    Science.gov (United States)

    Zhao, Jiale; Gao, Xiaojiang; Yang, Jin

    2017-04-01

    The tidal flat along the Changjiang (Yangtze) River estuary has long been reclaimed for the agricultural purposes, with the prevailing hydrological conditions during such pedogenic transformations being of great importance to their successful development. In this study, samples of surface sediment from Chongming Dongtan, situated at the mouth of the Changjiang River estuary, were collected and analyzed in order to understand how hydrological management can influence the concentrations of heavy metals and salt ions in pore water, and chemical fractionation of heavy metals during the reclamation process. We performed a series of experiments that simulated three different hydrological regimes: permanent flooding (R1), alternative five-day periods of wetting and drying (R2), continuous field capacity (R3). Our results exhibited good Pearson correlations coefficients between heavy metals and salt ions in the pore water for both R1 and R2. In particular, the concentrations of salt ions in the pore water decreased in all three regimes, but showed the biggest decline in R2. With this R2 experiment, the periodic concentration patterns in the pore water varied for Fe and Mn, but not for Cr, Cu, Pb and Zn. Neither the fractionation of Ni nor the residual fractions of any metals changed significantly in any regime. In R1, the reducible fractions of heavy metals (Cr, Cu, Zn and Pb) in the sediment decreased, while the acid extractable fractions increased. In R2, the acid extractable and the reducible fractions of Cr, Cu, Zn and Pb both decreased, as did the oxidizable fraction of Cu. These data suggest that an alternating hydrological regime can reduce both salinity and the availability of heavy metals in sediments.

  19. Decreased Sensitivity to Changes in the Concentration of Metal Ions as the Basis for the Hyperactivity of DtxR(E175K)

    Energy Technology Data Exchange (ETDEWEB)

    D’Aquino, J. Alejandro; Denninger, Andrew R.; Moulin, Aaron G.; D’Aquino, Katharine E.; Ringe, Dagmar; (Harvard-Med); (Brandeis)

    2010-01-12

    The metal-ion-activated diphtheria toxin repressor (DtxR) is responsible for the regulation of virulence and other genes in Corynebacterium diphtheriae. A single point mutation in DtxR, DtxR(E175K), causes this mutant repressor to have a hyperactive phenotype. Mice infected with Mycobacterium tuberculosis transformed with plasmids carrying this mutant gene show reduced signs of the tuberculosis infection. Corynebacterial DtxR is able to complement mycobacterial IdeR and vice versa. To date, an explanation for the hyperactivity of DtxR(E175K) has remained elusive. In an attempt to address this issue, we have solved the first crystal structure of DtxR(E175K) and characterized this mutant using circular dichroism, isothermal titration calorimetry, and other biochemical techniques. The results show that although DtxR(E175K) and the wild type have similar secondary structures, DtxR(E175K) gains additional thermostability upon activation with metal ions, which may lead to this mutant requiring a lower concentration of metal ions to reach the same levels of thermostability as the wild-type protein. The E175K mutation causes binding site 1 to retain metal ion bound at all times, which can only be removed by incubation with an ion chelator. The crystal structure of DtxR(E175K) shows an empty binding site 2 without evidence of oxidation of Cys102. The association constant for this low-affinity binding site of DtxR(E175K) obtained from calorimetric titration with Ni(II) is K{sub a} = 7.6 {+-} 0.5 x 10{sup 4}, which is very similar to the reported value for the wild-type repressor, K{sub a} = 6.3 x 10{sup 4}. Both the wild type and DtxR(E175K) require the same amount of metal ion to produce a shift in the electrophoretic mobility shift assay, but unlike the wild type, DtxR(E175K) binding to its cognate DNA [tox promoter-operator (toxPO)] does not require metal-ion supplementation in the running buffer. In the timescale of these experiments, the Mn(II)-DtxR(E175K)-toxPO complex

  20. Effects of silicate ion concentration on the formation of ceramic oxide layers produced by plasma electrolytic oxidation on Al alloy

    Science.gov (United States)

    Lee, Jung-Hyung; Kim, Seong-Jong

    2017-01-01

    Plasma electrolytic oxidation (PEO) coatings were fabricated on 5083 Al alloy in KOH electrolyte solution with adding various concentrations of Na2SiO3. Changes in voltage-time response and micro-discharge evolution were analyzed, and the surface and cross-section of the resulting coating layer were further characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The results showed that discharge characteristics were evidently changed with different Na2SiO3 concentrations, particularly higher Na2SiO3 concentrations leading to lower dielectric breakdown voltages. It was found that porous surface structure became prevalent with increasing Na2SiO3 concentration. The EDS analysis confirmed the incorporation of Si element in the PEO coatings. The result of XRD analysis revealed that metastable phases such as γ- and η-alumina were produced as a result of PEO, while amorphous phases appeared with excessive Na2SiO3 concentrations (10 and 14 g/L). The coating thickness was significantly increased about 2-8 times with increasing Na2SiO3, almost depending on Na2SiO3 concentration.

  1. Surface-modified concentration-gradient Ni-rich layered oxide cathodes for high-energy lithium-ion batteries

    Science.gov (United States)

    Liao, Jin-Yun; Manthiram, Arumugam

    2015-05-01

    Concentration-gradient layered Li[Ni0.8Co0.2]0.7[Ni0.2Mn0.8]0.3O2 oxide with Ni-rich in the core and Mn-rich in the surface region has been synthesized through a condition-controlled tank reactor reaction. While the Ni-rich core facilitates high capacity, the Mn-rich surface enables good cyclability and thermal stability. The concentration-gradient sample exhibits a higher capacity of 204 mA h g-1 at C/5 rate with superior cyclability and thermal stability compared to the constant-concentration LiNi0.62Co0.14Mn0.24O2 sample, which has the same net Ni, Co, and Mn contents as those present in the concentration-gradient sample. The concentration-gradient sample was also coated with a thin layer of Al2O3 on the surface to stabilize the electrode/electrolyte interface and thereby further improve the electrochemical performance. Both the structural (gradient structure) and surface (Al2O3 coating) modifications help suppress side reactions between electrode and electrolyte and reduce the decline in voltage during cycling. The Al2O3-coated concentration-gradient sample exhibits improved long-term cyclability, rate capability, and thermal stability compared to the pristine uncoated sample.

  2. Photoluminescence and spectroscopic dependence of fluorophosphate glasses on samarium ions concentration and the induced defects by gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Marzouk, M.A., E-mail: marzouk_nrc@yahoo.com [Glass Research Department, National Research Centre, 33 El Bohouth Street (former EL Tahrir), P.O. 12622, Dokki, Giza (Egypt); Hamdy, Y.M. [Spectroscopy Department, National Research Centre, 33 El Bohouth Street (former EL Tahrir), P.O. 12622, Dokki, Giza (Egypt); ElBatal, H.A. [Glass Research Department, National Research Centre, 33 El Bohouth Street (former EL Tahrir), P.O. 12622, Dokki, Giza (Egypt); Ezz ElDin, F.M. [National Institute for Radiation Research & Technology, Nasr City, Cairo (Egypt)

    2015-10-15

    Combined optical, FTIR and photoluminescence spectra of varying Sm{sup 3+} ions in NaF–AlF{sub 3}–phosphate glasses were investigated before and after successive gamma irradiation. Optical (UV–visible) absorption of the base undoped glass reveals UV absorption which becomes broadened and strong with progressive gamma irradiation. The UV absorption of the undoped glass is related to unavoidable trace iron impurity (Fe{sup 3+}) contaminated within the chemicals used for its preparation. Upon gamma irradiation, ferrous ions present in noticeable percent within the impurity due to the reducing nature of phosphate glass interact with positive holes during the irradiation process and are transformed to ferric ions through photochemical reactions and the additionally formed Fe{sup 3+} ions impart their characteristic strong absorption in the UV region. Sm{sup 3+} containing glasses show characteristic small peaks arranged into two regions from about 350 to 900 nm and from about 1000 to 1600 nm. Such absorption peaks are more distinct with the increase of Sm{sub 2}O{sub 3} content. Most of the limited number of absorption peaks are due to transitions from the {sup 6}H{sub 5/2} level to the various excited {sup 2s+1}L{sub J} levels. The majority of the transitions in the spectra are assumed to originate from induced electric dipole (ED) interactions with the selection rule ∆J≤6. The intense band {sup 6}P{sub 3/2}←{sup 6}H{sub 5/2} around 25,000 cm{sup −1} (~400 nm) is spin-allowed. The emission spectra of Sm{sup 2+} ions were recorded under the excitation wavelength of 402 nm for all prepared Sm{sub 2}O{sub 3}-containing glasses. The photoluminescence spectra show four emission lines, of which three consist of strong bands while the last line is a weak band. The wavelengths of the four luminescence peaks occur at about 560, 596, 642 and 702 nm and they are assigned to transitions from {sup 4}G{sub 5/2} to {sup 6}H{sub 5/2}, {sup 6}H{sub 7/2}, {sup 6}H{sub 9

  3. Correlation of radiative properties of rare earth ions (Pr3+ and Nd3+) in chlorophosphate glasses—0.1 and 0.5 mol% concentrations

    Indian Academy of Sciences (India)

    Y C Ratnakaram; A Viswanadha Reddy

    2001-10-01

    Optical properties of chlorophosphate glasses of the type 50P2O5–30Na2HPO4–20RCl (R = potassium and lead) activated by 0.1 and 0.5 mol% of Pr3+ and Nd3+ have been investigated. Optical band gaps (opt) have been reported for 0.1 and 0.5 mol% concentrations of Pr3+ and Nd3+ doped potassium and lead chlorophosphate glasses. Energy levels and optical transitions of Pr3+ and Nd3+ are assigned. Spectroscopic parameters (1, 2, 3, 4f and ), spectral intensities (expt), Judd–Ofelt intensity parameters (2, 4 and 6) and radiative lifetimes (R) are correlated for 0.1 and 0.5 mol% concentrations of these two ions in potassium and lead chlorophosphate glasses

  4. Immobilization of α-amylase and amyloglucosidase onto ion-exchange resin beads and hydrolysis of natural starch at high concentration.

    Science.gov (United States)

    Gupta, Kapish; Jana, Asim Kumar; Kumar, Sandeep; Maiti, Mithu

    2013-11-01

    α-Amylase was immobilized on Dowex MAC-3 with 88 % yield and amyloglucosidase on Amberlite IRA-400 ion-exchange resin beads with 54 % yield by adsorption process. Immobilized enzymes were characterized to measure the kinetic parameters and optimal operational parameters. Optimum substrate concentration and temperature were higher for immobilized enzymes. The thermal stability of the enzymes enhanced after the immobilization. Immobilized enzymes were used in the hydrolysis of the natural starch at high concentration (35 % w/v). The time required for liquefaction of starch to 10 dextrose equivalent (DE) and saccharification of liquefied starch to 96 DE increased. Immobilized enzymes showed the potential for use in starch hydrolysis as done in industry.

  5. Concentration of zinc ions in perchlorate medium by a menbrane-gel using an acid extractant (DEHPA

    Directory of Open Access Journals (Sweden)

    Belhadji L.

    2013-07-01

    Full Text Available Recent decades, it is an awareness of the importance of ecological balance in the environment, balances threatened by industrial pollution. A new spirit presides we seek to minimize pollution of receiving waters. The present work is to study the liquid-gel-extraction of zinc ions in perchlorate medium by an acid extractant: the di (ethyl-2 hexyl phosphorique acid, or DEHPA. Two types of polymers were used as supports of solvent extraction: a polybutadiene rubber cross-linked respectively with 0.1% dicumyl peroxide and 0.4% dicumyl peroxide, vulcanized at 160°C, one is most cross-linked than the other. The liquid-gel extraction is based on the principles of the liquid-liquid extraction.

  6. Effect of Deposition Time on the Photoelectrochemical Properties of Cupric Oxide Thin Films Synthesized via Electrodeposition Method

    Directory of Open Access Journals (Sweden)

    Yaw Chong Siang

    2016-01-01

    Full Text Available The main aim of this study was to investigate the effect of deposition time on the physicochemical and photoelectrochemical properties of cupric oxide (CuO thin films synthesized via electrodeposition method. Firstly, the electrodeposition of amorphous CuO films on fluorine-doped tin oxide (FTO working electrodes with varying deposition time between 5 and 30 min was carried out, followed by annealing treatment at 500 °C. Resultant nanocrystalline CuO thin films were characterised using field emission-scanning electron microscopy (FE-SEM, photocurrent density, and photoluminescence measurements. Through FE-SEM analysis, it was observed that the surface of thin films was composed of irregular-sized CuO nanocrystals. A smaller CuO nanocrystals size will lead to a higher photoactivity due to the increase in overall catalytic surface area. In addition, the smaller CuO nanocrystals size will prolongs the electron-hole recombination rate due to the increase in copious amount of surface defects. From this study, it was revealed that the relationship between deposition time and CuO film thickness was non-linear. This could be due to the detachment of CuO thin films from the FTO surface at an increasing amount of CuO mass being deposited. It was observed that the amount of light absorbed by CuO thin films increased with film thickness until a certain extent whereby, any further increase in the film thickness will result in a reduction of light photon penetration. Therefore, the CuO nanocrystals size and film thickness have to be compromised in order to yield a higher catalytic surface area and a lower rate of surface charge recombination. Finally, it was found that the deposition time of 15 min resulted in an average CuO nanocrystals size of 73.7 nm, optimum film thickness of 0.73 μm, and corresponding photocurrent density of 0.23 mA/cm2 at the potential bias of - 0.3 V (versus Ag/AgCl. The PL spectra for the deposition time of 15 min has the lowest

  7. Particle size distributions, PM2.5 concentrations and water- soluble inorganic ions in different public indoor environments: a case study in Jinan, China

    Institute of Scientific and Technical Information of China (English)

    Can DONG; Lingxiao YANG; Chao YAN; Qi YUAN; Yangchun YU; Wenxing WANG

    2013-01-01

    In this study, we collected particles with aerodynamic diameter≤2.5μm (PM2.5) from three different public indoor places (a supermarket, a commercial office, and a university dining hall) in Jinan, a medium-sized city located in northern China. Water- soluble inorganic ions of PM2.5 and particle size distributions were also measured. Both indoor and outdoor PM2.5 levels (102.3-143.8 μg·m- 3 and 160.2-301.3 μg·m-3, respectively) were substantially higher than the value recommended by the World Health Organization (25 I.μg·m-3), and outdoor sources were found to be the major contributors to indoor pollutants. Diurnal particle number size distributions were different, while the maximum volume concentrations all appeared to be approximately 300nm in the three indoor locations. Concentrations of indoor and outdoor PM2.5 were shown to exhibit the same variation trends for the supermarket and dining hall. For the office, PM2.5 concentrations during nighttime were observed to decrease sharply. Among others, SO42-, NH4+ and NO3- were found to be the dominant water-soluble ions of both indoor and outdoor particles. Concentrations of NO3- in the supermarket and office during the daytime were observed to decrease sharply, which might be attributed to the fact that the indoor temperature was much higher than the outdoor temperature. In addition, domestic activities such as cleaning, water usage, cooking, and smoking also played roles in degraded indoor air quality. However, the results obtained here might be negatively impacted by the small number of samples and short sampling durations.

  8. Peroxidase-like activity of water-soluble cupric oxide nanoparticles and its analytical application for detection of hydrogen peroxide and glucose.

    Science.gov (United States)

    Chen, Wei; Chen, Juan; Feng, Ye-Bin; Hong, Lei; Chen, Qi-Ying; Wu, Ling-Feng; Lin, Xin-Hua; Xia, Xing-Hua

    2012-04-07

    Water-soluble cupric oxide nanoparticles are fabricated via a quick-precipitation method and used as peroxidase mimetics for ultrasensitive detection of hydrogen peroxide and glucose. The water-soluble CuO nanoparticles show much higher catalytic activity than that of commercial CuO nanoparticles due to their higher affinity to hydrogen peroxide. In addition, the as-prepared CuO nanoparticles are stable over a wide range of pH and temperature. This excellent stability in the form of aqueous colloidal suspensions makes the application of the water-soluble CuO nanoparticles easier in aqueous systems. A colorimetric assay for hydrogen peroxide and glucose has been established based on the catalytic oxidation of phenol coupled with 4-amino-atipyrine by the action of hydrogen peroxide. This analytical platform not only confirms the intrinsic peroxidase-like activity of the water-soluble cupric oxide nanoparticles, but also shows its great potential applications in environmental chemistry, biotechnology and medicine.

  9. A new high transmission inlet for the Caltech nano-RDMA for size distribution measurements of sub-3 nm ions at ambient concentrations

    Directory of Open Access Journals (Sweden)

    A. Franchin

    2015-06-01

    from achieving a good transmission efficiency for the smallest nanoparticles. We developed a new high transmission inlet for the Caltech nano-radial DMA (nRDMA that increases the transmission efficiency to 12 % for ions as small as 1.3 nm in mobility equivalent diameter (corresponding to 1.2 × 10−4 m2 V−1 s−1 in electrical mobility. We successfully deployed the nRDMA, equipped with the new inlet, in chamber measurements, using a Particle Size Magnifier (PSM and a booster Condensation Particle Counter (CPC as a counter. With this setup, we were able to measure size distributions of ions between 1.3 and 6 nm, corresponding to a mobility range from 1.2 × 10−4 to 5.8 × 10−6 m2 V−1 s−1. The system was modeled, tested in the laboratory and used to measure negative ions at ambient concentrations in the CLOUD 7 measurement campaign at CERN. We achieved a higher size resolution than techniques currently used in field measurements, and maintained a good transmission efficiency at moderate inlet and sheath air flows (2.5 and 30 LPM, respectively. In this paper, by measuring size distribution at high size resolution down to 1.3 nm, we extend the limit of the current technology. The current setup is limited to ion measurements. However, we envision that future research focused on the charging mechanisms could extend the technique to measure neutral aerosol particles as well, so that it will be possible to measure size distributions of ambient aerosols from 1 nm to 1 μm.

  10. A new high transmission inlet for the Caltech nano-RDMA for size distribution measurements of sub-3 nm ions at ambient concentrations

    Science.gov (United States)

    Franchin, A.; Downard, A. J.; Kangasluoma, J.; Nieminen, T.; Lehtipalo, K.; Steiner, G.; Manninen, H. E.; Petäjä, T.; Flagan, R. C.; Kulmala, M.

    2015-06-01

    Reliable and reproducible measurements of atmospheric aerosol particle number size distributions below 10 nm require optimized classification instruments with high particle transmission efficiency. Almost all DMAs have an unfavorable potential gradient at the outlet (e.g. long column, Vienna type) or at the inlet (nano-radial DMA). This feature prevents them from achieving a good transmission efficiency for the smallest nanoparticles. We developed a new high transmission inlet for the Caltech nano-radial DMA (nRDMA) that increases the transmission efficiency to 12 % for ions as small as 1.3 nm in mobility equivalent diameter (corresponding to 1.2 × 10-4 m2 V-1 s-1 in electrical mobility). We successfully deployed the nRDMA, equipped with the new inlet, in chamber measurements, using a Particle Size Magnifier (PSM) and a booster Condensation Particle Counter (CPC) as a counter. With this setup, we were able to measure size distributions of ions between 1.3 and 6 nm, corresponding to a mobility range from 1.2 × 10-4 to 5.8 × 10-6 m2 V-1 s-1. The system was modeled, tested in the laboratory and used to measure negative ions at ambient concentrations in the CLOUD 7 measurement campaign at CERN. We achieved a higher size resolution than techniques currently used in field measurements, and maintained a good transmission efficiency at moderate inlet and sheath air flows (2.5 and 30 LPM, respectively). In this paper, by measuring size distribution at high size resolution down to 1.3 nm, we extend the limit of the current technology. The current setup is limited to ion measurements. However, we envision that future research focused on the charging mechanisms could extend the technique to measure neutral aerosol particles as well, so that it will be possible to measure size distributions of ambient aerosols from 1 nm to 1 μm.

  11. Changes in Sodium, Calcium, and Magnesium Ion Concentrations That Inhibit Geobacillus Biofilms Have No Effect on Anoxybacillus flavithermus Biofilms.

    Science.gov (United States)

    Somerton, B; Lindsay, D; Palmer, J; Brooks, J; Flint, S

    2015-08-01

    This study investigated the effects of varied sodium, calcium, and magnesium concentrations in specialty milk formulations on biofilm formation by Geobacillus spp. and Anoxybacillus flavithermus. The numbers of attached viable cells (log CFU per square centimeter) after 6 to 18 h of biofilm formation by three dairy-derived strains of Geobacillus and three dairy-derived strains of A. flavithermus were compared in two commercial milk formulations. Milk formulation B had relatively high sodium and low calcium and magnesium concentrations compared with those of milk formulation A, but the two formulations had comparable fat, protein, and lactose concentrations. Biofilm formation by the three Geobacillus isolates was up to 4 log CFU cm(-2) lower in milk formulation B than in milk formulation A after 6 to 18 h, and the difference was often significant (P ≤ 0.05). However, no significant differences (P ≤ 0.05) were found when biofilm formations by the three A. flavithermus isolates were compared in milk formulations A and B. Supplementation of milk formulation A with 100 mM NaCl significantly decreased (P ≤ 0.05) Geobacillus biofilm formation after 6 to 10 h. Furthermore, supplementation of milk formulation B with 2 mM CaCl2 or 2 mM MgCl2 significantly increased (P ≤ 0.05) Geobacillus biofilm formation after 10 to 18 h. It was concluded that relatively high free Na(+) and low free Ca(2+) and Mg(2+) concentrations in milk formulations are collectively required to inhibit biofilm formation by Geobacillus spp., whereas biofilm formation by A. flavithermus is not impacted by typical cation concentration differences of milk formulations.

  12. Determination of negative oxygen ions concentration in Lanshan County%蓝山县空气负氧离子浓度测定

    Institute of Scientific and Technical Information of China (English)

    扶巧梅; 李沅山; 何斌; 舒巍; 刘彩红

    2015-01-01

    选择蓝山县有代表性的地段作为取样点,采用 DLY —3F 型森林大气测量仪测定样点的空气负离子浓度。测定结果表明,蓝山空气质量超 CI 评价标准,水域周边空气负离子含量最高,整体空气清洁,利于休闲和生态旅游开发。%Selected the representative area of Lanshan County as sample points,,and determined negative oxygen ions concentration of sample point used by the DLY — 3F forest atmosphere measuring instrument.The results show that air quality of Lanshan County was exceed the standard of CI,and the negative oxygen ions concentration of water area was the highest.The air of Lanshan county was cleanness,and it could benefit leisure and eco-tourism development.

  13. The hydrophilicity vs. ion interaction selectivity plot revisited: The effect of mobile phase pH and buffer concentration on hydrophilic interaction liquid chromatography selectivity behavior.

    Science.gov (United States)

    Iverson, Chad D; Gu, Xinyun; Lucy, Charles A

    2016-08-05

    This work systematically investigates the selectivity changes on many HILIC phases from w(w)pH 3.7-6.8, at 5 and 25mM buffer concentrations. Hydrophilicity (kcytosine/kuracil) vs. ion interaction (kBTMA/kuracil) selectivity plots developed by Ibrahim et al. (J. Chromatogr. A 1260 (2012) 126-131) are used to investigate the effect of mobile phase changes on the selectivity of 18 HILIC columns from various classes. "Selectivity change plots" focus on the change in hydrophilicity and ion interaction that the columns exhibit upon changing mobile phase conditions. In general, the selectivity behavior of most HILIC columns is dominated by silanol activity. Minimal changes in selectivity are observed upon changing pH between w(w)pH 5 and 6.8. However, a reduction in ionic interaction is observed when the buffer concentration is increased at w(w)pH≥5.0 due to ionic shielding. Reduction of the w(w)pH to<5.0 results in decreasing cation exchange activity due to silanol protonation. Under all eluent conditions, the majority of phases show little change in their hydrophilicity.

  14. Effect of Cl-, SO4(2-), and fulvate anions on Cd2+ free ion concentrations in simulated rhizosphere soil solutions.

    Science.gov (United States)

    Chang Chien, Shui-Wen; Liao, Jui-Hung; Wang, Min-Chao; Mannepalli, Madhava Rao

    2009-12-30

    The binding between heavy metals and corresponding ligands affects their chemical behavior and toxicity in soil environments. The mechanisms of competitive complexation and/or chelation between Cd(2+) free cations and preferential concentrations of Cl(-), SO(4)(2-), and fulvate anions were investigated in simulated soil solutions at pH 4.00, 5.00 and 6.00. The Cd(2+) concentrations were calculated by a proposed equation, simulated by MINTEQ software, and directly determined by ion chromatography (IC). When Cl(-)/Cd or Cl(-)/Cd with SO(4)(2-)/Cd molar ratios of 3.18 and 4.05, the differences among Cd(2+) concentrations calculated by equation, simulated by MINTEQ software, and directly determined by IC were not significant, but their differences were pH independent for considering Cl(-)/Cd molar ratio and pH dependent for Cl(-)/Cd and SO(4)(2-)/Cd molar ratios. When Cl(-)/Cd, SO(4)(2-)/Cd, and additional FA/Cd molar ratios of 3.18 and 4.05, the Cd(2+) concentrations calculated by equation were significantly larger than those simulated by MINTEQ and determined by IC because in simulation and determination of Cd(2+) concentrations by IC, the complexation of Cd(2+) with ligands to form CdCl(+), CdSO(4), FACd(+) and FA(2)Cd had been considered, whereas in calculation this complexation aspect was ignored. Though IC can be used to determine Cd(2+) concentration in rhizosphere soil solutions ion chromatographic peak of Cd(2+) in 0.1M HCl saturation extract of slightly acidic soil and in deionized distilled water saturation extract of acidic soils still may be shielded by the vicinal chromatographic peaks of Mg(2+) and Mn(2+), respectively. The Cd(2+) concentrations in rhizosphere soil solutions of acidic or slightly acidic soils calculated by equation and/or simulated by Model may thus be used as potential alternatives for those determined by IC.

  15. Corrosion investigations on zircaloy-4 and titanium dissolver materials for MOX fuel dissolution in concentrated nitric acid containing fluoride ions

    Science.gov (United States)

    Jayaraj, J.; Krishnaveni, P.; Krishna, D. Nanda Gopala; Mallika, C.; Mudali, U. Kamachi

    2016-05-01

    Aqueous reprocessing of plutonium-rich mixed oxide fuels require fluoride as a dissolution catalyst in boiling nitric acid for an effective dissolution of the spent fuel. High corrosion rates were obtained for the candidate dissolver materials zircaloy-4 (Zr-4) and commercial pure titanium (CP-Ti grade 2) in boiling 11.5 M HNO3 + 0.05 M NaF. Complexing the fluoride ions either with Al(NO3)3 or ZrO(NO3)2 aided in decreasing the corrosion rates of Zr-4 and CP-Ti. From the obtained corrosion rates it is concluded that CP-Ti is a better dissolver material than Zr-4 for extended service life in boiling 11.5 M HNO3 + 0.05 M NaF, when complexed with 0.15 M ZrO(NO3)2. XPS analysis confirmed the presence of TiO2 and absence of fluoride on the surface of CP-Ti samples, indicating that effective complexation had occurred in solution leading to passivation of the metal and imparting high corrosion resistance.

  16. Radium-228 determination of natural waters via concentration on manganese dioxide and separation using Diphonix ion exchange resin.

    Science.gov (United States)

    Nour, S; El-Sharkawy, A; Burnett, W C; Horwitz, E P

    2004-12-01

    The objective of this work was to establish a new procedure for 228Ra determination of natural waters via preconcentration of radium on MnO2 and separation of its daughter, 228Ac, using Diphonix ion exchange resin. Following removal of potential interferences via passage through an initial Diphonix Resin column, the first daughter of 228Ra, 228Ac, is isolated by chromatographic separation via a second Diphonix column. A holding time of > 30 h for 228Ac ingrowth in between the two column separations ensures secular equilibrium. Barium-133 is used as a yield tracer. Actinium-228 is eluted from the second Diphonix Resin with 5 ml 1M 1-Hydroxyethane-1,1-diphosphonic acid (HEDPA) and quantified by addition of scintillation cocktail and LSC counting. Radium (and 133Ba) from the load and rinse solutions from the 2nd Diphonix column may be prepared for alpha spectrometry (for determination of 223Ra, 224Ra, and 226Ra) by BaSO4 microprecipitation and filtration. Decontamination tests indicate that U, Th, and Ra series nuclides do not interfere with these measurements, although high contents of 90Sr (90Y) require additional treatment for accurate measurement of 228Ra. Addition of stable Sr as a "hold back" carrier during the initial MnO2 preconcentration step was shown to remove most 90Sr interference.

  17. A combined process of activated carbon adsorption, ion exchange resin treatment and membrane concentration for recovery of dissolved organics in pre-hydrolysis liquor of the kraft-based dissolving pulp production process.

    Science.gov (United States)

    Shen, Jing; Kaur, Ishneet; Baktash, Mir Mojtaba; He, Zhibin; Ni, Yonghao

    2013-01-01

    To recover dissolved organics in pre-hydrolysis liquor (PHL) of the kraft-based dissolving pulp production process, a new combined process concept of sequential steps of activated carbon adsorption, ion exchange resin treatment, and membrane concentration, was proposed. The removal of lignin in the PHL was achieved in the activated carbon adsorption step, which also facilitates the subsequent operations, such as the membrane filtration and ion exchange resin treatment. The ion exchange resin treatment resulted in the removal/concentration of acetic acid, which opens the door for acetic acid recovery. The membrane filtration is to recover/concentrate the dissolved sugars. The combined process resulted in the production of PHL-based concentrate with relatively high concentration of hemicellulosic sugars, i.e., 22.13%.

  18. A new high-transmission inlet for the Caltech nano-RDMA for size distribution measurements of sub-3 nm ions at ambient concentrations

    Science.gov (United States)

    Franchin, Alessandro; Downard, Andy; Kangasluoma, Juha; Nieminen, Tuomo; Lehtipalo, Katrianne; Steiner, Gerhard; Manninen, Hanna E.; Petäjä, Tuukka; Flagan, Richard C.; Kulmala, Markku

    2016-06-01

    Reliable and reproducible measurements of atmospheric aerosol particle number size distributions below 10 nm require optimized classification instruments with high particle transmission efficiency. Almost all differential mobility analyzers (DMAs) have an unfavorable potential gradient at the outlet (e.g., long column, Vienna type) or at the inlet (nano-radial DMA), preventing them from achieving a good transmission efficiency for the smallest nanoparticles. We developed a new high-transmission inlet for the Caltech nano-radial DMA (nRDMA) that increases the transmission efficiency to 12 % for ions as small as 1.3 nm in Millikan-Fuchs mobility equivalent diameter, Dp (corresponding to 1.2 × 10-4 m2 V-1 s-1 in electrical mobility). We successfully deployed the nRDMA, equipped with the new inlet, in chamber measurements, using a particle size magnifier (PSM) and as a booster a condensation particle counter (CPC). With this setup, we were able to measure size distributions of ions within a mobility range from 1.2 × 10-4 to 5.8 × 10-6 m2 V-1 s-1. The system was modeled, tested in the laboratory and used to measure negative ions at ambient concentrations in the CLOUD (Cosmics Leaving Outdoor Droplets) 7 measurement campaign at CERN. We achieved a higher size resolution (R = 5.5 at Dp = 1.47 nm) than techniques currently used in field measurements (e.g., Neutral cluster and Air Ion Spectrometer (NAIS), which has a R ˜ 2 at largest sizes, and R ˜ 1.8 at Dp = 1.5 nm) and maintained a good total transmission efficiency (6.3 % at Dp = 1.5 nm) at moderate inlet and sheath airflows (2.5 and 30 L min-1, respectively). In this paper, by measuring size distributions at high size resolution down to 1.3 nm, we extend the limit of the current technology. The current setup is limited to ion measurements. However, we envision that future research focused on the charging mechanisms could extend the technique to measure neutral aerosol particles as well, so that it will be possible

  19. Corrosion investigations on zircaloy-4 and titanium dissolver materials for MOX fuel dissolution in concentrated nitric acid containing fluoride ions

    Energy Technology Data Exchange (ETDEWEB)

    Jayaraj, J.; Krishnaveni, P.; Krishna, D. Nanda Gopala; Mallika, C.; Mudali, U. Kamachi, E-mail: kamachi@igcar.gov.in

    2016-05-15

    Aqueous reprocessing of plutonium-rich mixed oxide fuels require fluoride as a dissolution catalyst in boiling nitric acid for an effective dissolution of the spent fuel. High corrosion rates were obtained for the candidate dissolver materials zircaloy-4 (Zr-4) and commercial pure titanium (CP-Ti grade 2) in boiling 11.5 M HNO{sub 3} + 0.05 M NaF. Complexing the fluoride ions either with Al(NO{sub 3}){sub 3} or ZrO(NO{sub 3}){sub 2} aided in decreasing the corrosion rates of Zr-4 and CP-Ti. From the obtained corrosion rates it is concluded that CP-Ti is a better dissolver material than Zr-4 for extended service life in boiling 11.5 M HNO{sub 3} + 0.05 M NaF, when complexed with 0.15 M ZrO(NO{sub 3}){sub 2}. XPS analysis confirmed the presence of TiO{sub 2} and absence of fluoride on the surface of CP-Ti samples, indicating that effective complexation had occurred in solution leading to passivation of the metal and imparting high corrosion resistance. - Highlights: • Zr-4 and CP-Ti exhibited high corrosion rate in boiling fluorinated nitric acid. • Corrosion rate decreased in fluorinated nitric acid containing ZrO(NO{sub 3}){sub 2} and Al(NO{sub 3}){sub 3}. • High inhibiting efficiency is exhibited by 0.15 M ZrO(NO{sub 3}){sub 2} when compared to Al(NO{sub 3}){sub 3}. • Corrosion rates of CP-Ti were negligible in complexed fluorinated nitric acid. • XPS analysis on CP-Ti confirmed the presence of TiO{sub 2} and absence of fluoride.

  20. Steric stabilization of nanoparticles with grafted low molecular weight ligands in highly concentrated brines including divalent ions.

    Science.gov (United States)

    Worthen, Andrew J; Tran, Vu; Cornell, Kevin A; Truskett, Thomas M; Johnston, Keith P

    2016-02-21

    Whereas numerous studies of stabilization of nanoparticles (NPs) in electrolytes have examined biological fluids, the interest has grown recently in media with much higher ionic strengths including seawater and brines relevant to environmental science and subsurface oil and gas reservoirs. Given that electrostatic repulsion is limited at extremely high ionic strengths due to charge screening, we have identified ligands that are well solvated in concentrated brine containing divalent cations and thus provide steric stabilization of silica nanoparticles. Specifically, the hydrodynamic diameter of silica nanoparticles with grafted low molecular weight ligands, a diol ether, [3-(2,3-dihydroxypropoxy)propyl]-trimethoxysilane, and a zwitterionic sulfobetaine, 3-([dimethyl(3-trimethoxysilyl)propyl]ammonio)propane-1-sulfonate, is shown with dynamic light scattering to remain essentially constant, indicating lack of aggregation, at room temperature and up to 80 °C for over 30 days. An extended DLVO model signifies that steric stabilization is strongly dominant against van der Waals attraction for ∼10 nm particles given that these ligands are well solvated even in highly concentrated brine. In contrast, polyethylene glycol oligomers do not provide steric stabilization at elevated temperatures, even at conditions where the ligands are soluble, indicating complicating factors including bridging of the ether oxygens by divalent cations.

  1. Relation between force and calcium ion concentration in different fibre types of the iliofibularis muscle of Xenopus laevis.

    Science.gov (United States)

    Stienen, G J; van der Laarse, W J; Diegenbach, P C; Elzinga, G

    1987-01-01

    Calcium activated isometric force was measured in segments of single muscle fibres of the iliofibularis muscle of Xenopus laevis skinned by freeze-drying. A subdivision in five different fibre types was made, based on the location of the fibres inside the muscle, fibre diameter and a quantitative histochemical assay for succinate dehydrogenase activity. The Ca2+ sensitivity was characterized by fitting a Hill curve to the force levels reached at different Ca2+ concentrations. The parameter n of this equation indicates the steepness and pK the midpoint of this force-pCa relation. A considerable variability in the Ca2+ sensitivity characteristics was found between different fibres. The parameter n varied between 1.1 and 4.2 while pK varied between 5.5 and 6.6. The distribution of the data indicates the presence of three groups with different Ca2+ sensitivity; a group of fibres with low Ca2+ sensitivity but with considerable variation of the steepness of the Ca2+ sensitivity curves (type 1 fibres), an intermediate group (type 2, 3 and 4 fibres) with also considerable variation in steepness of the Ca2+ sensitivity curves, in which the lowest values for n are found in type 3 and 4 fibres and a group with high Ca2+ sensitivity and low n containing at least one tonic (type 5) fibre. At sub-saturating Ca2+ concentrations occasionally a transient decrease of the rate of force development was found which resembled the force oscillation reported for some mammalian muscle fibres.

  2. Release of ATP from marginal cells in the cochlea of neonatal rats can be induced by changes in extracellular and intracellular ion concentrations.

    Directory of Open Access Journals (Sweden)

    Yating Peng

    Full Text Available BACKGROUND: Adenosine triphosphate (ATP plays an important role in the cochlea. However, the source of ATP and the mechanism by which it is released remain unclear. This study investigates the presence and release mechanism of ATP in vitro cultured marginal cells isolated from the stria vascularis of the cochlea in neonatal rats. METHODS: Sprague-Dawley rats aged 1-3 days old were used for isolation, in vitro culture, and purification of marginal cells. Cultured marginal cells were verified by flow cytometry. Vesicles containing ATP in these cells were identified by fluorescence staining. The bioluminescence assay was used for determination of ATP concentration in the extracellular fluid released by marginal cells. Assays for ATP concentration were performed when the ATP metabolism of cells was influenced, and ionic concentrations in intracellular and extracellular fluid were found to change. RESULTS: Evaluation of cultured marginal cells with flow cytometry revealed the percentage of fluorescently-labeled cells as 92.9% and 81.9%, for cytokeratin and vimentin, respectively. Quinacrine staining under fluorescence microscopy revealed numerous green, star-like spots in the cytoplasm of these cells. The release of ATP from marginal cells was influenced by changes in the concentration of intracellular and extracellular ions, namely extracellular K(+ and intra- and extracellular Ca(2+. Furthermore, changes in the concentration of intracellular Ca(2+ induced by the inhibition of the phospholipase signaling pathway also influence the release of ATP from marginal cells. CONCLUSION: We confirmed the presence and release of ATP from marginal cells of the stria vascularis. This is the first study to demonstrate that the release of ATP from such cells is associated with the state of the calcium pump, K(+ channel, and activity of enzymes related to the phosphoinositide signaling pathway, such as adenylate cyclase, phospholipase C, and phospholipase A(2.

  3. Effect of gelatin concentration on the synthetize of the LiFePO{sub 4}/C composite for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Naiqiang; Gao, Mengyao; Li, Zhongbo; Li, Chengming [State Key Laboratory of Chemical Resource Engineering, The Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, 15 BeiSanhuan East Road, Beijing 100029 (China); Wang, Weikun; Zhang, Hao; Yu, Zhongbao [Research Institute of Chemical Defense, 35 Huayuan North Road, Beijing 100191 (China); Huang, Yaqin, E-mail: huangyaqin9@sina.com [State Key Laboratory of Chemical Resource Engineering, The Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, 15 BeiSanhuan East Road, Beijing 100029 (China)

    2014-06-25

    Highlights: • Gelatin has been used to regulate and control the synthesis of LiFePO{sub 4}/C composite. • Influence of gelatin concentration on crystal structure of LiFePO{sub 4} has been observed. • The shape transformation from sphere-like to rod-like structure of LiFePO{sub 4}/C has been revealed. - Abstract: Gelatin is an effective additive of the cathode, which would regulate and control the crystal and morphology of LiFePO{sub 4}/C composite for enhancing electrochemical performance of the lithium ion battery. The influence of gelatin concentration on the preparation of LiFePO{sub 4}/C composite has been investigated. It is observed by SEM that the shape transformed from sphere-like to rod-like structure with the gelatin concentration increased from 1 wt.% to 5 wt.%; meanwhile, the lattice parameters first showed increase trend and then decrease. The LiFePO{sub 4}/C composite obtained with the 2 wt.% gelatin solution shows the lowest polarization and excellent rate performance.

  4. Low energy/cost desalination: low dose and low mean ion resident time in concentrate stream of electro-dialysis reversal.

    Science.gov (United States)

    Myint, M T; Ghassem, A; Nirmalakhandan, N

    2011-01-01

    Species, dose, and mean ion resident time (MIRT(c)) in the concentrate of electro-dialysis reversal (EDR) desalination are analysed. In the classical EDR, dimensions, flow, and velocity of dilute and concentrate are equal; Langelier saturation index (LSI) and CaSO4 saturation are used to control the scaling and fouling processes in concentrate, as such LSI water recovery rate (R) without any anti-scalant and without acid; this new EDR operated with LSI at 2.29 and CaSO4 saturation level 358.9% at lower dose and lower MIRT(c). Dose and MIRT(c) are proposed to address the controlling process. Monographs for the acids and SHMP requirements, and for the desalting cost including desalting power, membrane surface area, and chemicals usage, are developed. By lowering R and polar reversal interval, EDR can be operated at MIRT(c) < 130 min; at MIRT(c0 < 130 min, desalting cost/ energy can be minimised by eliminating chemicals requirement.

  5. Long-term observations of cluster ion concentration, sources and sinks in clear sky conditions at the high-altitude site of the Puy de Dôme, France

    Science.gov (United States)

    Rose, C.; Boulon, J.; Hervo, M.; Holmgren, H.; Asmi, E.; Ramonet, M.; Laj, P.; Sellegri, K.

    2013-11-01

    Cluster particles (0.8-1.9 nm) are key entities involved in nucleation and new particle formation processes in the atmosphere. Cluster ions were characterized in clear sky conditions at the Puy de Dôme station (1465 m a.s.l.). The studied data set spread over five years (February 2007-February 2012), which provided a unique chance to observe seasonal variations of cluster ion properties at high altitude. Statistical values of the cluster ion concentrations and diameters are reported for both positive and negative polarities. Cluster ions were found to be ubiquitous at the Puy de Dôme and displayed an annual variation with lower concentrations in spring. Positive cluster ions were less numerous than negative, but were larger in diameter. Negative cluster ion properties were not sensitive to the occurrence of a new particle formation (NPF) event, while positive cluster ions appeared to be significantly more numerous and larger on event days. The parameters of the balance equation for the positive cluster concentration are reported separately for the different seasons and for the NPF event days and non-event days. The steady-state assumption suggests that the ionization rate is balanced with two sinks: the ion recombination and the attachment onto background aerosol particles, referred to as "aerosol ion sink". The aerosol ion sink was predominant compared to the recombination sink. The positive ionization rates derived from the balance equation (Qcalc) were well correlated with the ionization rates obtained from radon measurement (Qmeas). When ignoring the gamma radiation contribution to the ion production, Qcalc is on average higher than Qmeas during the warm season. In contrast, when a seasonal gamma contribution is taken into account, Qmeas always exceeds Qcalc. We found that neither the aerosol ion sink nor the ionization rate (calculated or measured, with or without the gamma contribution) were significantly different on event days compared to non-event days

  6. Cytotoxicity of glass ionomer cement on human exfoliated deciduous teeth stem cells correlates with released fluoride, strontium and aluminum ion concentrations

    Directory of Open Access Journals (Sweden)

    Kanjevac Tatjana V.

    2015-01-01

    Full Text Available Stem cells from human exfoliated deciduous teeth (SHED can be used as a cell-based therapy in regenerative medicine and in immunomodulation. Pulp from human deciduous teeth can be stored as a source of SHED. Glass ionomer cements (GICs are commonly used in restorative dentistry and in cavity lining. GICs have lower biocompatibility and are cytotoxic for dental pulp cells. In this study, seven commonly used GICs were tested for their cytotoxic effects on SHED, for their potential to arrest mitosis in cells and induce chromosome aberrations, and were compared with the effects of composite. Fuji II, Fuji VIII, Fuji IX, Fuji plus and Vitrebond had significantly higher cytotoxic effects on SHED than composite. Only SHEDs that have been treated with Fuji I, Fuji IX, Fuji plus and composite recovered the potential for proliferation, but no chromosome aberrations were found after treatment with GICs. The cytotoxic effects of GICs on SHEDs were in strong correlation with combined concentrations of released fluoride, aluminum and strontium ions. Fuji I exhibited the lowest activity towards SHEDs; it did not interrupt mitosis and did not induce chromosome aberrations, and was accompanied by the lowest levels of released F, Al and Sr ions. Projekat Ministarstva nauke Republike Srbije, br. ON175069, br. ON175071 i br. ON175103

  7. Estimating bioconcentration factors, lethal concentrations and critical body residues of metals in the mollusks Perna viridis and Mytilus edulis using ion characteristics.

    Science.gov (United States)

    van Kolck, Maurits; Huijbregts, Mark A J; Veltman, Karin; Jan Hendriks, A

    2008-02-01

    Quantitative structure-activity relationships (QSARs) for metal bioconcentration factors (BCF) and median acute lethal water concentrations (LC50) were developed for two species of mollusks, Perna viridis and Mytilus edulis. These endpoints were related to four metal ion characteristics, the covalent index (chi(2)(m)r) (r represents the ion radius in A), the softness index (sigma(p)), the hydrolysis constant (K(OH)) and the ionic index (Z(2)/r). The BCF and LC50 were significantly correlated to chi(m)(2)r. The coefficients of determination r(2) for the relationships with other metal descriptors were much lower. Critical body residue (CBR) QSARs were derived by multiplying the chi(2)(m)r-based BCF and LC50 regressions. The CBRs were independent of the covalent index chi(2)(m)r, as BCF and LC50 scaled to chi(2)(m)r with slope that had opposite signs. Comparison of the estimated CBRs with independent empirical values confirmed the predicted trends, but substantial deviations were noted too.

  8. Ion concentrations of PM10–2.5 and PM2.5 aerosols over the eastern Mediterranean region: seasonal variation and source identification

    Directory of Open Access Journals (Sweden)

    N. A. Saliba

    2005-12-01

    Full Text Available The annual averages of particulate matters (PM10, PM10–2.5 (coarse and PM2.5 (fine in a densely populated area of Beirut were measured and found to be 84±27, 53±20 and 31±9 μg m−3, respectively. Ion Chromatography (IC analysis of the collected PM Teflon filters showed that NaCl, CaSO4 and Ca(NO32 were predominant in the coarse particles, while (NH42SO4 was the main salt in the fine particles. Using the non destructive Fourier Transform Infra Red-Attenuated Total Reflection (FTIR-ATR technique, CaCO3 was determined in the coarse filter. In addition, ATR measurements showed that inorganic salts present in the coarse particles are mostly water insoluble while salts found in fine particles are soluble. Concentrations of nitrates and calcium higher than the ones reported in neighboring Mediterranean countries were good indication of high traffic density and crustal dust abundance in Beirut, respectively. The study of the seasonal variation showed that long-range transport of SO2 from Eastern and Central Europe, sandy storms coming from Africa and marine aerosols are considered major sources of the determined inorganic ions. Considering the importance of the health and climate impacts of aerosols locally and regionally, this study constitutes a point of reference for eastern Mediterranean transport modeling studies and local regulatory and policy makers.

  9. The survival of cultured mouse cerebellar granule cells is not dependent on elevated potassium-ion concentration

    DEFF Research Database (Denmark)

    Mogensen, Helle Smidt; Hack, N; Balázs, R

    1994-01-01

    The effects of K(+)-induced membrane depolarization were studied on the survival and biochemical parameters in mouse and rat cerebellar granule cells grown in micro-well cultures. Cell numbers were determined by estimating DNA content using the Hoechst 33258 fluorochrome binding assay. DNA from d...... that although cultivation in 'high' K+ promotes biochemical differentiation in mouse cerebellar granule cells, these cells differ from their rat counterparts in that they do not develop a survival requirement for K(+)-induced membrane depolarization.......The effects of K(+)-induced membrane depolarization were studied on the survival and biochemical parameters in mouse and rat cerebellar granule cells grown in micro-well cultures. Cell numbers were determined by estimating DNA content using the Hoechst 33258 fluorochrome binding assay. DNA from...... degenerated cells was removed by prior DNAase treatment. These DNA estimates of cell numbers were comparable with values obtained by direct counting of fluorescein diacetate-stained viable cells. In agreement with previous studies, the survival of rat granule cells was promoted by increasing the concentration...

  10. Large-scale and green synthesis of octahedral flower-like cupric oxide nanocrystals with enhanced photochemical properties

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shi-Kuo; Pan, Yu-Yi; Wu, Mi; Huang, Fang-Zhi; Li, Chuan-Hao, E-mail: lichuanhao1983@163.com; Shen, Yu-Hua, E-mail: s_yuhua@163.com

    2014-10-01

    Graphical abstract: - Highlights: • A green method is reported for large-scale synthesis of CuO nanocrystals via a coordination-deposition technique. • Flower-like nanostructure can be rationally tailored by adjusting reaction parameters. • Flower-like nanostructure can be obtained in a wide reaction solution volume range. • Uniform flower-like nanocrystal film assembled by oil–water interfacial self-assembly method exhibits excellent PEC performance. - Abstract: In this work, a large-scale and green method is reported for the facile synthesis of octahedral flower-like CuO nanocrystals via a coordination-deposition route by using Fehling regents. Not any harmful organic chemicals were used during the reaction period. The obtained hierarchical nanostructure can be rationally tailored by varying the concentration of tartrate ions and reaction time. The typical flower-like CuO nanocrystals in the range of 200–250 nm are consisted of numerous small crystalline whiskers, which present a porous surface with a specific surface area of 32.12 m{sup 2}/g and a narrow band gap of 1.5 eV. Importantly, the flower-like CuO nanocrystals show an enhanced photocatalytic activity toward decomposing Rhodamine B (RhB) molecules. The degradation rate is about 87.9% in 40 min under visible light irradiation, which is about 2.5 times for the commercial CuO powers (35.2%). Moreover, the uniform flower-like monolayered CuO film exhibits an excellent photoelectrochemical (PEC) performance with a maximum photocurrent density of 58.8 μA/cm{sup 2}, which is nearly five times higher than the commercial CuO film. This novel synthesis approach provides a large-scale and green protocol for synthesizing hierarchical metal oxide nanocrystals that are useful for photocatalysis, PEC water splitting and photovoltaic device.

  11. Non-GABA(A)-mediated effects of lindane on neurite development and intracellular free calcium ion concentration in cultured rat hippocampal neurons.

    Science.gov (United States)

    Ferguson, C A; Audesirk, G

    1995-04-01

    Changes in transmembrane Ca(2+) fluxes and intracellular free Ca(2+) ion concentrations ([Ca(2+)](in)) regulate many aspects of neurite development in cultured neurons. Lindane has been shown to increase [Ca(2+)](in) in several cell types. It was therefore hypothesized that lindane exposure would increase [Ca(2+)](in) and thereby alter neurite development in cultured rat hippocampal neurons. The study reported here showed that lindane (50-100 muM) increased [Ca(2+)](in) during short-term exposure (up to 4 hr); in contrast, with long-term exposure (24-48 hr) lindane (1-50 mum) decreased [Ca(2+)](in) significantly below control levels. Lindane decreased neurite initiation at high concentrations (25 mum or above). Lindane increased dendrite number at low concentrations (0.5-1 muM), but decreased dendrite number at high concentrations (50 mum or above). Lindane decreased axon and dendrite elongation and branching at 50 mum. Loading neurons with 1 mum 1,2-bis-(o-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid (BAPTA), a calcium chelator that partially 'clamps' [Ca(2+)](in), eliminated the effects of 50 mum lindane on [Ca(2+)](in) in short-term exposures. BAPTA did not significantly reverse the inhibition of neurite initiation or axonal elongation caused by 50 mum lindane. However, BAPTA partially reversed the inhibition of dendrite elongation and completely reversed the inhibition of axon and dendrite branching caused by 50 mum lindane. Therefore, some, but not all, of lindane's effects on neurite development may be due to changes in [Ca(2+)](in). Picrotoxin, a gamma-aminobutyric acid A (GABA(A))-associated chloride channel antagonist, had no effect on [Ca(2+)](in) or any parameters of neurite growth, suggesting that the effects of lindane on neurite development and [Ca(2+)](in) were not mediated through actions on GABA(A)-associated chloride channels.

  12. Seawater nutrient and carbonate ion concentrations recorded as P/Ca, Ba/Ca, and U/Ca in the deep-sea coral Desmophyllum dianthus

    Science.gov (United States)

    Anagnostou, Eleni; Sherrell, Robert M.; Gagnon, Alex; LaVigne, Michele; Field, M. Paul; McDonough, William F.

    2011-05-01

    As paleoceanographic archives, deep sea coral skeletons offer the potential for high temporal resolution and precise absolute dating, but have not been fully investigated for geochemical reconstructions of past ocean conditions. Here we assess the utility of skeletal P/Ca, Ba/Ca and U/Ca in the deep sea coral D. dianthus as proxies of dissolved phosphate (remineralized at shallow depths), dissolved barium (trace element with silicate-type distribution) and carbonate ion concentrations, respectively. Measurements of these proxies in globally distributed D. dianthus specimens show clear dependence on corresponding seawater properties. Linear regression fits of mean coral Element/Ca ratios against seawater properties yield the equations: P/Ca coral (μmol/mol) = (0.6 ± 0.1) P/Ca sw(μmol/mol) - (23 ± 18), R2 = 0.6, n = 16 and Ba/Ca coral(μmol/mol) = (1.4 ± 0.3) Ba/Ca sw(μmol/mol) + (0 ± 2), R2 = 0.6, n = 17; no significant relationship is observed between the residuals of each regression and seawater temperature, salinity, pressure, pH or carbonate ion concentrations, suggesting that these variables were not significant secondary dependencies of these proxies. Four D. dianthus specimens growing at locations with Ωarag ⩽ 0.6 displayed markedly depleted P/Ca compared to the regression based on the remaining samples, a behavior attributed to an undersaturation effect. These corals were excluded from the calibration. Coral U/Ca correlates with seawater carbonate ion: U/Ca coral(μmol/mol) = (-0.016 ± 0.003) [CO32-] (μmol/kg) + (3.2 ± 0.3), R2 = 0.6, n = 17. The residuals of the U/Ca calibration are not significantly related to temperature, salinity, or pressure. Scatter about the linear calibration lines is attributed to imperfect spatial-temporal matches between the selected globally distributed specimens and available water column chemical data, and potentially to unresolved additional effects. The uncertainties of these initial proxy calibration regressions

  13. Emergency Treatment and Nursing for Batches of Patients with Cupric Chloride Toxicosis%氯化铜中毒患者的急救护理

    Institute of Scientific and Technical Information of China (English)

    王艳梅; 王科

    2011-01-01

    Objective To probe the emergency treatment and nursing for batches of patients with cupric chloride toxicosis. Methods The poisoning patients underwent a series of treating procedures concerning transferring patients promptly,cleaning skin,blocking the absorption of poison,take special antidote such as sodium dimercaptopropane sulphonate scientificly and reasonablely,as well as observing the changes of athogenetic condition closely, preventing complications and giving psychological counseling. Results Nine patients with cupric chloride toxicosis were discharged after recovery. Conclusion The using of antidote of sodium dimercaptopropane sulphonate in time with meticulous nursing plays the key role in improving the success ratio of the rescue.%目的 探讨急性氯化铜中毒患者的抢救与护理方法.方法 及时将患者脱离中毒现场、清洗皮肤、阻断毒物吸收,科学、合理地使用特效解毒剂二巯基丙磺酸钠注射液,密切观察病情变化并精心护理,预防并发症以及给予心理疏导.结果 9例急性氯化铜中毒全部痊愈出院.结论 及时使用特效解毒剂二巯基丙磺酸钠注射液,辅以全身心的护理,是提高氯化铜中毒患者抢救成功率的关键.

  14. Enrichment of sulfate-reducing bacteria and resulting mineral formation in media mimicking pore water metal ion concentrations and pH conditions of acidic pit lakes.

    Science.gov (United States)

    Meier, Jutta; Piva, Angela; Fortin, Danielle

    2012-01-01

    Acid mine drainage sites are extreme environments with high acidity and metal ion concentrations. Under anoxic conditions, microbial sulfate reduction may trigger the formation of secondary minerals as a result of H2S production and pH increase. This process was studied in batch experiments with enrichment cultures from acidic sediments of a pit lake using growth media set at different pH values and containing elevated concentrations of Fe²⁺ and Al³⁺. At initial pH values of 5 and 6, sulfate reduction occurred shortly after inoculation. Sulfate- reducing bacteria affiliated to the genus Desulfosporosinus predominated the microbial communities as shown by 16S rRNA gene analysis performed at the end of the incubation. At initial pH values of 3 and 4, sulfate reduction and cell growth occurred only after an extended lag phase, however, at a higher rate than in the less acidic assays. At the end of the growth phase, enrichments were dominated by Thermodesulfobium spp. suggesting that these sulfate reducers were better adapted to acidic conditions. Iron sulfides in the bulk phase were common in all assays, but specific aluminum precipitates formed in close association with cell surfaces and may function as a detoxification mechanism of dissolved Al species at low pH.

  15. Liquid chromatography-electrospray linear ion trap mass spectrometry analysis of targeted neuropeptides in Tac1(-/-) mouse spinal cords reveals significant lower concentration of opioid peptides.

    Science.gov (United States)

    Saidi, Mouna; Beaudry, Francis

    2015-08-01

    Tachykinin and opioid peptides play a central role in pain transmission, modulation and inhibition. The treatment of pain is very important in medicine and many studies using NK1 receptor antagonists failed to show significant analgesic effects in humans. Recent investigations suggest that both pronociceptive tachykinins and the analgesic opioid systems are important for normal pain sensation. The analysis of opioid peptides in Tac1(-/-) spinal cord tissues offers a great opportunity to verify the influence of the tachykinin system on specific opioid peptides. The objectives of this study were to develop an HPLC-MS/MRM assay to quantify targeted peptides in spinal cord tissues. Secondly, we wanted to verify if the Tac1(-/-) mouse endogenous opioid system is hampered and therefore affects significantly the pain modulatory pathways. Targeted neuropeptides were analyzed by high performance liquid chromatography linear ion trap mass spectrometry. Our results reveal that EM-2, Leu-Enk and Dyn A were down-regulated in Tac1(-/-) spinal cord tissues. Interestingly, Dyn A was almost 3 fold down-regulated (p<0.0001). No significant concentration differences were observed in mouse Tac1(-/-) spinal cords for Met-Enk and CGRP. The analysis of Tac1(-/-) mouse spinal cords revealed noteworthy decreases of EM-2, Leu-Enk and Dyn A concentrations which strongly suggest a significant impact on the endogenous pain-relieving mechanisms. These observations may have insightful impact on future analgesic drug developments and therapeutic strategies.

  16. The chemistry of river-lake systems in the context of permafrost occurrence (Mongolia, Valley of the Lakes). Part I. Analysis of ion and trace metal concentrations

    Science.gov (United States)

    Szopińska, Małgorzata; Szumińska, Danuta; Polkowska, Żaneta; Machowiak, Katarzyna; Lehmann, Sara; Chmiel, Stanisław

    2016-07-01

    This study provides a description of water chemistry in river-lake systems located in central Mongolia, at the borderline of permafrost occurrence. The analysis involved water samples collected from two river-lake systems: Baydrag River-Böön Tsagaan Lake system, and Shargalyuut/Tuyn Rivers-Orog Lake system. In the water samples, ions and trace elements were detected and quantified. Additionally, the parameters of pH, electrical conductivity (SEC), total dissolved solids (TDS) and total organic carbon (TOC) were determined. Principal Component Analysis (PCA) was performed on the sample results. Water chemistry is mostly influenced by geochemical and hydrometeorological processes. Permafrost thawing could increase the concentration of nitrogen (NH4+, NO3-) as well as Na+ and Ca2+, Cl- and SO42 -. However, it may also be an effect of other factors such as livestock farming. Seasonal drying out of lakes (e.g., Lake Orog) may also influence water chemistry by deflation of evaporites from exposed lake beds and, at the same time, with lower concentration of chemical compounds in water. The PCA shows that water samples can be divided into two groups. The first group contains lake samples, where water chemistry is shaped by prevailing evaporation processes, whereas the second includes samples from rivers and springs. Water chemistry of the latter is predominantly influenced by geochemical and hydro-meteorological processes.

  17. A transfer function type of simplified electrochemical model with modified boundary conditions and Padé approximation for Li-ion battery: Part 1. lithium concentration estimation

    Science.gov (United States)

    Yuan, Shifei; Jiang, Lei; Yin, Chengliang; Wu, Hongjie; Zhang, Xi

    2017-06-01

    To guarantee the safety, high efficiency and long lifetime for lithium-ion battery, an advanced battery management system requires a physics-meaningful yet computationally efficient battery model. The pseudo-two dimensional (P2D) electrochemical model can provide physical information about the lithium concentration and potential distributions across the cell dimension. However, the extensive computation burden caused by the temporal and spatial discretization limits its real-time application. In this research, we propose a new simplified electrochemical model (SEM) by modifying the boundary conditions for electrolyte diffusion equations, which significantly facilitates the analytical solving process. Then to obtain a reduced order transfer function, the Padé approximation method is adopted to simplify the derived transcendental impedance solution. The proposed model with the reduced order transfer function can be briefly computable and preserve physical meanings through the presence of parameters such as the solid/electrolyte diffusion coefficients (Ds&De) and particle radius. The simulation illustrates that the proposed simplified model maintains high accuracy for electrolyte phase concentration (Ce) predictions, saying 0.8% and 0.24% modeling error respectively, when compared to the rigorous model under 1C-rate pulse charge/discharge and urban dynamometer driving schedule (UDDS) profiles. Meanwhile, this simplified model yields significantly reduced computational burden, which benefits its real-time application.

  18. Concentration and selective fractionation of an antihypertensive peptide from an alfalfa white proteins hydrolysate by mixed ion-exchange centrifugal partition chromatography.

    Science.gov (United States)

    Boudesocque, Leslie; Kapel, Romain; Paris, Cedric; Dhulster, Pascal; Marc, Ivan; Renault, Jean-Hugues

    2012-09-15

    This article reports a promising use of the mixed ion-exchange centrifugal partition chromatography (MIXCPC) technique in the field of downstream processes. A complex alfalfa white protein concentrate hydrolysate (AWPC hydrolysate) showing anti-hypertensive properties was successfully fractionated by MIXCPC to yield a L-valyl-L-tryptophan (VW) enriched fraction in one run. This dipeptide shows an interesting anti-angiotensin converting enzyme (anti-ACE) activity. An analytical method based on RP-LC/MS-MS was developed to quantify the target VW peptide in both the starting material and the enriched fractions. The best results for the MIXCPC fractionation were obtained by the combined use of the quaternary biphasic solvent system, methyl-tert-butylether/acetonitrile/n-butanol/water (2:1:2:5, v/v) in the descending mode, of the lipophilic di(2-ethylhexyl)phosphoric acid (DEHPA) cation-exchanger with an exchanger (DEHPA)/peptides ratio of 15, and of two displacers: calcium chloride and hydrochloric acid. The complexity of the starting material involved the selectivity optimization by splitting the stationary phase into two sections that differed by their triethylamine concentration. From 1g of AWPC hydrolysate containing 0.26% of VW, 30.7 mg of a VW enriched fraction were recovered with a purity of 10.9%, corresponding to a purification factor of 41 and a recovery of 97%.

  19. Evaluation of 2 portable ion-selective electrode meters for determining whole blood, plasma, urine, milk, and abomasal fluid potassium concentrations in dairy cattle.

    Science.gov (United States)

    Megahed, A A; Hiew, M W H; Grünberg, W; Constable, P D

    2016-09-01

    Two low-cost ion-selective electrode (ISE) handheld meters (CARDY C-131, LAQUAtwin B-731; Horiba Ltd., Albany, NY) have recently become available for measuring the potassium concentration ([K(+)]) in biological fluids. The primary objective of this study was to characterize the analytical performance of the ISE meters in measuring [K(+)] in bovine whole blood, plasma, urine, milk, and abomasal fluid. We completed 6 method comparison studies using 369 whole blood and plasma samples from 106 healthy periparturient Holstein-Friesian cows, 138 plasma samples from 27 periparturient Holstein-Friesian cows, 92 milk samples and 204 urine samples from 16 lactating Holstein-Friesian cows, and 94 abomasal fluid samples from 6 male Holstein-Friesian calves. Deming regression and Bland-Altman plots were used to characterize meter performance against reference methods (indirect ISE, Hitachi 911 and 917; inductively coupled plasma-optical emission spectroscopy). The CARDY ISE meter applied directly in plasma measured [K(+)] as being 7.3% lower than the indirect ISE reference method, consistent with the recommended adjustment of +7.5% when indirect ISE methods are used to analyze plasma. The LAQUAtwin ISE meter run in direct mode measured fat-free milk [K(+)] as being 3.6% lower than the indirect ISE reference method, consistent with a herd milk protein percentage of 3.4%. The LAQUAtwin ISE meter accurately measured abomasal fluid [K(+)] compared to the indirect ISE reference method. The LAQUAtwin ISE meter accurately measured urine [K(+)] compared to the indirect ISE reference method, but the median measured value for urine [K(+)] was 83% of the true value measured by inductively coupled plasma-optical emission spectroscopy. We conclude that the CARDY and LAQUAtwin ISE meters are practical, low-cost, rapid, accurate point-of-care instruments suitable for measuring [K(+)] in whole blood, plasma, milk, and abomasal fluid samples from cattle. Ion-selective electrode methodology is

  20. A novel solid-phase extraction for the concentration of sweeteners in water and analysis by ion-pair liquid chromatography-triple quadrupole mass spectrometry.

    Science.gov (United States)

    Gan, Zhiwei; Sun, Hongwen; Wang, Ruonan; Feng, Biting

    2013-01-25

    A highly sensitive method for the simultaneous trace (ng/L) quantification of seven commonly used artificial sweeteners in a variety of water samples using solid-phase extraction and ion-pair high-performance liquid chromatography (HPLC) triple quadrupole mass spectrometer with an electrospray ionization source (ESI-MS) in negative ion multiple reaction monitoring mode was developed. Ten solid phase extraction (SPE) cartridges were tested to evaluate their applicability for the pre-concentration of the analytes, and their loading and eluting parameters were optimized. Satisfactory recoveries (77-99%) of all of the studied sweeteners were obtained using a Poly-Sery PWAX cartridge with 25 mM sodium acetate solution (pH 4) as wash buffer and methanol containing 1mM tris (hydroxymethyl) amino methane (TRIS) as eluent. The method is sound and does not require pH adjustment or buffering of water samples. The HPLC separation was performed on an Athena C18-WP column with water and acetonitrile, both containing 5mM ammonium acetate and 1mM TRIS as mobile phases, in gradient elution mode. The linearity, precision, and accuracy of the method were evaluated, and good reproducibility was obtained. Method quantification limits varied between 0.4 and 7.5 ng/L for different water samples. The post-extraction spike method was applied to assess matrix effects, and quantification was achieved using internal standard calibration to overcome the unavoidable matrix effects during ESI-MS analysis. The method was applied to the analysis of thirteen water samples from Tianjin, China, including wastewater, tap water, surface water, and groundwater. The method described here is time-saving, accurate and precise, and is suitable for monitoring artificial sweeteners in different water matrices.

  1. Concentrations of some metabolites in the breath of healthy children aged 7-18 years measured using selected ion flow tube mass spectrometry (SIFT-MS).

    Science.gov (United States)

    Enderby, B; Lenney, W; Brady, M; Emmett, C; Spaněl, P; Smith, D

    2009-09-01

    Using selected ion flow tube mass spectrometry (SIFT-MS), measurements have been made of the levels of several metabolites in the exhaled breath of 200 healthy school children. Thus, concentration distributions of each metabolite have been obtained for the first time in the paediatric age range. The median values (in parentheses) of the concentrations in parts per billion, ppb, were ammonia (628), acetone (297), methanol (193), ethanol (187), isoprene (37), propanol (16), acetaldehyde (23) and pentanol (15). Hydrogen cyanide was not present in the breath above the detection limit of 2 ppb in the majority of subjects. The water vapour level (humidity) of the breath samples was routinely measured as a check on the sample integrity. Such data are essential if SIFT-MS breath analyses are to be used as a clinical tool to aid diagnosis and/or as a monitor of disease in children. The levels of metabolites usually followed a log-normal distribution and the levels of some compounds were similar to those obtained previously in adults. Lower values were found in the levels of acetone, ammonia, methanol and isoprene. There were no major variations in relation to gender. Some metabolites showed significant variation in relation to age and body mass index. To our knowledge, these are the first measurements of exhaled mouth breath pentanol levels. The median ammonia levels in mouth-exhaled breath of these children decreased with age, whereas in older adults, ammonia has been shown to increase with age. Breath acetone levels were significantly increased for those who had not eaten for more than 6 h prior to providing the breath sample, although dietary control was not a mandatory aspect of the protocol.

  2. Interactions of Zn(II) Ions with Humic Acids Isolated from Various Type of Soils. Effect of pH, Zn Concentrations and Humic Acids Chemical Properties.

    Science.gov (United States)

    Boguta, Patrycja; Sokołowska, Zofia

    2016-01-01

    The main aim of this study was the analysis of the interaction between humic acids (HAs) from different soils and Zn(II) ions at wide concentration ranges and at two different pHs, 5 and 7, by using fluorescence and FTIR spectroscopy, as well as potentiometric measurements. The presence of a few areas of HAs structures responsible for Zn(II) complexing was revealed. Complexation at α-sites (low humified structures of low-molecular weight and aromatic polycondensation) and β-sites (weakly humified structures) was stronger at pH 7 than 5. This trend was not observed for γ-sites (structures with linearly-condensed aromatic rings, unsaturated bonds and large molecular weight). The amount of metal complexed at pH5 and 7 by α and γ-structures increased with a decrease in humification and aromaticity of HAs, contrary to β-areas where complexation increased with increasing content of carboxylic groups. The stability of complexes was higher at pH 7 and was the highest for γ-structures. At pH 5, stability decreased with C/N increase for α-areas and -COOH content increase for β-sites; stability increased with humification decrease for γ-structures. The stability of complexes at α and β-areas at pH 7 decreased with a drop in HAs humification. FTIR spectra at pH 5 revealed that the most-humified HAs tended to cause bidentate bridging coordination, while in the case of the least-humified HAs, Zn caused bidentate bridging coordination at low Zn additions and bidentate chelation at the highest Zn concentrations. Low Zn doses at pH 7 caused formation of unidentate complexes while higher Zn doses caused bidentate bridging. Such processes were noticed for HAs characterized by high oxidation degree and high oxygen functional group content; where these were low, HAs displayed bidentate bridging or even bidentate chelation. To summarize, the above studies have showed significant impact of Zn concentration, pH and some properties of HAs on complexation reactions of humic

  3. 钠盐浓度对厌氧产氢颗粒污泥从蔗糖中产氢的影响%Effect of Sodium Ion Concentration on Hydrogen Production from Sucrose by Anaerobic Hydrogen-producing Granular Sludge

    Institute of Scientific and Technical Information of China (English)

    郝小龙; 周明华; 俞汉青; 沈琴琴; 雷乐成

    2006-01-01

    This work evaluated the effects of sodium ion concentration, ranging from 0 to 16000mg·L-1(Na+), on the conversion of sucrose to hydrogen by a high-activity anaerobic hydrogen-producing granular sludge. At the optimum sodium ion concentration [1000-2000mg·L-1(Na+)] for hydrogen production at 37℃, the maximum sucrose degradation rate, the specific hydrogen production yield and the specific hydrogen production rate were 393.6-413.1mg·L-1·h-1, 28.04-28.97ml·g-1, 7.52-7.83ml·g-1·h-1, respectively. The specific production yields of propionate, butyrate and valerate decreased, with increasing sodium ion concentration, whereas the specific acetate production yield increased, meanwhile the specific production yields of ethanol and caproate were less than 55.3 and 12.6mg·g-1, respectively. The hybrid fermentation composition gradually developed from acetate, propionate and butyrate to acetate with the increase in sodium ion concentration.

  4. Study on HNS-Ⅳ Initiated by Flyer Driven by Cupric Azide%叠氮化铜驱动飞片起爆HNS-Ⅳ的研究

    Institute of Scientific and Technical Information of China (English)

    郭俊峰; 曾庆轩; 李明愉; 李兵

    2015-01-01

    针对以叠氮化铜微装药为基础的MEMS起爆传爆序列,利用数值模拟的方法研究起爆序列结构对起爆性能的影响.研究结果表明:飞片的剪切形状与文献结果相符.在装药直径一定的情况下,随着装药厚度的增加,飞片速度增加;当装药厚度为0.5mm、装药直径大于0.7mm时,增加装药直径不能进一步增加飞片速度;当叠氮化铜的尺寸为Φ0.7mm×0.5mm、加速膛长度为0.56mm时,系统能够起爆HNS-IV炸药.利用文献数据拟合得到了HNS-IV炸药的冲击起爆判据,模拟结果符合HNS-Ⅳ的冲击起爆判据.%Aimed at MEMS booster train based on micro charge involving cupric azide, numerical simulation method was utilized to study the effect of the structure of booster train on shock-initiation performance. Simulation results indicate that the shear of flyer shape is consistent with literature results. To a certain charge diameter, the flyer velocity is increased as the charge thickness increasing. While the flyer velocity cannot continue to increase with the diameter increasing, when the charge thickness is 0.5 mm and the charge diameter exceeds 0.7mm. When the charge size of cupric azide is Φ 0.7mm×0.5 mm and the length of barrel is 0.56 mm, HNS-IV explosive can be initiated by this system. The shock-initiation criterion of HNS-Ⅳ explosive fitted by literature results is determined, which is consistent with the simulation results.

  5. Multicusp ion sources (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Leung, K.N. (Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 (United States))

    1994-04-01

    During the last decade, different types of multicusp ion sources, such as high current, high concentration H[sup +], H[sup +][sub 2], or N[sup +] ion sources, negative ion sources, radio-frequency-driven sources, and high charge state ion sources have been developed at the Lawrence Berkeley Laboratory. This article reviews the history of the research and development of these ion sources and their applications.

  6. Polyethylene glycol grafted flower-like cupric nano oxide for the hollow-fiber solid-phase microextraction of hexaconazole, penconazole, and diniconazole in vegetable samples.

    Science.gov (United States)

    Zendegi-Shiraz, Amene; Sarafraz-Yazdi, Ali; Es'haghi, Zarrin

    2016-08-01

    A simple, rapid, highly efficient, and reliable sample preparation method has been developed for the extraction and analysis of triazole pesticides from cucumber, lettuce, bell pepper, cabbage, and tomato samples. This new sorbent in the hollow-fiber solid-phase microextraction method is based on the synthesis of polyethylene glycol-polyethylene glycol grafted flower-like cupric oxide nanoparticles using sol-gel technology. Afterward, the analytes were analyzed by high-performance liquid chromatography with ultraviolet detection. The main parameters that affect microextraction efficiency were evaluated and optimized. This method has afforded good linearity ranges (0.5-50 000 ng/mL for hexaconazol, 0.012-50 000 ng/mL for penconazol, and 0.02-50 000 ng/mL for diniconazol), adequate precision (2.9-6.17%, n = 3), batch-to-batch reproducibility (4.33-8.12%), and low instrumental LODs between 0.003 and 0.097 ng/mL (n = 8). Recoveries and enrichment factors were 85.46-97.47 and 751-1312%, respectively.

  7. Phytochemical profile and ABTS cation radical scavenging, cupric reducing antioxidant capacity and anticholinesterase activities of endemic Ballota nigra L. subsp. anatolica P.H. Davis from Turkey

    Institute of Scientific and Technical Information of China (English)

    Abdulselam Erta; Mehmet Boa; Yeter Yeil

    2014-01-01

    Objective: To evaluate the chemical compositions and biological activities of an endemic Ballotanigra Methods: Essential oil and fatty acid composition were determined by GC/MS analysis. ABTS cation radical decolourisation and cupric reducing antioxidant capacity assays were carried out to indicate the antioxidant activity. The anticholinesterase potential of the extracts were determined by Ellman method. L. subsp. anatolica P.H. Davis. Results: The major compounds in the fatty acid composition of the petroleum ether extract were identified as palmitic (36.0%) and linoleic acids (14.3%). The major components of essential oil were 1-hexacosanol (26.7%), germacrene-D (9.3%) and caryophyllene oxide (9.3%). The water extract indicated higher ABTS cation radical scavenging activity than α-tocopherol and BHT, at 100 µg/mL. The acetone extract showed 71.58 and 44.71% inhibitory activity against butyrylcholinesterase and acetylcholinesterase enzyme at 200 µg/mL, respectively. Conclusions: The water and acetone extracts of Ballota nigra subsp. anatolica can be investigated in terms of both phytochemical and biological aspects to find natural active compounds.

  8. Distribution of Negative Oxygen Ions Concentration and Assessment of Air Quality in Campus%校园空气负氧离子浓度分布与空气质量评价

    Institute of Scientific and Technical Information of China (English)

    叶宏萌; 郑茂钟; 姜嘉祺; 谢行冬

    2015-01-01

    Level of negative oxygen ions concentration reflects not only the air quality, but also directly affect the comfort and health.This paper studied distribution and evaluation of negative oxygen ions concentration in campus of Wuyi university.The re-sults showed that negative oxygen ions concentration was affected by human activity, altitude, the air flow, dynamic water and vege-tation distribution and other comprehensive factors in the different functional areas of the campus.Meanwhile, negative oxygen ions changes according to weather and diurnal variations.Ranges of negative oxygen ion concentration are as follows:heavy rain days>rain days>rain cloudy>clear;diurnal variation order:AM>evening>noon.In summary, the measurement results showed that the air quality levels achieved stability three or four, air was fresh and conducive to human health.%空气负氧离子浓度水平不仅反映了空气质量,还直接影响人们的舒适程度和健康状况。研究武夷学院空气负氧离子浓度含量发现,其受人类活动力度、海拔高度、空气流通状况、动态水体和植被分布等综合因素影响,并具有明显的气象变化和日变化特征。负氧离子浓度含量排序为:暴雨天>小雨天>雨后阴天>晴天;一日中上午>傍晚>中午。测量结果表明该校园整体空气质量等级达到四级或者三级,空气清新,有利于师生健康。

  9. Visualization of Steady-State Ionic Concentration Profiles Formed in Electrolytes during Li-Ion Battery Operation and Determination of Mass-Transport Properties by in Situ Magnetic Resonance Imaging.

    Science.gov (United States)

    Krachkovskiy, Sergey A; Bazak, J David; Werhun, Peter; Balcom, Bruce J; Halalay, Ion C; Goward, Gillian R

    2016-06-29

    Accurate modeling of Li-ion batteries performance, particularly during the transient conditions experienced in automotive applications, requires knowledge of electrolyte transport properties (ionic conductivity κ, salt diffusivity D, and lithium ion transference number t(+)) over a wide range of salt concentrations and temperatures. While specific conductivity data can be easily obtained with modern computerized instrumentation, this is not the case for D and t(+). A combination of NMR and MRI techniques was used to solve the problem. The main advantage of such an approach over classical electrochemical methods is its ability to provide spatially resolved details regarding the chemical and dynamic features of charged species in solution, hence the ability to present a more accurate characterization of processes in an electrolyte under operational conditions. We demonstrate herein data on ion transport properties (D and t(+)) of concentrated LiPF6 solutions in a binary ethylene carbonate (EC)-dimethyl carbonate (DMC) 1:1 v/v solvent mixture, obtained by the proposed technique. The buildup of steady-state (time-invariant) ion concentration profiles during galvanostatic experiments with graphite-lithium metal cells containing the electrolyte was monitored by pure phase-encoding single point imaging MRI. We then derived the salt diffusivity and Li(+) transference number over the salt concentration range 0.78-1.27 M from a pseudo-3D combined PFG-NMR and MRI technique. The results obtained with our novel methodology agree with those obtained by electrochemical methods, but in contrast to them, the concentration dependences of salt diffusivity and Li(+) transference number were obtained simultaneously within the single in situ experiment.

  10. The power of Nb-substituted TiO2 in Li-ion batteries: Morphology transformation induced by high concentration substitution

    Science.gov (United States)

    Yang, Hao; Lan, Chun-Kai; Duh, Jenq-Gong

    2015-08-01

    This study aims to investigate the power potential of Li-ion batteries using a hydrothermal process to synthesize nanoscale Nb-TiO2 with high surface area. By substituting Nb into anatase TiO2, the rate capability of Li-ion batteries is improved with the formation of nanoplate Nb-TiO2 containing (001) facets and NbOx species. In addition, the high solubility of Nb promotes the transformation of TiO2 from hollow-like to plate-like morphology, accelerating the Li-ion surface transportation over a large contact area. With respect to rate capability, Nb-TiO2 displays a high capacity of 220 mAh g-1 at 0.5C and retains 127 mAh g-1 at 10C. Additionally, the cyclability test exhibits less degradation after 10,000 cycles. In order to investigate the mechanisms of capability improvement, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) are applied to measure the Li-ion diffusivity and surface charge-transfer resistance. The results demonstrate that both Li-ion diffusivity and surface charge-transfer ability are enhanced, leading to pseudocapacitance. Thus, it can be concluded that nanoplate Nb-TiO2 exhibits superior rate capability by the improvement of pseudocapacitance. This study derives a novel process to synthesize nanoplate TiO2 and should provide a potential approach for industrial fabrication of high power Li-ion batteries.

  11. 珠江河口霍乱弧菌数量与离子浓度关系研究%Research on the correlation of Vibrio cholerae and ion concentration in the Pearl River estuary

    Institute of Scientific and Technical Information of China (English)

    岳玉娟; 王多春; 龚建华

    2013-01-01

    OBJECTIVE To study the correlation between the positive rate of Vibrio cholerae (V. Cholerae) and ion concentration in the Pearl River estuary, and discuss the influence of ion concentration on the dynamics of V. Cholerae. METHODS Through analyzing the monthly data of 24 sampling points in the Pearl River estuary from March 2006 to Feb. 2007, Spearman' s rank correlation was adopted to investigate the correlation of the positive rate of V. Cholerae and the ion concentration concluding Mg2+, K+, Ca2+ and Na+ based on the sampling points. RESULTS Almost all of the values of Mg2+, K+, Ca2+ and Na+ concentrations in the downstream were bigger than that in the urban area, and the highest was 30 times. Under the significance level 0.05, V. Cholerae was significantly passively correlated with Mg2+ concentration (r, = -0.541) and was significantly positively correlated with K+ concentration (r, = 0.544) and Ca2+ concentration (r, = 0.567) in the urban area, but the correlation of the two was not significant in the downstream. CONCLUSION V. Cholerae is correlated with the ion concentration in the urban area with lower ion concentration, but the correlation of the two is not significant in the downstream with higher ion concentration. Therefore, V. Cholerae is correlated with the ion concentrations of Mg2+, K+ and Ca2+ in certain threshold scope.%目的 分析珠江河口水体霍乱弧菌阳性检出率与离子浓度之间关系,探讨水体中离子浓度对霍乱弧菌数量的影响.方法 对2006年3月~2007年2月珠江河口24个采样点每月采样1次的霍乱弧菌数量与水体中Mg2+、K+、Ca2+、Na+浓度数据,采用Spearman秩相关函数,研究基于采样点的霍乱弧菌检出率与离子浓度之间的相关关系.结果 珠江河口下游入海口区每个采样点的Mg2+、K+、Ca2+、Na+浓度年均值几乎所有的值均大于珠江河口广州城区的值,最高可达30倍.在0.05的检验水准下,广州城区霍乱弧菌阳性检出率与Mg2

  12. A multi-module microfluidic platform for continuous pre-concentration of water-soluble ions and separation of oil droplets from oil-in-water (O/W) emulsions using a DC-biased AC electrokinetic technique.

    Science.gov (United States)

    Das, Dhiman; Phan, Dinh-Tuan; Zhao, Yugang; Kang, Yuejun; Chan, Vincent; Yang, Chun

    2017-03-01

    A novel continuous flow microfluidic platform specifically designed for environmental monitoring of O/W emulsions during an aftermath of oil spills is reported herein. Ionized polycyclic aromatic hydrocarbons which are toxic are readily released from crude oil to the surrounding water phase through the smaller oil droplets with enhanced surface area. Hence, a multi-module microfluidic device is fabricated to form ion enrichment zones in the water phase of O/W emulsions for the ease of detection and to separate micron-sized oil droplets from the O/W emulsions. Fluorescein ions in the water phase are used to simulate the presence of these toxic ions in the O/W emulsion. A DC-biased AC electric field is employed in both modules. In the first module, a nanoporous Nafion membrane is used for activating the concentration polarization effect on the fluorescein ions, resulting in the formation of stable ion enrichment zones in the water phase of the emulsion. A 35.6% amplification of the fluorescent signal is achieved in the ion enrichment zone; corresponding to 100% enrichment of the fluorescent dye concentration. In this module, the main inlet is split into two channels by using a Y-junction so that there are two outlets for the oil droplets. The second module located downstream of the first module consists of two oil droplet entrapment zones at two outlets. By switching on the appropriate electrodes, either one of the two oil droplet entrapment zones can be activated and the droplets can be blocked in the corresponding outlet.

  13. Co-ordination of a new bis-terpyridine ligand with cupric perchlorate yielding a dinuclear M 2L species

    Science.gov (United States)

    Knight, James C.; Prabaharan, Ravi; Edwards, Peter G.; Amoroso, Angelo J.

    2011-03-01

    We report the synthesis of a new bis-terpyridine ligand which could potentially yield a variety of polynuclear complexes. An investigation of the co-ordination chemistry of this ligand with Cu(II) ions in a 1:1 ratio yielded a complex with a 2:1 ratio of Cu to ligand. The crystal structure of the dinuclear copper(II) complex shows the two equivalent copper cations are co-ordinated via five donor atoms in a highly distorted square pyramidal arrangement. The structure was solved in a monoclinic space group C2/c with cell parameters, a = 21.340(5), b = 14.004(5), c = 18.368(5) Å, α = 90°, β = 106.575(5)°, γ = 90°, volume = 5261(3) Å 3, Z = 4.

  14. Ion funnel ion trap and process

    Science.gov (United States)

    Belov, Mikhail E [Richland, WA; Ibrahim, Yehia M [Richland, WA; Clowers, Biran H [West Richland, WA; Prior, David C [Hermiston, OR; Smith, Richard D [Richland, WA

    2011-02-15

    An ion funnel trap is described that includes a inlet portion, a trapping portion, and a outlet portion that couples, in normal operation, with an ion funnel. The ion trap operates efficiently at a pressure of .about.1 Torr and provides for: 1) removal of low mass-to-charge (m/z) ion species, 2) ion accumulation efficiency of up to 80%, 3) charge capacity of .about.10,000,000 elementary charges, 4) ion ejection time of 40 to 200 .mu.s, and 5) optimized variable ion accumulation times. Ion accumulation with low concentration peptide mixtures has shown an increase in analyte signal-to-noise ratios (SNR) of a factor of 30, and a greater than 10-fold improvement in SNR for multiply charged analytes.

  15. Effects of chloride ion concentration and pH values on the corrosion behavior of Cr12Ni3Co12Mo4W ultra-high-strength martensitic stainless steel

    Institute of Scientific and Technical Information of China (English)

    Hui-yan Li; Chao-fang Dong; Kui Xiao; Xiao-gang Li; Ping Zhong

    2016-01-01

    The effects of Cl− ion concentration and pH values on the corrosion behavior of Cr12Ni3Co12Mo4W ultra-high-strength marten-sitic stainless steel (UHSMSS) were investigated by a series of electrochemical tests combined with observations by stereology microscopy and scanning electron microscopy. A critical Cl− ion concentration was found to exist (approximately 0.1wt%), above which pitting occurred. The pitting potential decreased with increasing Cl− ion concentration. A UHSMSS specimen tempered at 600°C exhibited a better pitting cor-rosion resistance than the one tempered at 400°C. The corrosion current density and passive current density of the UHSMSS tempered at 600°C decreased with increasing pH values of the corrosion solution. The pits developed a shallower dish geometry with increasing polariza-tion potential. A lacy cover on the pits of the UHSMSS tempered at 400°C accelerated pitting, whereas corrosion products deposited in the pits of the UHSMSS tempered at 600°C hindered pitting.

  16. Effects of chloride ion concentration and pH values on the corrosion behavior of Cr12Ni3Co12Mo4W ultra-high-strength martensitic stainless steel

    Science.gov (United States)

    Li, Hui-yan; Dong, Chao-fang; Xiao, Kui; Li, Xiao-gang; Zhong, Ping

    2016-11-01

    The effects of Cl- ion concentration and pH values on the corrosion behavior of Cr12Ni3Co12Mo4W ultra-high-strength martensitic stainless steel (UHSMSS) were investigated by a series of electrochemical tests combined with observations by stereology microscopy and scanning electron microscopy. A critical Cl- ion concentration was found to exist (approximately 0.1wt%), above which pitting occurred. The pitting potential decreased with increasing Cl- ion concentration. A UHSMSS specimen tempered at 600°C exhibited a better pitting corrosion resistance than the one tempered at 400°C. The corrosion current density and passive current density of the UHSMSS tempered at 600°C decreased with increasing pH values of the corrosion solution. The pits developed a shallower dish geometry with increasing polarization potential. A lacy cover on the pits of the UHSMSS tempered at 400°C accelerated pitting, whereas corrosion products deposited in the pits of the UHSMSS tempered at 600°C hindered pitting.

  17. Interpretation with a Donnan-based concept of the influence of simple salt concentration on the apparent binding of divalent ions to the polyelectrolytes polystyrenesulfonate and dextran sulfate

    Science.gov (United States)

    Marinsky, J.A.; Baldwin, Robert F.; Reddy, M.M.

    1985-01-01

    It has been shown that the apparent enhancement of divalent metal ion binding to polyions such as polystyrenesulfonate (PSS) and dextran sulfate (DS) by decreasing the ionic strength of these mixed counterion systems (M2+, M+, X-, polyion) can be anticipated with the Donnan-based model developed by one of us (J.A.M.). Ion-exchange distribution methods have been employed to measure the removal by the polyion of trace divalent metal ion from simple salt (NaClO4)-polyion (NaPSS) mixtures. These data and polyion interaction data published earlier by Mattai and Kwak for the mixed counterion systems MgCl2-LiCl-DS and MgCl2-CsCl-DS have been shown to be amenable to rather precise analysis by this model. ?? 1985 American Chemical Society.

  18. Effects of low concentrations of O2 and CO on the ion-clustering reactions in the lower ionosphere of Mars

    Science.gov (United States)

    Sieck, L. W.; Gorden, R., Jr.; Ausloos, P.

    1973-01-01

    It is demonstrated that under conditions which approximate those of the Martian ionosphere traces of CO and O2 can be effectively incorporated in ion clusters via ion-molecule reaction schemes initiated by the CO2(+) ion. For example, when 0.3% CO is added to CO2, (CO)2(+), and /(CO)2CO2/(+) appear as the major cations (584 A radiation, 300 K). In mixtures containing O2 in addition to CO, (CO2,O2+) and /(CO2)2O2/(+) are important species. A recently proposed mechanism to account for the low abundance of CO and O2 in the Martian atmosphere is discussed in the light of these observations.

  19. Establishment of the conditions for the determination of the concentration of the uranyl ion in perchloric media by Fluorescence; Establecimiento de las condiciones para la determinacion de la concentracion del ion uranilo en medio perclorico por Fluorescencia

    Energy Technology Data Exchange (ETDEWEB)

    Contreras R, A.; Ordonez R, E.; Fernandez V, S.M. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)]. e-mail: contraida@yahoo.com.mx

    2004-07-01

    The influence of the p H is reported in the spectra of luminescence of the ion uranyl in sodium perchlorate 2M. The best spectra were observed to ph <3 that to neutral and basic p Hs this is explained by the present species. They were carried out four calibration curves for the uranyl in perchloric acid media, taking into account the area under the curve, the maximum height of two characteristic peaks of this ion, in those that one observes a better correlation with the maximum height of the peak located to 486.7 nm. (Author)

  20. Determination of lignin in marine sediment using alkaline cupric oxide oxidation-solid phase extraction-on-column derivatization-gas chromatography

    Science.gov (United States)

    Zhang, Ting; Li, Xianguo; Sun, Shuwen; Lan, Haiqing; Du, Peirui; Wang, Min

    2013-03-01

    Lignin serves as one of the most important molecular fossils for tracing Terrestrial Organic Matters (TOMs) in marine environment. Extraction and derivatization of lignin oxidation products (LOPs) are crucial for accurate quantification of lignin in marine sediment. Here we report a modification of the conventional alkaline cupric oxide (CuO) oxidation method, the modification consisting in a solid phase extraction (SPE) and a novel on-column derivatization being employed for better efficiency and reproducibility. In spiking blanks, recoveries with SPE for the LOPs are between 77.84% and 99.57% with relative standard deviations (RSDs) ranging from 0.57% to 8.04% ( n=3), while those with traditional liquid-liquid extraction (LLE) are from 44.52% to 86.16% with RSDs being from 0.53% to 13.14% ( n=3). Moreover, the reproducibility is greatly improved with SPE, with less solvent consumption and shorter processing time. The average efficiency of on-column derivatization for LOPs is 100.8% ± 0.68%, which is significantly higher than those of in-vial or in-syringe derivatization, thus resulting in still less consumption of derivatizing reagents. Lignin in the surface sediments sampled from the south of Yangtze River estuary, China, was determined with the established method. Recoveries of 72.66% to 85.99% with standard deviation less than 0.01mg/10g dry weight are obtained except for p-hydroxyben-zaldehyde. The lignin content Σ8 (produced from 10 g dry sediment) in the research area is between 0.231 and 0.587 mg. S/V and C/V ratios (1.028 ± 0.433 and 0.192 ± 0.066, respectively) indicate that the TOMs in this region are originated from a mixture of woody and nonwoody angiosperm plants; the high values of (Ad/Al)v suggest that the TOMs has been highly degraded.

  1. Behaviour of the pH adjustment, Ion exchange and concentrate precipitation stages in the acid leaching of uranium phosphate ores; Tratamiento de disoluciones de lixiviacion de minerales de uranio en presencia de fosfatos. Comportamiento en las etapas de ajuste de PH, cambio de ion y precipitacion de concentrados

    Energy Technology Data Exchange (ETDEWEB)

    Estrada Aguilar, J.; Uriarte Hueda, A.

    1962-07-01

    The uranium recovery from acid leach solutions of uranium-phosphate ores has been studied. Relations have been found between the solution characteristics and the results obtained at different stages of the process. The following data can thus be predicted: solids to remove and uranium recovery in the pH adjustment stage, uranium capacity of the resin, more suitable eluating agent, elution velocity and uranium concentration in the eluate in the ion exchange stage, and composition of the concentrate produced by direct precipitation of the eluate in the concentrate precipitation stage. (Author) 8 refs.

  2. High affinity capture and concentration of quinacrine in polymorphonuclear neutrophils via vacuolar ATPase-mediated ion trapping: Comparison with other peripheral blood leukocytes and implications for the distribution of cationic drugs

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Caroline; Gagné, Valérie; Fernandes, Maria J.G.; Marceau, François, E-mail: francois.marceau@crchul.ulaval.ca

    2013-07-15

    Many cationic drugs are concentrated in acidic cell compartments due to low retro-diffusion of the protonated molecule (ion trapping), with an ensuing vacuolar and autophagic cytopathology. In solid tissues, there is evidence that phagocytic cells, e.g., histiocytes, preferentially concentrate cationic drugs. We hypothesized that peripheral blood leukocytes could differentially take up a fluorescent model cation, quinacrine, depending on their phagocytic competence. Quinacrine transport parameters were determined in purified or total leukocyte suspensions at 37 °C. Purified polymorphonuclear leukocytes (PMNLs, essentially neutrophils) exhibited a quinacrine uptake velocity inferior to that of lymphocytes, but a consistently higher affinity (apparent K{sub M} 1.1 vs. 6.3 μM, respectively). However, the vacuolar (V)-ATPase inhibitor bafilomycin A1 prevented quinacrine transport or initiated its release in either cell type. PMNLs capture most of the quinacrine added at low concentrations to fresh peripheral blood leukocytes compared with lymphocytes and monocytes (cytofluorometry). Accumulation of the autophagy marker LC3-II occurred rapidly and at low drug concentrations in quinacrine-treated PMNLs (significant at ≥ 2.5 μM, ≥ 2 h). Lymphocytes contained more LAMP1 than PMNLs, suggesting that the mass of lysosomes and late endosomes is a determinant of quinacrine uptake V{sub max}. PMNLs, however, exhibited the highest capacity for pinocytosis (uptake of fluorescent dextran into endosomes). The selectivity of quinacrine distribution in peripheral blood leukocytes may be determined by the collaboration of a non-concentrating plasma membrane transport mechanism, tentatively identified as pinocytosis in PMNLs, with V-ATPase-mediated concentration. Intracellular reservoirs of cationic drugs are a potential source of toxicity (e.g., loss of lysosomal function in phagocytes). - Highlights: • Quinacrine is concentrated in acidic organelles via V-ATPase-mediated ion

  3. Cupric citrate as growth promoter for broiler chickens in different rearing stages Citrato cúprico como promotor de crescimento de frangos de corte diferentes em fases de criação

    Directory of Open Access Journals (Sweden)

    Mônica Maria de Almeida Brainer

    2003-01-01

    Full Text Available Feeding cupric citrate as alternative to cupric sulfate to broilers has been suggested in the literature. Day-old male broiler chicks (1,200 were used in an experiment to evaluate the efficacy of cupric citrate supplementation (75 mg Cu kg-1 during the 1-21, 22-42 or 1-42 d periods in comparison to an unsupplemented diet and a diet supplemented with cupric sulfate (200 mg Cu kg-1, 1-42 d. A randomized block design was used, with five treatments, six replicates and 40 birds per pen. The diets, based on corn and soybean meal, and water were offered ad libitum during the 42-day experimental period. Over the entire period, there was no effect of copper supplementation (P > 0.05 on bird live weight, weight gain, feed intake, feed conversion and mortality. Cupric citrate supplementation on the 22-42 d period resulted in worse feed conversion as compared to broilers receiving cupric sulfate (2.014 vs. 1.967, P Citrato cúprico foi apontado como alternativa ao sulfato cúprico como promotor de crescimento na dieta de frangos. Este trabalho avaliou a eficácia do citrato cúprico em diferentes fases da criação de frangos de corte. Foram utilizados 1200 pintos machos, em um experimento em blocos casualizados, com cinco tratamentos, seis repetições e 40 aves por parcela. Os tratamentos consistiram de uma dieta não suplementada ou suplementada com citrato cúprico anidro (75 mg Cu kg-1 de 1 a 21 dias, de 22 a 42 dias ou de 1 a 42 dias, ou com sulfato cúprico pentahidratado (200 mg Cu kg-1 de 1 a 42 dias. Foram avaliados o desempenho das aves e o resíduo de cobre na cama. Dietas, à base de milho e farelo de soja, e água foram fornecidas à vontade durante todo o período experimental. Não houve efeito da suplementação de cobre (P > 0,05 sobre o peso vivo, ganho de peso, consumo de ração, conversão alimentar e mortalidade mais refugagem. Os frangos que receberam citrato cúprico na ração a partir dos 22 dias tiveram, no período 22-42 dias

  4. Assessment of Ethidium bromide and Ethidium monoazide bromide removal from aqueous matrices by adsorption on cupric oxide nanoparticles.

    Science.gov (United States)

    Fakhri, Ali

    2014-06-01

    The present study was undertaken to develop an effective adsorbent and to study the adsorption of Ethidium bromide and Ethidium monoazide bromide from aqueous solution using the CuO nanoparticles. The characteristics of CuO nanoparticles were determined and found to have a surface area 89.59m(2)/g. Operational parameters such as pH, contact time and adsorbent concentration, initial concentration and temperature were also studied. The amount of removal increases with the increase in pH from one to seven and reaches the maximum when the pH is nine. Adsorption data fitted well with the Langmuir, Freundlich and Florry-Huggins models. The results show that the best fit was achieved with the Langmuir isotherm equation with maximum adsorption capacities of 0.868 and 0.662mg/g for Ethidium bromide and Ethidium monoazide bromide, respectively. The adsorption process was found to follow pseudo-second-order kinetics. The calculated thermodynamic parameters, namely ΔG, ΔH and ΔS showed that adsorption of Ethidium bromide and Ethidium monoazide bromide was spontaneous and endothermic under examined conditions.

  5. Pre-concentration of some heavy metal ions with AlO–HQ and AlO–PHQ and their studies by FTIR and spectroscopy

    Directory of Open Access Journals (Sweden)

    Mostafa M. Kamal

    2015-07-01

    Full Text Available Immobilization of HQ and PHQ on the surface of alumina, Al2O3 (referred to it by AlO as an application for cation exchange of Al(III in solution, using them for the extraction of some heavy metal ions from their solutions and calculating their capacity was studied. Immobilization of HQ or PHQ on Al2O3 was carried out and used for the extraction of some metal ions such as Fe(III, Cu(II, Co(II and Ni(II from its solution. Spectra of substrate (AlO–HQ, AlO–PHQ or AlO–Cu at universal buffer solution (pH 7.2 ± 0.1 were recorded, solution of metal ion was added after contact time, filtered, and the solid precipitate was dissolved in pure ethanol, a peak at 305 nm was observed corresponding to HQ–Al(III. On addition of Cu(II ion solution to AlO–HQ, a peak at 380 nm appeared corresponding to HQ–Cu(II, the peak at 305 nm decreased until it disappeared. The capacity of AlO–HQ was 100 mmol/g, whereas on addition of Fe(III ion solution, new two peaks appeared at 580 and 455 nm corresponding to the formation of HQ–Fe(III coordinated complex. The capacity of AlO–HQ for Fe(III ion was 100 mmol/g. On addition of Ni(II and Co(II, the capacity of AlO–HQ for the extraction of Ni(II and Co(II are 62.5 and 150 mmol/g, respectively. In the same conditions, and in the same way, Uv–visible absorption spectra of some metal ions extracted by AlO–PHQ were determined and the capacity of these metals was calculated as: [Cu(II: 500, Fe(III: 500, Ni(II: 75 and Co(II: 250 mmol/g]. As an application, extraction of Ni(II from real solution sample (nickel nut by AlO–PHQ was observed.

  6. Scientific Opinion on the safety and efficacy of copper compounds (E4 as feed additives for all species: cupric chelate of amino acids hydrate, based on a dossier submitted by Zinpro Animal Nutrition Inc.

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP

    2013-02-01

    Full Text Available Cupric chelate of amino acids hydrate is safe for all animal species/categories up to the authorised maximum of total copper content in complete feed. Consumption surveys include copper from foodstuffs of animal origin. Since the supplementation of animal feed with copper-containing compounds has not essentially changed over the last decade, no change in the contribution of foodstuffs originating from supplemented animals to the overall copper intake of consumers is expected. No concerns for consumer safety are expected from the use of cupric chelate of amino acids hydrate in animal nutrition, which would substitute for other copper sources. The additive should be considered as a skin and eye irritant and, owing to its amino acid/peptide component, as a skin/respiratory sensitiser. Potential risks to soil organisms have been identified as a result of the application of piglet manure. Levels of copper in other types of manure are too low to create a potential risk within the timescale considered. There might also be a potential environmental concern related to the contamination of sediment resulting from drainage and the run-off of copper to surface water. In order to draw a final conclusion, further model validation is needed and some further refinement to the assessment of copper-based feed additives in livestock needs to be considered, for which additional data would be required. The use of copper-containing additives in aquaculture up to the authorised maximum of total copper content in complete feeds is not expected to pose an appreciable risk to the environment. The extent to which copper-resistant bacteria contribute to the overall antibiotic resistance situation cannot be quantified at present. Cupric chelate of amino acids hydrate is recognised as an efficacious source of copper to meet animal requirements.

  7. Indoor/outdoor relationships of PM10, PM2.5, and PM1 mass concentrations and their water-soluble ions in a retirement home and a school dormitory

    Science.gov (United States)

    Hassanvand, Mohammad Sadegh; Naddafi, Kazem; Faridi, Sasan; Arhami, Mohammad; Nabizadeh, Ramin; Sowlat, Mohammad Hossein; Pourpak, Zahra; Rastkari, Noushin; Momeniha, Fatemeh; Kashani, Homa; Gholampour, Akbar; Nazmara, Shahrokh; Alimohammadi, Mahmood; Goudarzi, Gholamreza; Yunesian, Masud

    2014-01-01

    Indoor/outdoor particulate matter (PM10, PM2.5, and PM1) and their water-soluble ions were measured in a retirement home and a school dormitory in Tehran, from May 2012 to January 2013. Hourly indoor/outdoor PM concentrations were measured using GRIMM dust monitors and 24-h aerosol samples were collected by low-volume air samplers. Water-soluble ions were determined using an ion chromatography (IC) instrument. Although the mean outdoor PM concentrations in both sampling sites were almost equal, the mean indoor PM10 in the school dormitory was approximately 1.35 times higher than that in the retirement home. During a Middle Eastern dust storm, the 24-h average PM10, PM2.5, and PM1 concentrations were respectively 3.4, 2.9, and 1.9 times as high as those in normal days outdoors and 3.4, 2.8, and 1.6 times indoors. The results indicated that secondary inorganic aerosols were the dominant water-soluble ions of indoor and outdoor PM. We found that the smaller the particle, the higher the percentage of secondary inorganic aerosols. Except for PM10 in the school dormitory, strong correlations were found between indoor and outdoor PM. We estimated that nearly 45% of PM10, 67% of PM2.5, and 79% of PM1 in the retirement home, and 32% of PM10, 76% of PM2.5, and 83% of PM1 in the school dormitory originated from outdoor environment.

  8. 铜皂比色法测定稻谷中脂肪酸的研究%The Study of the Determination of Free Fatty Acids in the Grain by the Colorimetric Method of Cupric Acetate-pyridine

    Institute of Scientific and Technical Information of China (English)

    姚云艳; 孙成

    2012-01-01

    Introduce a simple and rapid colorimetric method to determine the free fatty acids in grain. Free fatty acids were extracted by isooctane and used cupric acetate-pyridine as a color developing reagent. The method was more objective, accurate, and easier to perform.%介绍一种简单快速的比色法测定稻谷中脂肪酸含量。采用异辛烷作为提取溶剂,醋酸铜一吡啶溶液作为显色指示剂。该法具有直观准确、易于操作的特点。

  9. 离子色谱仪最小检出浓度的测量不确定度评定%The evaluation of measurement uncertainty on ion chromatography's minimum detectable concentration

    Institute of Scientific and Technical Information of China (English)

    罗海燕

    2012-01-01

      本文在离子色谱仪检测的实践基础之上,结合 JJG 823-93《离子色谱仪》国家计量检定规程与 JJF 1059-1999《测量不确定度评定与表示》国家计量技术规范,讨论了离子色谱仪最小检出浓度的测量不确定度来源,并提出了相应的评定方法,为离子色谱仪的使用者提供参考。%  Based on the practice of the ion chromatography detection,this article combined with JJG 823-93 ion chromatograph national verification regulation and JJF 1059-1999 evaluation and expression of uncertainty in measurement national calibration technical specification,discussed the sources of measurement uncertainty on ion chromatography minimum detectable concentration, and proposed an appropriate assessment method,provided a reference for users of the ion chromatograph.

  10. Reactive Geochemical Transport Modeling of Concentrated AqueousSolutions: Supplement to TOUGHREACT User's Guide for the PitzerIon-Interaction Model

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Guoxiang; Spycher, Nicolas; Xu, Tianfu; Sonnenthal, Eric; Steefel , Carl

    2006-12-15

    In this report, we present: -- The Pitzer ion-interactiontheory and models -- Input file requirements for using the TOUGHREACTPitzer ion-interaction model and associated databases -- Run-time errormessages -- Verification test cases and application examples. For themain code structure, features, overall solution methods, description ofinput/output files for parameters other than those specific to theimplemented Pitzer model, and error messages, see the TOUGHREACT User'sGuide (Xu et al., 2005). The TOUGHREACT Pitzer version runs on aDEC-alpha architecture CPU, under OSF1 V5.1, with Compaq Digital FortranCompiler. The compiler run-time libraries are required for execution aswell as compilation. The code also runs on Intel Pentium IV andhigher-version CPU-based machines with Compaq Visual Fortran Compiler orIntel Fortran Compiler (integrated with the Microsoft DevelopmentEnvironment). The minimum hardware configuration should include 1 GB RAMand 1 GB (2 GB recommended) of available disk space.

  11. Adsorptive Removal of Benzene and Toluene from Aqueous Environments by Cupric Oxide Nanoparticles: Kinetics and Isotherm Studies

    Directory of Open Access Journals (Sweden)

    Leili Mohammadi

    2017-01-01

    Full Text Available Removal of benzene and toluene, as the major pollutants of water resources, has attracted researchers’ attention, given the risk they pose to human health. In the present study, the potential of copper oxide nanoparticles (CuO-NPs in eliminating benzene and toluene from a mixed aqueous solution was evaluated. For this, we performed batch experiments to investigate the effect of solution pH (3–13, dose of CuO-NPs (0.1–0.8 g, contact time (5–120 min, and concentration of benzene and toluene (10–200 mg/l on sorption efficiency. The maximum removal was observed at neutral pH. By using the Langmuir model, we measured the highest adsorption capacity to be 100.24 mg/g for benzene and 111.31 mg/g for toluene. Under optimal conditions, adsorption efficiency was 98.7% and 92.5% for benzene and toluene, respectively. The sorption data by CuO-NPs well fitted into the following models: Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich model. The experimental information well fitted in the Freundlich for benzene and Langmuir for toluene. Based on the results, adsorption followed pseudo-second-order kinetics with acceptable coefficients. The findings introduced CuO-NPs as efficient compounds in pollutants adsorption. In fact, they could be used to develop a simple and efficient pollutant removal method from aqueous solutions.

  12. Effect of Complex Ion Concentration on the Particle Size of Nano Zinc Aluminium Oxide(ZAO)%络离子浓度对掺铝氧化锌(ZAO)纳米粉体粒径的影响

    Institute of Scientific and Technical Information of China (English)

    颜东亮; 陈林; 宋杰光

    2011-01-01

    Zinc aluminium oxide (ZAO) nanoparticles were prepared by complex salt method. A new complex salt crystal, ( NH4 ) 1.95 ( Zn0.95 Al0.05 ) ( SO4 ) 2·6H2O, was synthesized in the experiment, which proved the formation of complex ion in the initial reaction solution. The influence of complex ion concentration on the particle size of ZAO powder was researched by adjusting the addition of (NH4 )2SO4. ZAO powders were characterized by XRD, SEM and laser particle size analyzer. The results indicated that the existing of complex ion decreased the concentration of dissociative metal ion and increased the controllability of primary particle size, which was in favor of the preparation of ZAO nanometer powder.%采用络盐法制备了掺铝氧化锌(ZAO)纳米粉体.通过新复合络盐晶体-(NH4)1.95(Zn0.95Al0.05)(SO4)2·6H2O的合成证实了反应初始溶液中形成了络离子.通过改变(NH4)2SO4的加入量研究了络离子浓度对ZAO粒径的影响.通过XRD、SEM和激光粒度仪对ZAO粉体进行了表征.结果表明:络离子的存在,降低了反应初始溶液中游离金属离子的浓度,使得产物的一次粒径的可调控性增强,有利于纳米级ZAO粉体的制备.

  13. Clinical relevance of the discrepancy in phenylalanine concentrations analyzed using tandem mass spectrometry compared with ion-exchange chromatography in phenylketonuria

    Directory of Open Access Journals (Sweden)

    Bridget M. Stroup

    2016-03-01

    Conclusion: Use of DBS analyzed using MS/MS to monitor blood phe concentrations in individuals with PKU yields significantly lower phe levels compared to plasma phe levels analyzed using IEC. Optimization of current testing methodologies for measuring phe in DBS, along with patient education regarding the appropriate technique for spotting blood on filter paper is needed to improve the accuracy of using DBS to measure phe concentrations in PKU management.

  14. 幼儿牙龈粘膜细胞钙离子浓度与患龋状况关系的研究%Analysis of relationship between gingival cell calcium ions concentration and caries status in children

    Institute of Scientific and Technical Information of China (English)

    刘芸; 石四箴

    2012-01-01

    Objective To measure the intramllnlar calcium ions cunuentration of gmgival cells and to discuss the relationship between the calcium ions concentration and caries status in children. Methods Fifty children aged 3-5 year-old were divided into caries free group and high caries-susceptibility group according to caries status. The lahial gingival deciduous cells in anterior mandibular zone were collected and died, and then the fluorescent intensity of calcium ions was measured by Laser Scanning Contocst Microscopy And the relationship between the fluorescent intensity and caries status was statistically analyzed. Results The fluorescent intensity of gingival cell calcium ions in high caries-susceptibility group was statistically lower than that of caries free group. No statistical difference of calcium ions florescent intensities was found among different genders, different ages. The florescent intensity of gingival cell calcium ions was negatively correlated with dft and CS1. Conclusion The calcium ions concentration of gingival cells is related with caries status to some extent in 3~5 aged children. The more serious the caries status is, the lower the calcium ions concentration is.%目的 测定幼儿牙龈粘膜细胞内钙离子浓度;探讨幼儿牙龈粘膜细胞内钙离子浓度与患龋状况的关系.方法 将50名3~5岁幼儿按患龋状况分为无龋组和龋病高危组.采集幼儿下前矛区唇侧牙龈粘膜脱落细胞,经染色后用激光扫描共聚焦显微镜测定细胞内钙离子的荧光强度,统计分析其与龋患程度的关系.结果 高危组幼儿牙龈粘膜细胞的钙离子荧光强度低于无龋组,两组间差异有高度统计学意义;不同性别,不同年龄间牙龈粘膜细胞的钙离子荧光强度无统计学差异;牙龈粘膜细胞钙离子荧光强度值与dft、CSI间分别呈等级负相关关系.结论 3~5岁幼儿牙龈粘膜细胞钙离子浓度与龋患程度有一定相关性,龋患程度重则钙离子浓度低.

  15. A comparative study of glycoprotein concentration, glycoform profile and glycosylation site occupancy using isotope labeling and electrospray linear ion trap mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chih-Yu; Ma, Yi-Chun; Pai, Pei-Jing [Department of Chemistry, National Taiwan University, No.1, Sec. 4, Roosevelt Rd., Taipei 10617, Taiwan (China); Her, Guor-Rong, E-mail: grher@ntu.edu.tw [Department of Chemistry, National Taiwan University, No.1, Sec. 4, Roosevelt Rd., Taipei 10617, Taiwan (China)

    2012-05-30

    Highlights: Black-Right-Pointing-Pointer Concentration, site occupancy and glycoform variation can be differentiated. Black-Right-Pointing-Pointer Glycopeptides and peptides were stable isotope labeled and analyzed by ESI-MS. Black-Right-Pointing-Pointer Nonglycosylated peptide provided glycoprotein concentration variation. Black-Right-Pointing-Pointer Glycoform variation was obtained by comparing d{sub 0} and d{sub 4} labeled glycopeptides. Black-Right-Pointing-Pointer The variation of glycosylation site occupancy could be calculated. - Abstract: A strategy is presented for comparative analysis of glycoproteins in which the variation of protein concentration, variation of glycosylation site occupancy and variation of glycoform profile can be determined. A comparative study was performed using stable isotope labeling of glycopeptides and peptides by formaldehyde-H{sub 2} and formaldehyde-D{sub 2} and analysis by ESI-MS analysis. The relative intensity of the nonglycosylated peptide provided information about protein concentration variation. Variation of the glycoform profile was obtained by comparing the glycoform profile of d{sub 0}- and d{sub 4}-dimethyl labeled glycopeptides. By knowing the variation of protein concentration and the variation of glycoform profile, the variation of glycosylation site occupancy could be calculated. The utility of the proposed strategy was demonstrated with ribonuclease B with different protein concentrations, different levels of glycosylation site occupancy and different glycoform profiles.

  16. Correlations in concentrations, xylem and phloem flows, and partitioning of elements and ions in intact plants. A summary and statistical re-evaluation of modelling experiments in Ricinus communis.

    Science.gov (United States)

    Peuke, Andreas D

    2010-03-01

    Within the last two decades, a series of papers have dealt with the effects of nutrition and nutrient deficiency, as well as salt stress, on the long-distance transport and partitioning of nutrients in castor bean. Flows in xylem and phloem were modelled according to an empirically-based modelling technique that permits additional quantification of the uptake and incorporation into plant organs. In the present paper these data were statistically re-evaluated, and new correlations are presented. Numerous relationships between different compartments and transport processes for single elements, but also between elements, were detected. These correlations revealed different selectivities for ions in bulk net transport. Generally, increasing chemical concentration gradients for mineral nutrients from the rhizosphere to the root and from the xylem to leaf tissue were observed, while such gradients decreased from root tissue to the xylem and from leaves to the phloem. These studies showed that, for the partitioning of nutrients within a plant, the correlated interactions of uptake, xylem and phloem flow, as well as loading and unloading of solutes from transport systems, are of central importance. For essential nutrients, tight correlations between uptake, xylem and phloem flow, and the resulting partitioning of elements, were observed, which allows the stating of general models. For non-essential ions like Na(+) or Cl(-), a statistically significant dependence of xylem transport on uptake was not detected. The central role of the phloem for adjusting, but also signalling, of nutrition status is discussed, since strong correlations between leaf nutrient concentrations and those in phloem saps were observed. In addition, negative correlations between phloem sap sugar concentration and net-photosynthesis, growth, and uptake of nutrients were demonstrated. The question remains whether this is only a consequence of an insufficient use of carbohydrates in plants or a

  17. Determination of Inorganic Anions in Water by Ion Chromatography Method to Explore the Minimum Detectable Concentration%水中无机阴离子最低检出浓度的计算--离子色谱法

    Institute of Scientific and Technical Information of China (English)

    金梓谦

    2014-01-01

    The method for determination of the minimum detectable concentration of the inorganic anions in water by ion chromatography method was explored, and the calculation results are given to meet the relevant requirements of environmental standards.%对离子色谱法测定水中无机阴离子的最低检出浓度的方法进行了探究,并给出计算结果,满足环境标准相关要求。

  18. UV-induced mutagenesis of oxidation activity of ferrous ion of Thiobacillus ferrooxidans

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    An excellent strain named T. f6 was isolated and screened, the dose and other condition for the UV-induced mutagenesis were studied and the richened positive mutant m+ T. f6 was applied in the column leaching of copper-contain ing sulfides. The results show that T. f6 is characterized by rapid oxidation of ferrous ion and cupric sulfide, high tolerance of toxic ion and short generation time. The best mutagenic effectiveness can be obtained under the dose of low kill rate of UV and low temperature treatment, under which the best richened m+ T. f6 can be shortened 1.4h. It was shown by the column leaching of copper that the leaching rate can be enhanced by at least 11% compared with the original one by the mutants.

  19. Material Exhibiting Efficient CO2 Adsorption at Room Temperature for Concentrations Lower Than 1000 ppm: Elucidation of the State of Barium Ion Exchanged in an MFI-Type Zeolite.

    Science.gov (United States)

    Itadani, Atsushi; Oda, Akira; Torigoe, Hiroe; Ohkubo, Takahiro; Sato, Mineo; Kobayashi, Hisayoshi; Kuroda, Yasushige

    2016-04-06

    Carbon dioxide (CO2) gas is well-known as a greenhouse gas that leads to global warming. Many efforts have been made to capture CO2 from coal-fired power plants, as well as to reduce the amounts of excess CO2 in the atmosphere to around 400 ppm. However, this is not a simple task, particularly in the lower pressure region than 1000 ppm. This is because the CO2 molecule is chemically stable and has a relatively low reactivity. In the present study, the CO2 adsorption at room temperature on MFI-type zeolites exchanged with alkaline-earth-metal ions, with focus on CO2 concentrations CO2, compared with other presented samples, such as the sodium-form and transition-metal ion-exchanged MFI-type zeolites. Ethyne (C2H2) was used as a probe molecule. Analyses were carried out with IR spectroscopy and X-ray absorption, and provided significant information regarding the presence of the M(2+)-O(2-)-M(2+) (M(2+): alkaline-earth-metal ion) species formed in the samples. It was subsequently determined that this species acts as a highly efficient site for CO2 adsorption at room temperature under very low pressure, compared to a single M(2+) species. A further advantage is that this material can be easily regenerated by a treatment, e.g., through the application of the temperature swing adsorption process, at relatively low temperatures (300-473 K).

  20. Effect of calcium chelators on heat coagulation and heat-induced changes of concentrated micellar casein solutions: The role of calcium-ion activity and micellar integrity

    NARCIS (Netherlands)

    Kort, de E.J.P.; Minor, M.; Snoeren, T.A.L.; Hooijdonk, van A.C.M.; Linden, van der E.

    2012-01-01

    There is general consensus that calcium chelators enhance heat stability in milk. However, they increase the heat stability to considerably different extents. For this reason, the effect of various calcium chelators on heat coagulation and heat-induced changes of concentrated micellar casein

  1. Effect of calcium chelators on heat coagulation and heat-induced changes of concentrated micellar casein solutions: The role of calcium-ion activity and micellar integrity

    NARCIS (Netherlands)

    Kort, de E.J.P.; Minor, M.; Snoeren, T.A.L.; Hooijdonk, van A.C.M.; Linden, van der E.

    2012-01-01

    There is general consensus that calcium chelators enhance heat stability in milk. However, they increase the heat stability to considerably different extents. For this reason, the effect of various calcium chelators on heat coagulation and heat-induced changes of concentrated micellar casein solutio

  2. Effective inhibition of the early copper ion burst release with ultra-fine grained copper and single crystal copper for intrauterine device application.

    Science.gov (United States)

    Xu, X X; Nie, F L; Wang, Y B; Zhang, J X; Zheng, W; Li, L; Zheng, Y F

    2012-02-01

    To solve the main problems of existing coarse grained copper (CG Cu) intrauterine devices (IUD)-namely burst release and a low transfer efficiency of the cupric ions during usage-ultra-fine grained copper (UFG Cu) and single crystal copper (SC Cu) have been investigated as potential substitutes. Their corrosion properties with CG Cu as a control have been studied in simulated uterine fluid (SUF) under different conditions using electrochemical measurement methods. Long-term immersion of UFG Cu, SC Cu and CG Cu samples in SUF at 37 °C have been studied for 300 days. A lower copper ion burst release and a higher efficiency release of cupric ions were observed for UFG Cu and SC Cu compared with CG Cu in the first month of immersion and 2 months later. The respective corrosion mechanisms for UFG Cu, SC Cu and CG Cu in SUF are proposed. In vitro biocompatibility tests show a better cellular response to UFG Cu and SC Cu than CG Cu. In terms of instantaneous corrosion behavior, long-term corrosion performance and in vitro biocompatibility, the three pure copper materials follow the order: UFG Cu>SC Cu>CG Cu, which indicates that UFG Cu could be the most suitable candidate material for intrauterine devices.

  3. Leaching of copper concentrates using NaCl and soluble copper contributed by the own concentrate; Lixiviacion de concentrados de cobre utilizando NaCl y el cobre soluble aportado por el propio concentrado

    Energy Technology Data Exchange (ETDEWEB)

    Herrero, O.; Bernal, N.; Quiroz, R.; Fuentes, G.; Vinals, J.

    2005-07-01

    Leaching of copper concentrates using cupric chloro complexes, generated in situ by the reaction between Cu(II), aported by the soluble copper content of the concentrate, and sodium chloride in acid media was studied. The concentrate samples were obtained from mineral processing plants from Antofagasta, Chile. Chemical and mineralogical characterization from original concentrates was made. Typical variable such as a chloride concentration, soluble copper concentration, leaching time, solid percentage and temperature were studied. DRX and EDS analyzed some of the residues. the experimental results indicated that it is possible to obtain solutions having high copper content (15 to 35 g/L) and 2 to 5 g/L free acid in order to submit this solution directly to a solvent extraction stage. The leaching tests use common reactive and low cost such as sodium chloride and sulfuric acid. (Author) 16 refs.

  4. Change in thermoluminescence behaviour of cubic Gd2O3:Yb3+ phosphors with successive increase in Yb3+ ion concentrations

    Science.gov (United States)

    Tamrakar, Raunak Kumar; Bisen, D. P.; Upadhyay, Kanchan

    2017-01-01

    Nanocrystalline Yb3+ doped Gd2O3 phosphors were synthesized by solid state reaction method (SSRM), and effect of Yb3+ concentrations (1 mol% to 7 mol%) on thermoluminescence properties were studied. The XRD technique shows the cubic structure of prepared phosphor for different concentrations of Yb3+. No phase change was found due to the dopant concentration. The crystal size was calculated by Scherer's formula, which is found in 20-60 nm range. The same was also confirmed from the field emission gun scanning electron microscopy (FEGSEM) image, which shows the formation of nanospheres having diameter 20-60 nm range. They are found to be quite uniform in shapes and sizes. Functional group analysis was studied by Fourier transform infrared spectroscopy (FTIR) techniques and the elemental analysis of prepared phosphor was studied by energy dispersive X-ray spectroscopic (EDX) analysis. The samples were irradiated with UV and gamma radiation for the doses varying from 5 to 30 min for UV and 0.5 kGy to 2 kGy for gamma respectively and their thermoluminescence (TL) characteristics have been studied. The effect of heating rate (3-7 °C s-1) and effect of Yb3+ concentration in TL glow curve have been studied. The TL glow curve of nanophosphor shows a peak at around 130 °C for UV and at 247 °C for gamma irradiation respectively. The TL response of the sample irradiated with different gamma doses shows a linear behaviour from 0.5 kGy to 2 kGy and become sublinear behaviour in the range of 5-25 min UV exposure before it saturates with further increase in the dose. Simple glow curve structure, easy method of synthesis and the linear dose response make the nanocrystalline phosphor a good candidate for radiation dosimetry, especially for the estimation of high doses of gamma rays where the nanocrystalline phosphors generally saturated.

  5. Influence of sulfate ion concentration and pH on the corrosion of Mg-Al-Zn-Mn (GA9 magnesium alloy

    Directory of Open Access Journals (Sweden)

    Sudarshana Shetty

    2015-09-01

    Full Text Available The corrosion behavior of Mg-Al-Zn-Mn (GA9 alloy in sodium sulfate solutions was studied over a range of concentrations and solution temperatures at different pH conditions by electrochemical techniques like Tafel extrapolation and electrochemical impedance spectroscopy (EIS. The studies were carried out in solutions with sodium sulfate concentrations 0.1M, 0.5M, 1M, 1.5M and 2M; and at five different temperatures of 30, 35, 40, 45 and 50 °C in a pH range of 3–12. As per the experimental data, the corrosion rate of the alloy increased with the increase in temperature, and also with the increase in concentration of sodium sulfate in the medium. It was observed that the rate of corrosion decreased with the increase in pH. The activation parameters like activation energy, enthalpy of activation and entropy of activation for the corrosion process were calculated. The surface morphology of the alloy was examined before and after corrosion using scanning electron microscopy (SEM.

  6. Behavior of the thermal expansion coefficient of {alpha}-MoO{sub 3} as a function of the concentration of the Nd{sup 3+} ion

    Energy Technology Data Exchange (ETDEWEB)

    Alfonso, J.E., E-mail: jealfonsoo@unal.edu.co [Department of Physics, Universidad Nacional de Colombia, Carrera 30 No. 45-03, Bogota 11001000 (Colombia); Garzon, R. [Engineering project, Universidad Distrital Francisco Jose de Caldas, Carrera 7 No. 40-53, Bogota 11001000 (Colombia); Moreno, L.C. [Department of Chemistry, Universidad Nacional de Colombia, Carrera 30 No 45-03, Bogota 11001000 (Colombia)

    2012-10-01

    We carried out a comparative study of the thermal dilatation coefficient of molybdenum trioxide with and without Nd{sup 3+} doping. The doped samples were obtained from a solid state reaction of MoO{sub 3} and Nd{sub 2}O{sub 3} in concentrations from 0.2 to 20.0 at%. The prepared samples were analyzed as a function of the temperature through X-Ray diffraction (XRD), the chemical composition of the resultant material was studied using Energy Dispersive X-ray Spectroscopy (EDS). The results of the XRD show that the MoO{sub 3} doped with Nd in concentrations of 0.2 and 1.0% atomic grows iso-structurally with {alpha}-MoO{sub 3}. Moreover, MoO{sub 3} doped with Nd{sup 3+} in concentrations of 5.0, 10.0 and 20.0% atomic exhibits the monoclinic phase Mo{sub 9}O{sub 26}. Finally, we determined that the values of the thermal expansion coefficient of MoO{sub 3}, doped and un-doped, differ by less than 3%.

  7. Study of concentration-dependent cobalt ion doping of TiO2 and TiO(2-x)Nx at the nanoscale.

    Science.gov (United States)

    Gole, James L; Prokes, Sharka M; Glembocki, O J; Wang, Junwei; Qiu, Xiaofeng; Burda, Clemens

    2010-07-01

    Experiments with a porous sol-gel generated TiO(2) nanocolloid and its corresponding oxynitride TiO(2-x)N(x) are carried out to evaluate those transformations which accompany additional doping with transition metals. In this study, doping with cobalt (Co(ii)) ions is evaluated using a combination of core level and VB-photoelectron and optical spectroscopy, complementing data obtained from Raman spectroscopy. Raman spectroscopy suggests that cobalt doping of porous sol-gel generated anatase TiO(2) and nitridated TiO(2-x)N(x) introduces a spinel-like structure into the TiO(2) and TiO(2-x)N(x) lattices. TEM and XPS data complemented by valence band-photoelectron spectra demonstrate that metallic cobalt clusters are not formed even at high doping levels. As evidenced by Raman spectroscopy, the creation of a spinel-like structure is commensurate with the room temperature conversion of the oxide and its oxynitride from the anatase to the rutile form. The onset of this kinetically driven process correlates with the formation of spinel sites within the TiO(2) and TiO(2-x)N(x) particles. Despite their visible light absorption, the photocatalytic activity of these cobalt seeded systems is diminished relative to the oxynitride TiO(2-x)N(x).

  8. Distribution Characteristic of Air Negative Ion Concentration in Three Landscape Dropping Waterscape Environment%3种小跌水景观空气负离子浓度分布特征

    Institute of Scientific and Technical Information of China (English)

    谭广文; 郭淑红; 曾非凡

    2014-01-01

    Distribution of microscale negative air ion concentration of three kinds of landscape dropping waterscape,in coastal tourist area of Yangjiang were investigated in this paper.The surveys were randomly conducted every quarter from December 2012 to October 2013, we carried out twelve experiments. Experimental results showed that, as wind speed was 1.1 m/s ~2.3 m/s, ,the negative air ion concentration of three landscape dropping waterscape were significantly higher than negative air ion concentration of tourist area road., high concentrations were determined in water body centered radius within 1.5 m, when distance is more than 1.5 m,concentrations sharply fell with increase of distance, till stable near bottom line; Aeroanion concentrations of small dropping waterscape was positively correlated with distance and humidity, little correlation with temperature. dropping waterscape is the most commonly form used in landscape design.It is concluded that distance between activity field and water body should be shorted, with two contact surfaces increased, appropriate planting shade trees is good for achieving favorable wind direction, so as to maximize realization of negative air ions to human body health benefits.%本研究以阳江银滩滨海旅游区3种景观小跌水为研究对象,进行微尺度下空气负离子浓度的分布观测。研究周期约为一年,按季度随机选择检测时间,2012年12月至2013年10月期间共检测12次,结果表明:在风速范围为1.1~2.3 m·s-1的情况下,滨海景观小跌水环境空气负离子浓度明显高于旅游区无水体的内路段,且高浓度尺度为以水体为中心半径0~1.5 m 处,1.5 m 之外随距离增加而浓度急剧下降,渐趋底线后缓和持平;小跌水负离子浓度与距离和湿度呈正相关关系,与温度相关性不大。小跌水是园林景观水体中最常用的形式,建议设计应缩短活动场地与水体间距离,增大两者接触面;适

  9. Collateral variations between the concentrations of mercury and other water soluble ions in volcanic ash samples and volcanic activity during the 2014-2016 eruptive episodes at Aso volcano, Japan

    Science.gov (United States)

    Marumoto, Kohji; Sudo, Yasuaki; Nagamatsu, Yoshizumi

    2017-07-01

    During 2014-2016, the Aso volcano, located in the center of the Kyushu Islands, Japan, erupted and emitted large amounts of volcanic gases and ash. Two episodes of the eruption were observed; firstly Strombolian magmatic eruptive episodes from 25 November 2014 to the middle of May 2015, and secondly phreatomagmatic and phreatic eruptive episodes from September 2015 to February 2016. Bulk chemical analyses on total mercury (Hg) and major ions in water soluble fraction in volcanic ash fall samples were conducted. During the Strombolian magmatic eruptive episodes, total Hg concentrations averaged 1.69 ± 0.87 ng g- 1 (N = 33), with a range from 0.47 to 3.8 ng g- 1. In addition, the temporal variation of total Hg concentrations in volcanic ash varied with the amplitude change of seismic signals. In the Aso volcano, the volcanic tremors are always observed during eruptive stages and quiet interludes, and the amplitudes of tremors increase at eruptive stages. So, the temporal variation of total Hg concentrations could provide an indication of the level of volcanic activity. During the phreatomagmatic and phreatic eruptive episodes, on the other hand, total Hg concentrations in the volcanic ash fall samples averaged 220 ± 88 ng g- 1 (N = 5), corresponding to 100 times higher than those during the Strombolian eruptive episode. Therefore, it is possible that total Hg concentrations in volcanic ash samples are largely varied depending on the eruptive type. In addition, the ash fall amounts were also largely different among the two eruptive episodes. This can be also one of the factors controlling Hg concentrations in volcanic ash.

  10. Mixed messages from benthic microbial communities exposed to nanoparticulate and ionic silver: 3D structure picks up nano-specific effects, while EPS and traditional endpoints indicate a concentration-dependent impact of silver ions.

    Science.gov (United States)

    Kroll, Alexandra; Matzke, Marianne; Rybicki, Marcus; Obert-Rauser, Patrick; Burkart, Corinna; Jurkschat, Kerstin; Verweij, Rudo; Sgier, Linn; Jungmann, Dirk; Backhaus, Thomas; Svendsen, Claus

    2016-03-01

    Silver nanoparticles (AgNP) are currently defined as emerging pollutants in surface water ecosystems. Whether the toxic effects of AgNP towards freshwater organisms are fully explainable by the release of ionic silver (Ag(+)) has not been conclusively elucidated. Long-term effects to benthic microbial communities (periphyton) that provide essential functions in stream ecosystems are unknown. The effects of exposure of periphyton to 2 and 20 μg/L Ag(+) (AgNO3) and AgNP (polyvinylpyrrolidone stabilised) were investigated in artificial indoor streams. The extracellular polymeric substances (EPS) and 3D biofilm structure, biomass, algae species, Ag concentrations in the water phase and bioassociated Ag were analysed. A strong decrease in total Ag was observed within 4 days. Bioassociated Ag was proportional to dissolved Ag indicating a rate limitation by diffusion across the diffusive boundary layer. Two micrograms per liter of AgNO3 or AgNP did not induce significant effects despite detectable bioassociation of Ag. The 20-μg/L AgNO3 affected green algae and diatom communities, biomass and the ratio of polysaccharides to proteins in EPS. The 20-μg/L AgNO3 and AgNP decreased biofilm volume to about 50 %, while the decrease of biomass was lower in 20 μg/L AgNP samples than the 20-μg/L AgNO3 indicating a compaction of the NP-exposed biofilms. Roughness coefficients were lower in 20 μg/L AgNP-treated samples. The more traditional endpoints (biomass and diversity) indicated silver ion concentration-dependent effects, while the newly introduced parameters (3D structure and EPS) indicated both silver ion concentration-dependent effects and effects related to the silver species applied.

  11. Notes on the exposure of several species of fish to sudden changes in the hydrogen-ion concentration of the water and to an atmosphere of pure oxygen

    Energy Technology Data Exchange (ETDEWEB)

    Wiebe, A.H.

    1931-01-01

    Several species of fish have been subjected to higher concentrations of dissolved oxygen when an atmosphere of pure oxygen was maintained over the surface of the water and also with a super-stratum of pure oxygen under pressure. Several species of fish have been subjected to sudden transfers from low O/sub 2/ to high O/sub 2/ and the reverse. (5.6 p.p.M. to 40.33 p.p.M. and from 41.0 to 7.3 p.p.M.) The results show (a) that different sizes of several species of fish tolerate large and sudden changes in the concentration of O/sub 2/ in either direction, (b) that these fish can live in water containing a large excess of dissolved oxygen with a super-stratum of pure oxygen over the surface (c) that several species of fish can stand pressure of 10 to 13 lbs. for a period of 24 hours and pressures from 15 to 19 lbs for shorter periods. The increase in dissolved oxygen is followed by a slowing down of the respiratory movements. No instances of exophthalmus, opaqueness of the lens, and of the accumulation of gas bubbles were observed. No fish were observed to lose their equilibrium except in the pressure experiment where depression occurred too rapidly. That exposure to a high concentration of dissolved oxygen with a super-stratum of pure oxygen at atmospheric pressures and under small pressure is not harmful is inferred from the small number of fish lost and from the length of time they survived the experiment. The data presented here suggest that they may by applicable to the problem of handling fish in transportation.

  12. [The Analysis for Probable Reasons of Cd4+ T-Cell Activation Non-Linear Dependence on Extra Cellular Calcium Ion Concentration in Human Peripheral Blood in vitro].

    Science.gov (United States)

    Litvinov, I S

    2015-01-01

    The analysis for probable reasons of CD4+ T-cell activation non-linear dependence on [Ca2+]o in HPB in vitro is the general aim of current work. At the beginning we pursued the analysis of receptor-dependent (the mixture of monoclonal antibodies (mAbs) to CD3 and CD28 molecules) and receptor-independent (phorbol-myristate-acetate and ionomycin mixture) means to activate T cells in vitro with different [Ca2+]o in HPB. The key role of intracellular T-cell signaling systems in activated T cells in their non-similar sensitivity to calcium ions in the blood was shown. The analysis of differentiation next stages of CD4+ T-cell activation in vitro relatively [Ca2+]o in PHB demonstrates the key role of the earliest induction stages in non-similar sensitivity to calcium ions in CD4+ T-cell activation in vitro. According to the pursued analysis; the non-similar sensitivity of CD4+ T-cell in vitro to activation is in no-way connected with pace differences on the primary stages of activation process. The comparison of CD4+ memory T cells with their naive T-cell precursors in the cell activation process in hypocalcemia conditions was made in the separate experimental series. The 1st maximum consists in average of 85% CD4+CD45R0high CD69+ memory T cells. Naive CD4+CD45RAlowCD69+ T cells constitute the remainder 15%. The 2nd maximum almost completely consists of CD4+CD45R0+CD69+ memory T cells. The ratio between CD4+CD69+ T cell maximums depends on donor ages and represents linear dependence with R = -0.981. The most probable candidate on the role of CD4+ T cell, being capable of activation in hypocalcemia conditions, are memory T lymphocytes, being resistant to ionomycin action (I R) subset. To check this assumption the mononuclear cells and their IR-fraction were prepared from donor PB. Then the mononuclear cells and their IR-fraction were activated by mAbs mixture at different [EGTA] values. For IR-fraction, enriched with CD4+CD45RA-CD45R0+ memory T cells, slightly seen 1st

  13. Spectroscopic study of Cu{sup 2+} and Cu{sup +} ions in high-transmission glass. Electronic structure and Cu{sup 2+}/Cu{sup +} concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, Susana; Rodriguez, Fernando [MALTA-CONSOLIDER-Team, DCITIMAC, Facultad de Ciencias, Universidad de Cantabria, 39005 Santander (Spain); Urra, Inigo [Departmento Construccion, Area de Energia y medioambiente, CIDEMCO-Tecnalia, 20730 Azpeitia (Spain); Valiente, Rafael, E-mail: gomezss@unican.e [MALTA-CONSOLIDER-Team, Departmento Fisica Aplicada, Facultad de Ciencias, Universidad de Cantabria, 39005 Santander (Spain)

    2010-07-28

    This work investigates the formation of photoluminescence centres in high-transmission glass (HTG) doped with Cu{sub 2}O and their capability to transform the solar spectrum by absorption/emission via Stokes-shifted PL into a more efficient spectrum for photovoltaic applications. Among the centres formed in HTG, both green photoluminescent Cu{sup +} and the non-photoluminescent Cu{sup 2+} centres are created but their relative concentration depends on the thermal treatment and the presence of other co-dopants. The measurement of the absorption coefficient {alpha}({lambda}) nearby the HTG optical gap for Cu{sup +} bands is accomplished by following the two-thickness method. This procedure allows us to obtain the actual absorption coefficient for the spectrum of each formed centre, from which we obtain the relative concentration of Cu{sup +}/Cu{sup 2+} as well as their absolute values. The analysis of the spectra provides information on the absorption cross sections, transition energies and bandwidths, the knowledge of which is essential to check the suitability of such centres for photovoltaic applications in solar cells.

  14. A novel method for simultaneous measurement of concentration and enrichment of NO synthesis-specific amino acids in human plasma using stable isotopes and LC/MS ion trap analysis.

    Science.gov (United States)

    Oosterink, J Efraim; Buijs, Nikki; van Goudoever, Johannes B; Schierbeek, Henk

    2014-05-01

    Stable isotope studies offer the opportunity to study the in-depth metabolic pathway of glutamine, citrulline, and arginine amino acids involved in NO synthesis. The use of multiple stable isotopes can be used to elucidate the exact transformation of glutamine to citrulline and arginine de novo synthesis. This novel method provides a purification step using cation exchange resin in combination with a rapid and easy derivatization procedure for a precise and robust measurement of the concentration and isotopic enrichments of NO synthesis-specific amino acids using a liquid chromatography mass spectrometry (LC/MS) ion trap system with high sensitivity and selectivity. The ethyl chloroformate derivatization procedure is beneficial in terms of robustness, velocity, simplicity, and derivative stability. In addition, the ethyl chloroformate derivatization can be performed at room temperature in an aqueous environment without incubation and the isolation of the derivatives from the reaction mixture also serves as a purification step. The concentration and enrichment of NO synthesis-specific amino acids as well as phenylalanine and tyrosine to determine protein turnover, were measured with good inter-day precision for the concentration (glutamine-citrulline-arginine pathway by using stable isotope studies.

  15. Light-induced changes in hydrogen, calcium, potassium, and chloride ion fluxes and concentrations from the mesophyll and epidermal tissues of bean leaves. Understanding the ionic basis of light-induced bioelectrogenesis

    Science.gov (United States)

    Shabala; Newman

    1999-03-01

    Noninvasive, ion-selective vibrating microelectrodes were used to measure the kinetics of H+, Ca2+, K+, and Cl- fluxes and the changes in their concentrations caused by illumination near the mesophyll and attached epidermis of bean (Vicia faba L.). These flux measurements were related to light-induced changes in the plasma membrane potential. The influx of Ca2+ was the main depolarizing agent in electrical responses to light in the mesophyll. Changes in the net fluxes of H+, K+, and Cl- occurred only after a significant delay of about 2 min, whereas light-stimulated influx of Ca2+ began within the time resolution of our measurements (5 s). In the absence of H+ flux, light caused an initial quick rise of external pH near the mesophyll and epidermal tissues. In the mesophyll this fast alkalinization was followed by slower, oscillatory pH changes (5-15 min); in the epidermis the external pH increased steadily and reached a plateau 3 min later. We explain the initial alkalinization of the medium as a result of CO2 uptake by photosynthesizing tissue, whereas activation of the plasma membrane H+ pump occurred 1.5 to 2 min later. The epidermal layer seems to be a substantial barrier for ion fluxes but not for CO2 diffusion into the leaf.

  16. Light-Induced Changes in Hydrogen, Calcium, Potassium, and Chloride Ion Fluxes and Concentrations from the Mesophyll and Epidermal Tissues of Bean Leaves. Understanding the Ionic Basis of Light-Induced Bioelectrogenesis1

    Science.gov (United States)

    Shabala, Sergey; Newman, Ian

    1999-01-01

    Noninvasive, ion-selective vibrating microelectrodes were used to measure the kinetics of H+, Ca2+, K+, and Cl− fluxes and the changes in their concentrations caused by illumination near the mesophyll and attached epidermis of bean (Vicia faba L.). These flux measurements were related to light-induced changes in the plasma membrane potential. The influx of Ca2+ was the main depolarizing agent in electrical responses to light in the mesophyll. Changes in the net fluxes of H+, K+, and Cl− occurred only after a significant delay of about 2 min, whereas light-stimulated influx of Ca2+ began within the time resolution of our measurements (5 s). In the absence of H+ flux, light caused an initial quick rise of external pH near the mesophyll and epidermal tissues. In the mesophyll this fast alkalinization was followed by slower, oscillatory pH changes (5–15 min); in the epidermis the external pH increased steadily and reached a plateau 3 min later. We explain the initial alkalinization of the medium as a result of CO2 uptake by photosynthesizing tissue, whereas activation of the plasma membrane H+ pump occurred 1.5 to 2 min later. The epidermal layer seems to be a substantial barrier for ion fluxes but not for CO2 diffusion into the leaf. PMID:10069851

  17. 用离子浓度表示的氧化还原滴定的林邦滴定曲线方程%The redox titration of Ringbom titration curve equation is expressed by ion concentration

    Institute of Scientific and Technical Information of China (English)

    乔成立; 李文新

    2013-01-01

    Derived that ion concentration expressed reversible symmetrical complex redox titration and reversible asymmetric complex redox titration curve equation from redox the reaction equilibrium relationship and Ringbom adverse thought,so as to lay the foundation for solving the problem in the theory of the redox titration by redox titration curve equation.%用氧化还原反应平衡关系和林邦副反应思想推导出用离子浓度表示的可逆对称的复杂氧化还原滴定和可逆不对称的复杂氧化还原滴定的滴定曲线方程,为用氧化还原滴定曲线方程解决氧化还原滴定的理论问题奠定基础。

  18. 离子色谱法测定饮用水中氯化物的不确定度评定%Uncertainty Evaluation of the Determination of Chloride Ion Concentration in Drinking Water by Ion Chromatogram(IC)

    Institute of Scientific and Technical Information of China (English)

    封蓉芳; 陈军; 缪英

    2011-01-01

    目的:为减少实验误差,提高检测结果精确度,评定水中氯化物的不确定度。方法:分析水中氯化物不确定度的来源,通过计算得出该法测定水中氯化物的扩展不确定度。结果:测量结果表明扩展不确定度U95=0.54mg/L,适用于每个水样的检测结果。结论:该方法简便,适合于每一个样本的检测结果,可参考用于水中某些检测参数的不确定评定。%Objective : To evaluate the uncertainty of measuring Cl-concentration in drinking water.This study was to decrease experimental error and increase the accuracy of results.Methods: The source of Measurement uncertainty of the chloride determination in wate

  19. Evaluation of air cleanness degree of the urban environment based on negative air ion concentration%基于空气负离子浓度的城市环境空气清洁度评价

    Institute of Scientific and Technical Information of China (English)

    王薇; 余庄; 冀凤全

    2013-01-01

      选取安徽合肥和广东深圳为研究对象,收集其空气正、负离子浓度、风速、空气温度、相对湿度、材料和植物负离子浓度等数据并分析.结果显示,空气负离子浓度与风速、水、植物、相对湿度等有较为密切的关系,其中最主要的影响是水,其次是风,最小的是气温;并根据对城市室内外环境的实测研究,利用空气离子单极系数及安倍空气离子评价指数对城市室内外环境的空气质量进行初步评价,结果表明,从城市室内环境到城市居住区环境、城镇、自然生态环境空气清洁度逐步变好.城市居住区环境中,以低层高密度住区的空气质量最好,空气负离子浓度为289个/cm3,空气质量达到1.7,空气清洁度为最清洁;而高层居住区最差,空气负离子浓度为139个/cm3,空气质量达到0.08,空气清洁度为重污染.城市室内环境中以自然通风和有新风进入的房间空气质量最好,同时放置负离子发生器对室内空气质量也有显著提高.因此,建议在城市规划建设中采取有效措施以提高空气负离子浓度的分布,从而改善城市生态环境以创造舒适宜居的空气环境,并把空气负离子浓度列为室内环境的监测和评价指标,为今后城乡建设规划、城市林业规划和环境能源保护提供科学依据和设计思路.%In this study, we conducted test in Hefei of Anhui province and Shenzhen of Guangdong province in China, where we chose different typical sites to measure and research. The measurements included negative air ion concentration, positive air icon concentration, wind speed, air temperature, relative humidity and negative air icon concentration in materials and plants. The results showed that negative air icon concentration had a closer relation with wind speed, water, plants and air humidity than other factors, the most important factor was the water, followed by wind, and the minimal was air temperature

  20. Mass concentration and ion composition of coarse and fine particles in an urban area in Beirut: effect of calcium carbonate on the absorption of nitric and sulfuric acids and the depletion of chloride

    Directory of Open Access Journals (Sweden)

    H. Kouyoumdjian

    2006-01-01

    Full Text Available Levels of coarse (PM10-2.5 and fine (PM2.5 particles were determined between February 2004 and January 2005 in the city of Beirut, Lebanon. While low PM mass concentrations were measured in the rainy season, elevated levels were detected during sand storms originating from Arabian desert and/or Africa. Using ATR-FTIR and IC, it was shown that nitrate, sulfate, carbonate and chloride were the main anionic constituents of the coarse particles, whereas sulfate was mostly predominant in the fine particles in the form of (NH42SO4. Ammonium nitrate was not expected to be important because the medium was defined as ammonium poor. In parallel, the cations Ca2+ and Na+ dominated in the coarse, and NH4+, Ca2+ and Na+ in the fine particles. Coarse nitrate and sulfate ions resulted from the respective reactions of nitric and sulfuric acid with a relatively high amount of calcium carbonate. Both CaCO3 and Ca(NO32 crystals identified by ATR-FTIR in the coarse particles were found to be resistant to soaking in water for 24 h but became water soluble when they were formed in the fine particles suggesting, thereby, different growth and adsorption phenomena. The seasonal variational study showed that nitrate and sulfate ion concentrations increased in the summer due to the enhancement of photochemical reactions which facilitated the conversion of NO2 and SO2 gases into NO3- and SO42-, respectively. While nitrate was mainly due to local heavy traffic, sulfates were due to local and long-range transport phenomena. Using the air mass trajectory HYSPLIT model, it was found that the increase in the sulfate concentration correlated with wind vectors coming from Eastern and Central Europe. Chloride levels, on the other hand, were high when wind originated from the sea and low during sand storms. In addition to sea salt, elevated levels of chloride were also attributed to waste mass burning in proximity to the site. In comparison to other neighboring Mediterranean

  1. Blood concentrations of ions and metals in amateur and elite runners using neutron activation analyses; Concentracoes de ions e metais em sangue de atletas amadores e de elite usando analise por ativacao neutronica

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Luciana Kovacs dos

    2012-07-01

    In this study Br, Ca, Cl, Fe, I, K, Mg, Na, S and Zn concentration were investigated in blood of Brazilian athletes (endurance) using Neutron Activation Analyses technique (NAA). The blood samples were collected from male amateur athletes (AR) and male and female elite athletes (ER), ranging from 18 to 36 year old. The blood samples were collected at the LABEX/UNICAMP and they were irradiated in the nuclear reactor IEA-R1 at IPEN (Sao Paulo, Brazil). The range (at rest) established for AR and ER were compared with the control group (CG), subjects of same gender and age but not involved with physical activities, and showed significant differences for Ca (51 - 439 mgL{sup -1} for CG, 162 - 410 mgL{sup -1} for AR and 64 - 152 mgL{sup -1} for ER) and Br (7.4 - 30.6 mgL{sup -1} for CG, 4.0 - 9.6 mgL{sup -1} for AR and 1.9 - 3.5 mgL{sup -1} for ER), suggesting that a strong dependency of these limits in function of adopted physical training exists. We also performed a systematic investigation for the AR before, during and after the exercise program. These data can be considered for the preparation of a balanced diet, for evaluating the performance of the athletes during the period of competition preparation as well as contributing for proposing new protocols of clinical evaluation not reported in the literature yet. (author)

  2. Research on the Effect of Ammonium Ion Concentration on Nickel Smelting Technology%铵离子浓度对沉镍工艺的影响研究

    Institute of Scientific and Technical Information of China (English)

    杨小山; 魏万林

    2012-01-01

    在红土镍矿湿法浸出过程中,采用氨法沉镁提取镁盐产品后产生的大量工业废水,如直接排放会影响生态环境,一般都会回用做为镍冶炼工业用水.试验表明含铵浓度不超过0.5 g/L时,对沉镍时Ni、Mn沉淀率和耗碱量无影响,反而可以提高含镁废水中的镁含量,有利于含镁废水的氨法沉镁生产工艺.同时解决了镍冶炼过程中含镁母液氨法沉镁后的废水排放问题,达到了生产用水的循环综合利用,有效的节约了水资源,降低了生产成本.%Much quantity of waste water is discharged when magnesium product is produced by ammonia method during nickel is extracted by wet method from laterite nickel ore. The environment will be polluted if the waste water is discharged directly. Waste water is often recycled to be industrial water for nickel smelting. It is showed by experiment that there has no effect on depositing rate of Ni, Mn and the quantity of consumed alkali if the concentration of ammonium is less than 0. 5 g/L. In such a case, the magnesium contented in the waste water is improved and favorable for magnesium production by ammonia depositing method. It can solve the problem of waste water discharging during nickel smelting process because the waste water is recycled to be industrial water after magnesium is deposited by ammonia method. The water resource is saved and the production cost is decreased effectively.

  3. Treatment of wastewater containing high concentration nickel ions with precipitation-microfiltration-complexation-ultrafiltration processes%化学沉淀-微滤-络合-超滤处理高浓度含镍废水

    Institute of Scientific and Technical Information of China (English)

    张学俊; 曾坚贤; 张鹏; 申少华; 易良刚; 田俊; 李敏

    2016-01-01

    The wastewater containing high concentration (5562.71mg/L) of nickel ion was first completely precipitated at pH 9, and subsequently treated by a ceramic microfiltration membrane with a pore diameter of 0.5μm. During the concentration process, the membrane flux (J) dropped significantly at the initial stage, then declined slowly, and finally decreased at a rapid rate again. The nickel rejection coefficient (RNi) was found to be approx. 1. When the volume concentration factor (VCF) increased from 1to 10, the nickel concentration in the retentate (Cr) increased from 5562.71 to 55507.76mg/L, whereas the nickel concentration in the permeate (Cp) remained nearly constant at approx. 13.26mg/L. Then, the complexation-ultrafiltration process was studied using the permeation fluid from the microfiltration process as the feed solution. Poly (ethylene imine) was employed as the complexing agent. The effects of the polymer/metal mass ratio (rp/m), pH, temperature and operating pressure on RNi and J were investigated. Further, the process of ultrafiltration concentration was studied. The results showed that RNi increased with increasingrp/m or pH and decreased slightly with temperature, and that the operating pressure exerted no effect on RNi;J increased with temperature or operating pressure. With increasing pH,Jincreased at first, and then reached a constant value. The effect of rp/m on J was insignificant. The ultrafiltration concentration experiment was carried out at rp/m=7 and pH=9. When VCF increased from 1to 30,J only declined by 9.76%.Cr increased linearly from 13.26to 396.64mg/L, whereas Cp remained roughly unchanged at about 0.04mg/L. Nickel ions were concentrated effectively, and the permeation solution from the ultrafiltration process was discharged directly.%在pH=9下,镍离子浓度为5562.71mg/L的镍废水经充分沉淀后,以0.5μm孔径陶瓷膜微滤处理,发现浓缩时膜通量(J)先快速降低,经缓慢下降后,再较快

  4. Concentration dependence of intensity parameters and radiative properties of Sm{sup 3+} ions doped in BaO–ZnO–B{sub 2}O{sub 3} glasses

    Energy Technology Data Exchange (ETDEWEB)

    Nanda, Kirti; Kundu, R.S.; Pal, Inder [Department of Applied Physics, Guru Jambheshwar University of Science & Technology, Hisar 125001 (India); Punia, R., E-mail: rajeshpoonia13@gmail.com [Department of Applied Physics, Guru Jambheshwar University of Science & Technology, Hisar 125001 (India); Department of Physics, Indira Gandhi University, Mirpur, Rewari 123401 (India); Kishore, N. [Department of Applied Physics, Guru Jambheshwar University of Science & Technology, Hisar 125001 (India)

    2016-08-15

    Glass samples with compositions xSm{sub 2}O{sub 3}- (100−x)[0.1BaO–0.4ZnO–0.5B{sub 2}O{sub 3}]; x = 0.5, 1.0, 1.5 and 2.0 have been prepared using melt quench technique. Optical absorption and fluorescence spectra have been recorded for prepared glass samples at room temperature. The spectral intensities of Sm{sup 3+} transition observed in absorption spectra have been calculated by using Judd–Ofelt theory. The intensity parameters (Ω{sub 2}, Ω{sub 4} and Ω{sub 6}) have been estimated by applying least square fit method on the experimental (f{sub exp}) and calculated (f{sub cal}) oscillator strengths. The variation of Ω{sub 2} observed with the increase in Sm{sup 3+} ion concentration, is attributed to decease in covalency of rare earth oxygen bond due to change in optical basicity of host glass matrix. From the fluorescence spectra, four emission spectral lines have been observed that correspond to the transition from {sup 4}G{sub 5/2} ground state to lower lying {sup 6}H{sub 5/2}, {sup 6}H{sub 7/2}, {sup 6}H{sub 9/2} and {sup 6}H{sub 11/2} states with an excitation wavelength of 402 nm. The intensity parameters and the emission measurements have been used to estimate the various radiative parameters such as transition probabilities (A{sub R}), radiative lifetime (τ{sub R}), branching ratio (β{sub R}) and stimulated emission cross-sections (σ{sub e}) of luminescent levels. The value of σ{sub e} is found to decrease with increase in concentration of Sm{sup 3+} ions and it possesses higher value for glass sample with x = 0.5 for transition lying in the visible region indicating its importance for photonic applications. - Highlights: • Sm{sup 3+} ions doped BaO–ZnO–B{sub 2}O{sub 3} glasses have been prepared by melt-quench technique. • Judd–Ofelt intensity parameters have been obtained from absorption spectra. • Radiative properties have been estimated from Judd–Ofelt theory.

  5. Ion-Ion Neutralization.

    Science.gov (United States)

    1980-12-31

    plasma were identified using a downstream quadrupole mass spectrometer. In these experimento it is a simple matter to establish H+(H 2 0):f as the...pressure as predicted by the Thomson t2rnary mechanism whicK hzr been suownr to be valid experimentally at hiTh rrsurs (,han and Peron, 1:EI4 hereafter t...of NO , NO2 ions in various gases and the ternary recombination coefficients of these ions in the higher pres:;ure ( Thomson ) re"ie. Equation (5) cr>n

  6. Evaluation of copper ion of antibacterial effect on Pseudomonas aeruginosa, Salmonella typhimurium and Helicobacter pylori and optical, mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young-Hwan [School of Materials Science and Engineering, University of Yonsei, Seoul (Korea, Republic of); Choi, Yu-ri; Kim, Kwang-Mahn [Department and Research Institute of Dental Biomaterials and Bioengineering, College of Dentistry, University of Yonsei, Seoul (Korea, Republic of); Choi, Se-Young, E-mail: sychoi@yonsei.ac.kr [School of Materials Science and Engineering, University of Yonsei, Seoul (Korea, Republic of)

    2012-02-01

    Antibacterial effect on Pseudomonas aeruginosa, Salmonella typhimurium and Helicobacter pylori of copper ion was researched. Also, additional effects of copper ion coating on optical and mechanical properties were researched as well. Copper ion was coated on glass substrate as a thin film to prevent bacteria from growing. Cupric nitrate was used as precursors for copper ion. The copper ion contained sol was deposited by spin coating process on glass substrate. Then, the deposited substrates were heat treated at the temperature range between 200 Degree-Sign C and 250 Degree-Sign C. The thickness of deposited copper layer on the surface was 63 nm. The antibacterial effect of copper ion coated glass on P. aeruginosa, S. typhimurium and H. pylori demonstrated excellent effect compared with parent glass. Copper ion contained layer on glass showed a similar value of transmittance compared with value of parent glass. The 3-point bending strength and Vickers hardness were 209.2 MPa, 540.9 kg/mm{sup 2} which were about 1.5% and 1.3% higher than the value of parent glass. From these findings, it is clear that copper ion coating on glass substrate showed outstanding effect not only in antibacterial activity but also in optical and mechanical properties as well.

  7. Evaluation of copper ion of antibacterial effect on Pseudomonas aeruginosa, Salmonella typhimurium and Helicobacter pylori and optical, mechanical properties

    Science.gov (United States)

    Kim, Young-Hwan; Choi, Yu-ri; Kim, Kwang-Mahn; Choi, Se-Young

    2012-02-01

    Antibacterial effect on Pseudomonas aeruginosa, Salmonella typhimurium and Helicobacter pylori of copper ion was researched. Also, additional effects of copper ion coating on optical and mechanical properties were researched as well. Copper ion was coated on glass substrate as a thin film to prevent bacteria from growing. Cupric nitrate was used as precursors for copper ion. The copper ion contained sol was deposited by spin coating process on glass substrate. Then, the deposited substrates were heat treated at the temperature range between 200 °C and 250 °C. The thickness of deposited copper layer on the surface was 63 nm. The antibacterial effect of copper ion coated glass on P. aeruginosa, S. typhimurium and H. pylori demonstrated excellent effect compared with parent glass. Copper ion contained layer on glass showed a similar value of transmittance compared with value of parent glass. The 3-point bending strength and Vickers hardness were 209.2 MPa, 540.9 kg/mm2 which were about 1.5% and 1.3% higher than the value of parent glass. From these findings, it is clear that copper ion coating on glass substrate showed outstanding effect not only in antibacterial activity but also in optical and mechanical properties as well.

  8. Determination of nanogram per liter concentrations of volatile organic compounds in water by capillary gas chromatography and selected ion monitoring mass spectrometry and its use to define groundwater flow directions in Edwards Aquifer, Texas

    Science.gov (United States)

    Buszka, P.M.; Rose, D.L.; Ozuna, G.B.; Groschen, G.E.

    1995-01-01

    A method has been developed to measure nanogram per liter amounts of selected volatile organic compounds (VOCs) including dichlorodifluoromethane, trichlorofluoromethane, cis-1,2-dichloroethene, trichloroethene, tetrachloroethene, and the isomers of dichlorobenzene in water. The method uses purge-and-trap techniques on a 100 mL sample, gas chromatography with a megabore capillary column, and electron impact, selected ion monitoring mass spectrometry. Minimum detection levels for these compounds ranged from 1 to 4 ng/L in water. Recoveries from organic-free distilled water and natural groundwater ranged from 70.5% for dichlorodifluoromethane to 107.8% for 1,4-dichlorobenzene. Precision was generally best for cis-1,2-dichloroethene, tetrachloroethene, and the dichlorobenzene isomers and worst for dichlorodifluoromethane and trichlorofluoromethane. Blank data indicated persistent, trace-level introduction of dichlorodifluoromethane, 1,4-dichlorobenzene, and tetrachloroemene to samples during storage and shipment at concentrations less than the method reporting limits. The largest concentrations of the selected VOCs in 27 water samples from the Edwards aquifer near San Antonio, TX, were from confined-zone wells near an abandoned landfill. The results defined a zone of water with no detectable VOCs in nearly all of the aquifer west of San Antonio and from part of the confined zone beneath San Antonio.

  9. Preparation and electrochemical characterization of polyvinylchloride/ FeTiO{sub 3}-co-Fe{sub 3}O{sub 4} nanoparticles mixed matrix ion exchange membranes: Investigation of concentration and pH effects

    Energy Technology Data Exchange (ETDEWEB)

    Hosseini, Sayedmohsen; Hamidi, Alireza; Moghadassi, Abdolreza; Parvizian, Fahime [Faculty of Engineering, Arak University, Arak (Iran, Islamic Republic of); Madaeni, Sayed Siavash [Faculty of Engineering, Razi University, Kermanshah (Iran, Islamic Republic of)

    2015-09-15

    Polyvinyl chloride based/FeTiO{sub 3}-co-Fe{sub 3}O{sub 4} nanoparticles mixed matrix heterogeneous cation exchange membranes were prepared by solution casting technique. The effect of using filler additives in casting solution and also electrolyte concentration and pH on electrochemical properties of membrane was studied. Membrane potential, transport number and selectivity were improved by using FeTiO{sub 3}/Fe{sub 3}O{sub 4} nanoparticles in membrane matrix. Utilizing FeTiO{sub 3}/ Fe{sub 3}O{sub 4} nanoparticles in membrane matrix also led to improvement of membrane ionic flux from 2.95*10{sup -5} to 4.15*10{sup -5} (mol/m{sup 2}·s) obviously. Similar trend was also found for membrane electrical conductivity. Moreover, the transport number, selectivity and membrane electrical conductivity were enhanced by increase of electrolyte concentration. Prepared membranes exhibited higher transport number/selectivity at pH 7 compared to other pH values. Obtained results showed that the membrane electrical resistance decreased initially by increase of electrolyte pH sharply and then began to increase. Membranes exhibited lower selectivity for bivalent ions compared to monovalent type. Modified membranes containing FeTiO{sub 3}/Fe{sub 3}O{sub 4} nanoparticles showed more appropriate electrochemical properties compared to other prepared membranes.

  10. Honeycomb Cupric Oxide and Hematite Nanotubes Synergism Photoelectro-reduction CO2%蜂窝状CuO和Fe2O3纳米管协同光电还原CO2

    Institute of Scientific and Technical Information of China (English)

    王祜英; 徐金凤; 井华; 张军; 李培强; 路福绥

    2013-01-01

    采用阳极氧化法在Fe上原位生长直立有序的Fe2O3纳米管阵列,脉冲电沉积法将蜂窝状CuO组装到Fe2O3NTs上,得到CuO HCs/Fe2O3NTs催化剂.结果表明:Fe2O3NTs呈“火山状”规则生长,蜂窝状CuO均匀分布在Fe2O3 NTs表面.修饰后,材料的能隙由原来的2.03 eV窄化为1.84 eV.同时发现该催化剂具有优良的光催化还原性能和电催化还原性能,光电催化还原CO2的主要生成产物为甲醇,甲醇在6h时含量峰值为3.77 mmol/L.该研究对光电催化还原CO2有一定的指导和借鉴意义.%Vertically aligned Fe2O3 nanotubes (Fe2O3 NTs) arrays were prepared on the iron foil by potentiostatic anodization method.The anodization experiments were performed under 30 V for 2 h (20 ℃).The ferrous foil was working electrode and titanium foil was counter electrode.The electrolytes were consisted of 0.25 wt% NH4F in an aqueous solution (Volume of water:glycol=3.:97).After sonicating for 5 min,the samples were put under oxygen atmosphere with the flow rate of 60 seem (standard cubic centimeters/min) and heated to 500 ℃ with the rate of 3 ℃.min-1 and maintained at 500 ℃ for 2 h.Then cooled to room temperature with the rate of 3 ℃.min-1.Honeycomb structure cupric oxide (CuO HCs) were decorated on the surface of Fe2O3 NTs by the pulse electrochemical deposition method.This was done by CHI660D potentiostat in 1 mol.L-1 CuSO4 solution (40 ℃) in a three-electrode configuration.The Fe2O3 NTs electrode worked as counter electrode,Hg/Hg2Cl2 in saturated KCl solution as reference electrode,and platinum wire as working electrode,respectively.A 10 ms cathodic pulse with a current density of-70 mA.cm-2 was employed.After that followed by a 1 ms anodic pulse and its density was +70 mA.cm-2 to prevent damage of the Fe2O3 NTs structure.Finally was a 1000 ms rest time.The electrodeposition time was 36 s,with a forward duty cycle of 0.99% (considering cathodic,anodic and rest components).Then the samples were

  11. 不同盐度胁迫对芦荟生长和离子吸收分配的影响%Effects of Salt Concentration on Growth, Ion Absorption and Distribution of Aloe vera L.

    Institute of Scientific and Technical Information of China (English)

    马艳萍

    2012-01-01

    为探索芦荟对微咸水灌溉栽培的适应性,研究不同盐浓度对其生长和离子吸收分配的影响.结果表明,长期(120天)以含盐溶液灌溉栽培,盐浓度达200 mmol/L NaCl显著抑制芦荟生长,100 mmol/LNaCl对芦荟生长的抑制作用显著减轻,50 mmol/L NaCl不抑制芦荟生长.同时,以50 mmol/L NaCl溶液灌溉对芦荟盐分离子吸收分配影响轻微,但盐浓度达100 mmol/LNaCl对芦荟影响显著:根、茎、叶中K+含量显著下降,Na+、Cl-含量显著增大,K+/Na+大幅减小.X-射线能谱分析结果进一步表明,叶片贮水组织是芦荟积累盐分离子的重要部位,但100 mmol/L NaCl胁迫下芦荟根尖和叶片细胞中的离子平衡受到显著干扰.结果说明,芦荟适于用微咸水灌溉栽培,叶片贮水组织在缓解其盐胁迫中可起重要作用.%To explore the adaptability of irrigating aloe with weakly brine water, the effects of different concentration salinity stresses on growth, ion absorption and distribution of aloe plants were investigated.Experimental results showed that irrigation with 200 mmol/L NaCl for 120 d significantly retarded aloe growth, but the negative effects of irrigating aloe with 100 mmol/L NaCl on aloe growth were significantly relieved, even irrigating with 50 mmol/L NaCl did not retard aloe growth.The effects of irrigating with 50 mmol/L NaCl on ion absorption, transportation and distribution of aloe plants were not significant, but irrigating with 100 mmol/L NaCl were significant: K + contents of root, stem and leaf significantly decreased, Na + and Cl- content significantly increased, K+Na+ ratio significantly decreased.X-ray microanalysis results further showed that leaf aqueous was a main part of accumulating salt ion but ion homeostasis in root and leaf cells of aloe plants were significantly interrupted under 100 mmol/L NaCl stress.The experiment results suggested that Aloe vera L.was suitable to be irrigated with weakly brine water, and leaf

  12. ION GUN

    Science.gov (United States)

    Dandl, R.A.

    1961-10-24

    An ion gun is described for the production of an electrically neutral ionized plasma. The ion gun comprises an anode and a cathode mounted in concentric relationship with a narrow annulus between. The facing surfaces of the rear portions of the anode and cathode are recessed to form an annular manifold. Positioned within this manifold is an annular intermediate electrode aligned with the an nulus between the anode and cathode. Gas is fed to the manifold and an arc discharge is established between the anode and cathode. The gas is then withdrawn from the manifold through the annulus between the anode and cathode by a pressure differential. The gas is then ionized by the arc discharge across the annulus. The ionized gas is withdrawn from the annulus by the combined effects of the pressure differential and a collimating magnetic field. In a 3000 gauss magnetic field, an arc voltage of 1800 volts, and an arc current of 0.2 amp, a plasma of about 3 x 10/sup 11/ particles/cc is obtained. (AEC)

  13. Influence of Sodium Ion Concentration in Dialysate on Blood Pressure of Hemodialysis Patients%透析液钠离子浓度对血液透析患者血压的影响

    Institute of Scientific and Technical Information of China (English)

    赵茜芸; 郝丽

    2012-01-01

    Objective To discuss the influence of changing sodium ion concentration in dialysate on the blood pressure of maintenance hemodialysis patients. Methods All 30 maintenance hemodialysis patients with hypertension, who received hemodialysis from 2009 July to 2012 February in our blood purification center,were selected with administration of 3 months of dialysis treat-ment:140 mmol/L sodium ion concentration in dialysate( dialysis mode A) and 135 mmol/L respectively (dialysis mode B). A-dopting self-comparison method, the blood pressure of patients 3 months before and after the treatment was observed. Results Compared with the values before dialysis, the blood pressure of patients with dialysis mode B was improved significantly after the dialysis,and the difference was statistically significant(( = 10. 037,18. 139.P 0. 05). Conclusion The dialysis mode B was obviously superior to dialysis mode A. The lowering sodium ion concentration in dialysate can reduce the occurrence of hypertension in maintenance hemodialysis patients.%目的 探讨透析液钠离子浓度的改变对维持性血液透析患者血压的影响.方法 选择2009年7月-2012年2月在我院血液净化中心进行血液透析的30例维持性血液透析的高血压患者,分别给予透析液钠离子浓度为140mmoL/L(透析模式A)和透析液钠离子浓度为135 mmol/L(透析模式B)的透析模式各透析3个月,采用自身对照,观察患者前3个月和后3个月血压的变化.结果 通过6个月的观察发现,透析模式B的患者透析后与透析前比较,血压显著改善,差异有统计学意义(t=10.037、18.139,P<0.01);透析模式A的患者透析后与透析前比较,差异无统计学意义(t=-0.218、0.264,P>0.05).结论 透析模式B的血压控制显著优于透析模式A,降低透析液钠离子的浓度可以降低维持性血液透析高血压患者高血压的发生.

  14. [Ion specificity during ion exchange equilibrium in natural clinoptilolite].

    Science.gov (United States)

    He, Yun-Hua; Li, Hang; Liu, Xin-Min; Xiong, Hai-Ling

    2015-03-01

    Zeolites have been widely applied in soil improvement and environment protection. The study on ion specificity during ion exchange equilibrium is of important significance for better use of zeolites. The maximum adsorption capacities of alkali ions during ion exchange equilibrium in the clinoptilolite showed obvious specificity. For alkali metal ions with equivalent valence, the differences in adsorption capacity increased with the decrease of ionic concentration. These results cannot be well explained by the classical theories including coulomb force, ionic size, hydration, dispersion force, classic induction force and surface complexation. We found that the coupling of polarization effects resulted from the quantum fluctuation of diverse alkali metal ions and electric field near the zeolite surface should be the primary reason for specific ion effect during ion exchange in zeolite. The result of this coupling effect was that the difference in the ion dipole moment increased with the increase of surface potential, which further expanded the difference in the adsorption ability between zeolite surface and ions, resulting in different ion exchange adsorption ability at the solid/liquid interface. Due to the high surface charge density of zeolite, ionic size also played an important role in the distribution of ions in the double diffuse layer, which led to an interesting result that distinct differences in exchange adsorption ability of various alkali metal ions were only detected at high surface potential (the absolute value was greater than 0.2 V), which was different from the ion exchange equilibrium result on the surface with low charge density.

  15. 空气负离子浓度分布特征及其与环境因子的关系%Characteristics of negative air ion concentration and its relationships with environmental factors

    Institute of Scientific and Technical Information of China (English)

    王薇

    2014-01-01

    Atmospheric ions are produced by many natural and anthropogenic sources and their concentrations vary widely between different environments. In this study, we conducted a week’s testing in a southern coastal province, China, where we chose 10 different typical sites to measure and research. The measurements included NAI concentration, PAI concentration, wind speed, air temperature, relative humidity and NAI concentration in materials and plants. The results showed that NAI concentration had a closer relation with wind speed, water, plants and air humidity than other factors, the most important factor was the water, followed by wind, and the minimal was air temperature. Based on the analysis of measured data to come to the conclusions: 1) The air friction can effectively and significantly increase the NAI concentration, and the two show a positive correlation. 2) The separation of positive and negative charges can be accelerated by the water in the impact and the injection process. The faster water flows, the more energy ionization corresponding friction increases. The NAI concentration of the surrounding environment is higher; in the meantime attenuation with distance, the NAI concentration has been reduced in constantly. 3) The NAI concentration is related to the structure and arrangement of species of plant community, the high layer structure of the plant, the lower layer structure of the plant, the lower layer structure of plant. 4) Relative humidity and the NAI concentration have a good correlation. 5) The relationship between temperature and NAI concentration should be further clarified. 6) The appropriate temperature, humidity and wind speed can make people feel comfortable, which are beneficial to human health. 7) All in all, in the natural ecological environment, the NAI concentration is greatest and air cleanliness is a most clean. These results and the analysis has important enlightenment to the city ecological environment construction, the author from

  16. Research on Concentrated Performance for Caffeine Solution by Ion-Exchange Resin%离子交换树脂对咖啡因溶液提浓性能的研究

    Institute of Scientific and Technical Information of China (English)

    杜德清; 夏丙堃; 尹进华

    2014-01-01

    选用不同型号阳离子交换树脂和洗脱剂,对1%咖啡因溶液交换、洗脱过程进行研究。结果表明:相比于724、D-113、D-151树脂,732树脂交换处理量达10 BV,洗脱速度快,单次洗脱浓度可达3.82%;80℃水更适合作为洗脱剂;经过3次叠加交换、洗脱后,1%咖啡因溶液提浓到7.39%,可为工业生产中结晶母液回收咖啡因过程提供参考。%Different types of cation-exchange resins and eluent were used in the ion-exchange and elution process of 1% caffeine solution.Compared with types of 724,D-113 and D-151 resins,732 resin showed an ex-change treatment capacity of 10 BV,a faster elusion rate and single elution concentration of 3.82%.Water with 80 ℃ was more suitable for eluent.Concentration of caffeine solution was elevated from 1% to 7.39% after three times of superimposed exchange elution.The results provided reference for the process of recycling caffe-ine from crystallizing mother solution in industrial production.

  17. RESEARCH ON THE INFLUENCE OF H+ IONS CONCENTRATION ON THE DYNAMICS OF THE ACTIVITIES OF CERTAIN DEHYDROGENASES OF THE KREBS CYCLE IN THE MONILINIA LAXA (ADERH. & RUHL. HONEY FUNGUS PARASITIC ON PLUM TREES

    Directory of Open Access Journals (Sweden)

    Tutu Elena

    2010-09-01

    Full Text Available During the process of nutrition, thus in that of their growth, microorganisms are subject to the influences of certain environmental factors that condition the microbial activity determining either the growth and reproduction, or the inhibition of activity and the inactivation of microorganisms. A well known means of expressing the H+ ions concentration in a certain environment is the pH, an important chemical factor that is closely observed when growing ascomycetes, for any alteration of its value entails conformational alterations of their enzymes, the characteristics of the substrate, such that they can no longer interact with the active site of the enzyme or be subject to catalysis. The present study comprises the results of our research on certain oxidoreductase implied in the steps of the Krebs cycle in the Monilinia laxa (Aderh.&Ruhl. Honey, a fungus that parasites the prune. The enzymatic determinations took place at 7 and 14 days from the mycelium of the fungus cultivated in Leonian media, whose pH was adjusted to values between 2.0 and 9.0 by using NaOH 1N and HCl 0,1N solutions. We registered different values of the dehydrogenasic activity, directly correlated with the physiological condition of the fungus (given its age and with the initial pH value of the culture’s environment.

  18. Catalytic Decomposition of Nitric Oxide over Nano-sized PbTiO3 Supported Cupric Oxide%纳米晶PbTiO3负载CuO催化NO分解

    Institute of Scientific and Technical Information of China (English)

    邢丽; 薛念华; 陈向科; 郭学锋; 丁维平; 陈懿

    2005-01-01

    A large specific surface area perovskite-type mixed oxide PbTiO3 supported cupric oxide was synthesized as a catalyst for NO decomposition and characterized by techniques such as XPS, XRD,H2-TPR before and after NO deconlposition reactions. The catalytic properties were tested with a fix-bed micro-reactor. The results showed that the PbTiO3 was inactive for the reactions, but 1wt % Cu/PbTiO3 catalyst gave fairly good activities for NO decomposition at temperature as low as 473K. Copper species were found well-dispersed but weakly interacted with the support before NO decomposition, and the NO decomposition caused significant change in the environment of the copper species, which became Cu(Ⅰ) and most probably incorporated into surface crystal lattice of the nano-sized PbTiO3. In NO reaction, a large amount of oxygen atoms from the decomposition of NO penetrated into the nano-sized PbTiO3 support and caused small expansion of crystal lattice. The transport of oxygen between the copper species and the catalyst support may be helpful to speed up the kinetic regeneration of active metal sites from oxygen occupancy and resulted in good catalytic performance.

  19. Simultaneous total antioxidant capacity assay of lipophilic and hydrophilic antioxidants in the same acetone-water solution containing 2% methyl-beta-cyclodextrin using the cupric reducing antioxidant capacity (CUPRAC) method.

    Science.gov (United States)

    Ozyürek, Mustafa; Bektaşoğlu, Burcu; Güçlü, Kubilay; Güngör, Nilay; Apak, Reşat

    2008-12-07

    Antioxidants are health beneficial compounds that can protect cells from the damage caused by unstable molecules known as reactive oxygen species (ROS). This work reports the capacity assay of both lipophilic and hydrophilic antioxidants simultaneously, by making use of their 'host-guest' complexes with methyl-beta-cyclodextrin (M-beta-CD), a cyclic oligosaccharide, in acetonated aqueous medium using the cupric reducing antioxidant capacity (CUPRAC) method. Thus the order of antioxidant potency of various compounds irrespective of their lipophilicity could be established in the same solvent medium. M-beta-CD was introduced as the water solubility enhancer for lipophilic antioxidants. Two percent M-beta-CD (w/v) in an acetone-H(2)O (9:1, v/v) mixture was found to sufficiently solubilize beta-carotene, lycopene, vitamin E, vitamin C, synthetic antioxidants and other phenolic antioxidants. This assay was validated through linearity, additivity, precision, and recovery. The validation results demonstrate that the CUPRAC assay is reliable and robust. In acetonated aqueous solution of M-beta-CD, only CUPRAC and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays were capable of measuring carotenoids together with hydrophilic antioxidants. The CUPRAC antioxidant capacities of a wide range of polyphenolics and flavonoids were experimentally reported in this work as trolox equivalent antioxidant capacity (TEAC) in the CUPRAC assay, and compared to those found by reference methods, ABTS/horseradish peroxidase (HRP)-H(2)O(2) and ferric reducing antioxidant power (FRAP) assays.

  20. 纳米氢氧化铜催化糠醛加氢反应工艺条件考察%STUDY ON THE PROCESS CONDITIONS OF FURFURAL HYDROGENATION CATALYZED BY NANOMETER CUPRIC HYDROXIDE

    Institute of Scientific and Technical Information of China (English)

    廉金超

    2013-01-01

    以纳米氢氧化铜为催化剂,对糠醛加氢制糠醇反应工艺条件进行考察,最终优化了反应工艺条件,即在反应温度为200℃、反应压力为6 MPa、糠醛与催化剂质量比为200 g/g、反应时间为3h的条件下,糠醛转化率为97%,糠醇选择性为96.6%.%The process conditions of furfural hydrogenation to furfuryl alcohol with nanometer cu-pric hydroxide catalyst were investigated and optimum process conditions were obtained as follows: a reaction temperature of 200 ℃ , a reaction pressure of 6 MPa, a reaction time of 3 h and the mass ratio of furfural to catalyst was 200 g/g, under such conditions the conversion of furfural reached 97% and the selectivity to furfuryl alcohol was 96. 6%.

  1. Concentration device

    DEFF Research Database (Denmark)

    2013-01-01

    A concentration device (2) for filter filtration concentration of particles (4) from a volume of a fluid (6). The concentration device (2) comprises a filter (8) configured to filter particles (4) of a predefined size in the volume of the fluid (6). The concentration device (2) comprises...

  2. Concentrated Ownership

    DEFF Research Database (Denmark)

    Rose, Caspar

    2014-01-01

    , especially minority shareholders. Concentrated ownership is associated with benefits and costs. Concentrated ownership may reduce agency costs by increased monitoring of top management. However, concentrated ownership may also provide dominating owners with private benefits of control.......This entry summarizes the main theoretical contributions and empirical findings in relation to concentrated ownership from a law and economics perspective. The various forms of concentrated ownership are described as well as analyzed from the perspective of the legal protection of investors...

  3. Experimental investigation of ion-ion recombination at atmospheric conditions

    Directory of Open Access Journals (Sweden)

    A. Franchin

    2015-02-01

    Full Text Available We present the results of laboratory measurements of the ion-ion recombination coefficient at different temperatures, relative humidities and concentrations of ozone and sulfur dioxide. The experiments were carried out using the Cosmics Leaving OUtdoor Droplets (CLOUD chamber at CERN, the walls of which are made of conductive material, making it possible to measure small ions. We produced ions in the chamber using a 3.5 GeV c−1 beam of positively-charged pions (π+ from the CERN Proton Synchrotron (PS and with galactic cosmic rays, when the PS was switched off. The range of the ion production rate varied from 2 to 100 cm−3s−1, covering the typical range of ionization throughout the troposphere. The temperature ranged from −55 to 20 °C, the relative humidity from 0 to 70%, the SO2 concentration from 0 to 40 ppb, and the ozone concentration from 200 to 700 ppb. At 20 °C and 40% RH, the retrieved ion-ion recombination coefficient was (2.3 ± 0.7 × 10−6cm3s−1. We observed no dependency of the ion-ion recombination coefficient on ozone concentration and a weak variation with sulfur dioxide concentration. However, we found a strong dependency of the ion-ion recombination coefficient on temperature. We compared our results with three different models and found an overall agreement for temperatures above 0 °C, but a disagreement at lower temperatures. We observed a strong dependency of the recombination coefficient on relative humidity, which has not been reported previously.

  4. Concentration of serum sodium ion after extracorporeal circulation in open heart surgery.%体外循环心脏直视手术术后血清钠离子浓度的变化

    Institute of Scientific and Technical Information of China (English)

    苏泓洁; 孔令文; 向小勇; 赵兴吉; 都定元; 张为民; 谭远康; 卢仁福

    2011-01-01

    目的 分析体外循环心脏直视手术患者术后血清中钠离子的含量变化.方法 选取2008年8月至2010年8月在我院及重庆医科大学附属第一医院就诊行体外循环心脏直视手术的82例患者,检测这些患者术舌血清中钠离子浓度,并分析导致钠离子含量变化的原因.结果 术后有50例患者出现低钠血症(血清中钠离子的含量小于135 mmol/L,),低钠血症的发生率为61.1%(50/82),其中7例患者的低钠血症持续1~3 d,30例患者的低钠血症持续4~9 d,余13例患者的低钠血症的持续时间超过9 d.主动脉阻断时间与术后低钠血症的发生率正相关,术后多巴胺和硝普钠的给药时间与低钠血症的发生率负相关.结论 低钠血症的出现可能与手术创伤、手术对机体内分泌的刺激和体外循环有关.行体外循环心脏直视手术患者术后出现低钠血症的几率较高,纠正低钠血症有利于患者的术后恢复,临床上应注意纠正术后低钠血症.%Objective To detect the concentration of serum sodium ion after extracorporeal circulation in open heart surgery. Methods 82 patients who underwent extracorporeal circulation in open heart surgery from Aug,2008 to Aug, 2010, and the concentration of serum sodium ion after surgery was detected. Results 50 patients had hyponatremia after surgery, and the incidence of hyponatremia was 61.1% (50/82). 7 of 50 patients had hyponatremia less than 3 days; 30 of 50 patients had hyponatremia for 4 to 9 days; while the rest 13 patients had hyponatremia more than 9 days. The time length of aortic occlusion is positive correlated to hyponatremia, while the time length of dopamine and sodium nitroprusside using is negative correlated to hyponatremia. Conclusion Hyponatremia may be related to trauma of surgery, stimuli of hormonal system after surgery and extracorporeal circulation. The incidence of hyponatremia after extracorporeal circulation in open heart surgery is higher, and

  5. Ion Colliders

    CERN Document Server

    Fischer, W

    2014-01-01

    High-energy ion colliders are large research tools in nuclear physics to study the Quark-Gluon-Plasma (QGP). The range of collision energy and high luminosity are important design and operational considerations. The experiments also expect flexibility with frequent changes in the collision energy, detector fields, and ion species. Ion species range from protons, including polarized protons in RHIC, to heavy nuclei like gold, lead and uranium. Asymmetric collision combinations (e.g. protons against heavy ions) are also essential. For the creation, acceleration, and storage of bright intense ion beams, limits are set by space charge, charge change, and intrabeam scattering effects, as well as beam losses due to a variety of other phenomena. Currently, there are two operating ion colliders, the Relativistic Heavy Ion Collider (RHIC) at BNL, and the Large Hadron Collider (LHC) at CERN.

  6. Concentration risk

    Directory of Open Access Journals (Sweden)

    Matić Vesna

    2016-01-01

    Full Text Available Concentration risk has been gaining a special dimension in the contemporary financial and economic environment. Financial institutions are exposed to this risk mainly in the field of lending, mostly through their credit activities and concentration of credit portfolios. This refers to the concentration of different exposures within a single risk category (credit risk, market risk, operational risk, liquidity risk.

  7. Modeling the Lithium Ion Battery

    Science.gov (United States)

    Summerfield, John

    2013-01-01

    The lithium ion battery will be a reliable electrical resource for many years to come. A simple model of the lithium ions motion due to changes in concentration and voltage is presented. The battery chosen has LiCoO[subscript 2] as the cathode, LiPF[subscript 6] as the electrolyte, and LiC[subscript 6] as the anode. The concentration gradient and…

  8. Modeling the Lithium Ion Battery

    Science.gov (United States)

    Summerfield, John

    2013-01-01

    The lithium ion battery will be a reliable electrical resource for many years to come. A simple model of the lithium ions motion due to changes in concentration and voltage is presented. The battery chosen has LiCoO[subscript 2] as the cathode, LiPF[subscript 6] as the electrolyte, and LiC[subscript 6] as the anode. The concentration gradient and…

  9. Synthesis of aminated XAD-4 chelating resins and their adsorption towards cupric ion%胺化XAD-4螯合树脂的合成及其对Cu2+的吸附

    Institute of Scientific and Technical Information of China (English)

    周赟; 晏欣; 李红霞

    2010-01-01

    通过XAD-4树脂和氯代乙酰氯的Friedel-Crafts反应合成了氯乙酰化XAD-4树脂,再将氯乙酰化XAD-4树脂分别与二乙烯三胺、三乙烯四胺和四乙烯五胺反应制备了三种氨基螯合树脂,用电导率法研究了它们对Cu2+的吸附动力学.红外光谱和碱基全交换容量测定结果表明氯乙酰基被成功地引入到XAD-4树脂上以及二乙烯三胺、三乙烯四胺和四乙烯五胺被键合到氯乙酰化XAD-4树脂上.吸附动力学测试表明,螯合树脂对金属铜离子的吸附速率和吸附量与氨基含量密切相关,二级速率方程可用来描述螯合树脂对金属铜离子的吸附动力学.

  10. Ion-binding of glycine zwitterion with inorganic ions in biologically relevant aqueous electrolyte solutions.

    Science.gov (United States)

    Fedotova, Marina V; Kruchinin, Sergey E

    2014-06-01

    The ion-binding between inorganic ions and charged functional groups of glycine zwitter-ion in NaCl(aq), KCl(aq), MgCl2(aq), and CaCl2(aq) has been investigated over a wide salt concentration range by using integral equation theory in the 3D-RISM approach. These systems mimic biological systems where binding of ions to charged residues at protein surfaces is relevant. It has been found that the stability of ion pairs formed by the carboxylate group and added inorganic cations decreases in the sequence Mg(2+)>Ca(2+)>Na(+)>K(+). However, all formed ion pairs are weak and decrease in stability with increasing salt concentration. On the other hand, at a given salt concentration the stability of (-NH3(+):Cl(-))aq ion pairs is similar in all studied systems. The features of ion-binding and the salt concentration effect on this process are discussed.

  11. Synthesis and characterization of composite polymer, polyethylene glycol grafted flower-like cupric nano oxide for solid phase microextraction of ultra-trace levels of benzene, toluene, ethyl benzene and o-xylene in human hair and water samples.

    Science.gov (United States)

    Sarafraz-Yazdi, Ali; Zendegi-Shiraz, Amene; Es'haghi, Zarrin; Hassanzadeh-Khayyat, Mohammad

    2015-10-30

    In this research, poly (ethylene glycol)-poly (ethylene glycol) grafted flower-like cupric oxidenano particles (PEG-PEG-g-CuO NPs) as a novel fiber coating of solid-phase microextraction (SPME) were synthesized by using sol-gel technology. This fiber was successfully applied to extract and determine the ultra-trace levels of benzene, toluene, ethyl benzene and o-xylene in human hair using head space-solid-phase microextraction (HS-SPME) coupled to gas chromatography-flame ionization detector. Characterization and chemical composition of the nano particle was performed by Fourier transform infrared spectroscopy (FT-IR), energy dispersion spectroscopy (EDS) and back scatter analysis (BSA). These methods confirmed the successful fabrication of PEG-g-CuO NPs. The surface morphology of the fibers were inspected by scanning electron microscopy. The scanning electron microscopy (SEM) revealed many "crack-like" features and highly porous structure on the surface of fiber. The synthesized nanocomposites were used for preconcentration and extraction of benzene, toluene, ethyl benzene and o-xylene (BTEX). The effects of operating parameters such as: desorption temperature and time, extraction temperature, extraction time, stirring speed and salt effect were investigated and optimized. Under the optimal conditions, the method detection limits and the limits of quantification were between 0.00025-50.00000pgmL(-1) and 0.00200-200.00000pgmL(-1), respectively. Linearity was observed over a range 0.00200-200000.00000pgmL(-1). The relative standard deviations for one fiber (repeatability; n=5) were obtained from 3.30 up to 5.01% and between fibers or batch to batch (n=3; reproducibility) in the range of 3.63-6.21%. The developed method was successfully applied to simultaneous determination of BTEX in human hairs, tap water and distillate water.

  12. A novel planar ion funnel design for miniature ion optics

    Science.gov (United States)

    Chaudhary, A.; van Amerom, Friso H. W.; Short, R. T.

    2014-10-01

    The novel planar ion funnel (PIF) design presented in this article emphasizes simple fabrication, assembly, and operation, making it amenable to extreme miniaturization. Simulations performed in SIMION 8.0 indicate that ion focusing can be achieved by using a gradient of electrostatic potentials on concentric metal rings in a plane. A prototype was fabricated on a 35 × 35 mm custom-designed printed circuit board (PCB) with a center hole for ions to pass through and a series of concentric circular metal rings of increasing diameter on the front side of the PCB. Metal vias on the PCB electrically connected each metal ring to a resistive potential divider that was soldered on the back of the PCB. The PIF was tested at 5.5 × 10-6 Torr in a vacuum test setup that was equipped with a broad-beam ion source on the front and a micro channel plate (MCP) ion detector on the back of the PIF. The ion current recorded on the MCP anode during testing indicated a 23× increase in the ion transmission through the PIF when electric potentials were applied to the rings. These preliminary results demonstrate the functionality of a 2D ion funnel design with a much smaller footprint and simpler driving electronics than conventional 3D ion funnels. Future directions to improve the design and a possible micromachining approach to fabrication are discussed in the conclusions.

  13. 离子色谱法测定浓磷酸中的Cl-,SO42-,NO3-%Determination of Cl-, SO42-and NO3- in Concentrated Phosphoric Acid by Ion Chromatography

    Institute of Scientific and Technical Information of China (English)

    王婷; 王存进; 杜晓磊

    2016-01-01

    采用离子色谱法测定浓磷酸中的Cl-, SO42-, NO3-.将浓磷酸稀释至400倍体积,以0.22μm滤膜过滤,使用阴离子交换色谱-抑制电导检测器测定浓磷酸中的Cl-,SO42-,NO3-.采用高容量色谱柱,以1.0 mmol/L Na2CO3-24 mmol/L NaOH混合液为流动相,将无机阴离子与浓磷酸基体分离,以标准加入法定量.氯离子、硝酸盐、硫酸盐的检出限为0.05~0.12 mg/L,加标回收率为96.6%~100.0%,测定结果的相对标准偏差为7.0%~10.0%(n=5).该方法分离效果好,可用于浓磷酸中Cl-,SO42-,NO3-的同时测定.%Cl-, SO42-, NO3- in phosphoric acid were determined by ionchromatography. After being diluted to 400 fold volume and filtered with 0.22 μm film filtration, Cl-, SO42- and NO3- were determined by ion exchange chromatography with sup-pressed conductivity detection. The anions were separated from phosphoric acid with high capacity column and 1.0 mmol/L Na2CO3-24 mmol/L NaOH as the mobile phase and quantified by standard addition method. The detection limits were 0.05-0.12 mg/L, the recoveries were 96.6%-100.0%, and the relative standard deviations were 7.0%-10.0%(n=5). This method can be used for simultaneous determination of inorganic anions in concentrated phosphoric acid with good seperation.

  14. Ion Chromatography.

    Science.gov (United States)

    Mulik, James D.; Sawicki, Eugene

    1979-01-01

    Accurate for the analysis of ions in solution, this form of analysis enables the analyst to directly assay many compounds that previously were difficult or impossible to analyze. The method is a combination of the methodologies of ion exchange, liquid chromatography, and conductimetric determination with eluant suppression. (Author/RE)

  15. Ion binding to biological macromolecules.

    Science.gov (United States)

    Petukh, Marharyta; Alexov, Emil

    2014-11-01

    Biological macromolecules carry out their functions in water and in the presence of ions. The ions can bind to the macromolecules either specifically or non-specifically, or can simply to be a part of the water phase providing physiological gradient across various membranes. This review outlines the differences between specific and non-specific ion binding in terms of the function and stability of the corresponding macromolecules. Furthermore, the experimental techniques to identify ion positions and computational methods to predict ion binding are reviewed and their advantages compared. It is indicated that specifically bound ions are relatively easier to be revealed while non-specifically associated ions are difficult to predict. In addition, the binding and the residential time of non-specifically bound ions are very much sensitive to the environmental factors in the cells, specifically to the local pH and ion concentration. Since these characteristics differ among the cellular compartments, the non-specific ion binding must be investigated with respect to the sub-cellular localization of the corresponding macromolecule.

  16. ADVANCED TECHNOLOGY WASTEWATER TREATMENT OF NITRITE IONS

    Directory of Open Access Journals (Sweden)

    E.G. Morozov

    2012-06-01

    Full Text Available The main reason for high concentration of nitrite ions in water is the existence of sources of industrial and agricultural pollution. Contamination of drinking water, juices, wine and other liquids of nitrite ions as a result of improper use of nitrogen fertilizers has an adverse effect on living organism, because under the influence of enzymes nitrite ions in living organisms form high carcinogenic nitrosamines, and the interaction of nitrite ions from blood hemoglobin causes such toxicity that leads to disease cyanosis [1]. Therefore removal of nitrite ions from water has received increased attention. The paper discusses an innovative wastewater treatment technology from the nitrite ion with hypochlorite produced during electrolysis.

  17. ADVANCED TECHNOLOGY WASTEWATER TREATMENT OF NITRITE IONS

    OpenAIRE

    E. G. Morozov; V.M. Nikol`skii; T.V. Saprunova; A.A. Yakovlev

    2012-01-01

    The main reason for high concentration of nitrite ions in water is the existence of sources of industrial and agricultural pollution. Contamination of drinking water, juices, wine and other liquids of nitrite ions as a result of improper use of nitrogen fertilizers has an adverse effect on living organism, because under the influence of enzymes nitrite ions in living organisms form high carcinogenic nitrosamines, and the interaction of nitrite ions from blood hemoglobin causes such toxicity t...

  18. Concentrating Radioactivity

    Science.gov (United States)

    Herrmann, Richard A.

    1974-01-01

    By concentrating radioactivity contained on luminous dials, a teacher can make a high reading source for classroom experiments on radiation. The preparation of the source and its uses are described. (DT)

  19. Ion permeable microcapsules for the release of biologically available ions for remineralization.

    Science.gov (United States)

    Davidson, Michael T; Greving, Theresa A; McHale, William A; Latta, Mark A; Gross, Stephen M

    2012-03-01

    The objective of this study was to investigate the effect of chemical structure, ion concentration, and ion type on the release rate of biologically available ions useful for remineralization from microcapsules with ion permeable membranes. A heterogeneous polymerization technique was utilized to prepare microcapsules containing either an aqueous solution of K₂HPO₄, Ca(NO₃)₂, or NaF. Six different polyurethane-based microcapsule shells were prepared and characterized based on ethylene glycol, butanediol, hexanediol, octanediol, triethylene glycol, and bisphenol A structural units. Ion release profiles were measured as a function of initial ion concentration within the microcapsule, ion type, and microcapsule chemical structure. The rate of ion release increased with initial concentration of ion stored in the microcapsule over a range of 0.5-3.0M. The monomer used in the synthesis of the membrane had a significant effect on ion release rates at 3.0 M salt concentration. At 1.0 M, the ethylene glycol released ions significantly faster than the hexanediol-, octanediol-, and butanediol-based microcapsules. Ion release was fastest for fluoride and slowest for phosphate for the salts used in this study. It was concluded that the microcapsules are capable of releasing calcium, phosphate, and fluoride ions in their biologically available form.

  20. Ion focusing

    Energy Technology Data Exchange (ETDEWEB)

    Cooks, Robert Graham; Baird, Zane; Peng, Wen-Ping

    2017-01-17

    The invention generally relates to apparatuses for focusing ions at or above ambient pressure and methods of use thereof. In certain embodiments, the invention provides an apparatus for focusing ions that includes an electrode having a cavity, at least one inlet within the electrode configured to operatively couple with an ionization source, such that discharge generated by the ionization source is injected into the cavity of the electrode, and an outlet. The cavity in the electrode is shaped such that upon application of voltage to the electrode, ions within the cavity are focused and directed to the outlet, which is positioned such that a proximal end of the outlet receives the focused ions and a distal end of the outlet is open to ambient pressure.

  1. Concentration effect of Sm{sup 3+} ions in B{sub 2}O{sub 3}–PbO–PbF{sub 2}–Bi{sub 2}O{sub 3}–ZnO glasses – Structural and luminescence investigations

    Energy Technology Data Exchange (ETDEWEB)

    Arunkumar, S.; Marimuthu, K., E-mail: mari_ram2000@yahoo.com

    2013-07-15

    Graphical abstract: -- Highlights: •δ and revel the ionic nature and the Same decreases with Sm{sup 3+} ion content. •Higher Ω{sub 4} revels the higher rigidity and higher covalency around the Sm{sup 3+} ion site. •τ{sub exp} decreases with increase in Sm{sup 3+} ion due to energy transfer between Sm{sup 3+} ions. •Energy transfer between the Sm{sup 3+}–Sm{sup 3+} ion site is due to dipole–dipole interaction. •0.5SmPbFB glass possesses higher A, β{sub R} and xτ{sub R}, potential for laser applications. -- Abstract: Concentration dependent spectroscopic properties of Sm{sup 3+} ions are investigated in the prepared xSm:PbFB lead fluorobororate glasses with the composition (40 − x)B{sub 2}O{sub 3} + 20PbO + 16PbF{sub 2} + 12Bi{sub 2}O{sub 3} + 12ZnO + xSm{sub 2}O{sub 3} (where x = 0.05, 0.1, 0.5, 1, 2 and 3 wt.%). Surface morphological analysis and structural behaviors of the prepared glasses have been explored through SEM, EDX, XRD, FTIR and Raman spectral analysis. The amorphous nature of the prepared glasses have been confirmed through XRD spectral analysis. The presence of BO{sub 3}, BO{sub 4}, B–O–B and Pb/Bi–O–B vibrational stretching units in the prepared glasses are confirmed through FTIR and Raman spectral analysis. The optical characterizations were carried out using UV–vis–NIR absorption, luminescence spectra and decay curves of the present glasses. The calculated bonding parameter (β{sup ¯} and δ) values reveal the ionic nature of the Sm–O bond in the prepared glasses. The Judd–Ofelt intensity parameters, Ω{sub λ}, were evaluated from the measured oscillator strength of the various absorption bands to study the bonding environment around the Sm{sup 3+} ions in the prepared glasses. From the JO intensity parameters and emission spectral measurements, the radiative properties such as stimulated emission cross-section (σ{sub P}{sup E}), branching ratio (β{sub R}) and radiative lifetime (τ{sub R}) for the {sup 6}H

  2. Influence of ion species ratio on grid-enhanced plasma source ion implantation

    Institute of Scientific and Technical Information of China (English)

    Wang Jiu-Li; Zhang Gu-Ling; Liu Yuan-Fu; Wang You-Nian; Liu Chi-Zi; Yang Si-Ze

    2004-01-01

    @@ Grid-enhanced plasma source ion implantation (GEPSII) is a newly proposed technique to modify the inner-surface properties of a cylindrical bore. In this paper, a two-ion fluid model describing nitrogen molecular ions N2+ and atomic ions N+ is used to investigate the ion sheath dynamics between the grid electrode and the inner surface of a cylindrical bore during the GEPSII process, which is an extension of our previous calculations in which only N2+ was considered.Calculations are concentrated on the results of ion dose and impact energy on the target for different ion species ratios in the core plasma. The calculated results show that more atomic ions N+ in the core plasma can raise the ion impact energy and reduce the ion dose on the target.

  3. Response of thermal ions to electromagnetic ion cyclotron waves

    Science.gov (United States)

    Anderson, B. J.; Fuselier, S. A.

    1994-01-01

    Electromagnetic ion cyclotron waves generated by 10 - 50 keV protons in the Earth's equatorial magnetosphere will interact with the ambient low-energy ions also found in this region. We examine H(+) and He(+) distribution functions from approx. equals 1 to 160 eV using the Hot Plasma Composition Experiment instrument on AMPTE/CCE to investigate the thermal ion response to the waves. A total of 48 intervals were chosen on the basis of electromagnetic ion cyclotron (EMIC) wave activity: 24 with prevalent EMIC waves and 24 with no EMIC waves observed on the orbit. There is a close correlation between EMIC waves and perpendicular heated ion distributions. For protons the perpendicular temperature increase is modest, about 5 eV, and is always observed at 90 deg pitch angles. This is consistent with a nonresonant interaction near the equator. By contrast, He(+) temperatures during EMIC wave events averaged 35 eV and sometimes exceeded 100 eV, indicating stronger interaction with the waves. Furthermore, heated He(+) ions have X-type distributions with maximum fluxes occurring at pitch angles intermediate between field-aligned and perpendicular directions. The X-type He(+) distributions are consistent with a gyroresonant interaction off the equator. The concentration of He(+) relative to H(+) is found to correlate with EMIC wave activity, but it is suggested that the preferential heating of He(+) accounts for the apparent increase in relative He(+) concentration by increasing the proportion of He(+) detected by the ion instrument.

  4. Response of thermal ions to electromagnetic ion cyclotron waves

    Science.gov (United States)

    Anderson, B. J.; Fuselier, S. A.

    1994-10-01

    Electromagnetic ion cyclotron waves generated by 10 - 50 keV protons in the Earth's equatorial magnetosphere will interact with the ambient low-energy ions also found in this region. We examine H(+) and He(+) distribution functions from approx. equals 1 to 160 eV using the Hot Plasma Composition Experiment instrument on AMPTE/CCE to investigate the thermal ion response to the waves. A total of 48 intervals were chosen on the basis of electromagnetic ion cyclotron (EMIC) wave activity: 24 with prevalent EMIC waves and 24 with no EMIC waves observed on the orbit. There is a close correlation between EMIC waves and perpendicular heated ion distributions. For protons the perpendicular temperature increase is modest, about 5 eV, and is always observed at 90 deg pitch angles. This is consistent with a nonresonant interaction near the equator. By contrast, He(+) temperatures during EMIC wave events averaged 35 eV and sometimes exceeded 100 eV, indicating stronger interaction with the waves. Furthermore, heated He(+) ions have X-type distributions with maximum fluxes occurring at pitch angles intermediate between field-aligned and perpendicular directions. The X-type He(+) distributions are consistent with a gyroresonant interaction off the equator. The concentration of He(+) relative to H(+) is found to correlate with EMIC wave activity, but it is suggested that the preferential heating of He(+) accounts for the apparent increase in relative He(+) concentration by increasing the proportion of He(+) detected by the ion instrument.

  5. Single ion implantation in semiconductor nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Niepelt, Raphael; Johannes, Andreas; Gnauck, Martin; Slowik, Irma; Geburt, Sebastian; Ronning, Carsten [Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet, Jena (Germany)

    2011-07-01

    Ion implantation is well established as a standard doping technique for semiconductor nanowires. The concentration of dopant atoms per area is typically determined by total beam current monitoring during the irradiation. However, at extremely low ion fluencies, it is not possible to distinguish the exact number of implanted ions in a nanometer sized structure, as the ions are distributed statistically over the irradiated area that is usually far wider than the nanostructure of interest. In our experiments we implanted electrically contacted semiconductor nanostructures that were connected to a preamplifier/amplifier setup. As with every impinging ion a certain amount of energy is deposited inside the material, one can detect signals directly induced by the ion implantation and the nanostructures themselves can act as a radiation sensor. This leads to a countable and very precisely adjustable ion dose during the implantation down to doping with single ions.

  6. Acid-base characterization, coordination properties towards copper(II) ions and DNA interaction studies of ribavirin, an antiviral drug.

    Science.gov (United States)

    Nagaj, Justyna; Starosta, Radosław; Jeżowska-Bojczuk, Małgorzata

    2015-01-01

    We have studied processes of copper(II) ion binding by ribavirin, an antiviral agent used in treating hepatitis C, which is accompanied usually by an increased copper level in the serum and liver tissue. Protonation equilibria and Cu(II) binding were investigated using the UV-visible, EPR and NMR spectroscopic techniques as well as the DFT (density functional theory) calculations. The spectroscopic data suggest that the first complex is formed in the water solution at pH as low as 0.5. In this compound Cu(II) ion is bound to one of the nitrogen atoms from the triazole ring. Above pH6.0, the metal ion is surrounded by two nitrogen and two oxygen atoms from two ligand molecules. The DFT calculations allowed to determine the exact structure of this complex. We found that in the lowest energy isomer two molecules of the ligand coordinate via O and N4 atoms in trans positions. The hypothetical oxidative properties of the investigated system were also examined. It proved not to generate plasmid DNA scission products. However, the calf thymus (CT)-DNA binding studies showed that it reacts with ribavirin and its cupric complex. Moreover, the interaction with the complex is much more efficient.

  7. Complexes of Nitrocellulose with Cupric Chloride,

    Science.gov (United States)

    1985-11-01

    sp&cifique. La variation de la viscositf avec le gradient de vitesse 6tait conforms A un comportement pseudo- plastique non-Newtonien. Un facteur...E00196. 0L 41 3 1. - Z a ra a1.. .0 r-: .*.*U Coo 1. .0-0 a sac ~~~ 0 aaa WCS~1 rh U6 VhS . O.p U r1 t0 66 d h C g 6 U 6 *~~~~~~ a:u.’ ;a sC us* h. .a

  8. Existence domains of slow and fast ion-acoustic solitons in two-ion space plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Maharaj, S. K., E-mail: smaharaj@sansa.org.za [South African National Space Agency (SANSA) Space Science, P.O. Box 32, Hermanus 7200 (South Africa); Bharuthram, R., E-mail: rbharuthram@uwc.ac.za [University of the Western Cape, Robert Sobukwe Road, Bellville, 7535 (South Africa); Singh, S. V., E-mail: satyavir@iigs.iigm.res.in; Lakhina, G. S., E-mail: lakhina@iigs.iigm.res.in [Indian Institute of Geomagnetism, New Panvel (West), Navi Mumbai 410218 (India)

    2015-03-15

    A study of large amplitude ion-acoustic solitons is conducted for a model composed of cool and hot ions and cool and hot electrons. Using the Sagdeev pseudo-potential formalism, the scope of earlier studies is extended to consider why upper Mach number limitations arise for slow and fast ion-acoustic solitons. Treating all plasma constituents as adiabatic fluids, slow ion-acoustic solitons are limited in the order of increasing cool ion concentrations by the number densities of the cool, and then the hot ions becoming complex valued, followed by positive and then negative potential double layer regions. Only positive potentials are found for fast ion-acoustic solitons which are limited only by the hot ion number density having to remain real valued. The effect of neglecting as opposed to including inertial effects of the hot electrons is found to induce only minor quantitative changes in the existence regions of slow and fast ion-acoustic solitons.

  9. The Kinetics of Sorption of Lead Ions on Clinoptilolite in the H-Form

    Science.gov (United States)

    Akimbaeva, A. M.; Ergozhin, E. E.

    2008-03-01

    The kinetics of ion exchange of lead ions on clinoptilolite in the H-form was studied experimentally. The kinetic parameters of sorption of lead ions by the natural zeolite were calculated as depending on zeolite dispersity and solution concentration.

  10. Seletividade de fungicidas cúpricos e sistêmicos sobre o fungo Cladosporium cladosporioides em cafeeiro Selectivity of cupric and systemic fungicides on Cladosporium cladosporioides in coffee plants

    Directory of Open Access Journals (Sweden)

    Sára Maria Chalfoun

    2007-03-01

    plants cv 'Acaiá Cerrado MG 1474' were selected and sprayed with cupric and systemic fungicides alone or associated copper oxichloride (50% of metallic copper. Commercial 'Calda Viçosa' was used as copper products and epoxiconazole as a systemic product. The incidence of Cladosporium cladosporioides was evaluated four times using a scale. It was verified that on the treatments with the fungicide epoxiconazole applied isolate or in combination with copper fungicide the fungus was found at low levels but increased until may. On the treatments with copper fungicides the fungus incidence was high since may indicating that it was not affected or even was favored by previous applications of copper fungicides.

  11. ION VATAMANU

    Directory of Open Access Journals (Sweden)

    l. Povar

    2012-12-01

    Full Text Available Ion Vatamanu was a chemist, writer and public figure. He was equally passionate about both his chosen fields of activity: chemistry and poetry. Chemistry, with its perfect equilibrium of logic and precision, provided inspiration for lyrical creativity, whereas poetry writing enlivened his imagination and passion for chemistry. He loved his parents. He adored his wife Elena, whom he often gifted a sea of flowers. He loved his daughters Mihaela, Mariana, and Leontina. He loved life, and he loved people.

  12. A Metal-Organic Compound as Cathode Material with Superhigh Capacity Achieved by Reversible Cationic and Anionic Redox Chemistry for High-Energy Sodium-Ion Batteries.

    Science.gov (United States)

    Fang, Chun; Huang, Ying; Yuan, Lixia; Liu, Yaojun; Chen, Weilun; Huang, Yangyang; Chen, Kongyao; Han, Jiantao; Liu, Qingju; Huang, Yunhui

    2017-06-06

    Although sodium-ion batteries (SIBs) are considered as alternatives to lithium-ion batteries (LIBs), the electrochemical performances, in particular the energy density, are much lower than LIBs. A metal-organic compound, cuprous 7,7,8,8-tetracyanoquinodimethane (CuTCNQ), is presented as a new kind of cathode material for SIBs. It consists of both cationic (Cu(II) ↔Cu(I) ) and anionic (TCNQ(0) ↔TCNQ(-) ↔ TCNQ(2-) ) reversible redox reactions, delivering a discharge capacity as high as 255 mAh g(-1) at a current density of 20 mA g(-1) . The synergistic effect of both redox-active metal cations and organic anions brings an electrochemical transfer of multiple electrons. The transformation of cupric ions to cuprous ions occurs at near 3.80 V vs. Na(+) /Na, while the full reduction of TCNQ(0) to TCNQ(-) happens at 3.00-3.30 V. The remarkably high voltage is attributed to the strong inductive effect of the four cyano groups. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Electron Beam Ion Sources

    OpenAIRE

    Zschornacka, G.; Schmidt, M.; Thorn, A.

    2014-01-01

    Electron beam ion sources (EBISs) are ion sources that work based on the principle of electron impact ionization, allowing the production of very highly charged ions. The ions produced can be extracted as a DC ion beam as well as ion pulses of different time structures. In comparison to most of the other known ion sources, EBISs feature ion beams with very good beam emittances and a low energy spread. Furthermore, EBISs are excellent sources of photons (X-rays, ultraviolet, extreme ultraviole...

  14. Ion Beam Extraction by Discrete Ion Focusing

    DEFF Research Database (Denmark)

    2010-01-01

    An apparatus (900) and methods are disclosed for ion beam extraction. In an implementation, the apparatus includes a plasma source (or plasma) (802) and an ion extractor (804). The plasma source is adapted to generate ions and the ion extractor is immersed in the plasma source to extract a fraction...... of the generated ions. The ion extractor is surrounded by a space charge (810) formed at least in part by the extracted ions. The ion extractor includes a biased electrode (806) forming an interface with an insulator (808). The interface is customized to form a strongly curved potential distribution (812......) in the space-charge surrounding the ion extractor. The strongly curved potential distribution focuses the extracted ions towards an opening (814) on a surface of the biased electrode thereby resulting in an ion beam....

  15. Statistical evaluation of biogeochemical variables affecting spatiotemporal distributions of multiple free metal ion concentrationsin an urban estuary

    Science.gov (United States)

    Free metal ion concentrations have been recognized as a better indicator of metal bioavailability in aquatic environments than total dissolved metal concentrations. However, our understanding of the determinants of free ion concentrations, especially in a metal mixture, is limite...

  16. Fast ion generation and bulk plasma heating with three-ion ICRF scenarios