| 1. |
- Abelev, Betty, et al.
(författare)
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Long-range angular correlations on the near and away side in p-Pb collisions at root S-NN=5.02 TeV
- 2013
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Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 719:1-3, s. 29-41
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Tidskriftsartikel (refereegranskat)abstract
- Angular correlations between charged trigger and associated particles are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV for transverse momentum ranges within 0.5 < P-T,P-assoc < P-T,P-trig < 4 GeV/c. The correlations are measured over two units of pseudorapidity and full azimuthal angle in different intervals of event multiplicity, and expressed as associated yield per trigger particle. Two long-range ridge-like structures, one on the near side and one on the away side, are observed when the per-trigger yield obtained in low-multiplicity events is subtracted from the one in high-multiplicity events. The excess on the near-side is qualitatively similar to that recently reported by the CMS Collaboration, while the excess on the away-side is reported for the first time. The two-ridge structure projected onto azimuthal angle is quantified with the second and third Fourier coefficients as well as by near-side and away-side yields and widths. The yields on the near side and on the away side are equal within the uncertainties for all studied event multiplicity and p(T) bins, and the widths show no significant evolution with event multiplicity or p(T). These findings suggest that the near-side ridge is accompanied by an essentially identical away-side ridge. (c) 2013 CERN. Published by Elsevier B.V. All rights reserved.
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| 2. |
- Abelev, Betty, et al.
(författare)
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Measurement of prompt J/psi and beauty hadron production cross sections at mid-rapidity in pp collisions at root s=7 TeV
- 2012
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Ingår i: Journal of High Energy Physics. - 1029-8479. ; :11
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Tidskriftsartikel (refereegranskat)abstract
- The ALICE experiment at the LHC has studied J/psi production at mid-rapidity in pp collisions at root s = 7 TeV through its electron pair decay on a data sample corresponding to an integrated luminosity L-int = 5.6 nb(-1). The fraction of J/psi from the decay of long-lived beauty hadrons was determined for J/psi candidates with transverse momentum p(t) > 1,3 GeV/c and rapidity vertical bar y vertical bar < 0.9. The cross section for prompt J/psi mesons, i.e. directly produced J/psi and prompt decays of heavier charmonium states such as the psi(2S) and chi(c) resonances, is sigma(prompt J/psi) (p(t) > 1.3 GeV/c, vertical bar y vertical bar < 0.9) = 8.3 +/- 0.8(stat.) +/- 1.1 (syst.)(-1.4)(+1.5) (syst. pol.) mu b. The cross section for the production of b-hadrons decaying to J/psi with p(t) > 1.3 GeV/c and vertical bar y vertical bar < 0.9 is a sigma(J/psi <- hB) (p(t) > 1.3 GeV/c, vertical bar y vertical bar < 0.9) = 1.46 +/- 0.38 (stat.)(-0.32)(+0.26) (syst.) mu b. The results are compared to QCD model predictions. The shape of the p(t) and y distributions of b-quarks predicted by perturbative QCD model calculations are used to extrapolate the measured cross section to derive the b (b) over bar pair total cross section and d sigma/dy at mid-rapidity.
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| 3. |
- Falk, Magnus, et al.
(författare)
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Self-powered wireless carbohydrate/oxygen sensitive biodevice based on radio signal transmission
- 2014
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 9:10, s. e109104/1-e109104/9
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Tidskriftsartikel (refereegranskat)abstract
- Here for the first time, we detail self-contained (wireless and self-powered) biodevices with wireless signal transmission. Specifically, we demonstrate the operation of self-sustained carbohydrate and oxygen sensitive biodevices, consisting of a wireless electronic unit, radio transmitter and sep. sensing bioelectrodes, supplied with elec. energy from a combined multi-enzyme fuel cell generating sufficient current at required voltage to power the electronics. A carbohydrate/oxygen enzymic fuel cell was assembled by comparing the performance of a range of different bioelectrodes followed by selection of the most suitable, stable combination. Carbohydrates (viz. lactose for the demonstration) and oxygen were also chosen as bioanalytes, being important biomarkers, to demonstrate the operation of the self-contained biosensing device, employing enzyme-modified bioelectrodes to enable the actual sensing. A wireless electronic unit, consisting of a micropotentiostat, an energy harvesting module (voltage amplifier together with a capacitor) and a radio microchip, were designed to enable the biofuel cell to be used as a power supply for managing the sensing devices and for wireless data transmission. The electronic system used required current and voltages greater than 44 μA and 0.57 V, resp. to operate; which the biofuel cell was capable of providing, when placed in a carbohydrate and oxygen contg. buffer. In addn., a USB based receiver and computer software were employed for proof-of concept tests of the developed biodevices. Operation of bench-top prototypes was demonstrated in buffers contg. different concns. of the analytes, showcasing that the variation in response of both carbohydrate and oxygen biosensors could be monitored wirelessly in real-time as analyte concns. in buffers were changed, using only an enzymic fuel cell as a power supply.
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| 4. |
- Abelev, Betty, et al.
(författare)
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Underlying Event measurements in pp collisions at root s=0.9 and 7 TeV with the ALICE experiment at the LHC
- 2012
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Ingår i: Journal of High Energy Physics. - 1029-8479. ; :7
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Tidskriftsartikel (refereegranskat)abstract
- We present measurements of Underlying Event observables in pp collisions at root s = 0 : 9 and 7 TeV. The analysis is performed as a function of the highest charged-particle transverse momentum p(T),L-T in the event. Different regions are defined with respect to the azimuthal direction of the leading (highest transverse momentum) track: Toward, Transverse and Away. The Toward and Away regions collect the fragmentation products of the hardest partonic interaction. The Transverse region is expected to be most sensitive to the Underlying Event activity. The study is performed with charged particles above three different p(T) thresholds: 0.15, 0.5 and 1.0 GeV/c. In the Transverse region we observe an increase in the multiplicity of a factor 2-3 between the lower and higher collision energies, depending on the track p(T) threshold considered. Data are compared to PYTHIA 6.4, PYTHIA 8.1 and PHOJET. On average, all models considered underestimate the multiplicity and summed p(T) in the Transverse region by about 10-30%.
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| 5. |
- Falk, Magnus, et al.
(författare)
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Miniature biofuel cell as a potential power source for glucose-sensing contact lenses
- 2013
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 85:13, s. 6342-6348
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Tidskriftsartikel (refereegranskat)abstract
- A microscale membrane-less biofuel cell, capable of generating elec. energy from human lachrymal liq., was developed by using the ascorbate and oxygen naturally present in tears as fuel and oxidant. The biodevice is based on three-dimensional nanostructured gold electrodes covered with abiotic (conductive org. complex) and biol. (redox enzyme) materials functioning as efficient anodic and cathodic catalysts, resp. Three-dimensional nanostructured electrodes were fabricated by modifying 100 μm gold wires with 17 nm gold nanoparticles, which were further modified with tetrathiafulvalene-tetracyanoquinodimethane conducting complex to create the anode and with Myrothecium verrucaria bilirubin oxidase to create the biocathode. When operated in human tears, the biodevice exhibited the following characteristics: an open circuit voltage of 0.54 V, a maximal power d. of 3.1 μW cm-2 at 0.25 V and 0.72 μW cm-2 at 0.4 V, with a stable c.d. output of over 0.55 μA cm-2 at 0.4 V for 6 h of continuous operation. These findings support the authors' proposition that an ascorbate/oxygen biofuel cell could be a suitable power source for glucose-sensing contact lenses to be used for continuous health monitoring by diabetes patients.
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| 6. |
- Krikstolaityte, Vida, et al.
(författare)
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Mediatorless Carbohydrate/Oxygen Biofuel Cells with Improved Cellobiose Dehydrogenase Based Bioanode
- 2014
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Ingår i: Fuel Cells. - : John Wiley & Sons. - 1615-6846 .- 1615-6854. ; 14:6, s. 792-800
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Tidskriftsartikel (refereegranskat)abstract
- Direct electron transfer (DET) between cellobiose dehydrogenase from Humicola insolens ascomycete (HiCDH) and gold nanoparticles (AuNPs) was achieved by modifying AuNPs with a novel, pos. charged thiol N-(6-mercapto)hexylpyridinium (MHP). The DET enabled the use of the HiCDH enzyme as an anodic biocatalyst in the design of a mediatorless carbohydrate/oxygen enzymic fuel cell (EFC). A biocathode of the EFC was based on bilirubin oxidase from Myrothecium verrucaria (MvBOx) directly immobilized on the surface of AuNPs. The following parameters of the EFC based on Au/AuNP/MHP/HiCDH bioanode and Au/AuNP/MvBOx biocathode were obtained in quiescent air satd. PBS, pH 7.4, contg.: (i) 5 mM glucose-open-circuit voltage (OCV) of 0.65 ± 0.011 V and the maximal power d. of 4.77 ± 1.34 μW cm-2 at operating voltage of 0.50 V; or (ii) 10 mM lactose-OCV of 0.67 ± 0.006 V and the maximal power d. of 8.64 ± 1.91 μW cm-2 at operating voltage of 0.50 V. The half-life operation times of the EFC were estd. to be at least 13 and 44 h in air satd. PBS contg. 5 mM glucose and 10 mM lactose, resp. Among advantages of HiCDH/MvBOx FCs are (i) simplified construction, (ii) relatively high power output with glucose as biofuel, and (iii) the absence of the inhibition of the HiCDH based bioanode by lactose, when compared with the best previously reported CDH based bioanode.
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| 7. |
- Pita, Marcos, et al.
(författare)
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Oxygen biosensor based on bilirubin oxidase immobilized on a nanostructured gold electrode
- 2013
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Ingår i: Bioelectrochemistry. - : Elsevier. - 1567-5394 .- 1878-562X. ; 94, s. 69-74
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Tidskriftsartikel (refereegranskat)abstract
- Gold disk electrodes modified with gold nanoparticles have been used as a scaffold for the covalent immobilization of bilirubin oxidase. The nanostructured bioelectrodes were tested as mediator-less biosensors for oxygen in a buffer that mimics the content and the compn. of human physiol. fluids. Chronoamperometry measurements showed a detection limit towards oxygen of 6 ± 1 μM with a linear range of 6-300 μM, i.e. exceeding usual physiol. ranges of oxygen in human tissues and fluids. The biosensor presented is the first ever-reported oxygen amperometric biosensor based on direct electron transfer of bilirubin oxidase.
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| 8. |
- Schulz, Christopher, et al.
(författare)
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Enhancement of enzymatic activity and catalytic current of cellobiose dehydrogenase by calcium ions
- 2012
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Ingår i: Electrochemistry Communications. - : Elsevier BV. - 1388-2481. ; 17, s. 71-74
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Tidskriftsartikel (refereegranskat)abstract
- Cellobiose dehydrogenase (CDH) has recently become a redox enzyme at focus in bioelectrochemistry especially for the construction of sugar biosensors and biofuel cell anodes. The present study shows that an increase in the CaCl2 concentration to up to 100 mM led to an increase in the maximal catalytic current generated by two different Ascomycete and one Basidiomycete CDH immobilised on a spectroscopic graphite electrode. For the Ascomycete Myriococcum therrnophilum CDH the catalytic current was increased 5.1 fold, whereas Ascomycete Humicola insolens CDH showed a four-fold increase and Basidiomycete Phanerochaete chrysosporium CDH showed an increase by a factor of 2.4. On the other hand, the addition of a monovalent cation salt, KCl (up to 100 mM), to the buffers increased the catalytic currents only up to 2-fold for Myriococcum thermophilum CDH. Activity assays in solution with cyt c accepting solely the electrons from the CYTCDH domain also revealed an increased activity in the presence of CaCl2. Experiments with the isolated DHCDH domain from Humicola insolens have shown that the catalytic turnover is totally independent on the addition of KCl or CaCl2 to the solution. The results indicate a positive effect of metal cations, particularly Ca2+, on the electron transfer between the DHCDH and the CYTCDH domains or between the CYTCDH domain and the final electron acceptor, whereas the first hypothesis is favoured. These findings are of interest both for the construction of 3 rd generation biosensors and biofuel cell anodes, and also for a deeper understanding of the electron transfer mechanism in CDH. (C) 2012 Elsevier B.V. All rights reserved.
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| 9. |
- Shao, Minling, et al.
(författare)
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Optimization of a Membraneless Glucose/Oxygen Enzymatic Fuel Cell Based on a Bioanode with High Coulombic Efficiency and Current Density
- 2013
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Ingår i: ChemPhysChem. - : Wiley. - 1439-7641 .- 1439-4235. ; 14:10, s. 2260-2269
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Tidskriftsartikel (refereegranskat)abstract
- After initial testing and optimization of anode biocatalysts, a membraneless glucose/oxygen enzymatic biofuel cell possessing high coulombic efficiency and power output was fabricated and characterized. Agaricus meleagris (AmPDH) and flavodehydrogenase domains of various cellobiose dehydrogenases (DHCDH) were tested during the pre-screening. Myrothecium verrucaria adsorbed on graphite. Optimization showed that the current density for the mixed enzyme electrode could be further improved by using a genetically engineered variant of the non-glycosylated flavodehydrogenase domain of cellobiose dehydrogenase from Corynascus thermophilus expressed in E. coli (ngDH(CtCDHC310Y)) with a high glucose-turnover rate in combination with an Os-complex-modified redox polymer with a high concentration of Os complexes as well as a low-density graphite electrode. AmPDH/ngDH(CtCDHC310Y) anode showed not only a similar maximum voltage as with the biofuel cell based only on the ngDH(CtCDHC310Y) anode (0.55 V) but also a substantially improved maximum power output (20 Wcm(-2)) at 300 mV cell voltage in air-saturated physiological buffer. Most importantly, the estimated half-life of the mixed biofuel cell can reach up to 12 h, which is apparently longer than that of a biofuel cell in which the bioanode is based on only one single enzyme.
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