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| 2. |
- Galtsov, N. N., et al.
(författare)
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Intercalation of fullerite C60 with N2 molecules : an investigation by X-ray powder diffraction
- 2007
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Ingår i: Low temperature physics (Woodbury, N.Y., Print). - : American Institute of Physics (AIP). - 1063-777X .- 1090-6517. ; 33:10, s. 881-885
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Tidskriftsartikel (refereegranskat)abstract
- The lattice parameter a of fullerite C60 intercalated with N2 molecules is investigated in the temperature interval 6–295K by x-ray diffraction. It is found that the interstitial molecular N2 has a considerable effect on both the orientational phase transition temperature Tc and the orientational glass formation temperature Tg. Hysteresis of a(T) in the Tc and Tg regions is detected, along with an abrupt change in volume over the region defining Tc. Complete intercalation of C60 with N2 molecules results in a 0.2% increase in the lattice parameter, which persists over the whole temperature range. Evidence is also obtained that the interstitial guest molecular N2 induces a slight deformation of the cubic symmetry of the C60 host lattice.
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| 5. |
- Prokhvatilov, A.I., et al.
(författare)
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Hysteretic phenomena in Xe-doped C60 from X-ray diffraction
- 2005
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Ingår i: Low Temperature Physics. - : AIP Publishing. - 1063-777X .- 1090-6517. ; 31:5, s. 585-589
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Tidskriftsartikel (refereegranskat)abstract
- Polycrystalline fullerite C60 intercalated with Xe atoms at 575 K and a pressure of 200 MPa was studied by powder x-ray diffraction. The integrated intensities of a few brighter reflections have been utilized to evaluate the occupancy of the octahedral interstitial sites in C60 crystals, which turned out to be (34±4)%, and in good agreement with another independent estimate. It is found that reflections of the (h00) type become observable in Xe-doped C60. The presence of xenon in the octahedral sites affects both the orientational phase transition as well as the glassification process, decreasing both characteristic temperatures as well as smearing the phase transition over a greater temperature range. Considerable hysteretic phenomena have been observed close to the phase transition and the glassification temperature. The signs of the two hysteresis loops are opposite. There is reliable evidence that at the lowest temperatures studied the thermal expansion of the doped crystal is negative under cool-down.
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| 6. |
- Panchal, V., et al.
(författare)
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Atmospheric doping effects in epitaxial graphene: correlation of local and global electrical studies
- 2016
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Ingår i: 2D Materials. - : IOP Publishing. - 2053-1583. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- We directly correlate the local (20 nm scale) and global electronic properties of a device containing mono-, bi- and tri-layer epitaxial graphene (EG) domains on 6H-SiC (0001) by simultaneously performing local surface potential measurements using Kelvin probe force microscopy and global transport measurements. Using well-controlled environmental conditions we investigate the doping effects of N-2, O-2, water vapour and NO2 at concentrations representative of the ambient air. We show that presence of O-2, water vapour and NO2 leads to p-doping of all EG domains. However, the thicker layers of EG are significantly less affected. Furthermore, we demonstrate that the general consensus of O-2 and water vapour present in ambient air providing majority of the p-doping to graphene is a common misconception. We experimentally show that even the combined effect of O-2, water vapour, and NO2 at concentrations higher than typically present in the atmosphere does not fully replicate p-doping from ambient air. Thus, for EG gas sensors it is essential to consider naturally occurring environmental effects and properly separate them from those coming from targeted species.
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| 8. |
- Zamora-Ros, R., et al.
(författare)
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Dietary intakes and food sources of phytoestrogens in the European Prospective Investigation into Cancer and Nutrition (EPIC) 24-hour dietary recall cohort
- 2012
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Ingår i: European Journal of Clinical Nutrition. - : Springer Science and Business Media LLC. - 0954-3007 .- 1476-5640. ; 66:8, s. 932-941
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND/OBJECTIVES: Phytoestrogens are estradiol-like natural compounds found in plants that have been associated with protective effects against chronic diseases, including some cancers, cardiovascular diseases and osteoporosis. The purpose of this study was to estimate the dietary intake of phytoestrogens, identify their food sources and their association with lifestyle factors in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. SUBJECTS/METHODS: Single 24-hour dietary recalls were collected from 36 037 individuals from 10 European countries, aged 35-74 years using a standardized computerized interview programe (EPIC-Soft). An ad hoc food composition database on phytoestrogens (isoflavones, lignans, coumestans, enterolignans and equol) was compiled using data from available databases, in order to obtain and describe phytoestrogen intakes and their food sources across 27 redefined EPIC centres. RESULTS: Mean total phytoestrogen intake was the highest in the UK health-conscious group (24.9 mg/day in men and 21.1 mg/day in women) whereas lowest in Greece (1.3 mg/day) in men and Spain-Granada (1.0 mg/day) in women. Northern European countries had higher intakes than southern countries. The main phytoestrogen contributors were isoflavones in both UK centres and lignans in the other EPIC cohorts. Age, body mass index, educational level, smoking status and physical activity were related to increased intakes of lignans, enterolignans and equol, but not to total phytoestrogen, isoflavone or coumestan intakes. In the UK cohorts, the major food sources of phytoestrogens were soy products. In the other EPIC cohorts the dietary sources were more distributed, among fruits, vegetables, soy products, cereal products, non-alcoholic and alcoholic beverages. CONCLUSIONS: There was a high variability in the dietary intake of total and phytoestrogen subclasses and their food sources across European regions.
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| 9. |
- Aleksandrovskii, A.N., et al.
(författare)
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On the polyamorphism of fullerite-based orientational glasses.
- 2005
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Ingår i: Low Temperature Physics. - : AIP Publishing. - 1063-777X .- 1090-6517. ; 31:5, s. 429-444
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Tidskriftsartikel (refereegranskat)abstract
- The dilatometric investigation in the temperature range of 2–28 K shows that a first-orderpolyamorphous transition occurs in the orientational glasses based on C60 doped with H2, D2 andXe. A polyamorphous transition was also detected in C60 doped with Kr and He. It is observed thatthe hysteresis of thermal expansion caused by the polyamorphous transition (and, hence, the transitiontemperature) is essentially dependent on the type of doping gas. Both positive and negativecontributions to the thermal expansion were observed in the low-temperature phase of the glasses.The relaxation time of the negative contribution occurs to be much longer than that of the positivecontribution. The positive contribution is found to be due to phonon and libron modes, whilst thenegative contribution is attributed to tunneling states of the C60 molecules. The characteristictime of the phase transformation from the low-T phase to the high-T phase has been found for theC60–H2 system at 12 K. A theoretical model is proposed to interpret these observed phenomena.The theoretical model proposed, includes a consideration of the nature of polyamorphism inglasses, as well as the thermodynamics and kinetics of the transition. A model of noninteractingtunneling states is used to explain the negative contribution to the thermal expansion. The experimentaldata obtained is considered within the framework of the theoretical model. From the theoreticalmodel the order of magnitude of the polyamorphous transition temperature has been estimated.It is found that the late stage of the polyamorphous transformation is described well by theKolmogorov law with an exponent of n = 1. At this stage of the transformation, the two-dimensionalphase boundary moves along the normal, and the nucleation is not important.
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| 10. |
- Ankerst, J., et al.
(författare)
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Comparison of the bronchodilating effects of formoterol and albuterol delivered by hydrofluoroalkane pressurized metered-dose inhaler
- 2005
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Ingår i: Treat Respir Med. ; 4:2, s. 123-7
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To compare the onset of bronchodilation with a new formoterol hydrofluoroalkane (HFA) pressurized metered-dose inhaler (pMDI) with albuterol (salbutamol) HFA pMDI. PATIENTS AND METHODS: Thirty patients with stable mild or moderate asthma (23 using inhaled corticosteroids, mean FEV(1) 82% of predicted, >or=15% reversibility to terbutaline 1mg after 30 minutes) received formoterol HFA (Oxis) 2 x 4.5microg, albuterol HFA (Ventoline) Evohaler) 2 x 100microg, or placebo at three separate visits in this randomized, double-blind, double-dummy, three-way crossover study. FEV(1) was measured before and 3, 10, 20, 30 and 60 minutes after inhalation. Change in FEV(1) at 3 minutes after inhalation was the primary variable. RESULTS: Mean baseline FEV(1) was stable on all study days (range 2.92-2.94L). FEV(1) values at 3 minutes were: formoterol 3.22L (8% increase), albuterol 3.23L (9% increase) and placebo 2.99L (both p < 0.001 vs placebo). Maximum FEV(1) increased similarly with formoterol and albuterol, with no differences observed between the active treatments at any time point. Patients rated treatment effective at 3 minutes in 15 of 30, 19 of 30 and 7 of 30 cases with formoterol, albuterol and placebo, respectively. All treatments were well tolerated. CONCLUSION: In stable, mild, or moderate asthma, formoterol 9microg and albuterol 200microg, both by HFA pMDI, provided equally rapid and effective bronchodilation.
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