| 1. |
- Lind, Lars, et al.
(författare)
-
Heterogeneous contributions of change in population distribution of body mass index to change in obesity and underweight NCD Risk Factor Collaboration (NCD-RisC)
- 2021
-
Ingår i: eLife. - : eLife Sciences Publications Ltd. - 2050-084X. ; 10
-
Tidskriftsartikel (refereegranskat)abstract
- From 1985 to 2016, the prevalence of underweight decreased, and that of obesity and severe obesity increased, in most regions, with significant variation in the magnitude of these changes across regions. We investigated how much change in mean body mass index (BMI) explains changes in the prevalence of underweight, obesity, and severe obesity in different regions using data from 2896 population-based studies with 187 million participants. Changes in the prevalence of underweight and total obesity, and to a lesser extent severe obesity, are largely driven by shifts in the distribution of BMI, with smaller contributions from changes in the shape of the distribution. In East and Southeast Asia and sub-Saharan Africa, the underweight tail of the BMI distribution was left behind as the distribution shifted. There is a need for policies that address all forms of malnutrition by making healthy foods accessible and affordable, while restricting unhealthy foods through fiscal and regulatory restrictions.
|
|
| 2. |
- Akerman, J. J., et al.
(författare)
-
Dislocation-mediated creep of highly separated vortices in a-axis-oriented HgBa2CaCu2O6+delta thin films
- 2001
-
Ingår i: Physical Review B Condensed Matter. - 0163-1829 .- 1095-3795. ; 64:2
-
Tidskriftsartikel (refereegranskat)abstract
- Using ac susceptibility, we determine the critical current density J(c) and the flux creep activation energy U of an a-axis-oriented HgBa2CaCu2O6+delta thin film. The critical current density at helium temperatures is found to be 4.6 x 10(4) A/cm(2), i.e., about two orders of magnitude smaller than for corresponding films with c-axis orientation. The temperature and ac field dependent activation energy is consistent with dislocation-mediated flux creep and well described by U(T,H-ac)=U-o(1-t(4))H-ac(-1/2) with t=T/T-c, T-c=120K, and U-o = 0.77 eV Oe(1/2) for temperatures T>45 K and in the field range studied. The activation energy is of the same order as that found in c-axis-oriented films. Below T = 45 K the activation energy is observed to decrease as thermally assisted quantum creep becomes increasingly important.
|
|
| 3. |
- Akerman, J. J., et al.
(författare)
-
Two-stage crossover from thermal to quantum flux creep of dilute vortex ensembles in various high-T-c superconducting thin films
- 2001
-
Ingår i: Physical Review B Condensed Matter. - 0163-1829 .- 1095-3795. ; 64:9
-
Tidskriftsartikel (refereegranskat)abstract
- The thermal-to-quantum flux creep crossover at low vortex densities has been studied in YBa2Cu3O7, TlBa2CaCu2O7-delta, and HgBa2CaCu2O6+delta thin films using ac susceptibility. The crossover temperatures T-cr are 10-11, 17, and 30 K, respectively. Both thermal and quantum flux creep is suppressed as the vortex density is decreased. We observe a two-stage nature in the crossover behavior which appears to be a general property of all the three materials studied.
|
|
| 4. |
- Allen, P. D., et al.
(författare)
-
Low-frequency low-field magnetic susceptibility of ferritin and hemosiderin
- 2000
-
Ingår i: Biochimica et Biophysica Acta - Molecular Basis of Disease. - 0925-4439 .- 1879-260X. ; 1500:2, s. 186-196
-
Tidskriftsartikel (refereegranskat)abstract
- Low-frequency low-field magnetic susceptibility measurements were made on four samples of mammalian tissue iron oxide deposits. The samples comprised: (1) horse spleen ferritin; (') dugong liver hemosiderin; (3) thalassemic human spleen ferritin; and (4) crude thalassemic human spleen hemosiderin. These samples were chosen because Mossbauer spectroscopic measurements on the samples indicated that they exemplified the variation in magnetic and mineral structure found in mammalian tissue iron oxide deposits. The AC-magnetic susceptometry yielded information on the magnetization kinetics of the four samples indicating samples 1, 2, and 3 to be superparamagnetic with values of around 10(11) s(-1) for the preexponential frequency factor in the Neel-Arrhenius equation and values for characteristic magnetic anisotropy energy barriers in the range 250-400 K. Sample 4 was indicated to he paramagnetic at all temperatures above 1.3 K. The AC-magnetic susceptometry data also indicated a larger magnetic anisotropy energy distribution in the dugong liver sample compared with samples 1 and 3 in agreement with previous Mossbauer spectroscopic data on these samples. At temperatures below 200 K, samples 1-3 exhibited Curie-Weiss law behavior, indicating weak particle-particle interactions tending to favor antiparallel alignment of the particle magnetic moments. These interactions were strongest for the dugong liver hemosiderin. possibly reflecting the smaller separation between mineral particles in this sample. This is the first magnetic susceptometry study of hemosiderin iron deposits and demonstrates that the AC-magnetic susceptometry technique is a fast and informative method of studying such tissue iron oxide deposits.
|
|
| 5. |
- Bhatt, Pramod, et al.
(författare)
-
Ferromagnetism above room temperature in nickel-tetracyanoethylene thin films
- 2009
-
Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 19:36, s. 6610-6615
-
Tidskriftsartikel (refereegranskat)abstract
- Room temperature ferromagnetic ordering is reported in Ni-tetracyanoethylene (TCNE) thin films fabricated on Au substrates using physical vapor deposition (PVD) under ultra high vacuum conditions. This technique enables the preparation of very clean films without having any kind of contamination from oxygen-containing species, solvents or precursor molecules. Film stoichiometry was obtained from X-ray photoelectron spectroscopy (XPS) measurements. XPS derived stoichiometry points to a similar to 1 : 2 ratio between Ni and TCNE resulting in Ni(TCNE)(x), x approximate to 2. No evidence of pure Ni metal in the in situ grown films was present in the XPS or the ultraviolet photoelectron spectroscopy (UPS) measurements within the detection limits of the techniques.
|
|
| 6. |
- Bhatt, Pramod, et al.
(författare)
-
Room temperature magnetism in thin film nickel-tetracynoethylene
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Room temperature magnetic ordering is reported in Ni-Tetracynoethelene (TCNE) thin films fabricated on gold substrates using physical vapor deposition (PVD) under ultra high vacuum conditions. This technique enables preparation of very clean films without having any kind of contamination from oxygen-containing species, solvents or precursor molecules. Film thickness and stoichiometry were obtained from x-ray photoelectron spectroscopy (XPS) measurements. XPS derived stoichiometry points to a 1:2 ratio between Ni and TCNE resulting in Ni(TCNE)x, x ~ 2. No evidence of pure Ni metal in the in situ grown films were present in the XPS and UPS measurements within the detection limits of the techniques.
|
|
| 7. |
|
|
| 8. |
- Desai, R., et al.
(författare)
-
Bulk magnetic properties of CdFe(2)O(4)in nano-regime
- 2007
-
Ingår i: Bulletin of Materials Science. - : Springer Science and Business Media LLC. - 0250-4707 .- 0973-7669. ; 30:3, s. 197-203
-
Tidskriftsartikel (refereegranskat)abstract
- Cadmium ferrite particles have been synthesized using co-precipitation technique followed by a low temperature (600 degrees C) annealing in a time scale much shorter than reported in literature. Incorporation of sodium chloride during annealing helps to form a single phase spinel structure with a final particle size of around 50 nm. Even at such a short length scale we observe the overall magnetic properties to be similar to those of the bulk. The observed magnetic properties can be explained on the basis of an anti-ferromagnetic core with a shell containing 'ferromagnetic-like', but canted spin structure.
|
|
| 9. |
- Fang, Mei, 1984-, et al.
(författare)
-
Co-precipitation of iron oxide nanoparticles by rapid mixing
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Synthesis of Magnetite appears to be a topic of continued interest because of its versatility and the variety applications. Among the chemical techniques to synthesize Fe3O4, co-precipitation approach although very common, seems to be extremely sensitive to the consequences of nucleation, growth and most of all the rate of the reaction involved. This work is an attempt to demonstrate the complexities of obtaining monodispersed nanosized Fe3O4 particles. We consider the role of rapid mixing and its consequences on co-precipitation at ice-point, room temperature and boiling water temperatures on the magnetic properties of Fe3O4. We obtained crystallites varying in the range from 6.6 nm (grown in ice-water) to 7.9 nm (grown in boiling water) as determined from the broadening of XRD diffraction peaks using the Scherrer approach. With the increase of the particle size, the saturate magnetization of iron oxides increases from 52 emu/g to 63 emu/g, and the coercivity increases from 0.5 Oe to 7.9 Oe. Layers of nanosized magnetic particles on glass substrates show unusual wavelength dependence of Faraday rotation loops which show a reversal phenomenon in the sign of the magnetization around 550.
|
|
| 10. |
- Fang, Mei, 1984-, et al.
(författare)
-
Effect of Fe3O4 nanoparticles on the optical transmission properties of 3D magnetic photonic crystals
- 2010
-
Ingår i: Physics Review.
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Magnetic and optical properties of three-dimensional magnetic photonic crystals (MPCs), consisting of silica spheres in the size range 190-680nm embedded with 8, 9 and 13 nm Fe3O4 nanoparticles, have been investigated. All the PC-films, with and without embedded magnetic nanoparticles, show five band gaps at well defined wavelengths in their optical transmission spectrum. The band gaps are found to be a linear function of the constituent sphere size in the MPC films. From the slope of this function, the deduced refractive index for the constituents in the films is found to increase with the concentration of the embedded magnetite nanoparticles. The observed shifts in the photonic band gaps PBGs in the films is qualitatively explained in terms of the variations of refractive index and the contrast index difference arising from the concentration of the embedded nanoparticles. We also find that the angular dependence of PBG positions for MPCs at small incidence angles is strongly dependent on the p- and s- polarization states of the incident light. The polarization sensitivity of PBGs to the Fe3O4 concentration is also discussed.
|
|
