| 1. |
- Crescitelli, Rossella, 1985, et al.
(författare)
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Subpopulations of extracellular vesicles from human metastatic melanoma tissue identified by quantitative proteomics after optimized isolation
- 2020
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Ingår i: Journal of Extracellular Vesicles. - : Wiley. - 2001-3078. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- The majority of extracellular vesicle (EV) studies conducted to date have been performed on cell lines with little knowledge on how well these represent the characteristics of EVs in vivo. The aim of this study was to establish a method to isolate and categorize subpopulations of EVs isolated directly from tumour tissue. First we established an isolation protocol for subpopulations of EVs from metastatic melanoma tissue, which included enzymatic treatment (collagenase D and DNase). Small and large EVs were isolated with differential ultracentrifugation, and these were further separated into high and low-density (HD and LD) fractions. All EV subpopulations were then analysed in depth using electron microscopy, Bioanalyzer (R), nanoparticle tracking analysis, and quantitative mass spectrometry analysis. Subpopulations of EVs with distinct size, morphology, and RNA and protein cargo could be isolated from the metastatic melanoma tissue. LD EVs showed an RNA profile with the presence of 18S and 28S ribosomal subunits. In contrast, HD EVs had RNA profiles with small or no peaks for ribosomal RNA subunits. Quantitative proteomics showed that several proteins such as flotillin-1 were enriched in both large and small LD EVs, while ADAM10 were exclusively enriched in small LD EVs. In contrast, mitofilin was enriched only in the large EVs. We conclude that enzymatic treatments improve EV isolation from dense fibrotic tissue without any apparent effect on molecular or morphological characteristics. By providing a detailed categorization of several subpopulations of EVs isolated directly from tumour tissues, we might better understand the function of EVs in tumour biology and their possible use in biomarker discovery.
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| 2. |
- Malmhäll, Roger, et al.
(författare)
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Compositional short-range-order effects in the Hall resistivity of amorphous Fe27Ni53P14B6
- 1979
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Ingår i: Journal of Applied Physics. - : American Institute of Physics (AIP). - 0021-8979 .- 1089-7550. ; 50:B11, s. 7656-7658
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Tidskriftsartikel (refereegranskat)abstract
- Hall resistivity ( ρH) studies confirm that the Curie temperature (Tc) can be varied reproducibly between 374 K and 368 K by suitably annealing the alloy at 250 °C and 300 °C respectively. This is explained as being due to changes in compositional short‐range‐order. The calculated magnetic susceptibility, obtained from the temperature dependence of ρH, shows a strong fluctuation contribution described by (T−Tc)−γ, with γ=1.54±0.04 in both cases. A significant contribution to the temperature dependence of the ohmic resistivity, which is also uneffected by the annealing conditions, is found to be of magnetic origin.
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| 3. |
- Malmhäll, Roger, et al.
(författare)
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Hall effect in Metglas 2826A and 2826 - dependence on temperature and pressure
- 1977
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Ingår i: Proceedings of International Conference on Magnetism, ICM 76. - : Elsevier. - 072040732X - 9780720407327 ; 86-88, s. 796-798
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Konferensbidrag (refereegranskat)abstract
- The Hall resistivity, ρH, of Metglas 2826A is measured for 0.6 ≤ T/Tc ≤ 1.9. Below To (∼255 K), the extraordinary Hall coefficient R1 is constant at +4.24 x x10-8 m3/As. The magnetic susceptibility, derived from our data, exhibits a Curie-Weiss behaviour above 350 K and varies as (T - Tc)-1.75 for (T - Tc) < 90 K. In 2826 at 300 K ρH drops linearly with increasing pressure.
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| 4. |
- Malmhäll, Roger, et al.
(författare)
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Hall resistivity of a magnetic amorphous alloy : Effects of thermal cycling and annealing
- 1978
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Ingår i: Journal of Non-Crystalline Solids. - : Elsevier. - 0022-3093 .- 1873-4812. ; 28:2, s. 159-176
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Tidskriftsartikel (refereegranskat)abstract
- We have studied the effects of thermal cycling and annealing on the Hall resistivity ρH and electrical resistivity ρ of an amorphous magnetic material, Metglas 2826A. Thermal cycling up to 600 K has no significant effect on ρ but changes ρH, especially at T > 300 K. Annealing at higher temperatures Ta affects ρH more strongly than it influences ρ. For Ta = 650 K the Curie temperature jumps by ∼ 300 K and this, combined with X-ray data, is regarded as being symptomatic of the onset of crystallization. It is demonstrated that, for a fixed T, the variation of the extraordinary Hall coefficient R1 is simple correlated with that of ρ for both the amorphous material and the annealed (crystallized) specimens. Furthermore, for a given Ta, the variations of R1 and ρ as functions of temperature exhibit the same formal relationship. The temperature dependence of ρ in the annealed specimens is rendered plausible in terms of recent theories of disordered materials. Room-temperature studies of electron spin resonance and the field dependence of the magnetization are also reported.
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| 5. |
- Malmhäll, Roger, et al.
(författare)
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Hall resistivity of Fe and Fe-Ni based amorphous alloys
- 1978
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Ingår i: Rapidly Quenched Metals III. - 0904357228 ; , s. 145-148
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Konferensbidrag (refereegranskat)abstract
- We report on Hall and ohmic studies of Fe and Fe-Ni based magnetic Metglas alloys in the temperature range 100-700 K and in magnetic fields up to 2.5 Tesla. While the saturation magnetization and the Curie temperature in these systems vary significantly, it is found that the extraordinary Hall coefficient, R1, at 300 K is almost a constant. While the temperature coefficient of the ohmic resistivity ρ is generally positive, dR1/dT is found to be of either sign. A cusp is observed in R1 and in dρ/dT for some of the alloys.
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| 6. |
- Malmhäll, Roger, et al.
(författare)
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Metglas 2826B—Transport, magnetic and thermal properties
- 1978
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Ingår i: Journal of Applied Physics. - : American Institute of Physics (AIP). - 0021-8979 .- 1089-7550. ; 49:3, s. 1727-1729
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Tidskriftsartikel (refereegranskat)abstract
- We report Hall resistivity, magnetization, heat capacity, and electrical resistivity studies on Metglas2826B (Fe29Ni49P14B6Si2) spanning the temperature regime 77 to 800K. The critical exponents for this system are found to be β = 0.40 ± 0.01, δ = 5.25 ± 0.10, and γ = 1.7 ± 0.1. The magnetic isotherms fit into universal scaling functions over a rather wide range of temperature both above and below Tc. The specific heat exhibits a sharp peak at Tc. The temperature derivative of the electrical resistivity has a marked change at Tc. Although Tc increases slightly on thermal cycling to higher temperatures, the critical exponents are not influenced by this.
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| 7. |
- Malmhäll, Roger, et al.
(författare)
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Transport properties of amorphous ferromagnets : Hall and ohmic resistivities
- 1979
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Ingår i: Physica status solidi. A, Applied research. - : John Wiley & Sons. - 0031-8965 .- 1521-396X. ; 53:2, s. 641-651
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Tidskriftsartikel (refereegranskat)abstract
- Simultaneous measurements are made of the ohmic resistivity (ϱ) and the Hall resistivity (ϱH) of a number of amorphous ferromagnetic Fe–Ni based alloys prepared by the rapid quenching technique. The temperature range of the experiments is 100 through 700 K and the applied magnetic fields are varied up to 2.5 T. It turns out that for all the amorphous alloys: (i) R1 ≈ 5 × 10−8 m3/As, (ii) ϱ ≈ 1.5 μΩm, (iii) ϱH has a sharp drop from which the ferromagnetic transition temperature (TC) can be determined to ≈ 5 K, (iv) the critical exponent γ ≈ 1.6 for (TC + 1) < < T < (TC + 50) K, and (v) the extraordinary Hall conductivity γHs is of the same order (≈ 5 × 104 Ω−1 m−1) as in crystalline Fe alloys. Further, in some cases (dϱ/dT) exhibits a well-defined anomaly at TC.
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| 8. |
- Rao, K.V., et al.
(författare)
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Hall effect in amorphous magnetic materials - METGLAS 2826 and 2826B
- 1976
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Ingår i: Solid State Communications. - : Elsevier. - 0038-1098 .- 1879-2766. ; 19:3, s. 193-195
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Tidskriftsartikel (refereegranskat)abstract
- Hall effect measurements on the ferromagnetic amorphous materials, Metglas 2826 and 2826B, indicate that they are rather similar to crystalline soft magnetic materials. The extra-ordinary Hall coefficient Ra is found to be 1.4 x 104 ρ2 (m3/As), where, ρ, is the electrical resistivity, and is in reasonable agreement with the predictions of theory. On the other hand, though unexpected, the ordinary Hall coefficient in all the amorphous alloys we have studied turns out to be of the order of 7 x 10-10 (m3/As).
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| 9. |
- Rao, K. Venkat, et al.
(författare)
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Magnetic and transport properties of transition-metal based glassy ribbons
- 1980
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Ingår i: IEEE Transactions on Magnetics. - : IEEE. - 0018-9464 .- 1941-0069. ; 16:5, s. 896-901
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Tidskriftsartikel (refereegranskat)abstract
- In this review, from our systematic studies on transition-metal based amorphous alloys of the type (AxB1-x)75P16B6Al3, where A,B, = Fe, Ni, Mn, or Co, we demonstrate that the temperature and the field dependence of the Hall resistivity, ρH , yields several useful parameters which characterize the magnetism, and the stability of these systems. The exponent for the fluctuation contribution to the magnetic susceptibility, χ, derived from these studies is found to vary from the value of 1.6, observed in general, to the Heisenberg value of 1.33 for the Fe-rich alloys. The ordinary Hall coefficient for the Ni-rich alloys is found to be negative, while a positive value is observed for all other systems studied so far. The ohmic resistivity, ρ measured simultaneously, is correlated with ρH studies in the light of current theories. It is shown that most of the T-dependence of ρ in the metal-metalloid systems is of magnetic origin. Similar studies on the binary amorphous Zr70(Fe, Co, Ni, Pd, Cu)30 alloys show that these systems can be understood only in terms of the extended Ziman theory. Finally, our recent evidence for deviations from the simple spin-wave theory in the magnetitions of amorphous Fe-Ni alloy system is correlated with ac-susceptibility studies to obtain a probable phase-diagram near the multicrtical point.
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