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| 2. |
- Piccinin, M, et al.
(författare)
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Cross-national coordinated analysis (IALSA) of age, sex, and education effects on change in MMSE scores
- 2006
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Ingår i: 59th Annual Scientific Meeting of the Gerontological Society of America, Dallas, TX, USA..
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Konferensbidrag (refereegranskat)abstract
- In a cross-national, multi-study (ALSA, CLS, H-70, HOPE, NAS, OCTO-Twin, LASA) analysis, we systematically address concerns regarding the effect of educational attainment on Mini-Mental Status Exam (MMSE) scores in a descriptive comparison of between-person dif-ferences and within-person age changes. We describe the coordinated analysis process and the first results from the IALSA network. Marked country and birth cohort differences in educa-tional attainment required a flexible modeling approach: median years in school ranged from 6 in LASA and the older Swedish cohorts to 12 in CLS and NAS. For studies with similarly coded education, higher educated participants scored higher and showed less decline. Ignoring the impact of declining health, on average, at age 80, men with six years of education scored between 25 and 27 on the MMSE and declined about 0.3 points per year. Older individuals tend to score lower and decline at a faster rate. Gender differences were mixed.
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| 4. |
- Thorvaldsson, K., et al.
(författare)
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A model for simultaneous heat, water and vapour diffusion.
- 1999
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Ingår i: Journal of Food Engineering. - 0260-8774 .- 1873-5770. ; 40:3, s. 167-172
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Tidskriftsartikel (refereegranskat)abstract
- A model for simultaneous heat, water and vapour diffusion was developed to use for prediction of the diffusion of water inside foods during heat processing. The model is based on Fourier's and Fick's Laws. The diffusion of liquid water is separated from the diffusion of water vapour. The model was evaluated in a drying process. Slabs of bread crumbs, 12×12×2 cm3 in size, were dried in a conventional oven at 210 °C and the local water content and temperatures were measured during the drying in the centre, halfway to the centre and at the surface. From the measurements, the diffusion coefficient as a function of temperature and concentration and several other material parameters were estimated. The results show that the measured water content slowly increases in the centre of the sample. During the increase, the temperature remains on a plateau. When the centre starts to dry the temperature increases. Halfway to the centre the water content also increases slightly before it starts to dry out, while the surface starts drying immediately. The simulated water content levels and temperatures conform well to the experimental values and show that the evaporation and condensation model describes well the diffusion mechanisms in a porous food.
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| 7. |
- Thorvaldsson, K., et al.
(författare)
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Method and instrument for measuring local water content inside food
- 1996
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Ingår i: Journal of Food Engineering. - : Elsevier BV. - 0260-8774 .- 1873-5770. ; 29:1, s. 1-11
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Tidskriftsartikel (refereegranskat)abstract
- A new method of measuring local water content inside food during heat processing has been evaluated. The method uses a fibre optic NIR-Instrument. The evaluation was mainly based on investigations of the influence of structure and temperature. The instrument was found to be very sensitive to both the structure and the temperature of the sample. The dependence on the temperature of the sample can be incorporated into the calibration and is thereby not an impediment to the measurements. The structural dependence makes quantitative measurements at different places in the sample difficult for inhomogeneous materials. However, measurements of dynamic changes in the water content in one spot work well for both homogenous and inhomogeneous materials and are probably the best application of the instrument. By using two or more optic fibres, the diffusion of water can also be measured. Copyright © 1996 Elsevier Science Limited.
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| 8. |
- Thorvaldsson, K., et al.
(författare)
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Rheology and structure of heat-treated pasta dough : Influence of water content and heating rate
- 1999
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Ingår i: Lebensmittel-Wissenschaft + Technologie. - : Academic Press. - 0023-6438 .- 1096-1127. ; 32:3, s. 154-161
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Tidskriftsartikel (refereegranskat)abstract
- The migration of water and the influence of water content and heating rate on the rheological and structural formation of pasta dough were investigated. The dough used in the study had two different water contents, 39.5 and 41.0%, and was made using water and wheat flour. The samples, 15 x 15 x 2 cm in size, were heated from 25 to 80°C in a conventional oven at two different temperatures, 100 and 150°C, to achieve two different heating rates. During the heating the local water content was measured in the centre of the samples with a fibre-optic NIR instrument. The temperature was measured in the centre, halfway to the centre and at the surface. The rheology of the heat-treated samples was studied by means of tensile tests. Young's modulus, stress at maximum load and energy to break point were calculated. The micro structure of the samples was characterised by CLSM, confocal laser scanning microscopy, and the microstructural parameters were quantified using image analysis. The changes in rheological properties during heating were studied by means of DMA. Untreated dough samples were heated from 25 to 90°C with a heating rate of 5° C/min and a compressing oscillation of 1 Hz. The changes in phase angle δ and storage modulus E' were measured. The most important results were that no migration of water inside the pasta dough could be found. Both the water content and the heating rate affected the structural and rhelogical properties of the pasta dough. There was a maximum in E' vs. temperature, which shifted towards higher temperatures with decreasing water content. Young's modulus was affected by both the heating rate and the water content. Energy to break point and stress at maximum load were affected by the heating rate. The pore size was affected by the water content. The swelling temperature seemed to increase as the heating rate increased
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| 9. |
- Thorvaldsson, K., et al.
(författare)
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Water diffusion in bread during baking
- 1998
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Ingår i: Lebensmittel-Wissenschaft + Technologie. - 0023-6438 .- 1096-1127. ; 31:42193, s. 658-663
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Tidskriftsartikel (refereegranskat)abstract
- A study of heat and water transport in bread during baking was performed. Loaves of bread were fermented twice and baked in a conventional oven at 225°C, with no forced convection, for 35 min. The local water content and two or three different temperatures were measured inside the bread during the baking process. Bread baked from wheat flour was used to investigate the mechanisms of water transport inside a loaf during baking. The water content was measured in the centre, 1 cm from the base, in the bottom crust, 1 cm under the top surface and in the top crust, using a fibre-optic NIR instrument. The temperature was measured on the bottom surface, in the centre, and 1 mm from the optic fibre. The results indicate that up to 70 ± 5°C, where a structural change is taking place, the water content in the centre changes little. However, after reaching this temperature the water content in the centre of the loaf rises due to vapour transport from the warmer regions. The water appears to be moving towards the coldest region, and not towards the geometrical centre. © 1998 Academic Press.
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| 10. |
- Thorvaldsson, K., et al.
(författare)
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Water transport in meat during reheating
- 1996
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Ingår i: Journal of Food Engineering. - : Elsevier BV. - 0260-8774 .- 1873-5770. ; 29:1, s. 13-21
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Tidskriftsartikel (refereegranskat)abstract
- A study of heat and water transport in meat during a heating process was conducted. The meat samples were heated from 10 to 100°C in a conventional oven at 175°C and local water content and temperatures were measured during the heating process. Using whole meat from bovine muscles, the mechanism behind water transport inside the sample during heating was investigated. The anisotropy of meat in terms of heat and water transport was also studied. The study yielded two main results: When heating commences, water moves towards the centre of the samples. At a centre temperature of ?70°C, water transport stops and changes direction. A theory for transport phenomena has been developed and is described in this paper. The results also indicate that, as expected, both water transport and heat transport are faster parallel to the meat fibres than perpendicular to them. Copyright © 1996 Elsevier Science Limited.
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