Effects of inclined baffle location and Prandtl number on natural convection in a cavity

The problem of steady, laminar, conjugate-natural convection in a square cavity with an adiabatic baffle mounted on a vertical wall at different positions is formulated. In this study, natural convection heat transfer in a square cavity with an adiabatic fin mounted on a vertical wall was investigated numerically. Navier-Stokes equations have been performed and they are solved using finite difference method (FDM). Results are obtained for various parameters as the baffle location (0.25 h 0.75), thickness (t=0.033), length of baffle (0.25 w 0.75), Rayleigh numbers (103 Ra 106). Prandtl number values are Pr=0.7, 1 and 7, is investigated. Results were presented with streamlines, isotherms, local and mean Nusselt numbers. It was found that Prandtl number and presence of the baffle on the wall have significant effect on natural convection.Bu çalışmada, düşey duvarına farklı pozisyonlarda adyabatik engel yerleştirilmiş kare bir hacimdeki laminar doğal taşınım ısı transferi formüle edilmiştir. Düşey duvarında engel bulunan kapalı hacimdeki ısı transferi nümerik olarak da incelenmiştir. Navier-Stokes denklemleri kullanılmış ve denklemler sonlu farklar metodu (FDM) ile çözülmüştür. Sonuçlar, engelin farklı yerleşimi (0.25 h 0.75), farklı kalınlığı (t=0.033), farklı uzunluğu (0.25 w 0.75) ve Rayleigh sayıları için (103 Ra 106) sunulmuştur. Prandtl sayısı değeri 0.7, 1 ve 7 alınmıştır. Sonuçlar, akım çizgileri, sıcaklık profilleri, yerel ve ortalama Nusselt sayıları şeklinde gösterilmiştir. Prandtl sayısı ve engelin duvar üzerindeki konumunun, doğal taşınımı önemli derecede etkilediği görülmüştür

Effect of Microwave Frying on Acrylamide Generation, Mass Transfer, Color, and Texture in French Fries

[EN] The objective of this work was to evaluate the effect of microwave power on acrylamide generation, as well as moisture and oil fluxes and quality attributes of microwave-fried potatoes. Concretely, 25 g of potato strips, in 250 mL of fresh oil (at room temperature), were subjected to three different microwave powers (315, 430, and 600 W) in a conventional microwave oven. Microwave frying resulted in an acrylamide reduction ranged from 37 to 83% compared to deep-oil frying. Microwave-fried French fries presented lower moisture and higher fat content than deep-oil fried potatoes. Concretely, microwave-fried potatoes presented values of moisture and texture more similar to potato chips than French fries, nonetheless with lower fat levels (less than 20 g/100 g wb) and acrylamide content (lower than 100 ¿g/kg wb) at the reference time. This study presents an alternative way of frying to address the production of healthier potato chips.The authors would like to thank the Universitat Politecnica de Valencia for the PhD scholarship given to Mariola Sansano Tomas.Sansano, M.; De Los Reyes Cánovas, R.; Andrés Grau, AM.; Heredia Gutiérrez, AB. (2018). Effect of Microwave Frying on Acrylamide Generation, Mass Transfer, Color, and Texture in French Fries. Food and Bioprocess Technology. 11(10):1934-1939. doi:10.1007/s11947-018-2144-zS193419391110AACC. (1995). Approved methods of the American association of cereal chemists (9th ed.). St. Paul: The Association.Adedeji, A. A., Ngadi, M. O., & Raghavan, G. S. V. (2009). Kinetics of mass transfer in microwave precooked and deep-fat fried chicken nuggets. Journal of Food Engineering, 91(1), 146–153.Ahrné, L., Andersson, C.-G., Floberg, P., Rosén, J., & Lingnert, H. (2007). Effect of crust temperature and water content on acrylamide formation during baking of white bread: steam and falling temperature baking. LWT-Food Science and Technology, 40(10), 1708–1715.Amrein, T. M., Limacher, A., Conde-Petit, B., Amadò, R., & Escher, F. (2006). Influence of thermal processing conditions on acrylamide generation and Browning in a potato model system. Journal of Agricultural and Food Chemistry, 54(16), 5910–5916.Andrés, A., Arguelles, Á., Castelló, M. L., & Heredia, A. (2013). Mass transfer and volume changes in French fries during air frying. Food and Bioprocess Technology, 6(8), 1917–1924.Barutcu, I., Sahin, S., & Sumnu, G. (2009). Acrylamide formation in different batter formulations during microwave frying. LWT - Food Science and Technology, 42(1), 17–22.Belgin Erdoǧdu, S., Palazoǧlu, T. K., Gökmen, V., Şenyuva, H. Z., & Ekiz, H. İ. (2007). Reduction of acrylamide formation in French fries by microwave pre-cooking of potato strips. Journal of the Science of Food and Agriculture, 87(1), 133–137.Biedermann, M., Noti, A., Biedermann-Brem, S., Mozzetti, V., & GROB, K. (2002). Experiments on acrylamide formation and possibilities to decrease the potential of acrylamide formation in potatoes. Mitteilungen aus Lebensmitteluntersuchung und Hygiene, 93(6), 668–687.Bråthen, E., & Knutsen, S. H. (2005). Effect of temperature and time on the formation of acrylamide in starch-based and cereal model systems, flat breads and bread. Food Chemistry, 92(4), 693–700.Buffler, C. R. (1993). Microwave cooking and processing: Engineering fundamentals for the food scientist. (A. Books, Ed.). New York: Van Nostrand Reinhold.Datta, A. K. (1990). Heat and mass transfer in the microwave processing of food. Chemical Engineering Progress, 86(6), 47–53.Datta, A. K. (2001). Handbook of microwave technology for food application. CRC Press.De los Reyes, R., Heredia, A., Fito, P., De los Reyes, E., & Andrés, A. (2007). Dielectric spectroscopy of osmotic solutions and osmotically dehydrated tomato products. Journal of Food Engineering, 80(4), 1218–1225. 2.Granda, C., & Moreira, R. G. (2005). Kinetics of acrylamide formation during traditional and vacuum frying of potato chips. Journal of Food Process Engineering, 28(5), 478–493.Lizhi, H., Toyoda, K., & Ihara, I. (2008). Dielectric properties of edible oils and fatty acids as a function of frequency, temperature, moisture and composition. Journal of Food Engineering, 88(2), 151–158.Oztop, M. H., Sahin, S., & Sumnu, G. (2007). Optimization of microwave frying of potato slices by using Taguchi technique. Journal of Food Engineering, 79(1), 83–91.Parikh, A., & Takhar, P. S. (2016). Comparison of microwave and conventional frying on quality attributes and fat content of potatoes. Journal of Food Science, 81(11), E2743–E2755.Pedreschi, F., & Moyano, P. (2005). Oil uptake and texture development in fried potato slices. Journal of Food Engineering, 70(4), 557–563.Sahin, S., Sumnu, G., & Oztop, M. H. (2007). Effect of osmotic pretreatment and microwave frying on acrylamide formation in potato strips. Journal of the Science of Food and Agriculture, 87(15), 2830–2836. https://doi.org/10.1002/jsfa.3034 .Sansano, M., Juan-Borrás, M., Escriche, I., Andrés, A., & Heredia, A. (2015). Effect of pretreatments and air-frying, a novel technology, on acrylamide generation in fried potatoes. Journal of Food Science, 80(5), 1120–1128.Sansano, M., Heredia, A., Peinado, I., & Andrés, A. (2017). Dietary acrylamide: What happens during digestion. Food Chemistry, 237, 58–64.Schiffmann, R. (2017). 7 - Microwave-assisted frying. In The microwave processing of foods (2nd edn, pp. 142–151). Sawston: Woodhead Publishing.Tang, J., Feng, H., & Lau, M. (2002). Microwave heating in food processing. In X.Young, J. Tang, C. Zhang, & W. Xin (Eds.), Advances in Agricultural Engineering (pp. 1–44). New York: Scientific Press.Tareke, E., Rydberg, P., Karlsson, P., Eriksson, S., & Törnqvist, M. (2002). Analysis of acrylamide, a carcinogen formed in heated foodstuffs. Journal of Agricultural and Food Chemistry, 50(17), 4998–5006.Taubert, D., Harlfinger, S., Henkes, L., Berkels, R., & Schömig, E. (2004). Influence of processing parameters on acrylamide formation during frying of potatoes. Journal of Agricultural and Food Chemistry, 52(9), 2735–2739.Venkatesh, M. S., & Raghavan, G. S. V. (2004). An overview of microwave processing and dielectric properties of agri-food materials. Biosystems Engineering, 88(1), 1–18

Relevance of genetic testing in the gene-targeted trial era: the Rostock Parkinson\u27s disease study

\ua9 The Author(s) 2024. Estimates of the spectrum and frequency of pathogenic variants in Parkinson’s disease (PD) in different populations are currently limited and biased. Furthermore, although therapeutic modification of several genetic targets has reached the clinical trial stage, a major obstacle in conducting these trials is that PD patients are largely unaware of their genetic status and, therefore, cannot be recruited. Expanding the number of investigated PD-related genes and including genes related to disorders with overlapping clinical features in large, well-phenotyped PD patient groups is a prerequisite for capturing the full variant spectrum underlying PD and for stratifying and prioritizing patients for gene-targeted clinical trials. The Rostock Parkinson’s disease (ROPAD) study is an observational clinical study aiming to determine the frequency and spectrum of genetic variants contributing to PD in a large international cohort. We investigated variants in 50 genes with either an established relevance for PD or possible phenotypic overlap in a group of 12 580 PD patients from 16 countries [62.3% male; 92.0% White; 27.0% positive family history (FH+), median age at onset (AAO) 59 years] using a next-generation sequencing panel. Altogether, in 1864 (14.8%) ROPAD participants (58.1% male; 91.0% White, 35.5% FH+, median AAO 55 years), a PD-relevant genetic test (PDGT) was positive based on GBA1 risk variants (10.4%) or pathogenic/likely pathogenic variants in LRRK2 (2.9%), PRKN (0.9%), SNCA (0.2%) or PINK1 (0.1%) or a combination of two genetic findings in two genes (∼0.2%). Of note, the adjusted positive PDGT fraction, i.e. the fraction of positive PDGTs per country weighted by the fraction of the population of the world that they represent, was 14.5%. Positive PDGTs were identified in 19.9% of patients with an AAO ≤ 50 years, in 19.5% of patients with FH+ and in 26.9% with an AAO ≤ 50 years and FH+. In comparison to the idiopathic PD group (6846 patients with benign variants), the positive PDGT group had a significantly lower AAO (4 years, P = 9 7 10−34). The probability of a positive PDGT decreased by 3% with every additional AAO year (P = 1 7 10−35). Female patients were 22% more likely to have a positive PDGT (P = 3 7 10−4), and for individuals with FH+ this likelihood was 55% higher (P = 1 7 10−14). About 0.8% of the ROPAD participants had positive genetic testing findings in parkinsonism-, dystonia/dyskinesia- or dementia-related genes. In the emerging era of gene-targeted PD clinical trials, our finding that ∼15% of patients harbour potentially actionable genetic variants offers an important prospect to affected individuals and their families and underlines the need for genetic testing in PD patients. Thus, the insights from the ROPAD study allow for data-driven, differential genetic counselling across the spectrum of different AAOs and family histories and promote a possible policy change in the application of genetic testing as a routine part of patient evaluation and care in PD

Movement distributions of stroke survivors exhibit distinct patterns that evolve with training

BACKGROUND: While clinical assessments provide tools for characterizing abilities in motor-impaired individuals, concerns remain over their repeatability and reliability. Typical robot-assisted training studies focus on repetition of prescribed actions, yet such movement data provides an incomplete account of abnormal patterns of coordination. Recent studies have shown positive effects from self-directed movement, yet such a training paradigm leads to challenges in how to quantify and interpret performance. METHODS: With data from chronic stroke survivors (n = 10, practicing for 3 days), we tabulated histograms of the displacement, velocity, and acceleration for planar motion, and examined whether modeling of distributions could reveal changes in available movement patterns. We contrasted these results with scalar measures of the range of motion. We performed linear discriminant analysis (LDA) classification with selected histogram features to compare predictions versus actual subject identifiers. As a basis of comparison, we also present an age-matched control group of healthy individuals (n = 10, practicing for 1 day). RESULTS: Analysis of range of motion did not show improvement from self-directed movement training for the stroke survivors in this study. However, examination of distributions indicated that increased multivariate normal components were needed to accurately model the patterns of movement after training. Stroke survivors generally exhibited more complex distributions of motor exploration compared to the age-matched control group. Classification using linear discriminant analysis revealed that movement patterns were identifiable by individual. Individuals in the control group were more difficult to identify using classification methods, consistent with the idea that motor deficits contribute significantly to unique movement signatures. CONCLUSIONS: Distribution analysis revealed individual patterns of abnormal coordination in stroke survivors and changes in these patterns with training. These findings were not apparent from scalar metrics that simply summarized properties of motor exploration. Our results suggest new methods for characterizing motor capabilities, and could provide the basis for powerful tools for designing customized therapy

MHD natural convection in an inclined wavy cavity with corner heater filled with a nanofluid

A mathematical modelling of MHD free convection in an inclined wavy enclosure filled with a Cu–water nanofluid in the presence of an isothermal corner heater has been carried out. The cavity is heated from the left bottom corner and cooled from the top wavy wall while the rest walls are adiabatic. Uniform magnetic field affects the heat transfer and fluid flow with an inclination angle to the axis View the MathML source. Wavy cavity is inclined to the horizontal direction. Mathematical model formulated using the single-phase nanofluid approach in dimensionless variables stream function, vorticity and temperature has been solved by finite difference method of the second order accuracy in a wide range of governing parameters: Hartmann number (Ha =0–100), inclination angle of the magnetic field (Х=0-П), undulation number (k =0–4), inclination angle of the cavity (E=0-П), solid volume fraction parameter of nanoparticles (?=0.0–0.05), and dimensionless time (т=0–0.27). Main efforts have been focused on the effects of these parameters on the fluid flow and heat transfer inside the cavity. Numerical results have been presented in the form of streamlines, isotherms and average Nusselt numbers

MHD free convection in a wavy open porous tall cavity filled with nanofluids under an effect of corner heater

A numerical analysis of MHD natural convection in a wavy open porous tall cavity filled with a Cu–water nanofluid in the presence of an isothermal corner heater has been carried out. The cavity is cooled from the left wavy wall and heated from the right bottom corner while the bottom wall is adiabatic. Uniform magnetic field affects the heat transfer and fluid flow with an inclination angle to the axis x¯. Mathematical model formulated using the single-phase nanofluid approach in dimensionless variables stream function, vorticity and temperature has been solved by finite difference method of the second order accuracy in a wide range of governing parameters: Rayleigh number (Ra = 100–1000), Hartmann number (Ha = 0–100), inclination angle of the magnetic field (γ = 0–π) and solid volume fraction parameter of nanoparticles (φ = 0.0–0.05). Main efforts have been focused on the effects of these parameters on the fluid flow and heat transfer inside the cavity. Numerical results have been presented in the form of streamlines, isotherms and average Nusselt numbers. It has been found heat transfer enhancement with Rayleigh number and heat transfer reduction with Hartmann number, while magnetic field inclination angle leads to non-monotonic changes of the heat transfer rate

MHD free convection in a wavy open porous tall cavity filled with nanofluids under an effect of corner heater

A numerical analysis of MHD natural convection in a wavy open porous tall cavity filled with a Cu–water nanofluid in the presence of an isothermal corner heater has been carried out. The cavity is cooled from the left wavy wall and heated from the right bottom corner while the bottom wall is adiabatic. Uniform magnetic field affects the heat transfer and fluid flow with an inclination angle to the axis x¯. Mathematical model formulated using the single-phase nanofluid approach in dimensionless variables stream function, vorticity and temperature has been solved by finite difference method of the second order accuracy in a wide range of governing parameters: Rayleigh number (Ra = 100–1000), Hartmann number (Ha = 0–100), inclination angle of the magnetic field (γ = 0–π) and solid volume fraction parameter of nanoparticles (φ = 0.0–0.05). Main efforts have been focused on the effects of these parameters on the fluid flow and heat transfer inside the cavity. Numerical results have been presented in the form of streamlines, isotherms and average Nusselt numbers. It has been found heat transfer enhancement with Rayleigh number and heat transfer reduction with Hartmann number, while magnetic field inclination angle leads to non-monotonic changes of the heat transfer rate