ORCID Profile
0000-0003-1477-5627
Current Organisations
Aarhus University
,
University of Sydney
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Publisher: Springer International Publishing
Date: 2016
Publisher: Elsevier BV
Date: 06-1995
Publisher: Elsevier BV
Date: 2015
Publisher: Elsevier BV
Date: 1997
Publisher: MDPI AG
Date: 09-01-2020
DOI: 10.3390/E22010084
Abstract: This work investigates the convergence dynamics of a numerical scheme employed for the approximation and solution of the Frank–Kamenetskii partial differential equation. A framework for computing the critical Frank–Kamenetskii parameter to arbitrary accuracy is presented and used in the subsequent numerical simulations. The numerical method employed is a Crank–Nicolson type implicit scheme coupled with a fourth order spatial discretisation as well as a Newton–Raphson update step which allows for the nonlinear source term to be treated implicitly. This numerical implementation allows for the analysis of the convergence of the transient solution toward the steady-state solution. The choice of termination criteria, numerically dictating this convergence, is interrogated and it is found that the traditional choice for termination is insufficient in the case of the Frank–Kamenetskii partial differential equation which exhibits slow transience as the solution approaches the steady-state. Four measures of convergence are proposed, compared and discussed herein.
Publisher: Springer Science and Business Media LLC
Date: 29-09-2017
Publisher: Elsevier BV
Date: 12-2013
DOI: 10.1016/J.BIOS.2013.06.059
Abstract: Current-time and steady state current behaviour was simulated for the cases of a hemispherical and flat inlaid disk electrodes located under a hemispherical polymer drop containing an enzyme which converts a substrate diffusing into the drop into a product that is electroactive at the electrode. As well, a cylindrical electrode with length much greater than its diameter and coated with a layer of polymer/enzyme was treated. The ratio of steady state currents at the hemispherical to the disk electrode is not, as has sometimes been assumed, always equal to π/2 indeed this is only approached for polymer drops with large spillover ratio, that is, having a radius much larger than that of the electrodes. Steady state currents for all electrode geometries (including the cylinder) go through a maximum for some spillover ratio and then approach a constant value for larger spillover ratios. This constant value is the same as that for the diffusion limited current in a semi-infinite medium. For a cylindrical electrode, the steady state current tends towards zero for large spillover ratios.
Publisher: Elsevier BV
Date: 08-2017
DOI: 10.1016/J.JAND.2017.03.016
Abstract: High consumption of protein has been associated with accelerated growth and adiposity in early childhood. To describe intake, food sources, correlates, and tracking of protein in young children. Secondary analysis of Melbourne Infant Feeding Activity and Nutrition Trial (InFANT). Dietary data were collected using three 24-hour dietary recalls at ages 9 and 18 months as well as 3.5 and 5 years. First-time mothers and their child (n=542) participated in an 18-month intervention to prevent childhood obesity and the cohort was followed-up with no intervention when children were aged 3.5 and 5 years. Protein intake, food sources, correlates, and tracking of protein. Child and maternal correlates of protein intake were identified using linear regression and tracking of protein intake was examined using Pearson correlations of residualized protein scores between time points. Mean protein (grams per day) intake was 29.7±11.0, 46.3±11.5, 54.2±13.8, and 60.0±14.8 at 9 and 18 months and 3.5 and 5 years, respectively. Protein intakes at all ages were two to three times greater than age-appropriate Australian recommendations. The primary source of protein at 9 months was breast/formula milk. At later ages, the principal sources were milk/milk products, breads/cereals, and meat/meat products. Earlier breastfeeding cessation, earlier introduction of solids, high dairy milk consumption (≥500 mL), and high maternal education were significant predictors of high protein intake at various times (P<0.05). Slight tracking was found for protein intakes at 9 months, 18 months, and 5 years (r=0.16 to 0.21 P<0.01). This study provides unique insights into food sources and correlates of young children's high protein intakes, and confirms that early protein intakes track slightly up to age 5 years. These finding have potential to inform nutrition interventions and strategies to address high protein intakes and protein-related obesity risk.
Publisher: Elsevier BV
Date: 12-1995
Publisher: Springer Science and Business Media LLC
Date: 14-03-2017
Publisher: Springer Science and Business Media LLC
Date: 10-01-2017
Publisher: Elsevier BV
Date: 09-2018
Publisher: Elsevier BV
Date: 09-2023
Publisher: Elsevier BV
Date: 09-2016
Publisher: Elsevier BV
Date: 10-2008
Publisher: Elsevier BV
Date: 12-2017
Publisher: Elsevier BV
Date: 04-1994
Publisher: Elsevier BV
Date: 07-2003
DOI: 10.1016/S0097-8485(02)00075-X
Abstract: The Crank-Nicolson (CN) simulation method has an oscillatory response to sharp initial transients. The technique is convenient but the oscillations make it less popular. Several ways of d ing the oscillations in two types of electrochemical computations are investigated. For a simple one-dimensional system with an initial singularity, sub ision of the first time interval into a number of equal subintervals (the Pearson method) works rather well, and so does ision with exponentially increasing subintervals, where however an optimum expansion parameter must be found. This method can be computationally more expensive with some systems. The simple device of starting with one backward implicit (BI, or Laasonen) step does d the oscillations, but not always sufficiently. For electrochemical microdisk simulations which are two-dimensional in space and using CN, the use of a first BI step is much more effective and is recommended. Division into subintervals is also effective, and again, both the Pearson method and exponentially increasing subintervals methods are effective here. Exponentially increasing subintervals are often considerably more expensive computationally. Expanding intervals over the whole simulation period, although capable of satisfactory results, for most systems will require more cpu time compared with sub ision of the first interval only.
Publisher: Elsevier BV
Date: 08-2017
DOI: 10.1016/J.CHEMBIOL.2017.07.012
Abstract: The α-oxoaldehyde methylglyoxal is a ubiquitous and highly reactive metabolite known to be involved in aging- and diabetes-related diseases. If not detoxified by the endogenous glyoxalase system, it exerts its detrimental effects primarily by reacting with biopolymers such as DNA and proteins. We now demonstrate that during ketosis, another metabolic route is operative via direct non-enzymatic aldol reaction between methylglyoxal and the ketone body acetoacetate, leading to 3-hydroxyhexane-2,5-dione. This novel metabolite is present at a concentration of 10%-20% of the methylglyoxal level in the blood of insulin-starved patients. By employing a metabolite-alkyne-tagging strategy it is clarified that 3-hydroxyhexane-2,5-dione is further metabolized to non-glycating species in human blood. The discovery represents a new direction within non-enzymatic metabolism and within the use of alkyne-tagging for metabolism studies and it revitalizes acetoacetate as a competent endogenous carbon nucleophile.
Publisher: Elsevier BV
Date: 04-2020
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9CP03851E
Abstract: Analytical solution for the set of differential equations solved numerically in the original article
Publisher: Elsevier BV
Date: 12-1995
Publisher: Elsevier BV
Date: 02-2022
Publisher: Wiley
Date: 25-01-2017
DOI: 10.1002/OBY.21750
Publisher: Elsevier BV
Date: 08-2017
DOI: 10.1016/J.JAND.2016.12.008
Abstract: Partnering and parenting are important life-stage transitions that often occur during young adulthood. Little is known about how these transitions affect two dietary behaviors linked to increased cardiometabolic disease risk: skipping breakfast and takeaway-food consumption. Our aim was to examine whether partnering and parenting transitions during a 5-year period were associated with change in diet quality, skipping breakfast, and takeaway-food consumption. We conducted a cohort study. Questionnaires were completed at baseline (2004 to 2006) and follow-up (2009 to 2011). Marital status and number of children were self-reported. Australian participants (n=1,402 [39% men]) aged 26 to 36 years were included. Diet quality was assessed using a Dietary Guideline Index. Breakfast skipping (not eating before 9 am the previous day) and frequent takeaway-food consumption (≥2 times/week) were reported. Linear regression (mean differences in Dietary Guideline Index) and log binomial regression (relative risks for skipping breakfast and frequent takeaway-food consumption) were adjusted for age, education, follow-up duration, day of the week (skipping breakfast only), the other transition, and baseline behavior. During the 5-year follow-up, 101 men and 93 women became married/living as married, and 149 men and 155 women had their first child. Diet quality improved among all groups and was similar at follow-up between those who experienced the transitions and those who did not. Compared to having no children, having a first child was associated with a lower risk of skipping breakfast for men (relative risk 0.65 95% CI 0.42 to 1.01) and women (relative risk 0.47 95% CI 0.31 to 0.72). Men who became partnered also had a lower risk of skipping breakfast than those who remained single (relative risk 0.64 95% CI 0.42 to 0.98). The transitions were not significantly associated with takeaway-food consumption. Life-stage transitions were not associated with better diet quality. Participants who became partnered or parents were more likely to eat breakfast at follow-up than those who remained single or had no children.
Publisher: Elsevier BV
Date: 08-2014
No related grants have been discovered for Dieter Britz.