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The Influence of Kynurenine Metabolites on Neurodegenerative Pathologies
As the kynurenine pathway’s links to inflammation, the immune system, and neurological disorders became more apparent, it attracted more and more attention. It is the main pathway through which the liver breaks down Tryptophan and the initial step in the creation of nicotinamide adenine dinucleotide (NAD+) in mammals. Immune system activation and the buildup of potentially neurotoxic substances can result from the dysregulation or overactivation of this pathway. Therefore, it is not shocking that kynurenines have been linked to neurological conditions (Depression, Parkinson’s, Alzheimer’s, Huntington’s Disease, Schizophrenia, and cognitive deficits) in relation to inflammation. Nevertheless, preclinical research has demonstrated that kynurenines are essential components of the behavioral analogs of depression and schizophrenia-like cognitive deficits in addition to mediators associated with neurological pathologies due to their neuromodulatory qualities. Neurodegenerative diseases have been extensively associated with neuroactive metabolites of the kynurenine pathway (KP) of tryptophan breakdown. In addition to being a necessary amino acid for protein synthesis, Tryptophan is also transformed into the important neurotransmitters tryptamine and serotonin in higher eukaryotes. In this article, a summary of the KP, its function in neurodegeneration, and the approaches being used currently to target the route therapeutically are discussed.
Journal Article
Simulating innovation : computer-based tools for rethinking innovation
Christopher Watts and Nigel Gilbert explore the generation, diffusion and impact of innovations, which can now be studied using computer simulations. Agent-based simulation models can be used to explain the innovation that emerges from interactions among complex, adaptive, diverse networks of firms, people, technologies, practices and resources. This book provides a critical review of recent advances in agent-based modelling and other forms of the simulation of innovation. Elements explored include: diffusion of innovations, social networks, organisational learning, science models, adopting and adapting, and technological evolution and innovation networks. Many of the models featured in the book can be downloaded from the book's accompanying website. Bringing together simulation models from several innovation-related fields, this book will prove a fascinating read for academics and researchers in a wide range of disciplines, including: innovation studies, evolutionary economics, complexity science, organisation studies, social networks, and science and technology studies. Scholars and researchers in the areas of computer science, operational research and management science will also be interested in the uses of simulation models to improve the understanding of organisation.
Book
Dietary intake of adolescent rowers - analysis of energy intake
Adequate energy intake (EI) is essential for adolescent athletes to support health, performance, and growth(1). Rowing is a physically demanding sport where intense training begins in adolescence. Research is needed to assess whether current EI is sufficient to support healthy physiological functions and training in adolescent rowers. The aim of this study was to evaluate the energy status (energy availability (EA) or energy balance (EB)) including EI and exercise energy expenditure (EEE) of adolescent rowers in New Zealand. A total of 35 rowers (23 females, 16.8yrs ± 1.9yrs; 12 males, 17.3yrs ± 1.6yrs) who had been rowing for at least one season participated. A bioimpedance analyser measured body composition in 11 participants (8 females, weight 63.0±7.0kg, fat free mass (FFM) 50.8 ± 6.5kg; 3 males, weight 78.5 ± 15.9kg, FFM 70.7 ± 12.2kg) enabling calculation of EA. Due to COVID-19 restrictions, the remaining 24 participants (15 females, 9 males) provided estimated body weight (74.7 ± 9.2kg) and EB was then used to evaluate energy status. All participants completed four days of food and training diaries, two ‘recovery’ and two ‘hard’ training days. EI was determined in FoodWorks10 software using the New Zealand Food Composition Database. For training, metabolic equivalent of tasks (MET)(2) were assigned using bodyweight, heart rate, and rating of perceived effort to estimate EEE. Paired sample t-tests or Wilcoxon Signed Rank test (non-parametric data) was used to determine differences between EI, EEE, EA, and EB on the high and low training days for each gender. Significance was set at p< 0.05. The average EI for females on hard and recovery days was 10837 ± 3304kJ and 10461 ± 2882kJ respectively, and for males was 15293 ± 3971kJ and 13319 ± 4943kJ, respectively. No significant differences were found between EI on hard vs. recovery days in both genders. Significant differences between average EEE on hard vs. recovery days were found in both genders (females, hard day 4609 ± 2446kJ, recovery day 3146 ± 1905kJ, p<0.001; males, hard day 6589 ± 1575kJ, recovery day 3326 ± 2890kJ, p = 0.001). EA on hard and recovery training days was classified as suboptimal at 142 ± 80kJ/FFMkg/day and 167 ± 79kJ/FFMkg/day respectively with no significant difference in EA between hard and recovery days (p = 0.092). Average EB on hard training days was −484 ± 4267kJ and on recovery training days was 572 ± 3265kJ, with no significant difference between training days (p = 0.177). Both genders showed no significant difference in EB between hard and recovery training days (females p = 0.221, males p = 0.978). The results suggest that adolescent rowers do not adjust their nutritional intake to match EEE. This may increase the risk of adolescent rowers presenting with suboptimal EB or EA, with females being at a greater risk than males.
Journal Article
الأوبئة والتاريخ : المرض والقوة والإمبريالية
يسلط هذا الكتاب الضوء على نقطتين مهمتين : الأولى ردود الأفعال في كل من المجتمعات الأوروبية والمجتمعات الشرقية القديمة ؛ مثل الهند والصين ومصر في التعامل مع هذه الأوبئة، ونمط التحكم في هذه الأوبئة وطرق مقاومتها. النقطة الثانية : هى إلقاء الضوء على العلاقة بين ظاهرة الاستعمار والإمبريالية وأدواتها الاقتصادية والقمعية وانتشار الأوبئة.
BOOK
Macronutrient intakes of adolescent rowers for growth, development and sports performance
Dietary intake plays a key role in athletic performance in rowing(1). Suboptimal nutrition within the adolescent rowing population may negatively affect performance, normal growth and development, professional athlete development, and career longevity. Previous research has indicated that suboptimal carbohydrate intakes are a common issue in rowing(2). The quality of nutritional intake in adolescent rowers has seldom been explored. During moderate training, adolescent athletes should aim for 5-7g.kg-1 of carbohydrates, 1.3-1.8g.kg-1 of protein, and 20-35% energy from fat(3). This study aimed to examine the dietary intake of adolescent rowers in New Zealand and compare it with nutritional guidelines for normal growth, development, and sports performance. A cross-sectional study design involved data collection on two ‘hard’ training days, and two ‘recovery’ days from rowers (14-21 years) recruited from clubs and secondary schools around New Zealand. Participants completed four 24-hour collection periods, recording food intake, training duration and intensity. The food records were verified for accuracy, and dietary data was entered into Foodworks software for nutritional analysis. IBM SPSS software was used to calculate mean intakes for carbohydrate, protein, fat, and standard deviations. Independent t-tests were used to compare carbohydrate and protein intakes between males and females. Of the initial 40 participants, 35 fully (n = 23 females, 16.8 ± 1.9 years and n = 12 males, 17.3 ± 1.6 years) completed the study. Participants consumed 319 ± 116g (4.5 ± 1.7g.kg-1/day) of carbohydrates, 121 ± 56 g (1.7 ± 0.7 g.kg-1/day) of protein and 113 ± 46 g (1.6 ± 0.6g.kg-1/day) of fat per day. Females consumed 290 ± 80g (4.4 ± 1.3g.kg-1/day) of carbohydrates and males consumed 400 ± 78 g (5.0 ± 1.4g.kg-1/day) per day, with no significant difference between males and females intake per kilogram of bodyweight per day (p = 0.165). Minimum carbohydrate levels of 5g.kg-1 per day were only achieved by 7 females (30.4%) and 4 (33.3%) males. Females consumed significantly less protein per day, 106 ± 38g (1.6 ± 0.6 g.kg-1/day), in comparison to males who consumed 164 ± 46 grams (2.0 ± 0.5 g.kg-1/day) per day (p = 0.04). Fourteen females (60.9%) and 10 males (83.3%) consumed more than the minimum requirement of 1.3g.kg-1 of protein per day. The findings suggest that 2 out of 3 adolescent rowers in New Zealand fail to reach the minimum recommendations for carbohydrate intake(3), and males more readily meet the recommended intakes of protein when compared to females. Nutrition education for adolescent rowers in New Zealand should emphasise adequate carbohydrate and protein intakes that meet sports nutrition guidelines in order to support normal growth, development and optimised performance for these athletes.
Journal Article
Depressive symptoms as a barrier to engagement in physical activity in older adults with and without Alzheimer’s disease
Physical activity shows promise for reduced risk of Alzheimer's disease (AD) and protection against cognitive decline among individuals with and without AD. Older adults face many barriers to adoption of physically active lifestyles and people with AD face even further challenges. Physical activity is a promising non-pharmacological approach to improve depressive symptoms, but little is known about the impact of depressive symptoms as a potential barrier to engagement in physical activity. The present study aimed to investigate depressive symptoms as a potential barrier for participation in physical activity across a range of dementia severity.
We used longitudinal structural equation modelling to investigate the bi-directional relationship between depressive symptoms and physical activity in 594 older adults with and without AD over a 2 year longitudinal follow up. Participants ranged from no cognitive impairment to moderately severe AD.
We found that depressive symptoms predicted reduced engagement in subsequent physical activity, but physical activity did not predict subsequent reductions in depressive symptoms.
We conclude that depressive symptoms may be an important barrier to engagement in physical activity that may be addressed in clinical practice and intervention research.
Journal Article
An information theoretic limit to data amplification
In recent years generative artificial intelligence has been used to create data to support scientific analysis. For example, generative adversarial networks (GANs) have been trained using Monte Carlo simulated input and then used to generate data for the same problem. This has the advantage that a GAN creates data in a significantly reduced computing time. N training events for a GAN can result in N G generated events with the gain factor G being greater than one. This appears to violate the principle that one cannot get information for free. This is not the only way to amplify data so this process will be referred to as data amplification which is studied using information theoretic concepts. It is shown that a gain greater than one is possible whilst keeping the information content of the data unchanged. This leads to a mathematical bound, 2 log ( Generated Events ) ⩾ 3log(Training Events) , which only depends on the number of generated and training events. This study determined the conditions for both the underlying and reconstructed probability distributions to ensure this bound. In particular, the resolution of variables in amplified data is not improved by the process but the increase in sample size can still improve statistical significance. The bound was confirmed using computer simulation and analysis of GAN generated data from the literature.
Journal Article
Training load influences gut microbiome of highly trained rowing athletes
Despite the importance of the gut microbiome on physical performance and health, little is known on the impact of training on an athlete's gut health.
This study investigates the effect of training load on markers of gut health.
Whole stool (24 h) samples were collected from 23 highly trained rowers (mean ± SD; age 19.2 ± 1.1 y; weight 80.1 ± 11.4 kg; height 1.83 ± 0.09 m) following periods of high (HT) and low training load (LT). The microbiome and short-chain fatty acid concentrations were characterized from the whole stool samples. Three-day weighted food records were used to determine diet quality (ADIcore), macronutrient, and fiber intakes during HT and LT.
By design, training duration (147%) and intensity (130%) were greater during (HT), compared with (LT) (
< 0.001). Carbohydrate, fat, protein, and fiber intake remained stable, but ADIcore was higher in HT (55 ± 10) compared with LT (49 ± 9; t(15) = 2.78,
0.014; CI: 1.34 to 10.155). Stool frequency (1.11 ± 0.47 vs 0.67 ± 0.76;
0.007) was lower in HT compared with LT, and a greater number of participants were unable to produce a stool sample during LT (8% vs 47%). Short chain fatty acid (SCFA), propionic (120.64 ± 30.06 mm vs 91.35 ± 34.91 mm;
0.007), and butyric acid (104.76 ± 50.02 vs 64.23 ± 22.05 mm,
0.003) concentrations were lower in HT compared with LT. Alpha diversity, Shannon-Wiener diversity index (3.43 ± 0.37 vs 3.67 ± 0.34,
0.09) was lower in HT than LT. The abundance of the dominant
was greater at HT compared to LT and ratio of firmicutes to
(
= 16, 1.31 ± 1.19 vs 4.29 ± 3.88, t(15) = -3.44,
0.04, CI = -4.82 to -1.13) was lower in HT compared to LT.
Results of this study indicate that gut microbiome, SCFA concentrations, stool frequency, and diet quality vary between periods of high and low training load in athletes. The relationship between these factors and impact of such changes in gut health is currently unclear and warrants further investigation.
Journal Article