Carbohydrate needs of the young athlete

Carbohydrate (CHO) typically provides the majority of energy in the athlete’s diet and is essential to fuel high intensity exercise. Ensuring adequate energy is available to meet the demands of high energy expenditures is important in the young athlete to ensure proper growth, development, and maturation. Physiological and metabolic changes that accompany the transition from childhood to adolescence and to adulthood, combined with the additional energy expenditure arising from exercise, mean that the dietary needs of young athletes require special consideration. However, in contrast to the well-documented literature in adults, little research attention has been given to child and adolescent populations. Thus, the development of specific recommendations for CHO intake in young athletes is difficult. Nevertheless, it is possible to make some general recommendations. Both the total daily CHO intake and the timing of CHO consumption in relation to exercise can determine whether adequate CHO substrate is available for muscles and the central nervous system or whether CHO fuel sources might limit exercise performance. In terms of the overall diet, CHO should contribute to the majority of energy intake, which must be high enough to support growth and maturation whilst fuelling the additional physical activity, and consequently elevated energy expenditure, in young athletes. In particular, CHO is an important fuel for high intensity exercise in young athletes. Decrements in exercise performance, fatigue and changes in body composition may serve as useful indicators that CHO intake may not be adequate, particularly in female adolescent athletes. During exercise, drinks containing CHO could be considered for young athletes engaged in endurance exercise due to the preferential use of exogenous CHO in younger athletes in the pre- or early- pubertal stages. However, evidence on CHO loading and CHO for post-exercise recovery does not appear to be available in children or adolescents. This chapter provides an overview of the available evidence that can be used to inform recommendations for CHO intake and timing in young athletes. Where no direct evidence in young athletes is available, we have relied on the relevant adult-based literature whilst emphasising that the direct translation and application of these findings to children and adolescents must be viewed cautiously

Carbohydrate gel ingestion significantly improves the intermittent endurance capacity, but not sprint performance, of adolescent team games players during a simulated team games protocol

The aim of this study was to investigate the influence of ingesting a carbohydrate (CHO) gel on the intermittent endurance capacity and sprint performance of adolescent team games players. Eleven participants [mean age 13.5 ± 0.7 years, height 1.72 ± 0.08 m, body mass (BM) 62.1 ± 9.4 kg] performed two trials separated by 3–7 days. In each trial, they completed four 15 min periods of part A of the Loughborough Intermittent Shuttle Test (LIST), followed by an intermittent run to exhaustion (part B). In the 5 min pre-exercise, participants consumed 0.818 mL kg−1 BM of a CHO or a non-CHO placebo gel, and a further 0.327 mL kg−1 BM every 15 min during part A of the LIST (38.0 ± 5.5 g CHO h−1 in the CHO trial). Intermittent endurance capacity was increased by 21.1% during part B when the CHO gel was ingested (4.6 ± 2.0 vs. 3.8 ± 2.4 min, P < 0.05, r = 0.67), with distance covered in part B significantly greater in the CHO trial (787 ± 319 vs. 669 ± 424 m, P < 0.05, r = 0.57). Gel ingestion did not significantly influence mean 15 m sprint time (P = 0.34), peak sprint time (P = 0.81), or heart rate (P = 0.66). Ingestion of a CHO gel significantly increases the intermittent endurance capacity of adolescent team games players during a simulated team games protocol

ALEA III: 19th International Composition Competition for Young Composers

This is the concert program of the 19th International Composition Competition for Young Composers performance on Saturday, September 29, 2001 at 7:00 p.m., at the Tsai Performance Center, 685 Commonwealth Avenue, Boston, Massachusetts. Works performed were Croatoan III by Moritz Eggert, Triptique by Athanasia Tzanou, Portrait of George Dyer Riding a Bicyle by Tonino Tesei, Reflection by Sabang Cho, and Three Episodes by Lior Navok. Digitization for Boston University Concert Programs was supported by the Boston University Humanities Library Endowed Fund

13C flux analysis in industrial CHO cell culture applications

Industrial bioprocesses place extraordinary demands on the intermediary metabolism of host cells to meet the biosynthetic requirements for maximal growth and protein expression. Identifying host cell metabolic phenotypes that promote high recombinant protein titer is a major goal of the biotech industry. 13C metabolic flux analysis (MFA) provides a rigorous approach to quantify these metabolic phenotypes by applying stable isotope tracers to map the flow of carbon through intracellular metabolic pathways. We have conducted a series of 13C MFA studies to examine the impacts of IgG expression and other physiological stresses on CHO cell metabolism. First, we performed 13C MFA to characterize the metabolism of a IgG-expressing DHFR-deficient CHO host during four separate phases of a fed-batch culture. We found that peak specific growth rate during early exponential phase was associated with high lactate production and minimal citric acid cycle (CAC) flux. Conversely, we found that lactate metabolism switched from net production to net consumption as the culture transitioned from peak growth to peak IgG production. During stationary phase when IgG production peaked, energy was primarily generated through CAC and oxidative phosphorylation. Second, we examined nine CHOK1SV (Lonza) clones cultured in 3-liter fed-batch bioreactors, to assess their metabolism during stationary phase. Three of the clones did not express IgG. Six of the clones used the GS SystemTM to express one of three different IgGs. Four of the clones were genetically manipulated to be apoptosis-resistant by expressing Bcl-2Δ. Hierarchical clustering was performed to assess correlations amongst flux phenotypes of the nine clones. The six IgG-producing clones clustered together and were separated by host background (Bcl-2Δ or CHOK1SV). The lactate dehydrogenase (LDH) flux was most closely associated with specific IgG productivity: as IgG productivity increased, lactate production decreased. Additionally, elevated CAC fluxes corresponded strongly with increased specific productivity. This study provided further evidence of enhanced oxidative metabolism in high-producing CHO cell lines. Finally, 13C MFA was used to characterize the metabolic response of CHO cells to a novel medium variant designed to reduce ammonia production. Ammonia production was reduced by manipulating the amino acid composition of the culture medium; specifically, glutamine, glutamate, asparagine, aspartate, and serine levels were adjusted. Parallel 13C flux analysis experiments determined that, while ammonia production decreased by roughly 40%, CHO cell metabolic phenotype, growth, viability, and monoclonal antibody (mAb) titer were not significantly altered by the changes in media composition. This study illustrates how 13C flux analysis can be applied to assess the metabolic effects of media manipulations on mammalian cell cultures. The analysis revealed that adjusting the amino acid composition of CHO cell culture media can effectively reduce ammonia production while preserving fluxes throughout central carbon metabolism. Taken together, these studies provide several useful examples of how 13C MFA can be applied to assess metabolic responses of CHO cell cultures to high-yield IgG production and changing bioprocess conditions. This presentation will describe the methodology and its application to develop engineering strategies to enhance IgG productivity and titer of industrial CHO hosts

Parallel Acoustic Delay Line (PADL) Arrays for Photoacoustic Imaging Applications

Micromachining process, such as laser micromachining and IC microfabrication process, allows production of complex structures in limited space, which reduces both the size and cost of hardware. In this research, using the advantages of micromachining processes, parallel acoustic delay line (PADL) arrays made of optical fibers and single-crystalline silicon (SCS) have been developed to reduce the number of ultrasonic transducers and data acquisition (DAQ) electronics for real-time photoacoustic tomography (PAT). The PADL arrays allow real-time PAT with the significantly reduced number of ultrasonic transducers and DAQs. Handheld optical PADL array enables more practical operation for photoacoustic imaging applications by miniaturizing previously developed optical PADL array. Sixteen channels of optical fiber PADLs were fabricated and assembled with laser micromachined acrylic housing for the compact structure. By conducting ultrasonic transmission testing, acoustic properties of optical fibers have been characterized. PA imaging capability of optical fiber PADL array has been evaluated by PA imaging experiment. Microfabrication process makes it possible to use single-crystalline silicon as a material for acoustic delay lines. Acoustic properties of silicon were characterized by ultrasonic transmission testing. Based on the characterization result, silicon acoustic delay line was designed into a spiral coil shape to minimize the overall size. Silicon PADLs are better than optical fiber PADL for miniaturization due to the advantages of microfabrication process. Silicon PADL array achieved a channel reduction ratio of 16:1, which is twice the ratio of optical fiber PADL. The PA imaging experiment has demonstrated the PA imaging capability of silicon PADL array. For fast imaging speed and good spatial resolution, silicon PADL array has been improved by applying 3D-printed linker structures and tapered input terminal. Linker structure design has been evaluated by both structural and acoustic simulation. The final design of linker structure is 3D-printed polymer linker to securely hold silicon delay lines with minimal contacts. Tapered input terminal was designed to reduce acoustic acceptance angle for better spatial resolution. Tapered input terminal was evaluated by acoustic simulation with different designs. Those designs and techniques are expected to provide new solutions to reduce the cost and complexity of ultrasonic receiving systems for photoacoustic imaging applications

Low-carbohydrate diets for gestational diabetes

Nutrition therapy provides the foundation for treatment of gestational diabetes (GDM), and has historically been based on restricting carbohydrate (CHO) intake. In this paper, randomized controlled trials (RCTs) are reviewed to assess the effects of both low- and higher CHO nutrition approaches in GDM. The prevailing pattern across the evidence underscores that although CHO restriction improves glycemia at least in the short-term, similar outcomes could be achievable using less restrictive approaches that may not exacerbate IR. The quality of existing studies is limited, in part due to dietary non-adherence and confounding effects of treatment with insulin or oral medication. Recent evidence suggests that modified nutritional manipulation in GDM from usual intake, including but not limited to CHO restriction, improves maternal glucose and lowers infant birthweight. This creates a platform for future studies to further clarify the impact of multiple nutritional patterns in GDM on both maternal and infant outcomes

13C flux analysis in industrial CHO cell culture applications

Industrial bioprocesses place extraordinary demands on the intermediary metabolism of host cells to meet the biosynthetic requirements for maximal growth and protein expression. Identifying host cell metabolic phenotypes that promote high recombinant protein titer is a major goal of the biotech industry. 13C metabolic flux analysis (MFA) provides a rigorous approach to quantify these metabolic phenotypes by applying stable isotope tracers to map the flow of carbon through intracellular metabolic pathways. We have conducted a series of 13C MFA studies to examine the metabolic impacts of multiple stressors on CHO cell metabolism. First, we analyzed the effects of various media compositions and supplementation regimens on CHO cell metabolism. The basal media developed in-house by an industrial collaborator was chemically altered to cause cells to produce less ammonia byproduct. This was tested against the basal media and the basal media supplemented with experimental levels of ammonia. From the comparison of the 13C flux analysis of CHO cells grown identically in the three media types, we have found that neither the chemical composition of the media nor the mere presence of ammonia in the cultures significantly altered cell metabolism. This suggests that the collaborator can use their new medium formulation without altering the metabolic phenotype of their IgG producing CHO cell lines. We are also implementing 13C MFA studies in several IgG producing cell lines to elucidate metabolic phenotypes associated with high-yield recombinant protein expression. From previous studies, it has been established that there exists a high-productivity metabolic phenotype largely identifiable by an increase in oxidative metabolism. We are engineering these proprietary IgG-producing CHO cells to up-regulate their citric acid cycle (CAC) metabolism to potentially increase IgG productivities. Through 13C stable isotope tracing, we can verify increased flux through the CAC and confirm the rational engineering of a high-productivity phenotype. These studies prove the value of 13C MFA in assessing the metabolic response to changing medium formulations or rational engineering of the host cell genome. This poster will outline the methodology used to elucidate CHO cell metabolic phenotypes in these studies as well as the potential use for this method in future studies to further increase IgG productivity and titer of industrial host lines

Modeling for Determinants of Human Trafficking

This study aims to identify robust push and pull factors of human trafficking. I test for the robustness of 78 push and 67 pull factors suggested in the literature. By employing an extreme bound analysis, running more than two million regressions with all possible combinations of variables for up to 180 countries during the period of 1995-2010, I show that crime prevalence robustly explains human trafficking prevalence both in destination and origin countries. My finding also implies that a low level of gender equality and development may have constraining effects on human trafficking outflows, contrary to expectations. The linkage between migration and human trafficking is less clear, and institutional quality matters more in origin countries than destinations.Human trafficking: push and pull factors: robustness; extreme bound analysis