Rethinking fat as a fuel for endurance exercise

Abstract

A key element contributing to deteriorating exercise capacity during physically demanding sport appears to be reduced carbohydrate availability coupled with an inability to effectively utilize alternative lipid fuel sources. Paradoxically, cognitive and physical decline associated with glycogen depletion occurs in the presence of an over-abundance of fuel stored as body fat that the athlete is apparently unable to access effectively. Current fuelling tactics that emphasize high-carbohydrate intakes before and during exercise inhibit fat utilization. The most efficient approach to accelerate the body’s ability to oxidize fat is to lower dietary carbohydrate intake to a level that results in nutritional ketosis (i.e., circulating ketone levels >0.5 mmol/L) while increasing fat intake for a period of several weeks. The coordinated set of metabolic adaptations that ensures proper interorgan fuel supply in the face of low-carbohydrate availability is referred to as keto-adaptation. Beyond simply providing a stable source of fuel for the brain, the major circulating ketone body, beta-hydroxybutyrate, has recently been shown to act as a signalling molecule capable of altering gene expression, eliciting complementary effects of keto-adaptation that could extend human physical and mental performance beyond current expectation. In this paper, we review these new findings and propose that the shift to fatty acids and ketones as primary fuels when dietary carbohydrate is restricted could be of benefit for some athletes.     

Strategic fit among knowledge attributes,knowledge management systems,and service positioning

Knowledge management systems (KMSs) support high-quality services while shaping and improving positioning of services. Given such strategic importance of KMS, this study explores the effects of different types of KMS, which respond to the attributes (i.e., diversity and tacitness) of collective knowledge, on service (re-)positioning. Through a case study of a financial consulting company at the core of KMSs, combinations of the two knowledge attributes are used to determine which type of KMS (i.e., information library, deepened stock, thought islands, and shared brain) offers the greatest efficiency and effectiveness in service (re-)positioning. The joint concerns of service innovation scope and specificity are also considered. Finally, the study discusses the theoretical and practical implications on KMS design and functionality in the new business age of service innovation.     

The study of systems and methods for scientometric analysis of scientific publications

This paper provides an overview of the methods and systems that are applied for scientometric analysis of scientific publications. Methods to identify promising research directions are described. The results of an experimental study aimed at determining the directions of scientific research within the subject area of “regenerative medicine” by using various methods are presented. Conclusions are made about the prospects and shortcomings of the applied methods. Directions for further research are proposed.     

A Human Resources Dilemma? Emergent Themes in the Experiences of Part-Time Librarians

Although many newly-graduated librarians are applying for and accepting part-time library employment after graduation, little research has been done into what working part-time means for these early career librarians. This article, based on a survey of recent LIS graduates who have worked part-time, provides a snapshot of part-time library employment and the advantages and disadvantages it affords to new librarians. This information is particularly relevant in light of the difficult job market for entry-level librarians. All of the surveyed librarians have worked in at least one part-time professional or paraprofessional position in a library after receiving their degree. Many of these respondents describe holding multiple part-time positions and receiving low salaries and few, if any, employment benefits. The themes documented in the open-ended short answers of these part-time librarians will help to guide further research into the professional and personal impact of part-time employment.     

The use of economic classifiers for the indexing of scientific publications

The experience from the application of the OKVED 2 economic classifier for indexing scientific publications is considered. More than 9500 articles on the subject of “Automation. Computer Engineering” in authoritative Russian magazines were the material for the study. Some means for the comparative analysis of economic statistics and results of the classification of scientific publications are shown.     

青少年运动缺乏症研究的10大问题

摘要：运动缺乏症（EDD）是一种儿科疾病,特点是中高强度体力活动（MVPA）下降,低于目前的推荐量,也与积极的健康结果（health outcomes）不一致。目前,大多数儿童和青少年符合EDD的诊断标准,因为他们没有达到日常MVPA的最低要求。本文的目的是强调10个与青少年EDD有关的重要研究问题。需要进行重要的研究来更好的定义EDD的临床表现,包括评估体力活动行以确定开始出现EDD的年龄或发育阶段;包括运动技巧和体能的运动起源（kinesiogenesis）的检测;以及对影响青少年MVPA的生活方式因素的评估。关于治疗EDD的干预措施和政策的研究问题,包括评估对卫生保健从业者进行运动医学重要性的教育和训练;确定在临床上识别和治疗EDD青少年的方法的有效性;开发敏感的、特效的、经济的方法以诊断青少年EDD;以及定制方法以促进本病诊疗的医疗保险赔付。如果未来研究不能优化EDD青少年的识别、治疗和管理方案,具有重大影响的生物医学、心理、经济和政治的新的卫生保健问题将会不断出现。     

Thermally multiplexed polymerase chain reaction

Amplification of multiple unique genetic targets using the polymerase chain reaction (PCR) is commonly required in molecular biology laboratories. Such reactions are typically performed either serially or by multiplex PCR. Serial reactions are time consuming, and multiplex PCR, while powerful and widely used, can be prone to amplification bias, PCR drift, and primer-primer interactions. We present a new thermocycling method, termed thermal multiplexing, in which a single heat source is uniformly distributed and selectively modulated for independent temperature control of an array of PCR reactions. Thermal multiplexing allows amplification of multiple targets simultaneously—each reaction segregated and performed at optimal conditions. We demonstrate the method using a microfluidic system consisting of an infrared laser thermocycler, a polymer microchip featuring 1 μl, oil-encapsulated reactions, and closed-loop pulse-width modulation control. Heat transfer modeling is used to characterize thermal performance limitations of the system. We validate the model and perform two reactions simultaneously with widely varying annealing temperatures (48 °C and 68 °C), demonstrating excellent amplification. In addition, to demonstrate microfluidic infrared PCR using clinical specimens, we successfully amplified and detected both influenza A and B from human nasopharyngeal swabs. Thermal multiplexing is scalable and applicable to challenges such as pathogen detection where patients presenting non-specific symptoms need to be efficiently screened across a viral or bacterial panel.     

The use of spatial manipulation to examine goalkeepers’ anticipation

This study investigated whether anticipation and search strategies of goalkeepers are influenced by temporally and spatially manipulated video of a penalty. Participants were clustered into three groups depending on skill: goalkeepers (n = 17), field players (n = 20) and control group (n = 20). An eye tracker was worn whilst watching 40 videos of a striker kicking to four corners of a goal in random order. All 40 videos were temporally occluded at foot-to-ball contact, and the non-kicking leg of 20 videos was spatially manipulated. Results showed that goalkeepers had significantly better predictions than the two groups with no differences between the two testing conditions. According to effect size, the percentage of fixation location and viewing time of the kicking leg and ball were greater for the goalkeepers and field players group than the control group irrespective of testing conditions. The fixations on the kicking leg and ball in conjunction with comparable predictions between spatially manipulated and control conditions suggest that goalkeepers may not rely on the non-kicking leg. Furthermore, goalkeepers appear to use a global perceptual approach by anchoring on a distal fixation point/s of the penalty taker whilst using peripheral vision to obtain additional information.     

The effect of l-citrulline and watermelon juice supplementation on anaerobic and aerobic exercise performance

Citrulline has been proposed as an ergogenic aid, leading to an interest in watermelon given its high citrulline concentration. The aim of this study was to determine the effects of a single, pre-exercise dose of l-citrulline, watermelon juice, or a placebo on the total maximum number of repetitions completed over 5 sets, time to exhaustion, maximal oxygen consumption (VO₂max), anaerobic threshold, and flow-mediated vasodilation. A randomised double-blind within-participants study design was used to examine these effects among 22 participants (n = 11 males). Supplementation included either a 7.5% sucrose drink containing 6 g of l-citrulline, 710 mL of watermelon juice (~1.0 g citrulline), or a 7.5% sucrose placebo drink. Supplementation was administered 1 or 2 h before exercise testing to investigate a timing effect. There was no significant effect between the three supplements for the total number of repetitions, time to exhaustion, VO₂max, anaerobic threshold, or flow-mediated vasodilation. There was also no interaction observed relative to gender or supplement timing (P > 0.05). A single dose of l-citrulline or watermelon juice as a pre-exercise supplement appears to be ineffective in improving exercise performance; however, greater doses of l-citrulline have been shown to be safe and are currently left unexamined.