An overview of chemical additives present in plastics: Migration, release, fate and environmental impact during their use, disposal and recycling

Over the last 60 years plastics production has increased manifold, owing to their inexpensive, multipurpose, durable and lightweight nature. These characteristics have raised the demand for plastic materials that will continue to grow over the coming years. However, with increased plastic materials production, comes increased plastic material wastage creating a number of challenges, as well as opportunities to the waste management industry. The present overview highlights the waste management and pollution challenges, emphasising on the various chemical substances (known as “additives”) contained in all plastic products for enhancing polymer properties and prolonging their life. Despite how useful these additives are in the functionality of polymer products, their potential to contaminate soil, air, water and food is widely documented in literature and described herein. These additives can potentially migrate and undesirably lead to human exposure via e.g. food contact materials, such as packaging. They can, also, be released from plastics during the various recycling and recovery processes and from the products produced from recyclates. Thus, sound recycling has to be performed in such a way as to ensure that emission of substances of high concern and contamination of recycled products is avoided, ensuring environmental and human health protection, at all times

Dynamics of cardiovascular functional indices of elite greco-roman wrestlers during annual training cycle

The solution of sportsmen training management problem combine various aspects among which recognition of individual peculiarities, assessment of organism mobilization and recovery function dynamics under the influence of training loads or changed external and internal factors, estimation of the fatigue extent as well as the achievement of fitness shape are relevant problems in practice and sport science. A great deal of solutions of resolving these problems is proposed and used in practice, however, these solutions are not the final ones. Changes of various functional indices during the dosed and maximal exercise tests reflect functional fitness and functional state of organism (Maud, Foster, 1995; Skernevičius ir kt., 2004; Skirius, 2002; Buliuolis, 2006; Vainoras ir kt., 2008; Poderys, 2008; Wilkinson et al., 2009). One of the most important requirements for the assessment of sportsman functional state changes is that exercises applied during the testing must not modify the training process (Viru, Viru, 2004; Skurvydas, 2008). The latter requirement is particularly relevant in the precompetition preparing stage (tapering). Furthermore, sportsmen must take part in competitions, where the climatic and the geographical conditions are not usual, for example, a different time zone and a sudden environmental change. Physical load is an optimal physiological stimulus to speed the organism adaptation to time zone and unusual climatic conditions, however, not vigorous trainings due to a new time zone over the first days are strongly recommended (Elliott, 1998; Reilly et al., 2000; Bompa, 2001; Poderys, Stanislovaitis, 2001; Buxton et al., 2003 Poderys, 2007). Therefore, the dosed exercise tests used to assess the adaptation process and sportsman’s shape are more requested, thus augmentation of information, which is provided by such tests is a relevant problem of sport physiology, sport science and sport practise. One of the substantial peculiarities of competition performance and predominant training loads in combat sports is fluctuative load intensity, which can not precisely be planed in advance. Therefore, the peculiarities of organism function mobilization and recovery are important factors influencing sportsman’s performance, so training of these peculiarities is a basic principle in sportsman’s physical and functional training. The aim of the study was to identify the dynamics of functional indices of cardiovascular system and their assessment potential in elite Greco-roman wrestlers during annual training cycle by using dosed tests. The tasks were as follows: 1. To identify the central and peripheral peculiarities of the cardiovascular system of elite greco-roman wrestlers using the repetitive dosed exercises. 2. To determine the dynamics of functional indices of the cardiovascular system using dosed test during the day, when sportsmen performed two heavy training sessions. 3. To identify the effect of concentrated mesocycle of speed and power training loads on dynamics of functional indices of the cardiovascular system. 4. To define the dynamics of functional indices of the cardiovascular system during the annual training cycle. 5. To determine the peculiarities of dynamics of the functional indices of the cardiovascular system in greco-roman wrestlers using the new method of functional indices fluctation links assessment (the method of algebraic data cointegration). The following methods designed for the assessment of functional indices were used: electrocardiography, measurement of arterial blood pressure, Roufier exercise test, vertical jumps tests, near-infrared spectroscopy, venous occlusion plethytsmography and model of functional evaluation of body functioning during exercise. CONCLUSIONS 1. During dosed exercise tests the synergical peculiarities of the dynamics of central and peripheral functional indices of cardiovascular system were significantly linked to the character of adaptation to physical loads. During repetitive dosed exercise tests, performed every 2 minutes, most of the central functional indices of the dynamics of cardiovacular system in non-sportsmen demonstrate the effect of physical load summation, whereas in elite greco-roman wrestlers as well as in other individuals, adapted to physical loads, functional indices were repeating. 1.1. The exclusively fast process of mobilization and recovery with absence of warming-up was characteristic of cardiovascular system reaction of elite greco-roman wrestlers. 1.2. Mobilization and recovery of muscular blood flow of elite greco-roman wrestlers were more similar to the endurance sports individuals, than the individuals of sprint sports. 1.3. During dosed exercise tests an oxygen consumption speed in the muscles was a typical sign of the organism, and onetime training of aerobic character did not change it substantially, whereas a more pronounced reaction of central indices of cardiovascular system to the first test seemed to be explained by a psychologic attitude of person to the forthcoming load performance. 1.4. Onetime performance of the dosed physical load may not have revealed many synergic central and peripheral peculiarities of cardiovascular system since the individual peculiarities and peculiarities of adaptation to physical loads summarized. For non-sportsmen while performing repetitive Roufie tests every two minutes the fatigue summation effects were typical; for moderate level sportsmen – more pronounced reaction of central functional indices of cardiovascular system to the first physical load; for elite sportsmen – repetition of functional indices (stability of reactions). 2. When sportsmen performed two heavy trainings sessions per day, assessment of reaction of cardiovascular system to dosed exercise tests alowed to follow the dynamics of functional state. Assessments of absolute indices meanings at relative rest, during exercises and their changes permitted to state the degree of occurred changes. The changes of proportional indices and their error values were higher than other euristic indices and provided a better reflection of individual peculiarities of sportsman organism. 3. During training camp while performing the concentrated heavy physical loads of speed and power the velocity of adaptation of cardiovascular system to loads increased, relative muscles power and indices of anaerobic capacity improved, however economy of cardiovascular system function decreased during dosed exercise test. 3.1. The significant peculiarity of recovery after physical loads was an adequate sequence in recovery of cardiovascular system indices. When functional state was normal, firstly, the ratio between regulatory and supplying systems recovered, then the indices of regulatory system and after that, the indices of supplying system. 3.2. During training camp, where two training mesocycles were combined, the fluctuation of the indices of cardiovascular system was undulated, however, this dynamics had purposeful character showing an increase of organism functional fitness: a decrease of the ST-segment depression during load, a decrease of the fluctuation of the RR, JT intervals and their ratio in electrocardiogram, decrease of velocity of adaptation and a half time recovery duration. 4. During the annual training cycle the purposeful and the most pronounced changes of cardiovascular system and muscles performance indices were observed in the basic preparation and in the speed and power preparation stages: 4.1. There was a possibility to separate two phases in the longest basic preparation stage: the first – impairment of body functions and their compatibility and the second – improvement of organism performance and functional state. 4.2. Performed testing during speed and power preparation stage showed the difficult character of training loads: many functional indices of cardiovascular system had the tendency of impairment. 4.3. During the special and recuperation stages the fluctuation of functional state indices of cardiovascular system was heterogeneous; although it had an expressed tendency of improvement it was still dependent on individual means of precompetition preparation. 4.4. For every sportsman individual, however, repeating reaction of cardiovascular system to dosed and maximal exercise tests was typical. Complex parameters, such as the sequence of ECG indice recovery and JT/RR ratio change during dosed exercise test, reflected the best the functional state and readiness alteration of cardiovascular system during the annual training cycle. 5. Body as the complex integral and dynamic system characterizes the individual changes of various indices of the functional levels and their interactions during physical loads, therefore the assessment of individual fractal and the tracing its dynamics is proper and promising method for assessment of alterations caused by training. 5.1 Assessments of the dynamics of functional indices interactions showed that the readiness of organism to perform forthcoming physical load began before performance of load. 5.2 When sportsmen performed two heavy trainings sessions during the day dynamics of functional state could be assessed meticulously applying the new assessment method of indices dynamics interaction. The interactions of different functional levels changed more in fatigued state. 5.3 Functional readiness of sportsman was a significant factor determining peculiarities of body reactions to exercise tests. It is hypothesized that for persons of insufficient functional preaparedness a sudden increase of training loads may result in the change of compatibility of their organism functional levels

Peculiarities in adaptation of body functioning during the exercise and recovery after the flight to beijing

The study participants were Lithuanian athletes (Track and Field Athletic) participants of 11th Juniors World Championship. All participants took part in assessments of their functional state in Lithuania and during the pre-competition training camp in Beijing. The subject underwent a Roufier test (30 squats per 45 seconds). Arterial blood pressure measurements and 12 synchronous lead ECG was registered during the exercise and recovery. The changes in RR interval or heart rate (HR), JT, JTa intervals, and in the ratio of intervals JT/RR, JTa/JT were analyzed...[...]