Application of a Reactive Agility Training Program Using Light-Based Stimuli to Enhance the Physical and Cognitive Performance of Car Racing Drivers: A Randomized Controlled Trial.

BACKGROUND: There is a need to develop strategies that could contribute to the physical and mental preparation of motorsport athletes. A common method used by experienced motorsport athlete physical trainers is flashing light devices to train or assess reactive agility, despite limited evidence. Therefore, in the present study, we determined the effects of a 6-week reactive agility training program using light-based stimuli on the physiological and cognitive abilities of car racing drivers. MATERIALS AND METHODS: The CONSORT guidelines for randomized controlled trial were used. In a single-blinded randomized controlled trial, 24 car racing drivers (EXP, n = 12; CON, n = 12) performed a comprehensive battery of cognitive tests marketed specifically at motorsport athletes from Vienna test system (VTS) at rest or during moderate intensity exercise on a bicycle. Physiological abilities were determined via a maximal incremental cardio-respiratory treadmill test. Baseline and post-intervention tests were performed on three consecutive days. Participants in EXP underwent a 6-week intervention consisting of 60-min training sessions twice a week using the Witty SEM light stimulus. RESULTS: Participants in EXP but not in CON performed some of the VTS cognitive tasks with higher accuracy and/or shorter reaction time after the intervention at rest and during exercise. Car racing drivers performed the STROOP word-reading condition more accurately when the task was performed during the exercise vs. rest, regardless of group. In addition, the intervention induced beneficial changes in peak heart rate (HR), HR at gas exchange threshold, ventilation, and relative maximal oxygen consumption (rVO2 max). In contrast, body mass and fat mass increased, while peak HR and rVO2 max decreased in CON. Finally, participants in EXP improved their reactive agility performance and reaction time throughout the training program. CONCLUSION: Overall, the reactive agility training program using light-based stimuli appeared to be efficient to induce beneficial effects on some physiological and cognitive performance measures; therefore, it may have the potential to contribute to car racing drivers' physical and mental performance.

National level adjustments to the challenges of the SARS-CoV2 pandemic on blood banking operations.

BACKGROUND: SARS-CoV2 causing coronavirus disease (COVID-19) is responsible for an unprecedented worldwide pandemic severely affecting all activities of societies including blood banking. We aimed to systematically collect key indicators in a nationally centralized blood banking system and to perform comparisons between 2020 and 2019. METHODS: Count data for January-December 2020 and 2019 were extracted from the integrated informatics system of Hungarian National Blood Transfusion Service and analyzed by simple graphics, tabulations, and statistics. RESULTS: Whole blood donation activity showed a highly significant decline due to a sharp decrease in field donations by an average fall of 24% (range:17%-28%) during March-May 2020 compared to identical period of 2019. A second, more moderate decline accompanied the second wave in late fall. The simultaneous increase in institutional donations did not counterbalance this decline. Donor exclusion rates fell significantly by an average of 1,1% (range:0.9%-1.6%) in the three spring lockdown-affected months. First-time and repeat donors showed decreased turn-out in larger proportions compared to highly repeat donors. Interestingly, among repeat and highly repeat donors, females showed less-pronounced declines compared to males while this was not observed among first-time donors. In June-September, a remarkable swing-back was observed among highly repeat female donors. Product utilization fell most notably for RBC (mean:26.2%) but also for PLT (mean:19.8%) and FFP (mean:24.3%) and showed a full recovery in June-September followed by a second decline. CONCLUSION: Trends and reaction patterns of blood banking reported by our study may be useful in future planning and adjustments of blood banking activities.

West Nile and Usutu Virus Infections and Challenges to Blood Safety in the European Union.

West Nile virus (WNV) and Usutu virus (USUV) circulate in several European Union (EU) countries. The risk of transfusion-transmitted West Nile virus (TT-WNV) has been recognized, and preventive blood safety measures have been implemented. We summarized the applied interventions in the EU countries and assessed the safety of the blood supply by compiling data on WNV positivity among blood donors and on reported TT-WNV cases. The paucity of reported TT-WNV infections and the screening results suggest that blood safety interventions are effective. However, limited circulation of WNV in the EU and presumed underrecognition or underreporting of TT-WNV cases contribute to the present situation. Because of cross-reactivity between genetically related flaviviruses in the automated nucleic acid test systems, USUV-positive blood donations are found during routine WNV screening. The clinical relevance of USUV infection in humans and the risk of USUV to blood safety are unknown.

Effects of exercise programs on balance in older women with age-related visual problems: a pilot study.

AIM: This study aimed to compare the effects of two exercise programs on balance and risk of falls in older women with age-related visual dysfunction. METHODS: Participants living in a residential home were randomly allocated to Group I (n=21) receiving a progressive, tailored multimodal exercise program in addition to the standard osteoporosis exercise program or Group II (n=20) receiving the standard osteoporosis exercise program alone. At baseline, and after the 6-month exercise program outcomes were measured. RESULTS: After the exercise program there was significant between-group difference in favor of the Group I in Timed Up and Go (TUG) test (p=0.001), but not in Berg Balance score (p=0.130), and Barthel Activity Index (p=0.662). In Group I the risk of falls reduced by 46%, but this result was not significant (RR=0.54, 95% CI 0.294-1.007). The mean length of event-free time was significantly longer in the Group I than in Group II (18.5 weeks, 95% CI 15.4-21.7 vs. 14.8 weeks, 95% CI 11.1-18.4; p=0.049). CONCLUSION: If the current osteoporosis guideline is applied for older adults with low vision, it would be worthwhile putting more emphasis on the inclusion of patient-tailored strength and balance exercises to improve balance and potentially reduce the risk of falls.

Ionophore-gold nanoparticle conjugates for Ag(+)-selective sensors with nanomolar detection limit.

We report on the synthesis and trace analytical application of ionophore-gold nanoparticle conjugates as a basis of a new concept in confining ionophores to ion-selective membranes using inert nanoparticle carriers.

Nafion/2,2'-bipyridyl-modified bismuth film electrode for anodic stripping voltammetry.

This paper describes the fabrication, characterisation and the application of a Nafion/2,2'-bipyridyl/bismuth composite film-coated glassy carbon electrode (NC(Bpy)BiFE) for the anodic stripping voltammetric determination of trace metal ions (Zn2+, Cd2+ and Pb2+). The NC(Bpy)BiFE electrode is prepared by first applying a 2.5 mm3 drop of a coating solution containing 0.5 wt% Nafion and 0.1% (w/v) 2,2'-bipyridil (Bpy) onto the surface of a glassy carbon electrode, while the Bi film was plated in situ simultaneously with the target metal ions at -1.4V. The main advantage of the polymer coated bismuth film electrode is that the sensitivity of the stripping responses is increased considerably due to the incorporation of the neutral chelating agent of 2,2'-bipyridyl (Bpy) in the Nafion film, while the Nafion coating improved the mechanical stability of the bismuth film and its resistance to the interference of surfactants. The key experimental parameters relevant to both the electrode fabrication and the voltammetric measurement were optimized on the basis of the stripping signals. With a 2 min deposition time in the presence of oxygen, linear calibration curves were obtained in a wide concentration range (about 2-0.001 microM) with detection limits of 8.6 nM (0.56 microg dm(-3)) for Zn2+, 1.1 nM (0.12 microg dm(-3)) for Cd2+ and 0.37 nM (0.077 microg dm(-3)) for Pb(2+). For nine successive preconcentration/determination/electrode renewal experiments the standard deviations were between 3 and 5% at 1.2 microM for zinc and 0.3-0.3 microM concentration level for lead and cadmium, respectively, and the method exhibited excellent selectivity in the presence of the excess of several potential interfering metal ions. The analytical utility of the stripping voltammetric method elaborated was tested in the assay of heavy metals in some real samples and the method was validated by ICP-MS technique.

Fluorescent iminodiacetamide derivatives as potential ionophores for optical zinc ion-selective sensors.

Fluorescent sensor molecules were synthesized by conjugation of iminodiacetamide derivatives with fluorescent moieties of different structures and their UV-visible and fluorescent properties were characterized in acetonitrile solvent. The fluorescent measurements revealed that the N-(2-naphthyl) and N-phenyl derivatives exhibit a distinct zinc ion-selectivity over alkali and alkaline earth metal ions, while N-(anthrylmethyl) and N-(3-methoxyphenyl) derivatives do not possess any ion-selectivities. In contrast to the fluorescent measurements, all ligands show Zn(2+) selectivity over Ca(2+) and Mg(2+) ions in plasticized PVC membranes using potentiometric signal transduction. This observation found for N-(anthrylmethyl) and N-(3-methoxyphenyl) derivatives can be ascribed to the more hindered interaction between the signalling group of the ionophore and the central metal ion in PVC membranes than in acetonitrile solution upon complexation. From the fluorescent measurements it can also be concluded that the ligands with metal ions form complexes mainly with 2:1 stoichiometry (L(2)M). On complex formation a considerable decrease in the fluorescent intensity was observed for all ligands except the N-(anthrylmethyl) derivative, where a 25 - 30 fold fluorescence enhancement was found, which is explained by the photoinduced electron transfer (PET) mechanism. All ionophores exhibited serious hydrogen ion interference, therefore complexation-induced spectral changes were measured in aprotic acetonitrile solution.

Electrochemical methods for the determination of the diffusion coefficient of ionophores and ionophore-ion complexes in plasticized PVC membranes.

The diffusion coefficients of active components in ion-selective membranes have a decisive influence on the life-time and detection limit of the respective ion-selective electrodes, as well as influencing the rate of polarization and relaxation processes of electrically perturbed ion sensors. Therefore, the rational design of mass transport controlled ion-selective electrodes with sub-nanomolar detection limits requires reliable data on the diffusion coefficients. We have implemented electrochemical methods for the quantitative assessment of both the diffusion coefficients of free ionophores and ion-ionophore complexes. The diffusion coefficients of the pH-sensitive chromoionophore ETH 5294 and the calcium-selective ionophore ETH 5234 were determined in plasticized PVC membranes with different PVC to plasticizer ratios. The diffusion coefficient of the free chromoionophore determined by a chronoamperometric method was validated with optical methods for a variety of membrane compositions. The calcium-selective ionophore ETH 5234 was used as a model compound to assess the diffusion coefficient of the ion-ionophore complex calculated from the time required for the complexes to cross a freshly prepared membrane during potentiometric ion-breakthrough experiments. The difference between the diffusion coefficients of the free ionophore ETH 5234 and the ion-ionophore complex was found to be significant and correlated well with the geometry of the respective species.

How to assess the limits of ion-selective electrodes: method for the determination of the ultimate span, response range, and selectivity coefficients of neutral carrier-based cation selective electrodes.

The span and range of an ion-selective electrode (ISE) has been identified by IUPAC as a potential or activity difference between the upper and lower detection limits of the electrode. Once the span is known, the ultimately attainable detection limit of the ISE can be calculated using its theoretical response slope. In this paper, we propose an original method for the determination of the ultimate span and response range of ISEs. The simple measurement of span is recommended to aid the fast screening of novel ionophores and help to focus optimization processes to the most promising candidates. The measurement of span is combined with a generally applicable procedure for the determination of the three seminal parameters of ISEs: the response slope, the ultimate selectivity coefficients, and detection limit. In the proposed procedure, following the span measurement, two subsequent exponential dilution experiments are completed in which the responses of the electrode for the primary and the interfering ions are tested using a solution of a discriminated ion and deionized water as diluting electrolytes in consecution. The advantages and the practical usefulness of the proposed methods and procedures are demonstrated through the evaluation of the performance characteristics of novel and well-characterized ionophore-based potassium and calcium sensors.

Spectrophotometric determination of the dissociation constants of crown ethers with grafted acridone unit in methanol based on Benesi-Hildebrand evaluation.

As potential chromo- and fluorophores for optical sensors a number of acridone grafted crown ethers containing NO2 group(s) and/or Br or Cl atom(s) in the aromatic rings (compounds) were studied by spectrophotometric method. In the first step of this work the acid-base and complexing properties of these compounds as well as those of the acridone, thioacridone and 4,5-dinitroacridone were investigated. Compounds proved to be very week acids and therefore the conventional spectrophotometric method based on the measurement of the ratio of the protonated/deprotonated forms of the compounds was not applicable for the determination of the dissociation constants (pKa values). Thus, a new spectrophotometric approach was elaborated for the pKa determination of these compounds, which is based on spectrophotometric titration in methanol with strong base and the titration results were evaluated by the Benesi-Hildebrand method. (In the studies with TEAOH, TMAOH and LiOMe, the complex formation between the ionophores and the cations of the bases could be excluded.) As it was expected, the experimentally determined pKa values depended on the nature of the substituents of the acridone moiety and pKa values ranged between 12.6 and 14.9. The lower pKa value of thioacridone compared to the acridone can be explained by the larger size of the sulfur atom. The outstandingly larger pKa value for 4,5-dinitroacridone can be attributed to the formation of intramolecular hydrogen-bonds between the ortho-position nitro group and the NH proton. As a trend, the strong electron withdrawing nitro substituents decreased considerably the pKa values of compounds and compared to that of the halogen (Cl and Br) atoms (for example compounds and) of weaker withdrawing effect.

Interaction of dopamine and acetylcholine with an amphiphilic resorcinarene receptor in aqueous micelle system.

The molecular recognition of neurotransmitters, dopamine and acetylcholine with an amphiphilic resorcinarene receptor was investigated in an aqueous sodium dodecylsulfate (SDS) micelle system by 1H NMR measurements. The interaction distances of these neurotransmitters from the hydrophilic cavity of the amphiphilic receptor were estimated based on the calculation of the ring current shift using the atomic coordinates obtained from molecular dynamics calculation.

Synthesis and characterization of covalently immobilized bis-crown ether based potassium ionophore.

The synthesis of a novel covalently immobilized crown ether based potassium ionophore is presented. Apart from previously proposed methods for the preparation of PVC linked ionophores based on the chemical modification of functionalized PVC polymers, the hereby proposed procedure involves the direct copolymerization of a suitable derivative of the bis-crown ether type potassium ionophore (BME 44) and vinyl chloride monomer. The analytical performance of the potentiometric ion selective electrodes incorporating the PVC bound ionophore were optimized and determined. Compared with electrodes based on other bis-crown ether type immobilized potassium selective ionophores a slightly improved logK(K, Na)(Pot) and a longer lifetime was found. Spectral imaging and chronoamperometry were used to study the mobility of different bis-crown ether derivatives in plasticized PVC membranes.

Chemical imaging of biological systems with the scanning electrochemical microscope.

A brief overview on recent advances in the application of scanning electrochemical microscopy (SECM) to the investigation of biological systems is presented. Special emphasis is given to the mapping of local enzyme activity by SECM, which is exemplified by relevant original systems.

Ion-transport and diffusion coefficients of non-plasticised methacrylic-acrylic ion-selective membranes.

The ion-transport behaviour of methacrylic-acrylic-based polymers for ion-selective electrode (ISE) membranes was investigated by a spectrophotometric method to determine the apparent diffusion coefficient. By observing the degree of deprotonation of the chromoionophore or chromogenic ionophore, the extent of penetration of cations into the polymer films was determined. The transport of the cations into the optode films depended on the stoichiometry of complexation by the ionophores. The apparent diffusion coefficients, estimated from the deprotonation data were of the order of 10(-12) to 10(-11)cm(2)s(-1). These values indicate that the apparent ion mobility in the methacrylic-acrylic ISE membranes is approximately a thousand times lower than that in plasticised PVC ISE membranes. For some ionophores, the value of the apparent diffusion coefficient could be modulated according to the ionophore content in the membrane and the data obtained for a calixarene containing membrane were tested against a model for facilitated diffusion with chained carriers. The data did not fit a model where intramolecular diffusion was limiting, but were consistent with a first-order rate-limiting mechanism involving an intermediate 1:2 complex between ion and ionophore. In this instance, the lowest values for D(app) were thus not necessarily obtained for lowest ionophore loading and in the range examined, a trend of decreasing D(app) with increasing ionophore was noted.

Optical biosensor for urea with improved response time.

An optical biosensor for urea measurements was developed. The operation of the sensor is based on the well-known urease enzyme-catalyzed hydrolysis of urea. The ammonium ions liberated in the reaction are detected with an ion selective optode membrane containing nonactin as ion selective ionophore and ETH 5294 chromoionophore in a thin (1 microm) plasticized poly(vinylchloride) film. The basic sensing element was home made of a microscope glass slide, a HeNe laser light source, photodiode light detector and light in coupling, de-coupling elements. The transducer membrane and the enzyme containing reaction layer were sandwich-cast with spin coating onto the surface of the sensing slide. The attenuation of the laser light propagating inside the glass wave-guide was used as signal for urea measurements. With this arrangement membranes provided good sensitivity (0.05 absorption unit when going from 0.1 to 1 mM urea) and short (16-20 s) response time. Taking advantage on the improved response time, flow injection urea measurements were made in the 0.01-2 mM concentration range. Thirty sample/hour analysis-rate, good peak-to-peak reproducibility (RSD=0.02) and recovery (95-104%) was achieved with buffer diluted urea solutions. Applications for the analysis of real samples are planned to do in the future.