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  • Author or Editor: E. Mák x
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Abstract  

Formation of conglomerates is of general interest because they offer the possibility of enantiomeric separation by preferential crystallization. A surprising result was obtained for the chiral epoxide 1a, 2, 7, 7a-tetrahydro-3-methoxynaphth-(2,3b)-oxirene, for which we have shown that the racemate crystals of a non racemic mixture can be easily transformed into a conglomerate by gentle heating and cooling within a defined temperature range. This transformation is not possible with the pure racemic mixture. Thus the enantiomeric excess seems to be the driving force for the conglomerate formation. Experiments have been carried out on analytical and preparative scale. Non racemic mixtures have been characterized by high pressure liquid chromatography on chiral stationary phase and crystal transformation has been monitored with differential scanning calorimetry (DSC) and infrared spectroscopy (IR).

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Abstract

Purpose

Diets other than those recommended by professionals, referred to in the present paper as “pseudo-diets”, can endanger the health of the people who follow them. It is therefore worth assessing why people begin such diets, the information they rely on, and the effects they experience.

Materials and Methods

We surveyed and compared people following two pseudo-diets: a ketogenic-like diet (KLD) and a vegan-like diet (VLD). The diets are defined as ketogenic and vegan by the dieters themselves. A cross-sectional study was carried out using self-developed anonymous online questionnaires. The survey participants were adults: 249 KLD and 203 VLD followers.

Results

The majority (85.14%) of the KLD followers stated that their motivation was weight loss, while 56.16% of the VLD followers stated that they were primarily motivated by ethical considerations. Only 11.64% of the KLD followers and 33.99% of the VLD followers had sought professional help. Both the variety and frequency of the adverse effects were robust in the KLD group, while the VLD followers experienced primarily positive outcomes. We found a statistically significant association between the seeking of professional help and an increase in desirable effects in both groups, and a decrease in adverse effects in the VLD group.

Conclusions

The dieters used several information sources but only occasionally turned to professionals. Given that dietary changes can represent a significant intervention, professional monitoring is highly recommended to ensure that the diet is valid, effective, personalised and safe.

Open access

Abstract

Purpose

Intensive exercise significantly lowers the pH of muscle and blood; beta-alanine supplementation can increase carnosine levels, the absence of which leads to an early acidosis and fatigue. The aim of our work is to investigate the effect of a single dose of beta-alanine supplementation on well-trained rowing athletes.

Materials/Methods

The spiroergometric parameters of the participants (n = 28) were examined a total of four times (T1,T2,T3,T4). After measurement (T3), participants received a beta-alanine supplementation at a dose of 50 mg/kg−1 body weight. We compared the results of the four measurements as well as the blood lactate values obtained from the fingertip before and after the tests.

Results

The different load physiological parameters and the lactate values measured after the tests did not show any significant difference. The mean lactate value prior to test (T4) was 1.8 (mmol*L−1), which is significantly higher than the mean-value of the two previous studies: T1 = 1.6 (mmol*L−1); (P = 0.00), T3 = 1.55 (mmol*L−1); (P = 0.04).

Conclusions

The higher lactate value measured before test (T4) was probably due to the longer time to return to the baseline values after the series load. In conclusion, a single dose of beta-alanine supplementation has no effect on performance. In order to elicit the ergogenic effect of beta-alanine, the use of short, intermittent diet therapy intervention is not recommended.

Open access