Quality and safety problems of sports nutrition products

The purpose of this work was to study the quality and safety of some sports nutrition products. The objects of study were sports nutrition products: protein bars of ‘ProteinBar’ (Russia) and ‘Bombbar’ (Russia); capsule forms of dietary supplements ω–3, ω–6, ω–9 firms ‘Sportline’ (Russia), ‘Multipower’ (Germany) and ‘Maxler’ (USA). According to the research results, the normalized safety indicators of the fat component of the studied products for sports nutrition (acid number and peroxide) are within acceptable values. The standardized safety indicators of the fat component do not fully reflect the safety requirements for the fat component of sports nutrition products, since there are no standards for the most important indicators of fat safety – the content of secondary oxidation products – copolymers insoluble in petroleum ether and epoxides. The results obtained in the course of the work showed that in almost all of the studied samples are content of epoxides (7.5–47.6 g -1 ) and secondary oxidation products – 1% or more

Resonance fluorescence and Autler-Townes spectra of a two-level atom driven by two fields of equal frequencies

We study the effects of driving a two-level atom by two intense field modes that have equal frequencies but are otherwise distinguishable; the intensity of one mode is also assumed to be greater than that of the other. We calculate first the dressed states of the system, and then its resonance fluorescence and Autler-Townes absorption spectra. We find that the energy spectrum of the doubly dressed atom consists of a ladder of doublet continua. These continua manifest themselves in the fluorescence spectrum, where they produce continua at the positions of the Mellow sideband frequencies omega(L)+/-2 Omega of the strong field, and in the Autler-Townes absorption spectrum, which becomes a two-continuum doublet

Predictors of atrial fibrillation in patients with dualchamber pacemakers

During prospective study the predictors of primary AF incidence were studied in 87 patients (mean age 64,3±10.5 years) with chronic ischemic heart disease after dual chamber pacemakers (DCP) implantation: 39 - with sick sinus syndrome (SSS), 43 - with the atrioventricular block II-III degree (AVB), 5 - with binodal disease. The end point was the primary incidence of sustained paroxysmal AF (>30 seconds). The primary AF development is noted at 16 (18,4%) patients later 10 months after DCP implantation. At comparison of groups with and without AF by means of Stjudents criterion and Fisher's nonparametric criterion the factors associating with AF have been revealed: presence AVB (p=0,004), a male (p=0,01), left atrium dilation (p=0,04), right ventricular stimulation percent >60% (p=0,009), atrial stimulation percent 30 сек. Первичное развитие ФП отмечено у 16 (18,4%) пациентов спустя 10 месяцев после имплантации ЭКС. При сравнении групп с ФП и без ФП с помощью критерия Стъюдента и непараметрического критерия Фишера были выявлены факторы, ассоциирующиеся с ФП: наличие АВБ (р=0,004), мужской пол (р=0,01), дилатация левого предсердия (р=0,04), доля правожелудочковой стимуляции >60% (р=0,009), доля предсердной стимуляции <35% (р=0,04), длительность детектируемой АВ-задержки <180мсек (р=0,03). Методом бинарной логистической регрессии выявлено 2 независимых предиктора ФП: длительность детектируемой АВ-задержки <180 мс и принадлежность к мужскому полу. Наличие в ЭКС алгоритма, способствующего спонтанному АВ проведению, достоверно снижало развитие ФП только при СССУ (р=0,02)

Fluorescence spectrum of a two-level atom driven by a multiple modulated field

We investigate the fluorescence spectrum of a two-level atom driven by a multiple amplitude-modulated field. The driving held is modeled as a polychromatic field composed of a strong central (resonant) component and a large number of symmetrically detuned sideband fields displaced from the central component by integer multiples of a constant detuning. Spectra obtained here differ qualitatively from those observed for a single pair of modulating fields [B. Blind, P.R. Fontana, and P. Thomann, J. Phys. B 13, 2717 (1980)]. In the case of a small number of the modulating fields, a multipeaked spectrum is obtained with the spectral features located at fixed frequencies that are independent of the number of modulating fields and their Rabi frequencies. As the number of the modulating fields increases, the spectrum ultimately evolves to the well-known Mellow triplet with the sidebands shifted from the central component by an effective Rabi frequency whose magnitude depends on the initial relative phases of the components of the driving held. For equal relative phases, the effective Rabi frequency of the driving field can be reduced to zero resulting in the disappearance of fluorescence spectrum, i.e., the atom can stop interacting with the field. When the central component and the modulating fields are 180 degrees out of phase, the spectrum retains its triplet structure with the sidebands located at frequencies equal to the sum of the Rabi frequencies of the component of the driving field. Moreover, we shaw that the frequency of spontaneous emission can be controlled and switched from one frequency to another when the Rabi frequency or initial phase of the modulating fields are varied

Weak-probe absorption and dispersion spectra in a two-level system driven by a strong trichromatic field

With the help of a probe-field method the time-behaviour of a two-level system subjected to a strong trichromatic near-resonant field is studied. The suitable Bloch equations are solved by a matrix exponent method which allows us to do without the continued fractions. It is shown that, when the Rabi frequency is sufficiently large, the profile of the weak-probe field absorption resembles a dispersion profile. The existence of a new type of parametric resonances not connected with the Rabi resonances is shown.On étudie à l'aide d'un champ sonde l'évolution temporelle d'un système à 2 niveaux soumis à un champ quasi résonnant à trois fréquences différentes. Les équations de Bloch correspondantes sont résolues par une méthode d'exponentielle de matrice qui permet de se passer de fractions continues. On montre que lorsque la fréquence de Rabi est suffisamment grande, le profil d'absorption du champ sonde ressemble à un profil de dispersion. On met en évidence l'existence d'un nouveau type de résonances paramétriques qui ne sont pas liées à des résonances de Rabi