Simulation of chlorophyll fluorescence rise and decay kinetics, and P700-related absorbance changes by using a rule-based kinetic Monte-Carlo method.

A model of primary photosynthetic reactions in the thylakoid membrane was developed and its validity was tested by simulating three types of experimental kinetic curves: (1) the light-induced chlorophyll a fluorescence rise (OJIP transients) reflecting the stepwise transition of the photosynthetic electron transport chain from the oxidized to the fully reduced state; (2) the dark relaxation of the flash-induced fluorescence yield attributed to the QA- oxidation kinetics in PSII; and (3) the light-induced absorbance changes near 820 or 705 nm assigned to the redox transitions of P700 in PSI. A model was implemented by using a rule-based kinetic Monte-Carlo method and verified by simulating experimental curves under different treatments including photosynthetic inhibitors, heat stress, anaerobic conditions, and very high light intensity.

[The place of novel oral anticoagulants in prevention and treatment of venous thromboembolism]. / Mesto novykh peroral'nykh antikoaguliantov v profilaktike i lechenii venoznykh tromboémbolii

The notion "venous thromboembolism" combines two processes: thrombosis of deep veins and pulmonary artery thromboembolism. The necessity in long-term adequate anticoagulant therapy as the basic treatment of patients with deep vain thrombosis does not give rise to doubts, it should be started prior to instrumental verification of the diagnosis. The past decade was marked by the appearance on the pharmaceutical market of a new oral anticoagulant: selective blocker of the Xa factor of blood coagulation system - rivaroxaban. According to the data of large-scale randomized clinical trials, the efficacy and safety of rivaroxaban are comparable to those of traditional conventional anticoagulant therapy (non-fractionated/low-molecular-weight heparin NFH/LMW + warfarin). Indisputable advantages of new agents are as follows: the lack of the necessity in laboratory monitoring, no interaction with foodstuff, minimal interaction with other drugs, minimal risk for the development of haemorrhage, and simplicity of dosing.

Study of the effect of reducing conditions on the initial chlorophyll fluorescence rise in the green microalgae Chlamydomonas reinhardtii.

Incubation of Chlamydomonas reinhardtii cells under nutrient deficiency results in the faster initial rise in the light-induced chlorophyll fluorescence kinetic curve. We showed that short-term anaerobic incubation of algal cells altered initial fluorescence in a way similar to nutrient starvation, suggesting an important role of the plastoquinones redox state in the observed effect. Bi-component analysis of highly resolved initial fluorescence rise kinetics in sulfur- or oxygen-depleted C. reinhardtii cells suggested that one of the mechanisms underlying the observed phenomenon involves primary closure (photochemical inactivation via Qa reduction) of ß-type PSII as compared to α-PSII. Moreover, results of modeling of the fluorescence curve brought us to the conclusion that accumulation of closed centers in α-PSII supercomplexes may also cause a faster initial fluorescence rise. The observed correlations between nutrient supply rate and initial fluorescence rise pattern in green algae can serve to characterize culture nutritional status in vivo.

[A method of determining the thickness of a histologic section using a spectrophotometer]. / Sposob opredeleniia tolshchiny gistologicheskogo sreza s pomoshch'iu spektrofotometra.

The authors show the possibility of determining the thickness of a histological section using a spectrophotometer with automatic recording of absorption spectrum. The thickness of the section in nanometers is calculated by graphic records of the sample interference pattern. Experimental setting has been defined which warrants stable results.