Tetra-arylborate lipophilic anions as targeting groups

Tetraphenylborate (TPB) anions traverse membranes but are excluded from mitochondria by the membrane potential (Δψ). TPB-conjugates also distributed across membranes in response to Δψ, but surprisingly, they rapidly entered cells. They accumulated within lysosomes following endocystosis. This pH-independent targeting of lysosomes makes possible new classes of probe and bioactive molecules

Spermine selectively inhibits high-conductance, but not low-conductance calcium-induced permeability transition pore

AbstractThe permeability transition pore (PTP) is a large channel of the mitochondrial inner membrane, the opening of which is the central event in many types of stress-induced cell death. PTP opening is induced by elevated concentrations of mitochondrial calcium. It has been demonstrated that spermine and other polyamines can delay calcium-induced swelling of isolated mitochondria, suggesting their role as inhibitors of the mitochondrial PTP. Here we further investigated the mechanism by which spermine inhibits the calcium-induced, cyclosporine A (CSA) — sensitive PTP by using three indicators: 1) calcium release from the mitochondria detected with calcium green, 2) mitochondrial membrane depolarization using TMRM, and 3) mitochondrial swelling by measuring light absorbance. We found that despite calcium release and membrane depolarization, indicative of PTP activation, mitochondria underwent only partial swelling in the presence of spermine. This was in striking contrast to the high-amplitude swelling detected in control mitochondria and in mitochondria treated with the PTP inhibitor CSA. We conclude that spermine selectively prevents opening of the high-conductance state, while allowing activation of the lower conductance state of the PTP. We propose that the existence of lower conductance, stress-induced PTP might play an important physiological role, as it is expected to allow the release of toxic levels of calcium, while keeping important molecules (e.g., NAD) within the mitochondrial matrix

Integration algorithms inertial–satellite navigation system

Розглянуто помилки інтегрованих навігаційних систем на базі інерціальної платформи і супутникової навігаційної системи. Розглядаються помилки інтегрованої системи в сталому режимі, час, витрачений на моделювання. В алгоритмах використані фільтри першого і другого порядку, а також фільтр Калмана. Показано, що фільтр Калмана дає дещо кращу точність за окремими параметрами, але вимагає більших обчислювальних витрат. Розглянуто як розімкнутий, так і замкнутий алгоритм інтегрування. Показані переваги замкнутої системи. Замкнута схема дозволяє забезпечити демпфірування коливань помилок системи.We consider the error of integrated navigation systems based on an inertial platform and the satellite navigation system. We consider the error of integrated system in the steady state, the time spent on modeling. In the algorithms used filters first and second order, as well as the Kalman filter. It is shown that the Kalman filter gives the better accuracy on the parameters, but requires large computational costs. We consider both open and closed integration algorithm. The advantages of a closed system are shown. A closed circuit allows for vibration damping system errors.Рассмотрены ошибки интегрированных навигационных систем на базе инерциальной платформы и спутниковой навигационной системы. Рассматриваются ошибки интегрированной системы в установившемся режиме, время, затраченное на моделирование. В алгоритмах использованы фильтры первого и второго порядка, а также фильтр Калмана. Показано, что фильтр Калмана дает немного лучшую точность по отдельным параметрам, но требует больших вычислительных затрат. Рассмотрены как разомкнутый, так и замкнутый алгоритм интегрирования. Показаны преимущества замкнутой системы

The single satellite system of data transmission of Ukraine: plans and implementation

The paper considers main features of the Single Satellite System of Data Transmission (with the “Ukrkosmos” state enterprise as operator) to be created by National Space Agency of Ukraine in conformity with the National Space Program

Project VARIANT: Current and field measurements on board SICH-1M satellite

International audienceVARIANT is a joint international space experiment on current density measurements in ionospheric-magnetospheric plasmas. The experiment will be performed onboard the Ukrainian remote sensing satellite SICH-1M, that will be launched in 2000 at the polar circular orbit with the inclination of around 83 degrees and altitude 670 +/- 30 km. The scientific payload includes three instruments for registration of space current density: a split Langmuir probe, a Rogovski coil and a Faraday cup. The first two of these instruments are dedicated to measure current density variations and the last the particles' fluxes. The equipment also includes sensors for measurements of the electric and magnetic field fluctuations in the frequency range from 0.1 Hz to 40 kHz. Main objectives of the VARIANT mission are as follows: (C) 2000 COSPAR