Inorganic Polyphosphate Modulates TRPM8 Channels

Polyphosphate (polyP) is an inorganic polymer built of tens to hundreds of phosphates, linked by high-energy phosphoanhydride bonds. PolyP forms complexes and modulates activities of many proteins including ion channels. Here we investigated the role of polyP in the function of the transient receptor potential melastatin 8 (TRPM8) channel. Using whole-cell patch-clamp and fluorescent calcium measurements we demonstrate that enzymatic breakdown of polyP by exopolyphosphatase (scPPX1) inhibits channel activity in human embryonic kidney and F-11 neuronal cells expressing TRPM8. We demonstrate that the TRPM8 channel protein is associated with polyP. Furthermore, addition of scPPX1 altered the voltage-dependence and blocked the activity of the purified TRPM8 channels reconstituted into planar lipid bilayers, where the activity of the channel was initiated by cold and menthol in the presence of phosphatidylinositol 4,5-biphosphate (PtdIns(4,5)P2). The biochemical analysis of the TRPM8 protein also uncovered the presence of poly-(R)-3-hydroxybutyrate (PHB), which is frequently associated with polyP. We conclude that the TRPM8 protein forms a stable complex with polyP and its presence is essential for normal channel activity

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