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Graphical abstract, The Drosophila S2 tissue culture cells are a widely used system for studies on mitosis. S2 cells are particularly sensitive to gene silencing by RNA interference (RNAi), allowing targeted inactivation of mitotic genes. S2 cells are also well suited for high-resolution light microscopy analysis of mitosis in fixed cells, and can be easily immunostained to detect mitotic components. In addition, S2 cells are amenable to transformation with plasmid encoding fluorescently tagged mitotic proteins, allowing in vivo analysis of their behavior throughout cell division. However, S2 cells have not been widely used for transmission electron microscopy (TEM) analysis, which provides ultrastructural details on the morphology of the mitotic apparatus that cannot be obtained with high-resolution confocal microscopy. Here, we describe a simple method for the ultrastructural analysis of mitosis in Drosophila S2 cells. • Our method, which involves fixation and sectioning of a cell pellet, provides excellent preservation of mitotic structures and allows analysis of a higher number of mitotic divisions per sample, compared to correlative light-electron microscopy. • Dividing cells are randomly oriented within the pellet and are sectioned along different planes, providing all-around information on the structure of the mitotic apparatus.

New accurate data of the neutron-proton spin-dependent total-cross-section difference ΔσL(np) at the neutron-beam kinetic energies 1.39, 1.69, 1.89, and 1.99 GeV are presented. In general, these data complete the measurements of energy dependence of ΔσL(np) over the Dubna Synchrophasotron energy region. Measurements were carried out at the Synchrophasotron of the Veksler and Baldin Laboratory of High Energies of the Joint Institute for Nuclear Research. The quasi-monochromatic neutron beam was produced by breakup of extracted polarized deuterons. The deuteron (and hence neutron) polarization direction was flipped every accelerator burst. The initial transverse (with respect to beam momentum) neutron polarization was changed to a longitudinal one and longitudinally polarized neutrons were transmitted through the large proton longitudinally polarized target. The target polarization direction was inverted after one to two days of measurements. Four different combinations of the beam and target parallel and antiparallel polarization directions, both oriented along the neutron-beam momentum, were used at each energy. A fast decrease in −ΔσL(np) with increasing energy above 1.1 GeV and a structure in the energy dependence around 1.8 GeV, first observed from our previous data, seem to be well revealed. The new results are also compared with model predictions and with phase-shift analysis fits. The ΔσL quantities for isosinglet state I = 0, deduced from the measured ΔσL(np) values and known ΔσL(pp) data, are also given. The results of the measurements of unpolarized total cross sections σ0tot(np) at 1.3, 1.4, and 1.5 GeV and σ0tot(nC) at 1.4 and 1.5 GeV are presented as well. These data were obtained using the same apparatus and high-intensity unpolarized deuteron beams extracted either from the Synchrophasotron or from the Nuclotron.

New accurate data on the neutron-proton spin-dependent total cross section difference Δσ L(np) at the neutron beam kinetic energies 1.4, 1.7, 1.9 and 2.0 GeV are presented. A number of physical and methodical results on investigation of an elasticnp→pn charge exchange process over a few GeV region are also presented. Measurements were carried out at the Synchrophasotron and Nuclotron of the Veksler and Baldin Laboratory of High Energies of the Joint Institute for Nuclear Research.

New accurate results of the neutron-proton spin-dependent total cross section difference $\Delta\sigma_{\mathrm L}(np)$ at the neutron beam kinetic energies 1.39, 1.69, 1.89 and 1.99 GeV are presented. Measurements were carried out in 2001 at the Synchrophasotron of the Veksler and Baldin Laboratory of High Energies of the Joint Institute for Nuclear Research. A quasi-monochromatic neutron beam was produced by break-up of extracted polarized deuterons. The deuteron (and hence neutron) polarization direction was flipped every accelerator burst. The vertical neutron polarization direction was rotated onto the neutron beam direction and longitudinally (L) polarized neutrons were transmitted through a large proton L-polarized target. The target polarization vector was inverted after 1-2 days of measurements. The data were recorded for four different combinations of the beam and target parallel and antiparallel polarization directions at each energy. A fast decrease of $\Delta\sigma_{\mathrm L}(np)$ with increasing energy above 1.1 GeV was confirmed. The structure in the $\Delta\sigma_{\mathrm L}(np)$ energy dependence around 1.8 GeV, first observed from our previous data, seems to be well pronounced. The new results are also compared with model predictions and with phase shift analysis fits. The $\Delta\sigma_{\mathrm L}$ quantities for isosinglet state I = 0, deduced from the measured $\Delta\sigma_{\mathrm L}(np)$ values and the known $\Delta\sigma_{\mathrm L}(pp)$ data, are also given. The results were completed by the measurements of unpolarized total cross sections $\sigma_{0\mathrm{tot}}(np)$ at 1.3, 1.4 and 1.5 GeV and $\sigma_{0\mathrm{tot}}(n$ C) at 1.4 and 1.5 GeV. These data were obtained using the same apparatus and high intensity unpolarized deuteron beams were extracted either from the Synchrophasotron, or from the Nuclotron.

Preliminary results of the ΔσL(np) at 1.4, 1.7, 1.9 and 2.0 GeV are presented. They were obtained during the two data-taking runs at the JINR Dubna Synchrophasotron in 2001 and complete the existing data above 1.1 GeV. The data analysis is in progress. The aim of the present studies is to determine the imaginary and real parts of the np spin-dependent forward scattering amplitudes over this energy range.

New results of the neutron-proton spin-dependent total cross section difference $\Delta\sigma_L(np)$ at the neutron beam kinetic energies 1.59, 1.79 and 2.20 GeV are presented. Measurements were performed at the Synchrophasotron of the Laboratory of High Energies of the Joint Institute for Nuclear Research in Dubna. A quasi-monochromatic neutron beam was produced by break-up of extracted polarized deuterons. Neutrons were transmitted through a large polarized proton target. Measurements were performed either with a parallel or an antiparallel beam and target polarizations, both oriented along the beam momentum. The results at the two higher energies were measured with two opposite beam and target polarization directions. Only one target polarization direction was available at 1.59 GeV. The present measurements agree well with existing data. A fast decrease of the $-\Delta\sigma_L(np)$ values with increasing energy above 1.1 GeV was confirmed. The new results are also compared with model predictions and with phase shift analysis fits. The $\Delta\sigma_L$ quantities for isosinglet state I=0, deduced from the measured $\Delta\sigma_L(np)$ values and known $\Delta\sigma_L(pp)$ data, are given.

New results for the np spin-dependent total cross section difference Δσp(np) at neutron beam kinetic energies of 1.59, 1.79 and 2.20 GeV are presented. Measurements of the Δσp(np) energy dependence were carried out at the Synchrophasotron of the Laboratory of High Energies of the Joint Institute for Nuclear Research in Dubna. The values of ΔσL were measured as a difference between the np total cross sections for parallel and antiparallel beam and target polarizations, both oriented along the beam momentum. A fast decrease of Δσp(np) with increasing energy above 1.1 GeV, as it was first seen from our previous data, was confirmed. The new results are also compared with model predictions and with the phase shift analysis fits. The ΔσL quantities for isosinglet state I=0, deduced from the measured values of Δσp(np) and known Δσp(pp) data, are given.

Electron microscopy (EM) has been used extensively for the study of nuclear transport as well as the structure of the nuclear pore complex (NPC) and nuclear envelope. However, there are specific challenges faced when carrying out EM in one of the main model organisms used: the yeast, Saccharomyces cerevisiae. These are due to the presence of a cell wall, vacuoles, and a densely packed cytoplasm which, for transmission EM (TEM), make fixation, embedding, and imaging difficult. These also present problems for scanning EM (SEM) because cell wall removal and isolation of nuclei can easily damage the relatively fragile NPCs. We present some of the protocols we use to prepare samples for TEM and SEM to provide information about yeast NPC ultrastructure and the location of nucleoporins and transport factors by immunogold labeling within that ultrastructure.

Results of the total cross section differenceΔσL in anp transmission experiment at 1.19, 2.49 and 3.65 GeV incident neutron beam kinetic energies are presented. Measurements were performed at the Synchrophasotron of the Laboratory of High Energies of the Joint Institute for Nuclear Research in Dubna. Results were obtained with a polarized beam of free quasi-monochromatic neutrons passing through the new Dubna frozen spin proton target. The beam and target polarizations were oriented longitudinally. The present results were obtained at the highest energies of free polarized neutrons that can be reached at present. They extend the energy range of existing results from PSI, LAMPF and Saclay measured between 0.066 and 1.10 GeV. The new results are compared withΔσL(pn) data determined as a difference betweenΔσL(pd) andΔσL(pp) ANL-ZGS measurements. The values ofΔσL for the isospin stateI=0 were deduced using knownpp data.

The tensor analyzing power {ital T}{sub 20} for the reaction {ital d}{sup {up_arrow}}+{sup 12}C{r_arrow}{ital p}(0{degree})+{ital X} has been measured in the region of proton internal momenta {ital k} in light-cone dynamics up to 1 GeV/{ital c}. Measurements have been carried out at Dubna Synchrophasotron with polarized deuteron beam at deuteron momenta up to 9 GeV/{ital c}. When {ital k} increases the experimental values of {ital T}{sub 20} have a tendency to approach the value ({minus}0.3) obtained by the calculation based on the reduced nuclear amplitude method in which the quark degrees of freedom are taken into account.

A polarimeter for polarized deuteron beams at the JINR synchrophasotron in the energy range of several GeV per nucleon is described. A left-right-symmetrical detector configuration is used to measure vector and tensor polarizations of deuterons in the forward scattering on a liquid hydrogen target. In this paper we present the results of various measurements to adjust optimum conditions for the working regime of the ion source.

We measured diffractive scattering cross sections of alpha-particles on carbon, aluminium, copper and lead using the beam of the Dubna synchrophasotron at 3.64 GeV/nucleon. The data are compared with model predictions of the Glauber-Sitenko multiple scattering theory. Large discrepancies between experiment and calculations appear at four-momentum transfers above ∼0.25 (GeV/c)2. Various theoretical attempts to improve the description of high-energy alpha-scattering data are discussed.

The tensor analyzing power A yy in inclusive breakup of 9 GeV/c deuterons on carbon has been measured at 85 mrad of the detected proton angle using polarized beam of the Synchrophasotron of the Laboratory for High Energies of JINR. The analyzing power A yy remains positive at the highest measured momentum of the proton in definite contradiction with the predictions based on the standard nucleon-nucleon potentials.

An intermediate-energy polarimeter has been effectively run at the slow extraction beam line of the Dubna synchrophasotron to measure the beam polarization and to fix optimum conditions for the working regime of the ion source POLARIS /1/. The polarimeter consists of a symmetrical left-right detector system to measure the elastic dp scattering in the four-momentum interval -t = 0.1 ÷ 0.5 GeV/c at 3 to 4 GeV/c. With beam intensities of 5 · 108 deuterons per spill on the target the polarization quantities could be determined with statistical accuracy of better than 10% during measuring periods of about 15 min. Vector and tensor polarizations larger than 60% of the expected theoretical values have been obtained in routine. No appreciable depolarization effects are found to occur during the acceleration process. Several experimental runs at the Dubna synchrophasotron with polarized deuteron beams at momenta up to 9 GeV/c have been done to investigate the deuteron break-up on protons and nuclei. Measurements of the tensor analyzing power T20 with tensor-polarized deuterons and of the polarization transfer coefficient with vectorpolarized deuterons have been carried out to investigate the short-range behaviour of nucleon-nucleon interaction /2/.

A system of nine wire spark chambers having magnetostrictive readout, data acquisition electronics used on-line with the computer BESM-3M located at a 1 km distance from the experimental area has been designed and tested using a negative pion beam of the Dubna synchrophasotron.