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This work investigates the detailed difference between dielectric function models, the Mermin model and the full Penn algorithm (FPA) model, for the determination of an electron inelastic mean free path (IMFP) with optical energy loss function (ELF), as an extension of our previous study [Da et al., Surf. Interface Anal. 51, 627 (2019)] by using the simple Drude-type ELF. In the conventional normal Mermin (NM) model, the approximations of ELF by the Drude equation will introduce inevitable fitting error. In order to enhance the accuracy of the NM model, our previous proposed extended Mermin model [Da et al., Phys. Rev. Lett. 113, 063201 (2014)], which is renamed as a super-extended Mermin algorithm (SE-MA) now, is employed to eliminate the error by expanding the definition of Drude oscillators used in the NM. In the SE-MA, the Drude-like oscillators allow the existence of negative strengths to express the fine structures of phonon–electron scattering and the plasmon lifetime broadening effect. Because in our previous study, the simple Drude-type ELF cannot include these complex structures, in this work, the electron IMFPs are calculated for five realistic materials, Al, Si, Cu, Au, and MgO. The difference between IMFPs calculated by the SE-MA model and the FPA model is material dependent and is significant in the low energy region, which is analyzed by using the Fano plot. This is due to the more important role played by the plasmon lifetime broadening effect.

We calculated electron inelastic mean free paths (IMFPs) for liquid water from its optical energy-loss function (ELF) for electron energies from 50 eV to 30 keV. These calculations were made with the relativistic full Penn algorithm (FPA) that has been used for previous IMFP and electron stopping-power calculations for many elemental solids. We also calculated IMFPs of water with three additional algorithms: the relativistic single-pole approximation (SPA), the relativistic simplified SPA, and the relativistic extended Mermin method. These calculations were made using the same optical ELF in order to assess any differences of the IMFPs arising from choice of the algorithm. We found good agreement among the IMFPs from the four algorithms for energies over 300 eV. For energies less than 100 eV, however, large differences became apparent. IMFPs from the relativistic TPP-2M equation for predicting IMFPs were in good agreement with IMFPs from the four algorithms for energies between 300 eV and 30 keV but there was poorer agreement for lower energies. We calculated values of the static structure factor as a function of momentum transfer from the FPA. The resulting values were in good agreement with results from first-principles calculations and with inelastic X-ray scattering spectroscopy experiments. We made comparisons of our IMFPs with earlier calculations from authors who had used different algorithms and different ELF data sets. IMFP differences could then be analyzed in terms of the algorithms and the data sets. Finally, we compared our IMFPs with measurements of IMFPs and of a related quantity, the effective attenuation length (EAL). There were large variations in the measured IMFPs and EALs (as well as their dependence on electron energy). Further measurements are therefore required to establish consistent data sets and for more detailed comparisons with calculated IMFPs.

Space solar missions such as {\it Yohkoh} and {\it RHESSI} observe the hard X- and gamma-ray emission from energetic electrons in impulsive solar flares. Their energization mechanism, however, is unknown. In this paper, we suggest that the internal shocks are created in the reconnection jet and that they are possible sites of particle acceleration. We examine how magnetic reconnection creates the multiple shocks by performing two-dimensional resistive magnetohydrodynamic simulations. In this paper, we use a very small grid to resolve the diffusion region. As a result, we find that the current sheet becomes thin due to the tearing instability, and it collapses to a Sweet-Parker sheet. The thin sheet becomes unstable to the secondary tearing instability. Fast reconnection starts by the onset of anomalous resistivity immediately after the secondary tearing instability. During the bursty, time-dependent magnetic reconnection, the secondary tearing instability continues in the diffusion region where the anomalous resistivity is enhanced. As a result, many weak shocks are created in the reconnection jet. This situation produces turbulent reconnection. We suggest that multiple fast shocks are created in the jet and that the energetic electrons can be accelerated by these shocks., 12 pages including 4 figures, AASTEX. submitted to ApJL, Papre including figures and animation are available at http://www.kwasan.kyoto-u.ac.jp/~tanuma/ApJL2005.html

The Kelvin--Helmholtz (KH) and tearing instabilities are likely to be important for the process of fast magnetic reconnection that is believed to explain the observed explosive energy release in solar flares. Theoretical studies of the instabilities, however, typically invoke simplified initial magnetic and velocity fields that are not solutions of the governing magnetohydrodynamic (MHD) equations. In the present study, the stability of a reconnecting current sheet is examined using a class of exact global MHD solutions for steady state incompressible magnetic reconnection, discovered by Craig & Henton. Numerical simulation indicates that the outflow solutions where the current sheet is formed by strong shearing flows are subject to the KH instability. The inflow solutions where the current sheet is formed by a fast and weakly sheared inflow are shown to be tearing unstable. Although the observed instability of the solutions can be interpreted qualitatively by applying standard linear results for the KH and tearing instabilities, the magnetic field and plasma flow, specified by the Craig--Henton solution, lead to the stabilization of the current sheet in some cases. The sensitivity of the instability growth rate to the global geometry of magnetic reconnection may help in solving the trigger problem in solar flare research., Accepted for publication in ApJ. Associated movie files and a PDF with high-resolution figures are available at http://www.pha.jhu.edu/~shirose/Craig/

Background Loss to follow-up (LTFU) is viewed as a major challenge in improving retention in HIV treatment. In Vietnam, the reasons for disengagement from clinics and the effect of injection drug use (IDU) on LTFU with unknown outcome (true LTFU) are not well known. Methods Patients receiving antiretroviral therapy (ART) from two HIV clinics in Hanoi were included in this observational study between 2007 and 2012, and followed up every 6 months until the end of 2013. The reasons for disengagement from the clinic, and ART status during imprisonment were investigated in patients with a history of IDU to identify true LTFU. The retention rate at 6-54 months and true LTFU rate were calculated. Cox proportional hazards regression models were performed to identify factors associated with true LTFU. Results There were 1,431 patients, with a follow-up time of 4,371 person-years (median 2.49 years). At the end of the follow-up period, 71 (5.0%) patients died, 79 (5.5%) transferred to other clinics, 16 (1.1%) disengaged from the clinics, and the calculated true LTFU was 45 (3.1%), with 12-month ART retention rate of 95.3% for the entire study population. Imprisonment was the most frequent reason for disengagement from the clinics. True LTFU correlated significantly with low CD4 count and high plasma viral load, but not history of IDU. Conclusion Imprisonment is a major cause of disengagement from HIV care among patients with a history of IDU. © 2015 Matsumoto et al.

An evolutionary process of fast magnetic reconnection in "free space," which is free from any influence from outer circumstances, has been studied semianalytically, and a self-similarly expanding solution has been obtained. The semianalytic solution is consistent with the results of the numerical simulations performed in our previous paper. This semianalytic study confirms the existence of self-similar growth. On the other hand, numerical study by time-dependent computer simulation clarifies the stability of the self-similar growth with respect to any MHD mode. These results confirm the stable self-similar evolution of the fast magnetic reconnection system.

ラウンドロビン試験を行い, 以下のことを明らかにした. 基板に穴のある特殊ホルダーを使えば, 単色化X線源を有するXPSでもPVC, NC-CA試料のClおよびN分に関する分解反応係数を求めることにより, 有機物試料損傷評価は可能である. このときの両者の反応係数の比は装置に関係しない値になり, 0.174 (±0.015)であることが明らかになった. これにより有機物のXPS分析において, 損傷量を評価できるようになった.

We examine magnetic reconnection triggered by a supernova (or a point explosion) in the interstellar medium by performing two-dimensional resistive magnetohydrodynamic (MHD) numerical simulations with high spatial resolution. We find that magnetic reconnection starts long after a supernova shock (fast-mode MHD shock) passes a current sheet. A current sheet evolves as follows: (1) Tearing-mode instability is excited by the supernova shock, and in its nonlinear stage the current sheet becomes thin. (2) The current-sheet thinning is saturated when the current-sheet thickness becomes comparable to that of the Sweet-Parker current sheet. After that, Sweet-Parker reconnection starts, and the current-sheet length increases. (3) "Secondary tearing-mode instability" occurs in the thin Sweet-Parker current sheet. (4) As a result, further current-sheet thinning occurs and anomalous resistivity sets in, because gas density decreases in the current sheet. Petschek reconnection starts and heats the interstellar gas. Magnetic energy is released quickly as magnetic islands move in the current sheet during Petschek reconnection. The released magnetic energy is determined by the interstellar magnetic field strength, not the energy of the initial explosion or the distance to the explosion. We suggest that magnetic reconnection is a possible mechanism to generate X-ray gas in the Galaxy.

X-ray astronomy satellites detected strong X-ray emission along Galactic ridge (Galactic Ridge X-ray Emission, GRXE). Origin and nature of the GRXE are not known. In the present paper, we propose a possible mechanism to explain the origin of GRXE. We solved two-dimensional resistive MHD (magnetohydrodynamics) equation numerically to examine the magnetic reconnection triggered by a supernova and the interstellar magnetic structure in Galaxy. Especially we find that the magnetic reconnection heats X-ray plasma in Galactic plane if reconnection occurs in locally strong magnetic fields of ∼ 30 μG. The released magnetic energy by the reconnection is determined by the magnetic field strength. The magnetic islands are generated by the reconnection. Heated plasma is confined by magnetic fields for a long time.

A new model, the magnetic reconnection model, is proposed to explain the heating of the superhot plasmas of Galactic center. In this model, the magnetic field is amplified by the rotation of the Galactic gas disk, and expand from the disk to outside by the Parker instability. The expanding magnetic loop collides with ambient field lines and induces magnetic reconnection in which the magnetic energy is efficiently converted into the thermal energy of the plasmas. MHD numerical simulations of the amplification process by the nonlinear magnetorotational instability and of the heating process by magnetic reconnection driven by the Parker instability are shown.

We present a scenario for the origin of the hot plasma in our Galaxy, as a model of a strong X-ray emission (Lx(2 - lOkeV) ∼ 1038 erg s−1), called Galactic Ridge X-ray Emission (GRXE), which has been observed near the Galactic plane. GRXE is thermal emission from hot component (∼ 7 keV) and cool component (∼ 0.8 keV). Observations suggest that the hot component is diffuse, and is not escaping away freely. Both what heats the hot component and what confines it in the Galactic ridge are still remained puzzling, while the cool component is believed to be made by supernovae. We propose a new scenario: the hot component of GRXE plasma is heated by magnetic reconnection, and confined in the helical magnetic field produced by magnetic reconnection or in the current sheet and magnetic field. We solved also the 2-dimensional magnetohydrodynamic (MHD) equations numerically to study how the magnetic reconnection creates hot plasmas and magnetic islands (helical tubes), and how the magnetic islands confine the hot plasmas in Galaxy. We conclude that the magnetic reconnection is able to heat up the cool component to hot component of GRXE plasma if the magnetic field is localized into intense flux tube with B lOCal ∼ 30 μG (the volume filling factor of f ∼ 0.1).

A quasi 1-dimensional carbon crystal has been synthesized by quenching of high temperature carbon gas on a room temperature metallic substrate. The structure is hexagonal and the sizes of the unit cell are 1.193 nm along the a-direction and 1.62 nm along the c-dirdtion. A parallel array of charbon chains is formed along the c-axis. The array is made of a triangular lattice of which inter-chain distance is 0.344 nm and the mean inter-atomic C-C distance along the chain is 0.133 nm. The crystal is half transparent in the visible region and has its specific weight as small as 1.46 g/cm3. In order to test the possibility of intercalation, reactions with potassium, sodium and iodine have been performed. In every reaction, the material has converted from an insulator to a conductor.

Raman scattering of the C-C vibration with ${\mathit{E}}_{2\mathit{g}2}$ symmetry in stage-2 C/Rb has been studied with different incident photon energies. Resonant enhancement occurs for laser energies in the blue region, close to the threshold for the valence- to conduction-band electronic transition ${\mathrm{\ensuremath{\Omega}}}_{\mathit{T}}$. The results were fitted with a two-band resonance enhancement model and the fitting procedure yields ${\mathrm{\ensuremath{\Omega}}}_{\mathit{T}}$=2.6\ifmmode\pm\else\textpm\fi{}0.15 eV, with a broadening of 0.13 eV. In the red spectral region, the Raman line exhibits a Fano-type distortion, indicating an interaction between the discrete one-phonon excited state, and a continuum which is attributed to electronic excitations.

We previously showed that in passive Heymann nephritis (PHN) rats, a large quantity of fibronectin (FN) fragments containing the central cell-binding (CCB) domain and adjacent domains are generated in the kidney and excreted into urine (Nishizawa et al., Biol Pharm Bull 1998; 21: 429-433). To ascertain whether the FN fragments could affect the progression of PHN, we investigated the effect of a 150 K FN fragment containing the CCB and carboxyl-terminal heparin-binding (Hep 2) domains on cultured rat mesangial cells. When rat mesangial cells cultured on FN-coated plates were exposed to the 150 K FN fragment, some mesangial cells detached from the FN substrate and then underwent apoptosis as judged by nuclear and DNA fragmentations. The 150 K FN fragment competitively inhibited the mesangial cell adhesion to the FN substrate in a dose-dependent manner. Furthermore, gelatinzymography of the conditioned medium of mesangial cells showed that the 150 K FN fragment induced and/or potentiated the extracellular matrix (ECM)-degrading proteinases including matrix metalloproteinases (MMPs) of mesangial cells. These results indicate that the 150 K FN fragment may elicit mesangial cell apoptosis by disrupting the mesangial cell adhesion through two distinct ways: the inhibition of mesangial cell adhesion and the ECM-degradation by the 150 K FN fragment-induced MMPs. Thus, FN fragments containing the CCB and adjacent domains generated in the kidneys of PHN rats may be involved in the evolution of the renal injury.

We recently found that two apoptotic DNase gamma-like endonucleases (36 and 38 kDa DNases) were present in Xenopus laevis larval and adult liver cell nuclei and that their activities increased in metamorphic climax. Here, we purified the main DNase gamma-like endonuclease from Xenopus laevis liver cell nuclei and characterized its physical and enzymatic properties in detail. The molecular mass of Xenopus liver nuclear endonuclease was 38,000 daltons as determined by SDS-polyacrylamide gel electrophoresis. A native molecular mass of 35,000 was estimated by gel filtration. The purified Xenopus liver endonuclease was a neutral one and required both Ca2+ and Mg2+ for DNase activity. Unlike the mammalian DNase gamma, the Ca2+/Mg2+ requirement could not be supplied by Mn2+. The inhibition profiles by aurintricarboxylic acid, sodium citrate and divalent metal ions such as Co2+, Ni2+, Cu2+ and Zn2+ were similar to those of mammalian DNase gamma. These results suggest that this endonuclease is a Xenopus laevis homolog of the mammalian apoptotic endonuclease DNase gamma.

We report here on the nucleotide sequence of the cDNA encoding human DNase gamma, which is a candidate for an apoptotic endonuclease. The cDNA clone isolated from a human spleen cDNA library is composed of a 918 bp open reading frame encoding a 305 amino acid precursor protein for DNase gamma. Northern blot analysis reveals that the expression of a single transcript of 1.5 kb DNase gamma mRNA is detected in the spleen and liver. The chromosomal localization of DNase gamma gene is mapped to chromosome 3 at region p21.1-p14.2 by fluorescence in situ hybridization (FISH). Characterization of thioredoxin-DNase gamma fusion protein (Trx-hDNase gamma) shows that the recombinant protein has a Ca(2+)/Mg(2+)- or Mn(2+)-dependent endonuclease activity that cleaves chromatin DNA to nucleosomal units. The optimum pH is around 7.2. Zn(2+) and aurintricarboxylic acid (ATA) inhibits the activity in dose-dependent manners. These properties are identical to those of purified DNase gamma.

DNase gamma, which cleaves chromosomal DNA into nucleosomal units (DNA ladder formation), has been suggested to be the critical component of apoptotic machinery. Using rat pheochromocytoma PC12 cells, which are differentiated to sympathetic neurons by nerve growth factor (NGF), we investigated whether DNase gamma-like enzyme is present in neuronal cells and is involved in neuronal cell death. The nuclear auto-digestion assay for DNase catalyzing internucleosomal DNA cleavage revealed that nuclei from neuronal differentiated PC12 cells contain acidic and neutral endonucleases, while nuclei from undifferentiated PC12 cells have only acidic endonuclease. The DNA ladder formation observed in isolated nuclei from neuronal differentiated PC12 cells at neutral pH requires both Ca(2+) and Mg(2+), and is sensitive to Zn(2+). The molecular mass of the neutral endonuclease present in neuronal differentiated PC12 cell nuclei is 32000 as determined by activity gel analysis (zymography). The properties of the neuronal endonuclease present in neuronal differentiated PC12 cell nuclei were similar to those of purified DNase gamma from rat thymocytes and splenocytes. Interestingly, in neuronal differentiated PC12 cells, internucleosomal DNA fragmentation is observed following NGF deprivation, whereas undifferentiated PC12 cells fail to exhibit DNA ladder formation during cell death by serum starvation. These results suggest that the DNase gamma-like endonuclease present in neuronal differentiated PC12 cell nuclei is involved in internucleosomal DNA fragmentation during apoptosis, induced by NGF deprivation.

The relationship between the cell cycle and Fas-mediated apoptosis was investigated using Jurkat cells. Analysis of the inducibility of apoptosis by anti-Fas antibody during the cell cycle synchronized by the thymidine double-block method, showed that apoptosis was induced in only 50% of the G2/M phase cells, while most of cells in the other phases underwent apoptosis. These observations indicate that G2/M phase cells are more resistant to Fas-mediated apoptosis than cells in other phases. Furthermore, a detailed analysis of G2/M phase found that only 20-30% of the cells underwent apoptosis 12 h after the removal of the second thymidine block (pre-G2/M phase). This suggests that Fas-mediated apoptosis is potently suppressed during the pre-G2/M phase. A possible explanation for the observation that cells in the pre-G2/M phase are less sensitive to anti-Fas antibody is lower expression level of Fas. To test this possibility, Fas expression levels on the cell surface during the cell cycle were examined. The content of Fas on the cell surface, however, did not change appreciably during the cell cycle. Thus, the suppression of apoptosis in the pre-G2/M phase is determined downstream after the receipt of the apoptotic signal through Fas.

Apoptotic response of keratinocytes to UVB irradiation has physiological significance on photocarcinogenesis. Here, we show that the sustained release of Smac/DIABLO from mitochondria is an important event for the onset of apoptosis in keratinocytes exposed to UVB irradiation. In human keratinocyte HaCaT cells, UVB irradiation at 500 J/m(2), but not at 150 J/m(2), induces apoptosis. Significant activations of caspases-9 and -3, and slight activation of caspase-7 were observed only in 500 J/m(2) UVB irradiated HaCaT cells. Correspondingly, the cleavage of PARP, a substrate of caspases-3 and -7, was detected in cells irradiated at 500 J/m(2) UVB, but not at 150 J/m(2). However, with both 150 and 500 J/m(2) UVB irradiation, cytochrome c, an activator of caspase-9 via the formation of apoptosome, was released from mitochondria to the cytosol at the same extent. In contrast, significant amounts of Smac/DIABLO are released from mitochondria to the cytosol only with 500 J/m(2) UVB irradiation, and that the level of XIAP is decreased. These results suggest that the extent of Smac/DIABLO efflux from mitochondria is a determinant whether a cell will undergo apoptosis or survival.

The Hall coefficient, resistivity and Seebeck coefficient of Ag/sub 2/Te have been measured over the temperature range from 100 to 300 K. These results indicate that the compound is highly degenerate. The effect of the magnetic field has also been studied up to 1.2 T. The size of the transversal magnetoresistance with a magnetic field of 1.2 T is about 15% at lower temperatures, but it decreases to about 5% at higher temperatures. The effect of the magnetic field on the Seebeck coefficient is on the other hand more intense at higher than at lower temperatures. The experimental results have been analyzed by numerically solving the Boltzmann transport equation.

We present some results on thermoelectrical properties of several levels of Sn doped Bi/sub 88/Sb/sub 12/ single crystal. Resistivity and Seebeck coefficient are measured between 100 and 300 K by applying magnetic field 0-1.2 T. Based on experimental results, these values have a strong dependence on magnetic field and the dependence is the same as that of the Sn doping effect.

The establishment of intrinsic semiconductivity of tellurium in the 1940s to 50s and the discovery of semiconductivity in the solid solution Bi-Sb alloy system in the 1950s and 60s are described in relation to thermoelectricity. The development of Peltier cooling devices using the Bi/sub 2/Te/sub 3/ family is also mentioned. As with recent studies, the merits of applying magnetic fields to thermoelectric materials are examined. Bi/sub 88/Sb/sub 12/ and the same alloy doped with various amounts of Sn were exposed to a magnetic field of 0.8 tesla. The magnetic field had a remarkable influence on the alloys; sometimes the Seebeck coefficient was enhanced by more than 50% and the sign of the Seebeck coefficient was changed. An application of a gradient magnetic field on a thermoelectric rod specimen possibly substitutes FGM. The Ettingshausen temperature gradient on Bi/sub 88/Sb/sub 12/ was also studied.

A Peltier current lead was proposed to reduce heat leak from the current lead. We studied two experiments as the principle of the Peltier current lead. In the first experiment, we measured Peltier cooling temperatures and resistivity of the semiconductors and copper lead; the purpose of this was for comparison with the second experiment. In the second experiment, the high temperature superconductor (HTS) was cooling down for Peltier effect at 77 K. Those temperatures were small, because the figure of merit of semiconductors, BiSb (n-type) and BiTe (p-type) were not enough values to be cooling HTS.

Galvanomagnetic and thermomagnetic effects were studied in order to serve the solid state energy conversion. A possible merit of the use of magnetic field in these effect is obvious because the Seebeck emf (longitudinal Nernst-Ettingshausen effect) or Peltier cooling (Nernst effect) could be enhanced under the magnetic field. Moreover, the Ettingshausen effect generates a temperature gradient under the magnetic field. Such three effects were studied experimentally. On a Bi/Sb sample, the temperature difference due to the Ettingshausen effect for the sample width of 10 mm, and the current density of 1 A/mm/sup 2/ was 23 K at the ambient temperature of 100 K and in the magnetic field of 1.0 tesla. The Nernst temperature difference under the relevant condition was 15.4K for 10 mm length.

Peltier current lead was proposed to reduce heat leak from the current lead. The temperature of the hot side of semiconductors was kept to be a room temperature and the liquid nitrogen was used to cool the system in the experiment. The experiment confirmed the principle of the Peltier current lead, and the reduction of the heat leak is calculated to be 30% for the liquid helium system and 40% for the liquid nitrogen system. We also proposed a new current lead system which is composed of semiconductors and high temperature superconducting material (HTS). This idea bases on the functionally gradient material (FGM), and the HTS is connected to the semiconductor directly. The temperature of the hot side of semiconductor is kept to be the liquid nitrogen temperature, the temperature of HTS can be expected to be lower than 77 K. Therefore, we can expect high current capacity of the HTS and/or high stability of the HTS. We use BiSb as a N-type semiconductor and BiTe as a P-type semiconductor in the experiment, and the temperature of the cold side of the semiconductor is 73 K in this experiment.

Two ovarian cancer cell lines named NOS4 and SKOV-3 have been shown to have different sensitivities to a cytotoxic anti-Fas antibody, CH-11. Although both cell lines express Fas molecules on the cell surfaces at the same intensities, apoptosis is induced by CH-11 in NOS4 cells but not in SKOV-3 cells. In this study, the different apoptosis-sensitivities of these cells were assessed. Both cell lines express almost the same levels of FADD, RIP, c-FLIP, FAP-1, Bax, Bcl-2 and Bcl-XL. Evidence of caspase-8, caspase-9 and caspase-3 activation and of cleavage of PARP and Bid was obtained in NOS4 cells but not in SKOV-3 cells. When triggered by FasL protein, DNA fragmentation and caspase-8 activation were observed in SKOV-3 cells, though they were not as clear as in NOS4 cells. All the anti-Fas antibody-mediated signals for apoptosis induction in NOS4 cells were completely blocked by a caspase-8-specific inhibitor, Z-IETD-FMK. These results indicate that the different sensitivities to the anti-Fas antibody are solely dependent on the activation of caspase-8, which could be influenced by yet unknown qualitative or quantitative abnormalities in molecules involved in DISC formation.

We propose the Galactic flare model for the origin of the X-ray gas in the Galactic halo. For this purpose, we examine the magnetic reconnection triggered by Parker instability (magnetic buoyancy instability), by performing the two-dimensional resistive numerical magnetohydrodynamic simulations. As a result of numerical simulations, the system evolves as following phases: Parker instability occurs in the Galactic disk. In the nonlinear phase of Parker instability, the magnetic loop inflates from the Galactic disk into the Galactic halo, and collides with the anti-parallel magnetic field, so that the current sheets are created in the Galactic halo. The tearing instability occurs, and creates the plasmoids (magnetic islands). Just after the plasmoid ejection, further current-sheet thinning occurs in the sheet, and the anomalous resistivity sets in. Petschek reconnection starts, and heats the gas quickly in the Galactic halo. It also creates the slow and fast shock regions in the Galactic halo. The magnetic field ($B\sim 3 \mu$G), for example, can heat the gas ($n\sim 10^{-3}$ cm$^{-3}$) to temperature of $\sim 10^6$ K via the reconnection in the Galactic halo. The gas is accelerated to Alfv\'en velocity ($\sim 300$ km s$^{-1}$). Such high velocity jets are the evidence of the Galactic flare model we present in this paper, if the Doppler shift of the bipolar jet is detected in the Galactic halo. Full size figures are available at http://www.kwasan.kyoto-u.ac.jp/~tanuma/study/ApJ2002/ApJ2002.html, Comment: 13 pages, 12 figures, uses emulateapj.sty, accepted by ApJ

To study the structure of a reconnection jet, we perform 3D resistive MHD simulations of magnetic reconnection triggered by the secondary tearing instability under simple assumptions. The results of 2D simulations have already revealed that fast reconnection occurs after current sheet thinning by the secondary tearing instability, and that the plasmoid ejection determines the reconnection rate. By performing 3D simulations, we find that the current sheet thinning occurs the same as with the 2D models. The Rayleigh-Taylor (RT) instability occurs in the reconnection jet, when the reconnection jet collides with the magnetic loop and high pressure gas created by the magnetic reconnection. The 3D structure, especially the helical magnetic field, appears because of RT instability. In the actual Sun, the fast reconnection will occur after the fractal tearing instability, although the magnetic Reynolds number is very large. The hot gas and high energy particles created by the reconnection may be confined by the helical and turbulent magnetic field, which will be created by the RT instability at the flare loop top.

Telomerase, the enzyme that synthesizes telomeric DNA, is repressed in normal human somatic cells but is activated with in vitro immortalization or during tumorigenesis. In this study, we investigated telomerase activity and expression of genes involved in telomerase activity in human myeloblastic leukemia ML-1 cells, differentiated synergistically by treatment with all-trans retinoic acid (ATRA) and granulocyte-macrophage colony-stimulating factor (GM-CSF). GM-CSF alone was not effective in changing telomerase activity whilst ATRA alone slightly decreased the activity. A combination of ATRA and GM-CSF remarkably reduced telomerase activity. We also detected remarkable suppression of hTERT mRNA expression in ML-1 cells treated with ATRA and GM-CSF. These results indicate that a synergistic down-regulation of telomerase activity and hTERT mRNA expression is induced by treatment with ATRA and GM-CSF in ML-1 cells.

Vapourization of carbon by utilization of resistive heating, electric arc discharge, magnetron sputtering or high-energy laser irradiation, and subsequent condensation of the vapour by quenching on a cooled substrate is being frequently employed to obtain carbyne and carbynoid films of various structures. The films generally consist of a matrix of amorphous carbon and more or less well ordered carbyne microcrystals.

X-ray astronomy satellites detected strong X-ray emission along Galactic ridge, called Galactic Ridge X-ray Emission (GRXE), which is thermal emission of super-hot diffuse plasma. It has been revealed that GRXE plasma is composed of mainly hot (7 keV) component and cool (0.8 keV) component (Kaneda et al. 1997). Origin and nature of the hot component is not known while the cool component is made of supernova remnants. We recently showed that a supernova (or other point explosion) and the Parker instability trigger magnetic reconnection, and we proposed a possible mechanism to explain the origin of GRXE (Tanuma et al. 1998; Yokoyama & Shibata 1995). We solved 2D resistive MHD equations numerically to examine the magnetic reconnection triggered by a supernova and Parker instability. We find that the reconnection heats the interstellar gas from 0.7 keV to 8 keV if local interstellar magnetic field strength is 30 μG. The re-connection accelerates and heats the interstellar medium. Magnetic islands are generated and confine the heated plasma. Thus, we propose that the reconnection is triggered by a point explosion, Parker instability, the collision of interstellar clouds etc., and reconnection can explain X-rays from Galactic ridge and halo.

Telomeres are the DNA-protein complexes found at the ends of linear chromosomes. The structure is believed to be important for chromosome stability and cell integrity, and thereby for cell senescence and immortality. Telomeric DNA consists of tandemly repeated sequences which are observed from human to yeast. For example, human and Saccharomyces telomeres have T2AG3 and TG1-3 repeats, respectively. Recently, various protein factors including replication factor C (RFC) have been found as telomere repeat sequence binding-proteins. Characterization of these proteins and their interactions with telomeres may provide a new insight into not only telomere functions but also aging, immortality and apoptosis of the cells.

Apoptosis is a mechanism for eliminating unwanted cells from the cell community of multicellular organisms. Abnormalities in the regulation of apoptosis may play a part in the aetiology of cancer, autoimmune diseases, AIDS, degenerative nerve diseases and malformation. On of the hallmarks of apoptosis is the enzymatic cleavage of genomic DNA into nucleosomal oligomers. The identification of an endonuclease responsible for apoptosis might help to explain how this cell suicide is regulated and why DNA is cleaved. Here, we found that gamma type of DNase was retained in apoptotic rat thymocyte nuclei. The mode of DNA cleavage, 3'-hydroxyl (OH)/5'-phosphoryl (P) ends, by homogeneously purified DNase gamma (Mr = 33 kDa) and its Zn2+ sensitivity match those observed in apoptosis in thymocytes induced by irradiation or glucocorticoid treatment, indicating that this endonuclease is a central component of the thymic apoptosis machinery.

The in vitro antioxidative activity of benzylideneascorbate (SBA) and the in vivo effect on adriamycin (ADR)-induced cardiotoxicity in a mouse model were investigated. The radical-scavenging activity of SBA was assayed in terms of reduction of chemiluminescence induced by O2-, generated in xanthine/xanthine oxidase and macrophage/phorbol myristate acetate reaction systems. SBA showed a strong antioxidative activity (IC50 = 3 to 4 microM) in both assay systems, though its activity was weaker than that of ascorbic acid (Asc). In the assay of the antioxidative activity against auto-oxidation of linolenic acid, SBA was stable and retained its potency for a long period of time in comparison with Asc, 6-palmitoylascorbic acid (6-P-Asc) and cysteamine (CysNH2). Electron spin resonance examination indicated that SBA strongly scavenged both superoxide anion and hydroxy radical. The in vivo protective effect of SBA against ADR-induced cardiotoxicity, in which active oxygen radicals play a role, was examined. The serum creatine phosphokinase activity, a parameter of cardiotoxicity, was remarkably increased from the 3rd day until the 4th day after ADR treatment. This elevation was significantly suppressed by SBA treatment, whereas Asc, 6-P-Asc and CysNH2 were ineffective. SBA could have clinical potential for the treatment of diabetes and other disorders in which active oxygen species play a pathogenic role.

High-performance liquid chromatography revealed that sodium 5,6-benzylidene-L-ascorbate (SBA), dissolved in distilled water, was gradually decomposed into ascorbic acid and benzaldehyde. Among these three compounds, ascorbic acid showed the most potent cytotoxic activity. The cytotoxic activity of each compound was significantly reduced during degradation in culture medium. Agarose gel electrophoresis and fluorometric determination of DNA revealed that ascorbic acid, as well as SBA, induced DNA fragmentation into nucleosomal oligomers in human myelogenous leukemic cell lines, but not in freshly isolated human peripheral blood cells. The results suggest that antitumor activity of SBA might be at least in part mediated by the action of ascorbic acid, a degradation product of SBA.

Protein kinase C (PKC)-related cDNA clones isolated from cDNA libraries of mouse P19 embryonal carcinoma cells and mouse brain encoded a 67-kDa protein, PKC lambda. PKC lambda shows the highest amino acid sequence identity with PKC zeta (72%), the third class of the PKC family. Northern blot analysis showed that the mRNA for PKC lambda is expressed in a wide variety of cells and tissues, including P19 and NIH 3T3 cells, as well as brain, kidney, testis, and ovary. In undifferentiated P19 cells, the mRNA for PKC lambda is the most abundant among all the PKC family members. The differentiation of P19 cells results in an increase in PKC alpha and epsilon, and a decrease in PKC lambda. Antiserum raised against a peptide of PKC lambda identified a 74-kDa protein in P19 cell extracts as well as in extracts from COS cells transfected with the PKC lambda expression plasmid. Autophosphorylation of the PKC lambda that immunoprecipitated with the specific antiserum was observed, indicating that PKC lambda possesses protein kinase activity. A phorbol ester binding assay using intact COS cells expressing PKC lambda failed to detect binding activity specific to PKC lambda at phorbol dibutylate concentrations up to 300 nM, suggesting that PKC lambda does not possess phorbol ester binding activity. These results, in conjunction with the results obtained in parallel experiments with PKC zeta and other PKC members, suggest a biochemical similarity between PKC lambda and zeta and their clear difference from other PKC members.

Poly(ADP-ribose) glycohydrolase, extensively purified to homogeneity from nuclei of human placenta, is composed of a single polypeptide with a molecular mass of 71,000 daltons on sodium dodecyl sulfate-polyacrylamide gel. Judging from its physico-chemical and catalytic properties, the enzyme is similar to the nuclear glycohydrolase (glycohydrolase I), but not to the cytoplasmic glycohydrolase (glycohydrolase II) that has been purified from guinea pig liver (Tanuma, S., Kawashima, K., and Endo, H. (1986) J. Biol. Chem. 261, 965-969; Maruta, H., Inageda, K., Aoki, T., Nishina, H., and Tanuma, S. (1991) Biochemistry 30, 5907-5912). The rates of hydrolysis of (ADP-ribose)n bound to various proteins by the purified nuclear glycohydrolase were higher than those of the corresponding free polymers. Kinetic analyses revealed that the enzyme had more activity toward poly(ADP-ribose) bound to histone H1 or to poly(ADP-ribose) polymerase than toward oligo(ADP-ribose) bound to cytoplasmic proteins from mitochondria or mRNA ribonucleoprotein although the Km and Vmax values were dependent on the chain length (n). In contrast, cytoplasmic glycohydrolase purified from human erythrocytes was more active toward oligo(ADP-ribose) (n = 2.6 or 4.2) bound to the cytoplasmic proteins than to poly(ADP-ribose) (n = 14.6) bound to histone H1, and their kinetic parameters of glycohydrolase II were rather dependent on the acceptor molecules for (ADP-ribose)n. These results suggest that poly(ADP-ribose) glycohydrolase I may play an important role in regulation of poly(ADP-ribosyl)ation levels on chromosomal proteins in nuclei.

Various tannins and related compounds were compared for their ability to stimulate the iodination (incorporation of radioactive iodine into an acid-insoluble fraction) of human peripheral blood monocytes. The stimulating activity of most of the monomeric and dimeric hydrolyzable tannins was generally higher than that of the trimeric and tetrameric compounds. Compounds that had dehydrohexahydroxydiphenoyl or chebuloyl groups had considerably less activity than those that had other functional groups (hexahydroxydiphenoyl, valoneoyl, dehydrodigalloyl, isodehydrodigalloyl, lactonized valoneoyl, hellinoyl, euphorbinoyl, dehydroeuphorbinoyl or woodfordinoyl group). The methylated derivative, nonacosa-O-methylcoriariin A, was essentially inactive, suggesting the requirement of a phenolic hydroxyl group. Three condensed tannins ((-)-epicatechin 3-O-gallate (ECG)-dimer, ECG-trimer and ECG-tetramer) significantly stimulated both monocyte iodination and their interleukin-1-like factor production. The results suggest the dependence of stimulation of monocyte iodination by tannins and related polyphenols on molecular weight.