Search

We aim at studying scaling relations of a small but well-defined sample of galaxy clusters that includes the recently discovered class of objects that are X-ray faint for their mass. These clusters have an average low X-ray surface brightness, a low gas fraction, and are underrepresented (by a factor of 10) in X-ray surveys or entirely absent in Sunyaev-Zeldovich (SZ) surveys. With the inclusion of these objects, we find that the temperature–mass relation has an unprecedentedly large scatter, 0.20 ± 0.03 dex at fixed mass, as wide as allowed by the temperature range, and the location of a cluster in this plane depends on its surface brightness. Clusters obey a relatively tight luminosity–temperature relation independently of their brightness. We interpret the wide difference in scatter around the two relations as due to the fact that X-ray luminosity and temperature are dominated by photons coming from small radii (in particular for T we used a 300 kpc aperture radius) and strongly affected by gas thermodynamics (e.g. shocks and cool cores), whereas mass is dominated by dark matter at large radii. We measure a slope of 2.0 ± 0.2 for the L 500 –T relation. Given the characteristics of our sample, this value is free from collinearity (degeneracy) between evolution and slope and from hypothesis on the undetected population, which both affect the analysis of X-ray-selected samples, and can therefore be profitably used both as reference and to break the aforementioned degeneracy of X-ray-selected samples. [ABSTRACT FROM AUTHOR]

We report here the results from the X-ray observations of 12 early-type galaxies (ETGs) observed with Swift and XMM-Newton, originally selected from a sample of galaxies with Spitzer and/or GALEX data. With the combined analysis of new X-ray and optical-UV observations and of previously available data from archives, we aim at investigating the relation between X-ray luminosity and evolutionary phases of ETGs. We will interpret the results with the additional aid of smoothed particle hydrodynamics chemo-photometric simulations. All galaxies have been detected in the X-ray band, with luminosities Lx > 1039 erg s-1. X-ray emitting gas has been detected in about half of the sample, with luminosities from ≥1039 to 1040 erg s-1. UVOT images show a variety of morphologies, from absence of peculiar features relative to optical wavelengths typical of red and dead early-types, to well defined almost circular rings clearly emerging in the U band, to more spectacular and complex features connected to recent or even ongoing star formation (SF). We find little evidence of any influence of the SF activity on their global X-ray properties, and in particular, on the luminosity-weighted age of the system, usually estimated in the nuclear region. However, with the present data we cannot exclude that such a relation exists on smaller scales, related to the specific sites where we see evidence of newly formed stars, such as outer rings and arcs and peculiar features observed in UV images. [ABSTRACT FROM AUTHOR]

The X-ray band provides a very powerful and unique way to explore the hot phase of the ISM in external galaxies. This phase has been known to exist in galaxies since the early Einstein observations, but only with recent detailed observations of objects in the local universe are we beginning to study it in detail and appreciate the importance of the hot ISM as a vehicle of chemical enrichment in different astrophysical environments. This knowledge can then be used to understand the properties of galaxies at the epoch of formation and their subsequent evolution, both in the field and in clusters. [ABSTRACT FROM AUTHOR]

Aims. Seyfert's Sextet (a.k.a HCG 79) is one of the most compact and isolated galaxy groups in the local Universe. It shows a prominent diffuse light component that accounts for ∼50% of the total observed light. This likely indicates that the group is in an advanced evolutionary phase, which would predict a significant hot gaseous component. Previous X-ray observations had suggested a low luminosity for this system, but with large uncertainties and poor resolution. Methods. We present the results from a deep (70 ks), high resolution Chandra observation of Seyfert's Sextet, requested with the aim of separating the X-ray emission associated with the individual galaxies from that of a more extended inter-galactic component. We discuss the spatial and spectral characteristics of this group we derive with those of a few similar systems also studied in the X-ray band. Results. The high resolution X-ray image indicates that the majority of the detected emission does not arise in the compact group but is concentrated towards the NW and corresponds to what appears to be a background galaxy cluster. The emission from the group alone has a total luminosity of ∼1× 1040 erg s-1 in the (0.5-5) keV band. Most of the luminosity can be attributed to the individual sources in the galaxies, and only ∼2 × 1039 erg s-1 is due to a gaseous component. However, we find that this component is also mostly associated with the individual galaxies of the Sextet, leaving little or no residual in a truly IGM component. The extremely low luminosity of the diffuse emission in Seyfert's Sextet might be related to its small total mass. [ABSTRACT FROM AUTHOR]

The evolution of the properties of the hot gas that fills the potential well of galaxy clusters is poorly known, since models are unable to give robust predictions, and observations lack a sufficient redshift leverage and are affected by selection effects. Here, with just two high-redshift, , clusters avoiding selection biases, we obtain a significant extension of the redshift range and we begin to constrain the possible evolution of the X-ray luminosity versus temperature relation. The two clusters, JKCS 041 at and ISCS J1438+3414 at , are, respectively, the most distant and the second most distant clusters, overall, that can be used for studying scaling relations. Their location in the X-ray luminosity versus temperature plane, with an X-ray luminosity five times lower than expected, suggests at the 95 per cent confidence level that the evolution of the intracluster medium has not been self-similar in the last three-quarters of the age of the Universe. Our conclusion is reinforced by data on a third, X-ray-selected, high-redshift cluster, too faint for its temperature when compared to a sample of similarly selected objects. Our data suggest that non-gravitational effects, such as the baryon physics, influence the evolution of galaxy clusters. Precise knowledge of evolution is central for using galaxy clusters as cosmological probes in planned X-ray surveys, such as WFXT or JDEM. [ABSTRACT FROM AUTHOR]

When lymphocytes from healthy donnors were tested as effector cells, the cytotoxic activities observed in spontaneous and in antibody-dependent cell-mediated cytotoxicity were positively correlated. However, with lymphocyte preparations obtained from renal patients, a dissociation between the two activities was occasionally observed. Human natural kilter cells are lymphocytes, with receptors for the Fc fragment of IgG molecules, but with no surface immunoglobulin. Their cytotoxicity is reduced by the presence of granulocytes or monocytes. After separation of resetting and non-rosetting cells with AET- (2-aminoethyIisothiouronium bromide hydro bromide) or neuraminidase-treated sheep erythrocytes, the majority of the activity was recovered in the non-rosetting fraction, but a portion of it was present consistently in the rosetting cell fraction. Cells in the latter fraction also displayed receptors for the Fc fragment of immunoglobulin G. [ABSTRACT FROM AUTHOR]

Tumour necrosis factor (TNF) and interferon-gamma (IFN-γ) induce differentiation of human myeloid cell lines along the monocytic lineage. In this study we investigated the effects of TNF and IFN-γ on the expression of the CD4 protein and messenger RNA (mRNA) in the two myeloid cell lines, ML3 and HL-60. We observed that CD4 antigen expression on ML3 cells is almost undetectable and that TNF and IFN-γ induced CD4 antigen expression on these cells. HL-60 cells express surface CD4 antigen at high density and treatment with TNF and IFN-γ caused a decrease of CD4 expression. We also investigated the expression of CD4 mRNA in ML3 and HL-60 cells. ML3 constitutively express, albeit at low levels, CD4 mRNA. TNF induced CD4 mRNA in ML3 cells and IFN-γ synergistically potentiated the effect of TNF, thus indicating that the enhanced expression of the CD4 protein on ML3 cells is due, at least in part, to an enhanced accumulation of the CD4 mRNA. CD4 mRNA is constitutively expressed in HL-60 cells at high levels. TNF and IFN-γ, alone or in combination, did not cause any significant change of CD4 mRNA expression in HL-60 cells, thus indicating that decrease of surface CD4, which accompanies differentiation with these cytokines, is likely due to alterations of the CD4 protein synthesis and/or transport to the plasma membrane. These results provide evidence that myeloid cell lines are heterogeneous in expression of CD4, and that in ML3 cells, which constitutively express Iow levels of CD4 mRNA and undetectable amounts of surface CD4, the predominant effect of the two cytokines is to induce both CD4 mRNA and protein. [ABSTRACT FROM AUTHOR]

In this work, we study the intracluster medium (ICM) of a galaxy cluster at the cosmic noon: JKCS 041 at z  = 1.803. A 28 h long Sunyaev-Zel'dovich (SZ) observation using MUSTANG-2 allows us to detect JKCS 041, even if intrinsically extremely faint compared to other SZ-detected clusters. We found that the SZ peak is offset from the X-ray centre by about 220 kpc in the direction of the brightest cluster galaxy, which we interpret as due to the cluster being observed just after the first passage of a major merger. JKCS 041 has a low central pressure and a low Compton Y compared to local clusters selected by their ICM, likely because the cluster is still in the process of assembly but also in part because of a hard-to-quantify bias in current local ICM-selected samples. JKCS 041 has a 0.5 dex fainter Y signal than another less massive z ∼ 1.8 cluster, exemplifying how much different weak-lensing mass and SZ mass can be at high redshift. The observations we present provide us with the measurement of the most distant resolved pressure profile of a galaxy cluster. Comparison with a library of plausibly descendants shows that JKCS 041 pressure profile will likely increase by about 0.7 dex in the next 10 Gyr at all radii. [ABSTRACT FROM AUTHOR]

Using deep two-color near-infrared HST imaging and unbiased grism spectroscopy, we present a detailed study of the z = 1.803 JKCS 041 cluster. We confirm, for the first time for a high-redshift cluster, a mass of log M ≳ 14.2 in solar units using four different techniques based on the X-ray temperature, the X-ray luminosity, the gas mass, and the cluster richness. JKCS 041 is thus a progenitor of a local system like the Coma cluster. Our rich dataset and the abundant population of 14 spectroscopically confirmed red-sequence galaxies allows us to explore the past star formation history of this system in unprecedented detail. Our most interesting result is a prominent red sequence down to stellar masses as low as log M/M⊙ = 9.8, corresponding to a mass range of 2 dex. These quiescent galaxies are concentrated around the cluster center with a core radius of 330 kpc. There are only few blue members and avoid the cluster center. In JKCS 041 quenching was therefore largely completed by a look-back time of 10 Gyr, and we can constrain the epoch at which this occurred via spectroscopic age-dating of the individual galaxies. Most galaxies were quenched about 1.1 Gyr prior to the epoch of observation. The less-massive quiescent galaxies are somewhat younger, corresponding to a decrease in age of 650 Myr per mass dex, but the scatter in age at fixed mass is only 380 Myr (at log M/M⊙ = 11). There is no evidence for multiple epochs of star formation across galaxies. The size–mass relation of quiescent galaxies in JKCS 041 is consistent with that observed for local clusters within our uncertainties, and we place an upper limit of 0.4 dex on size growth at fixed stellar mass (95% confidence). Comparing our data on JKCS 041 with 41 clusters at lower redshift, we find that the form of the mass function of red sequence galaxies has hardly evolved in the past 10 Gyr, both in terms of its faint-end slope and characteristic mass. Despite observing JKCS 041 soon after its quenching and the three-fold expected increase in mass in the next 10 Gyr, it is already remarkably similar to present-day clusters. [ABSTRACT FROM AUTHOR]

Suicide gene vectors are being developed in many laboratories as an attractive approach to cancer therapy. However, the development of these therapies is hampered by safety concerns and limitations of efficacy. The use of tumor-specific promoters, such as survivin promoter, can provide much needed specificity to target tumor cells. However, the expression levels from these promoters is often suboptimal and hence it is imperative to enhance the activity of the cytotoxic gene of interest. We tested apoptotic activity of several mutants of proapoptotic gene bax that constitutively translocate to the mitochondria and induce apoptosis. One of these mutants with deletion of serine at position S184 (S184del) was found to be most active and showed significant antitumor activity when expressed by the survivin promoter. In vitro testing shows that this vector (Sur-BaxS184del) induces cell killing in a variety of tumor cell lines of different origin with significantly higher efficacy than wild-type bax (Sur-BaxWT). The increase in cytotoxicity was a result of enhanced induction of apoptosis in tumor cells. In contrast to cytomegalovirus (CMV) promoter-driven bax (CMV-Bax), Sur-BaxS184del caused minimum toxicity in normal human dermal fibroblasts validating its specificity and safety. In a mouse tumor model (DA-3, murine breast cancer cells), we show that intratumoral injection of Sur-BaxS184del resulted in tumor growth retardation to the same level as CMV-Bax. This study highlights the effectiveness of using bax mutants in combination with survivin promoter for tumor-targeted suicide gene therapy in a nonviral vector. [ABSTRACT FROM AUTHOR]

NGC 925 ULX-1 and ULX-2 are two ultraluminous X-ray sources (ULXs) in the galaxy NGC 925, at a distance of 8.5 Mpc. For the first time, we analysed high quality, simultaneous XMM–Newton and NuSTAR data of both sources. Although at a first glance ULX-1 resembles an intermediate mass black hole candidate (IMBH) because of its high X-ray luminosity [(2–4) × 1040 erg s−1] and its spectral/temporal features, a closer inspection shows that its properties are more similar to those of a typical super-Eddington accreting stellar black hole and we classify it as a 'broadened disc' ULX. Based on the physical interpretation of this spectral state, we suggest that ULX-1 is seen at small inclination angles, possibly through the evacuated cone of a powerful wind originating in the accretion disc. The spectral classification of ULX-2 is less certain, but we disfavour an IMBH accreting at sub-Eddington rates as none of its spectral/temporal properties can be associated with either the soft or the hard state of Galactic accreting black hole binaries. [ABSTRACT FROM AUTHOR]

Context. Probing both star formation history and evolution of distant cluster galaxies is essential to evaluate the effect of dense environment on shaping the galaxy properties we observe today. Aims. We investigate the effect of cluster environment on the processing of the molecular gas in distant cluster galaxies. We study the molecular gas properties of two star-forming galaxies separated by 6 kpc in the projected space and belonging to a galaxy cluster selected from the Irac Shallow Cluster Survey, at a redshift z = 1.2, that is, ~ 2 Gyr after the cosmic star formation density peak. This work describes the first CO detection from 1 < z < 1.4 star-forming cluster galaxies with no clear reported evidence of active galactic nuclei. Methods. We exploit observations taken with the NOEMA interferometer at ~3 mm to detect CO(2−1) line emission from the two selected galaxies, unresolved by our observations. Results. Based on the CO(2−1) spectrum, we estimate a total molecular gas mass M(H2) = (2.2+0.50.4) × 1010M⊙ M (H 2) = (2.2 − 0.4 + 0.5) × 10 10 M ⊙ $ M{({\mathrm H}_2)}={(2.2_{-0.4}^{+0.5})}\times10^{10}M_\odot $ , where fully excited gas is assumed, and a dust mass Mdust < 4.2 × 108M⊙ for the two blended sources. The two galaxies have similar stellar masses and Hα-based star formation rates (SFRs) found in previous work, as well as a large relative velocity of ~400 km s−1 estimated from the CO(2−1) line width. These findings tend to privilege a scenario where both sources contribute to the observed CO(2−1). Using the archival Spitzer MIPS flux at 24 μm we estimate an SFR (24μm) = (28+12−8) M⊙/yr SFR (24 μ m) = (28 − 8 + 12) M ⊙ / yr $ \text{SFR}{(24\mu\mathrm m)}={(28_{-8}^{+12})}M_\odot/\text{yr} $ for each of the two galaxies. Assuming that the two sources contribute equally to the observed CO(2−1), our analysis yields a depletion timescale of τdep = (3.9+1.4−1.8) × 108 yr τ dep = (3.9 1.8 1.4) × 10 8 ⁢ yr $ \tau_\text{dep}={(3.9_{1.8}^{1.4})}\times10^8\text{yr} $ , and a molecular gas to stellar mass ratio of 0.17 ± 0.13 for each of two sources, separately. We also provide a new, more precise measurement of an unknown weighted mean of the redshifts of the two galaxies, z = 1.163 ± 0.001. Conclusions. Our results are in overall agreement with those of other distant cluster galaxies and with model predictions for main sequence (MS) field galaxies at similar redshifts. The two target galaxies have molecular gas mass and depletion times that are marginally compatible with, but smaller than those of MS field galaxies, suggesting that the molecular gas has not been sufficiently refueled. We speculate that the cluster environment might have played a role in preventing the refueling via environmental mechanisms such as galaxy harassment, strangulation, ram-pressure, or tidal stripping. Higher-resolution and higher-frequency observations will enable us to spatially resolve the two sources and possibly distinguish between different gas processing mechanisms. [ABSTRACT FROM AUTHOR]

We obtained an optical spectrum of a star we identify as the optical counterpart of the M31 Chandra source CXO J004318.8+412016, because of prominent emission lines of the Balmer series, of neutral helium, and a He II line at 4686 Å. The continuum energy distribution and the spectral characteristics demonstrate the presence of a red giant of K or earlier spectral type, so we concluded that the binary is likely to be a symbiotic system. CXO J004318.8+412016 has been observed in X-rays as a luminous supersoft source (SSS) since 1979, with effective temperature exceeding 40 eV and variable X-ray luminosity, oscillating between a few times 1035 erg s-1 and a few times 1037 erg s-1 in the space of a few weeks. The optical, infrared and ultraviolet colours of the optical object are consistent with an an accretion disc around a compact object companion, which may be either a white dwarf or a black hole, depending on the system parameters. If the origin of the luminous supersoft X-rays is the atmosphere of a white dwarf that is burning hydrogen in shell, it is as hot and luminous as post-thermonuclear flash novae, yet no major optical outburst has ever been observed, suggesting that the white dwarf is very massive (m ≥ 1.2 M⊙) and it is accreting and burning at the high rate m> 10-8 M⊙ yr-1 expected for Type Ia supernovae progenitors. In this case, the X-ray variability may be due to a very short recurrence time of only mildly degenerate thermonuclear flashes. [ABSTRACT FROM AUTHOR]

Context. GALEX detected a significant fraction of early-type galaxies, in particular S0s, showing far-UV bright structures, sometimes involving an entire galaxy out to its outskirts. These features suggest the presence of either recent ongoing and/or prolonged star formation episodes, shedding new light on the evolution of these systems. Aims. We aim at understanding the evolutionary path[s] of these early-type galaxies and the mechanisms at the origin of their UVbright structures. We investigate with a multiwavelength approach the link between the inner and outer galaxy regions of a set of 11 early-type galaxies that were selected because of their nearly passive stage of evolution in the nuclear region. Methods. This paper, second of a series, focuses on the information coming from the comparison between UV features detected by Swift-UVOT, which trace recent star formation, and the galaxy optical structure, which maps older stellar populations. We performed a surface photometric study of these early-type galaxies, observed with the Swift-UVOT UV filters W2 2030 Å λ0, M2 2231 Å λ0, W1 2634 Å λ0 and the UBV bands. BVRI photometry from other sources in the literature was also used. Our integrated magnitude measurements were analyzed and compared with corresponding values in the literature. We characterize the overall galaxy structure that best fits the UV and optical luminosity profiles using a single Sérsic law. Results. The galaxies NGC 1366, NGC 1426, NGC 3818, NGC 3962, and NGC 7192 show featureless luminosity profiles. Excluding NGC 1366, which has a clear edge-on disk (n ≈ 1-2), and NGC 3818, the remaining three galaxies have Sérsic's indices n ≈ 3-4 in the optical and a lower index in the UV. Bright ring- or arm-like structures are revealed by UV images and luminosity profiles of NGC 1415, NGC 1533, NGC 1543, NGC 2685, NGC 2974, and IC 2006. The ring- or arm-like structures differ from galaxy to galaxy. Sérsic indices of UV profiles for these galaxies are in the range n = 1:5-3 both in S0s and in galaxies classified as bona fide ellipticals, such as NGC 2974 and IC 2006.We note that in our sample optical Sérsic indices are usually higher than in the UV indices. (M2 - V) color profiles are bluer in ring- or arm-like structures than in the galaxy body. Conclusions. The lower values of Sérsic indices in the UV bands with respect to optical bands, suggesting the presence of a disk, point out that the role of the dissipation cannot be neglected in recent evolutionary phases of these early-type galaxies. [ABSTRACT FROM AUTHOR]

The impact of gut microbiota in eliciting innate and adaptive immune responses beneficial for the host in the context of effective therapies against cancer has been highlighted recently. Chemotherapeutic agents, by compromising, to some extent, the intestinal integrity, increase the gut permeability and selective translocation of Gram-positive bacteria in secondary lymphoid organs. There, anticommensal pathogenic Th17 T-cell responses are primed, facilitating the accumulation of Th1 helper T cells in tumor beds after chemotherapy as well as tumor regression. Importantly, the redox equilibrium of myeloid cells contained in the tumor microenvironment is also influenced by the intestinal microbiota. Hence, the anticancer efficacy of alkylating agents (such as cyclophosphamide) and platinum salts (oxaliplatin, cis-platin) is compromised in germ-free mice or animals treated with antibiotics. These findings represent a paradigm shift in our understanding of the mode of action of many compounds having an impact on the host-microbe mutualism. [ABSTRACT FROM AUTHOR]

Distinct cytotoxic agents currently used in the oncological armamentarium mediate their clinical benefit by influencing, directly or indirectly, the immune system in such a way that innate and adaptive immunity contributes to the tumoricidal activity. Now, we bring up evidence that both arms of anticancer immunity can be triggered through the intervention of the intestinal microbiota. Alkylating agents, such as cyclophosphamide, set up the stage for enhanced permeability of the small intestine, facilitating the translocation of selected arrays of Gram-positive bacteria against which the host mounts effector pTh17 cells and memory Th1 responses. In addition, gut commensals, through lipopolysaccharide and other bacterial components, switch the tumor microenvironment, in particular the redox equilibrium and the TNF production of intratumoral myeloid cells during therapies with platinum salts or intratumoral TLR9 agonists combined with systemic anti-IL10R Ab respectively. Consequently, antibiotics can compromise the efficacy of certain chemotherapeutic or immunomodulatory regimens. [ABSTRACT FROM AUTHOR]

ABSTRACT We present an analysis of the globular cluster (GC) population of the elliptical galaxy NGC 4261 based on Hubble Space Telescope Wide Field Planetary Camera 2 data in the B, V and I bands. We study the spatial distribution of the GCs in order to probe the anisotropy in the azimuthal distribution of the discrete X-ray sources in the galaxy revealed by Chandra images. The luminosity function of our GC sample (complete at the 90 per cent level for m V= 23.8 mag) peaks at m V= 25.1 mag, which corresponds to a distance consistent with previous measurements. The colour distribution can be interpreted as being the superposition of a blue and red GC component with average colours V− I= 1.01 mag and 1.27 mag, respectively. This is consistent with a bimodal colour distribution typical of elliptical galaxies. The red GC's radial profile is steeper than that of the galaxy surface brightness, while the profile of the blue subpopulation looks more consistent with it. The most striking finding is the significant asymmetry in the azimuthal distribution of the GC population about a north-east-south-west (NE-SW) direction. The lack of any obvious feature in the morphology of the galaxy suggests that the asymmetry could be the result of an interaction or a merger. [ABSTRACT FROM AUTHOR]

In this paper, we report on Chandra observations of the starburst galaxy NGC 922. NGC 922 is a drop-through ring galaxy with an expanding ring of star formation, similar in many respects to the Cartwheel galaxy. The Cartwheel galaxy is famous for hosting 12 ultraluminous X-ray sources (ULXs), most of which are in the star-forming ring. This is the largest number of ULXs seen in a single system and has led to speculation that the low metallicity of the Cartwheel (0.3 Z⊙) may optimize the conditions for ULX formation. In contrast, NGC 922 has metallicity near solar. The Chandra observations reveal a population of bright X-ray sources, including seven ULXs. The number of ULXs in NGC 922 and the Cartwheel scales with the star formation rate: we do not find any evidence for an excess of sources in the Cartwheel. Simulations of the binary population in these galaxies suggest that the ULX population in both systems is dominated by systems with strong wind accretion from supergiant donors onto direct-collapse black holes. The simulations correctly predict the ratio of the number of sources in NGC 922 and the Cartwheel. Thus, it would appear that the metallicity of the Cartwheel is not low enough to see a difference in the ULX population compared to NGC 922. [ABSTRACT FROM AUTHOR]

ABSTRACT Using observations from the Chandra and XMM-Newton X-ray observatories, we examine the interaction between the intragroup medium and central radio source in the nearby NGC 4261 galaxy group. We confirm the presence of cavities associated with the radio lobes and estimate their enthalpy to be ∼2.4 × 1058 erg. The mechanical power output of the jets is ≥1043 erg s−1, at least a factor of 60 greater than the cooling luminosity in the region the lobes inhabit. We identify rims of compressed gas enclosing the lobes, but find no statistically significant temperature difference between them and their surroundings, suggesting that the lobe expansion velocity is approximately sonic (). The apparent pressure of the radio lobes, based on the synchrotron minimum energy density argument, is a factor of 5 lower than that of the intragroup medium. Pressure balance could be achieved if the entrainment of thermal gas provided additional non-radiating particles in the lobe plasma, but the energy required to heat these particles would be ∼20 per cent of the mechanical energy output of the radio source. NGC 4261 has a relatively compact cool core, which should probably be categorized as a galactic corona. The corona is capable of fuelling the active nucleus for considerably longer than the inferred source lifetime, but can be only inefficiently heated by the active galactic nucleus (AGN) or conduction. The expansion of the radio lobes has affected the structure of the gas in the galaxy, compressing and moving the material of the corona without causing significant shock heating, and expelling gas from the immediate neighbourhood of the jets. We discuss the possible implications of this environment for the duration of the AGN outburst and consider mechanisms which might lead to the cessation of nuclear activity. [ABSTRACT FROM AUTHOR]

The radio source 3C 270, hosted by nearby elliptical galaxy NGC 4261, is the brightest known example of counterjet X-ray emission from a low-power radio galaxy. We report on the X-ray emission of the jet and counterjet from 130 ks of Chandra data. We argue that the X-ray emission is synchrotron radiation and that the internal properties of the jet and counterjet are remarkably similar. We find a smooth connection in X-ray hardness and X-ray-to-radio ratio between the jet and one of the X-ray components within the core spectrum. We observe wedge-like depressions in diffuse X-ray surface brightness surrounding the jets, and interpret them as regions where an aged population of electrons provides pressure to balance the interstellar medium of NGC 4261. About 20 per cent of the mass of the interstellar medium has been displaced by the radio source. Treating 3C 270 as a twin-jet system, we find an interesting agreement between the ratio of jet-to-counterjet length in X-rays and that expected if X-rays are observed over the distance that an outflow from the core would have travelled in . X-ray synchrotron loss times are shorter than this, and we suggest that most particle acceleration arises as a result of turbulence and dissipation in a stratified flow. We speculate that an episode of activity in the central engine beginning ago has led to an increased velocity shear. This has enhanced the ability of the jet plasma to accelerate electrons to X-ray-synchrotron-emitting energies, forming the X-ray jet and counterjet that we see today. [ABSTRACT FROM AUTHOR]

Arp 227 represents a prototypical example of an interacting mixed pair of galaxies located in a low-density environment. We investigate the gas properties of the pair in the X-ray, Hα, H i and CO bands. We also detect two additional members of the group in H i which indicates that the pair constitutes the dominant members of a loose group. The H i distribution shows a tail of gas that connects the spiral member, NGC 470, to the lenticular, NGC 474, showing that the two main members are currently undergoing interaction. The Hα emission reveals the presence of secondary components at the centre of NGC 470, superposed on the main component tracing the rotation of the galaxy. This latter maps a nearly unperturbed velocity field. The dominant, nearly unperturbed trend of the kinematics is confirmed by CO observations, although restricted to the centre of the galaxy. The X-ray luminosity of NGC 470 is comparable with that of a ‘normal’ spiral galaxy. NGC 474 on the other hand is very gas-poor and has not been detected in Hα. Its X-ray luminosity is consistent with the low end of the expected emission from discrete sources. Arp 227 as a loose group shows several signatures of galaxy–galaxy interaction. Our observations suggest the presence of signatures of interaction in the overall kinematics of the spiral companion. The ongoing interaction is clearly visible only in the outer H i halo of NGC 470. While the large shell system of NGC 474 could be associated with an accretion event, the secondary components in the Hα profile in the centre of NGC 470 could be due to the interaction with the companion. The low X-ray luminosity of NGC 470 seems to be a characteristic of dynamically young systems. All the above evidence suggest that Arp 227 is an evolving group in the early phase of its evolution and that its drivers are the accretion of faint galaxies and the ongoing large-scale interaction between NGC 470 and 474. [ABSTRACT FROM AUTHOR]

Pharmacological control of interleukin- 12 (IL-12) production may be a key therapeutic strategy for modulating immunological diseases dominated by type-1 cytokine responses. In this study, we investigated the effects of pentoxifylline on the production of IL-12 by human blood mononuclear cells and primary human monocytes stimulated with heat-killed Staphylococcus aureus Cowan strain I (SAC) or lipopolysaccharide (LPS). Pentoxifylline potently suppressed production of IL-12 in a concentration-dependent manner. In these same experiments, tumour necrosis factor-a (TNF-α) production was inhibited and IL-10 and prostaglandin E2 (PGE2) production was enhanced by treatment with pentoxifylline. Suppression of IL-12 production by pentoxifylline was found to be independent of several known endogenous inhibitors of IL-12, such as IL-10, transforming growth factor-α (TGF-β), IL-4 and PGE2. RNase protection assays revealed that pentoxifylline inhibited accumulation of both IL-12 p40 and p35 mRNA, suggesting a predominant mRNA locus for pentoxifylline-induced IL-12 inhibition. Low levels of pentoxifylline added to the suppression of IL-12 production by suboptimal inhibiting doses of dexamethasone, suggesting that this drug combination may have therapeutic utility. These results provide a firm rationale for the use of pentoxifylline in clinical trials of immunological disorders characterized by inappropriate type-1 immune responses. [ABSTRACT FROM AUTHOR]

At least two distinct HLA-DR+ cell subsets lacking surface markers specific for B cells, monocytes or other known lineages are present in human peripheral blood. One subset is non-adherent to plastic, produces interferon-alpha (IFN-α) when incubated with cytomegalovirus-infected target cells and provides an accessory function requited for natural killer (NK) cell-mediated lysis of such cells. These non-adherent HLA-DR+ cells express the surface antigen recognized by antibody anti-D44 and do not stimulate mixed leucocyte reaction (MLR). The other HLA-DR+ cell subset is loosely adherent to plastic, produces only minimal levels of IFN-α when incubated with cytomegalovirus-infected target cells and does not provide the accessory function required for NK cell-mediated lysis of such cells. These HLA-DR+ cells stimulate a strong MLR, do not express D44 antigen and meet the criteria of dendritic cells (DC) morphologically and functionally. [ABSTRACT FROM AUTHOR]

• Color-Color-Intensity diagrams are used for classifying X-ray binaries. • Different X-ray colors are tested for CCI diagrams of separate classes of XRBs. • X-ray binaries with black holes are separated from neutron stars in all X-ray colors. • Soft BH XRBs spectral states are separated in X-ray colors with lowest energyband. X-ray binaries exhibit a wide range of properties but there are few accepted methods to determine the nature of the compact object. Color-Color-Intensity diagrams have been suggested as a means of distinguishing between systems containing black holes from those containing neutron stars. However, this technique has been verified with data from only one instrument (RXTE/ASM) with a single set of X-ray colors defined using data available only in pre-determined energy bands. We test a selection of X-ray colors with a more sensitive instrument to determine the reliability of this method. We use data from the MAXI /Gas Slit Camera, which allows users to specify energy-bands. We test X-ray colors that have been previously defined in the literature as well as ones that we define specifically in this paper. A representative set of systems are used to construct Color-Color-Intensity diagrams in each set of colors to determine which are best for separating different classes. For studying individual sources certain bands are more effective than others. For a specified energy range, the separation of soft states in black hole binaries was possible only where both soft and hard colors included information from the lowest energy band. We confirm that Color-Color-Intensity diagrams can distinguish between systems containing black holes or neutron stars in all X-ray colors tested; this suggests an universality in the accretion processes governing these different classes. We suggest possible physical processes driving different classes of X-ray binaries to different locations in Color-Color-Intensity diagrams. [ABSTRACT FROM AUTHOR]

The ultraviolet-optical colour magnitude diagram of rich galaxy groups is characterised by a well developed Red Sequence, a Blue Cloud and the so-called Green Valley. Loose, less evolved groups of galaxies which are probably not virialised yet may lack a well defined Red Sequence. This is actually explained in the framework of galaxy evolution. We are focussing on understanding galaxy migration towards the Red Sequence, checking for signatures of such a transition in their photometric and morphological properties. We report on the ultraviolet properties of a sample of early-type (ellipticals+S0s) galaxies inhabiting the Red Sequence. The analysis of their structures, as derived by fitting a Sérsic law to their ultraviolet luminosity profiles, suggests the presence of an underlying disk. This is the hallmark of dissipation processes that still must have a role to play in the evolution of this class of galaxies. Smooth particle hydrodynamic simulations with chemo-photometric implementations able to match the global properties of our targets are used to derive their evolutionary paths through ultraviolet-optical colour magnitude diagrams, providing some fundamental information such as the crossing time through the Green Valley, which depends on their luminosity. The transition from the Blue Cloud to the Red Sequence takes several Gyrs, being about 3-5 Gyr for the brightest galaxies and longer for fainter ones, if occurring.The photometric study of nearby galaxy structures in the ultraviolet is seriously hampered by either the limited field of view of the cameras (e.g., in Hubble Space Telescope) or by the low spatial resolution of the images (e.g., in the Galaxy Evolution Explorer). Current missions equipped with telescopes and cameras sensitive to ultraviolet wavelengths, such as Swift-UVOT and Astrosat-UVIT, provide a relatively large field of view and a better resolution than the Galaxy Evolution Explorer. More powerful ultraviolet instruments (size, resolution and field of view) are obviously bound to yield fundamental advances in the accuracy and depth of the surface photometry and in the characterisation of the galaxy environment. [ABSTRACT FROM AUTHOR]

We report the spectral and temporal variability properties of 18 candidate transient (TC) and potential transient (PTC) sources detected in deep multi-epoch Chandra observation of the nearby elliptical galaxies, NGC 3379, NGC 4278, and NGC 4697. Only one source can be identified with a background counterpart, leaving 17 TCs + PTCs in the galaxies. Of these, 14 are in the galaxy field, supporting the theoretical picture that the majority of field X-ray binaries (XRBs) will exhibit transient accretion for >75% of their lifetime. Three sources are coincident with globular clusters, including two high-luminosity candidate black hole (BH) XRBs, with LX = 5.4 × 1038 erg s–1and LX = 2.8 × 1039 erg s–1, respectively. The spectra, luminosities, and temporal behavior of these 17 sources suggest that the transient population is heterogeneous, including neutron star (NS) and BH XRBs in both normal and high-rate accretion modes, and super soft sources containing white dwarf binaries. Our TC and PTC detections are noticeably fewer than the number expected from the population synthesis (PS) models of Fragos et al., tailored to our new Chandra pointings of NGC 4278. We attribute this discrepancy to the PS assumption that the transient population is composed of NS XRBs, as well as differences between the statistical analysis and error estimates used in the model and our observations. [ABSTRACT FROM AUTHOR]

The International Society for the Biological Therapy of Cancer (iSBTc) has initiated in collaboration with the United States Food and Drug Administration (FDA) a programmatic look at innovative avenues for the identification of relevant parameters to assist clinical and basic scientists who study the natural course of host/tumor interactions or their response to immune manipulation. The task force has two primary goals: 1) identify best practices of standardized and validated immune monitoring procedures and assays to promote inter-trial comparisons and 2) develop strategies for the identification of novel biomarkers that may enhance our understating of principles governing human cancer immune biology and, consequently, implement their clinical application. Two working groups were created that will report the developed best practices at an NCI/FDA/iSBTc sponsored workshop tied to the annual meeting of the iSBTc to be held in Washington DC in the Fall of 2009. This foreword provides an overview of the task force and invites feedback from readers that might be incorporated in the discussions and in the final document. [ABSTRACT FROM AUTHOR]