192 research outputs found

    Far-infrared all sky diffuse mapping with AKARI

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    We discuss the capability of AKARI in recovering diffuse far-infrared emission, and examine the achieved reliability. Critical issues in making images of diffuse emission are the transient response and long-term stability of the far-infrared detectors. Quantitative evaluation of these characteristics are the key to achieving sensitivity comparable to or better than that for point sources (< 20 -- 95 MJy sr-1). We describe current activity and progress toward the production of high quality images of the diffuse far-infrared emission using the AKARI all-sky survey data.Comment: 4 pages, 8 figures, to appear in the Proceedings of the Conference "AKARI, a light to illuminate the misty Universe", Fukutake Hall, The University of Tokyo, Japan, 16-19 February 200

    AKARI Far-Infrared All Sky Survey

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    We demonstrate the capability of AKARI for mapping diffuse far-infrared emission and achieved reliability of all-sky diffuse map. We have conducted an all-sky survey for more than 94 % of the whole sky during cold phase of AKARI observation in 2006 Feb. -- 2007 Aug. The survey in far-infrared waveband covers 50 um -- 180 um with four bands centered at 65 um, 90 um, 140 um, and 160 um and spatial resolution of 3000 -- 4000 (FWHM).This survey has allowed us to make a revolutionary improvement compared to the IRAS survey that was conducted in 1983 in both spatial resolution and sensitivity after more than a quarter of a century. Additionally, it will provide us the first all-sky survey data with high-spatial resolution beyond 100 um. Considering its extreme importance of the AKARI far-infrared diffuse emission map, we are now investigating carefully the quality of the data for possible release of the archival data. Critical subjects in making image of diffuse emission from detected signal are the transient response and long-term stability of the far-infrared detectors. Quantitative evaluation of these characteristics is the key to achieve sensitivity comparable to or better than that for point sources (< 20 -- 95 [MJy/sr]). We describe current activities and progress that are focused on making high quality all-sky survey images of the diffuse far-infrared emission.Comment: To appear in Proc. Workshop "The Space Infrared Telescope for Cosmology & Astrophysics: Revealing the Origins of Planets and Galaxies". Eds. A.M. Heras, B. Swinyard, K. Isaak, and J.R. Goicoeche

    The AKARI diffuse maps

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    We descibe the calibration of maps of diffuse Galactic Plane emission, and present detailed observations of several complexes. We put especial atention on Cygnus X region showing its temperature and density maps

    A milestone to SPICA extragalactic surveys: The AKARI NEP survey

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    Large area surveys in the infrared wavelengths have revealed a significant evolution of the star formation activity of the universe in the past. The extragalactic sur- vey we have conduced with AKARI towards the north ecliptic pole (NEP) is unique, in terms of a comprehensive wavelength coverage from 2 to 24 micron using all 9 photometric bands of the Infrared Camera (IRC). We demonstrate that this IRC all-band photometry is capable of tracing a steep rise in the flux at the blue side of the polycyclic aromatic hydrocarbon (PAH) 6.2 micron emission feature of infrared luminous galaxies at z < 1. This allows us to estimate redshifts of mid-IR sources and identify `ultra-luminous starburst galaxies', based on mid-IR spectral energy distributions (SEDs). SPICA could inherit this unique capability of AKARI and extend the study to typical galaxy populations at z ~ 2, i.e. a critical period of galaxy formation

    PERBANDINGAN PENILAIAN SIKLUS HIDUP (LIFE CYCLE ASSESSMENT) PRODUKSI BIODIESEL SECARA KATALIS DARI CRUDE PALM OIL DAN CRUDE JATROPHA CURCAS OIL

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    Sektor energi memainkan peran penting bagi Indonesia dan bahkan dunia dalam mencapai tujuan pembangunannya. Salah satu isu yang berkaitan dengan negara-negara yang berusaha untuk memanfaatkan bahan bakunya telah muncul secara global dalam pengembangan produksi biodiesel, misalnya USA yang menggunakan kacang kedelai, Eropa menggunakan rapeseed dan Asia khususnya Indonesia menggunakan minyak sawit. Isu global lainnya menempatkan lingkungan sebagai pertimbangan utama, karena produksi biodiesel menghasilkan emisi gas yang meningkatkan risiko pemanasan global dan menyebabkan kerusakan lingkungan. Negara-negara Eropa mengklaim bahwa pengolahan biodiesel yang berasal dari minyak sawit menyebabkan peningkatan emisi karbon yang ditransfer ke atmosfer. Metode yang tepat untuk menganalisis masalah tersebut melalui Penilaian Siklus Hidup (LCA). Produksi biodiesel di Indonesia menggunakan kelapa sawit sebagai bahan bakunya. Selain itu, penggunaan jatropha juga dianjurkan karena merupakan tanaman yang tidak dapat dimakan dan beradaptasi dengan berbagai kondisi tanah kritis yang ada di Indonesia. Studi ini merupakan penilaian komparatif siklus hidup dari produksi biodiesel dari minyak sawit dan jarak yang diproduksi di Indonesia. Analisis dikelompokkan ke dalam tahapan produksi tidak stabil dan tahap produksi stabil untuk mengakomodasi karakteristik pertumbuhan alami dari kedua tanaman ini. Hasil penelitian ini menunjukkan bahwa produksi biodiesel dari kelapa sawit memberikan nilai yang lebih tinggi pada potensi pemanasan global (GWP) daripada jarak pagar. Penggunaan agro-kimia, seperti pupuk, herbisida, insektisida dan pestisida, memberikan kontribusi yang signifikan terhadap total nilai GWP, yaitu masing-masing 68,14% untuk kelapa sawit dan 37,56% untuk jarak pagar. Karakteristik emisi dari kedua tanaman selama periode produktivitas tidak stabil ditemukan berbedaJurnal Teknologi Industri Pertaniandengan produktivitas stabil. Nilai GWP dan konsumsi energi untuk memproduksi biodiesel dari kelapa sawit ditemukan lebih tinggi dari jarak pagar.Kata kunci: penilaian siklus hidup, minyak mentah sawit, minyak mentah jarak pagar, biodiese

    Complement-Mediated Virus Infectivity Neutralisation by HLA Antibodies Is Associated with Sterilising Immunity to SIV Challenge in the Macaque Model for HIV/AIDS.

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    Sterilising immunity is a desired outcome for vaccination against human immunodeficiency virus (HIV) and has been observed in the macaque model using inactivated simian immunodeficiency virus (SIV). This protection was attributed to antibodies specific for cell proteins including human leucocyte antigens (HLA) class I and II incorporated into virions during vaccine and challenge virus preparation. We show here, using HLA bead arrays, that vaccinated macaques protected from virus challenge had higher serum antibody reactivity compared with non-protected animals. Moreover, reactivity was shown to be directed against HLA framework determinants. Previous studies failed to correlate serum antibody mediated virus neutralisation with protection and were confounded by cytotoxic effects. Using a virus entry assay based on TZM-bl cells we now report that, in the presence of complement, serum antibody titres that neutralise virus infectivity were higher in protected animals. We propose that complement-augmented virus neutralisation is a key factor in inducing sterilising immunity and may be difficult to achieve with HIV/SIV Env-based vaccines. Understanding how to overcome the apparent block of inactivated SIV vaccines to elicit anti-envelope protein antibodies that effectively engage the complement system could enable novel anti-HIV antibody vaccines that induce potent, virolytic serological response to be developed

    Host cell species-specific effect of cyclosporine A on simian immunodeficiency virus replication

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    <p>Abstract</p> <p>Background</p> <p>An understanding of host cell factors that affect viral replication contributes to elucidation of the mechanism for determination of viral tropism. Cyclophilin A (CypA), a peptidyl-prolyl <it>cis-trans </it>isomerase (PPIase), is a host factor essential for efficient replication of human immunodeficiency virus type 1 (HIV-1) in human cells. However, the role of cyclophilins in simian immunodeficiency virus (SIV) replication has not been determined. In the present study, we examined the effect of cyclosporine A (CsA), a PPIase inhibitor, on SIV replication.</p> <p>Results</p> <p>SIV replication in human CEM-SS T cells was not inhibited but rather enhanced by treatment with CsA, which inhibited HIV-1 replication. CsA treatment of target human cells enhanced an early step of SIV replication. CypA overexpression enhanced the early phase of HIV-1 but not SIV replication, while CypA knock-down resulted in suppression of HIV-1 but not SIV replication in CEM-SS cells, partially explaining different sensitivities of HIV-1 and SIV replication to CsA treatment. In contrast, CsA treatment inhibited SIV replication in macaque T cells; CsA treatment of either virus producer or target cells resulted in suppression of SIV replication. SIV infection was enhanced by CypA overexpression in macaque target cells.</p> <p>Conclusions</p> <p>CsA treatment enhanced SIV replication in human T cells but abrogated SIV replication in macaque T cells, implying a host cell species-specific effect of CsA on SIV replication. Further analyses indicated a positive effect of CypA on SIV infection into macaque but not into human T cells. These results suggest possible contribution of CypA to the determination of SIV tropism.</p

    Class II MHC Self-Antigen Presentation in Human B and T Lymphocytes

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    Human CD4[superscript +] T cells process and present functional class II MHC-peptide complexes, but the endogenous peptide repertoire of these non-classical antigen presenting cells remains unknown. We eluted and sequenced HLA-DR-bound self-peptides presented by CD4[superscript +] T cells in order to compare the T cell-derived peptide repertoire to sequences derived from genetically identical B cells. We identified several novel epitopes derived from the T cell-specific proteome, including fragments of CD4 and IL-2. While these data confirm that T cells can present peptides derived from the T-cell specific proteome, the vast majority of peptides sequenced after elution from MHC were derived from the common proteome. From this pool, we identified several identical peptide epitopes in the T and B cell repertoire derived from common endogenous proteins as well as novel endogenous epitopes with promiscuous binding. These findings indicate that the endogenous HLA-DR-bound peptide repertoire, regardless of APC type and across MHC isotype, is largely derived from the same pool of self-protein.National Institutes of Health (U.S.) (grant P01AI039671)National Institutes of Health (U.S.) (P01AI045757

    Nef Alleles from All Major HIV-1 Clades Activate Src-Family Kinases and Enhance HIV-1 Replication in an Inhibitor-Sensitive Manner

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    The HIV-1 accessory factor Nef is essential for high-titer viral replication and AIDS progression. Nef function requires interaction with many host cell proteins, including specific members of the Src kinase family. Here we explored whether Src-family kinase activation is a conserved property of Nef alleles from a wide range of primary HIV-1 isolates and their sensitivity to selective pharmacological inhibitors. Representative Nef proteins from the major HIV-1 subtypes A1, A2, B, C, F1, F2, G, H, J and K strongly activated Hck and Lyn as well as c-Src to a lesser extent, demonstrating for the first time that Src-family kinase activation is a highly conserved property of primary M-group HIV-1 Nef isolates. Recently, we identified 4-amino substituted diphenylfuropyrimidines (DFPs) that selectively inhibit Nef-dependent activation of Src-family kinases as well as HIV replication. To determine whether DFP compounds exhibit broad-spectrum Nef-dependent antiretroviral activity against HIV-1, we first constructed chimeric forms of the HIV-1 strain NL4-3 expressing each of the primary Nef alleles. The infectivity and replication of these Nef chimeras was indistinguishable from that of wild-type virus in two distinct cell lines (U87MG astroglial cells and CEM-T4 lymphoblasts). Importantly, the 4-aminopropanol and 4-aminobutanol derivatives of DFP potently inhibited the replication of all chimeric forms of HIV-1 in both U87MG and CEM-T4 cells in a Nef-dependent manner. The antiretroviral effects of these compounds correlated with inhibition of Nef-dependent activation of endogenous Src-family kinases in the HIV-infected cells. Our results demonstrate that the activation of Hck, Lyn and c-Src by Nef is highly conserved among all major clades of HIV-1 and that selective targeting of this pathway uniformly inhibits HIV-1 replication
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