184 research outputs found

    Cyclic stretching of mesangial cells up-regulates intercellular adhesion molecule-1 and leukocyte adherence: A possible new mechanism for glomerulosclerosis

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    Intraglomerular hypertension is a primacy causal factor in the progressive glomerulosclerosis that characterizes diabetic nephropathy or severe renal ablation. However, inflammation of the glomerular mesangium also participates in at least the early phase of these diseases. In glomerulonephritis, where inflammation is thought to be the predominant causal factor, intraglomerular hypertension is also often present. Mesangial cells (MCs) are critical in orchestrating key functions of the glomerulus including extracellular matrix metabolism, cytokine production, and interaction with leukocytes. Because MCs are subject to increased stretching when intraglomerular hypertension is present, and in glomerulonephritis MC/leukocyte interactions seem to be mediated primarily via the up-regulation of intercellular adhesion molecule-1 (ICAM-1), we examine the possibility that cyclic stretching is a stimulus for increased MC ICAM-1 activity. We demonstrate that the normal low levels of MC ICAM-1 mRNA and protein are dramatically up-regulated by even short intervals of cyclic stretch. This effect is dose- and time-dependent, and requires little amplitude and a brief period of elongation for significant induction. Stretch-induced MC ICAM-1 also leads to a marked elevation in phagocytic leukocyte adherence. This stimulated adherence is equal or greater than that induced by the inflammatory cytokine tumor necrosis factor-α, whereas an additive effect occurs when both are applied in combination. Our results indicate that stretch-induced ICAM-1 may provide a direct link between hypertension and inflammation in the progression of injury and glomerulosclerosis in diabetes, renal ablation, and other forms of glomerulonephritis. © 2001 American Society for Investigative Pathology

    In vivo DNase I sensitivity of the Streptomyces coelicolor chromosome correlates with gene expression: implications for bacterial chromosome structure

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    For a bacterium, Streptomyces coelicolor A3(2) contains a relatively large genome (8.7 Mb) with a complex and adaptive pattern of gene regulation. We discovered a correlation between the physical structure of the S.coelicolor genome and the transcriptional activity of the genes therein. Twelve genes were surveyed throughout 72 h of growth for both in vivo sensitivity to DNase I digestion and levels of transcription. DNase I-sensitivity correlated positively with transcript levels, implying that it was predictive of gene expression, and indicating increased accessibility of transcribed DNA. The genome was fractionated based on the sensitivity to DNase I digestion, with the low molecular weight (frequently cut) fraction highly enriched for actively transcribed sequences when compared to the infrequently cut fraction, which was representative of the entire genome. This approach will allow comparison of nucleoid proteins, and any modifications thereof, associated with transcriptionally active and inactive regions of the bacterial genome

    Identification of Ambient Molecular Clouds Associated with Galactic Supernova Remnant IC443

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    The Galactic supernova remnant (SNR) IC443 is one of the most studied core-collapse SNRs for its interaction with molecular clouds. However, the ambient molecular clouds with which IC443 is interacting have not been thoroughly studied and remain poorly understood. Using Five College Radio Astronomy Observatory 14m telescope, we obtained fully sampled maps of ~ 1{\deg} \times 1{\deg} region toward IC443 in the 12CO J=1-0 and HCO+ J=1-0 lines. In addition to the previously known molecular clouds in the velocity range v_lsr = -6 to -1 km/s (-3 km/s clouds), our observations reveal two new ambient molecular cloud components: small (~ 1') bright clouds in v_lsr = -8 to -3 km/s (SCs), and diffuse clouds in v_lsr = +3 to +10 km/s (+5 km/s clouds). Our data also reveal the detailed kinematics of the shocked molecular gas in IC443, however the focus of this paper is the physical relationship between the shocked clumps and the ambient cloud components. We find strong evidence that the SCs are associated with the shocked clumps. This is supported by the positional coincidence of the SCs with shocked clumps and other tracers of shocks. Furthermore, the kinematic features of some shocked clumps suggest that these are the ablated material from the SCs upon the impact of the SNR shock. The SCs are interpreted as dense cores of parental molecular clouds that survived the destruction by the pre-supernova evolution of the progenitor star or its nearby stars. We propose that the expanding SNR shock is now impacting some of the remaining cores and the gas is being ablated and accelerated producing the shocked molecular gas. The morphology of the +5 km/s clouds suggests an association with IC443. On the other hand, the -3 km/s clouds show no evidence for interaction.Comment: Accepted for publication in ApJ. 15 pages (with emulateapj.cls), 17 figures, and 2 table

    A Systematic Search for Molecular Outflows Toward Candidate Low-Luminosity Protostars and Very Low Luminosity Objects

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    We present a systematic single-dish search for molecular outflows toward a sample of 9 candidate low-luminosity protostars and 30 candidate Very Low Luminosity Objects (VeLLOs; L_int < 0.1 L_sun). The sources are identified using data from the Spitzer Space Telescope catalogued by Dunham et al. toward nearby (D < 400 pc) star forming regions. Each object was observed in 12CO and 13CO J = 2-1 simultaneously using the sideband separating ALMA Band-6 prototype receiver on the Heinrich Hertz Telescope at 30 arcsecond resolution. Using 5-point grid maps we identify five new potential outflow candidates and make on-the-fly maps of the regions surrounding sources in the dense cores B59, L1148, L1228, and L1165. Of these new outflow candidates, only the map of B59 shows a candidate blue outflow lobe associated with a source in our survey. We also present larger and more sensitive maps of the previously detected L673-7 and the L1251-A IRS4 outflows and analyze their properties in comparison to other outflows from VeLLOs. The accretion luminosities derived from the outflow properties of the VeLLOs with detected CO outflows are higher than the observed internal luminosity of the protostars, indicating that these sources likely had higher accretion rates in the past. The known L1251-A IRS3 outflow is detected but not remapped. We do not detect clear, unconfused signatures of red and blue molecular wings toward the other 31 sources in the survey indicating that large-scale, distinct outflows are rare toward this sample of candidate protostars. Several potential outflows are confused with kinematic structure in the surrounding core and cloud. Interferometric imaging is needed to disentangle large-scale molecular cloud kinematics from these potentially weak protostellar outflows.Comment: 42 pages, 19 figures, Accepted for publication in the Astronomical Journa

    HST/NICMOS observations of the GLIMPSE9 stellar cluster

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    We present HST/NICMOS photometry, and low-resolution K-band spectra of the GLIMPSE9 stellar cluster. The newly obtained color-magnitude diagram shows a cluster sequence with H-Ks =1 mag, indicating an interstellar extinction Aks=1.6\pm0.2 mag. The spectra of the three brightest stars show deep CO band-heads, which indicate red supergiants with spectral type M1-M2. Two 09-B2 supergiants are also identified, which yield a spectrophotometric distance of 4.2\pm0.4 kpc. Presuming that the population is coeval, we derive an age between 15 and 27 Myr, and a total cluster mass of 1600\pm400 Msun, integrated down to 1 Msun. In the vicinity of GLIMPSE9 are several HII regions and SNRs, all of which (including GLIMPSE 9) are probably associated with a giant molecular cloud (GMC) in the inner galaxy. GLIMPSE9 probably represents one episode of massive star formation in this GMC. We have identified several other candidate stellar clusters of the same complex.Comment: 13 pages, 14 figures. accepted for publication in ApJ. A version with high-resolution figures can be found at the following location ftp://ftp.rssd.esa.int/pub/mmessine/ms.pdf New version with updated reference

    Massive stars in the Cl 1813-178 Cluster. An episode of massive star formation in the W33 complex

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    Young massive (M >10^4 Msun) stellar clusters are a good laboratory to study the evolution of massive stars. Only a dozen of such clusters are known in the Galaxy. Here we report about a new young massive stellar cluster in the Milky Way. Near-infrared medium-resolution spectroscopy with UIST on the UKIRT telescope and NIRSPEC on the Keck telescope, and X-ray observations with the Chandra and XMM satellites, of the Cl 1813-178 cluster confirm a large number of massive stars. We detected 1 red supergiant, 2 Wolf-Rayet stars, 1 candidate luminous blue variable, 2 OIf, and 19 OB stars. Among the latter, twelve are likely supergiants, four giants, and the faintest three dwarf stars. We detected post-main sequence stars with masses between 25 and 100 Msun. A population with age of 4-4.5 Myr and a mass of ~10000 Msun can reproduce such a mixture of massive evolved stars. This massive stellar cluster is the first detection of a cluster in the W33 complex. Six supernova remnants and several other candidate clusters are found in the direction of the same complex.Comment: 11 Figures. Accepted for publication in Ap

    Urgensi Pengaturan Injunction dalam Rancangan Undang-Undang Hukum Acara Perdata

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    The concept of injunction in common law countries is similar to the concept of provision, confiscation, and provisional determination so that the concept of injunction can be used to complete the deficiencies of provision, confiscation, and provisional determination. This research examines injunction arrangements in common law countries, in this case, the United States and Singapore, which are then transplanted into Indonesian law through the Indonesian Civil Procedure Bill. The research method was carried out normatively and then explained descriptively accompanied by a prescription on how provision, confiscation, and provisional determination should be regulated in Indonesia. Arrangements for provision, confiscation, and provisional determination are still scattered in various laws and even most of the Dutch colonial legacies are used without an official translation. This condition causes legal uncertainty that can be detrimental to justice seekers. The state’s efforts in establishing a unique Indonesian civil procedural law can be seen through the Indonesian Civil Procedure Bill. This bill also contains a concept similar to an injunction. The bill, which is expected to eliminate legal uncertainty for justice seekers, still does not specify a concept similar to the injunction in Indonesia.Konsep injunction di negara-negara common law memiliki kemiripan dengan konsep provisi, penyitaan, dan penetapan sementara sehingga konsep injunction tersebut dapat dimanfaatkan untuk melengkapi kekurangan dari provisi, penyitaan, dan penetapan sementara. Penelitian ini mengkaji pengaturan injunction di negara- negara common law dalam hal ini Amerika Serikat dan Singapura kemudian ditransplantasikan ke dalam hukum Indonesia melalui RUU Hukum Acara Perdata. Metode penelitian dilakukan secara normatif kemudian diterangkan secara deskriptif disertai dengan preskripsi tentang bagaimana seharusnya pengaturan provisi, penyitaan, dan penetapan sementara di Indonesia. Pengaturan provisi, penyitaan, dan penetapan sementara masih tersebar di berbagai undang-undang bahkan sebagian besar peninggalan kolonial Belanda yang dipakai tanpa adanya terjemahan resmi. Kondisi ini menyebabkan terjadinya ketidakpastian hukum yang dapat merugikan para pencari keadilan. Upaya negara dalam membentuk suatu hukum acara perdata khas Indonesia dapat dilihat melalui RUU Hukum Acara Perdata. RUU ini juga mengandung konsep yang mirip dengan injuction. RUU yang diharapkan dapat menghapuskan ketidakpastian hukum bagi para pencari keadilan masih tidak merinci konsep serupa injunction di Indonesia

    Phased Array Feed Calibration, Beamforming and Imaging

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    Phased array feeds (PAFs) for reflector antennas offer the potential for increased reflector field of view and faster survey speeds. To address some of the development challenges that remain for scientifically useful PAFs, including calibration and beamforming algorithms, sensitivity optimization, and demonstration of wide field of view imaging, we report experimental results from a 19 element room temperature L-band PAF mounted on the Green Bank 20-Meter Telescope. Formed beams achieved an aperture efficiency of 69% and system noise temperature of 66 K. Radio camera images of several sky regions are presented. We investigate the noise performance and sensitivity of the system as a function of elevation angle with statistically optimal beamforming and demonstrate cancelation of radio frequency interference sources with adaptive spatial filtering.Comment: 19 pages, 13 figure

    Experiences, Opportunities and Challenges of Implementing Task Shifting in Underserved Remote Settings: The Case of Kongwa District, Central Tanzania.

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    Tanzania is experiencing acute shortages of Health Workers (HWs), a situation which has forced health managers, especially in the underserved districts, to hastily cope with health workers' shortages by adopting task shifting. This has however been due to limited options for dealing with the crisis of health personnel. There are on-going discussions in the country on whether to scale up task shifting as one of the strategies for addressing health personnel crisis. However, these discussions are not backed up by rigorous scientific evidence. The aim of this paper is two-fold. Firstly, to describe the current situation of implementing task shifting in the context of acute shortages of health workers and, secondly, to provide a descriptive account of the potential opportunities or benefits and the likely challenges which might ensue as a result of implementing task shifting. We employed in-depth interviews with informants at the district level and supplemented the information with additional interviews with informants at the national level. Interviews focussed on the informants' practical experiences of implementing task shifting in their respective health facilities (district level) and their opinions regarding opportunities and challenges which might be associated with implementation of task shifting practices. At the national level, the main focus was on policy issues related to management of health personnel in the context of implementation of task shifting, in addition to seeking their opinions and perceptions regarding opportunities and challenges of implementing task shifting if formally adopted. Task shifting has been in practice for many years in Tanzania and has been perceived as an inevitable coping mechanism due to limited options for addressing health personnel shortages in the country. Majority of informants had the concern that quality of services is likely to be affected if appropriate policy infrastructures are not in place before formalising tasks shifting. There was also a perception that implementation of task shifting has ensured access to services especially in underserved remote areas. Professional discontent and challenges related to the management of health personnel policies were also perceived as important issues to consider when implementing task shifting practices. Additional resources for additional training and supervisory tasks were also considered important in the implementation of task shifting in order to make it deliver much the same way as it is for conventional modalities of delivering care. Task shifting implementation occurs as an ad hoc coping mechanism to the existing shortages of health workers in many undeserved areas of the country, not just in the study site whose findings are reported in this paper. It is recommended that the most important thing to do now is not to determine whether task shifting is possible or effective but to define the limits of task shifting so as to reach a consensus on where it can have the strongest and most sustainable impact in the delivery of quality health services. Any action towards this end needs to be evidence-based
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