1,653 research outputs found

    Accumulator

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    An accumulator particularly adapted for use in controlling the pressure of a stream of fluid in its liquid phase utilizing the fluid in its gaseous phase was designed. The accumulator is characterized by a shell defining a pressure chamber having an entry throat for a liquid and adapted to be connected in contiguous relation with a selected conduit having a stream of fluid flowing through the conduit in its liquid phase. A pressure and volume stabilization tube, including an array of pressure relief perforations is projected into the chamber with the perforations disposed adjacent to the entry throat for accommodating a discharge of the fluid in either gaseous or liquid phases, while a gas inlet and liquid to gas conversion system is provided, the chamber is connected with a source of the fluid for continuously pressuring the chamber for controlling the pressure of the stream of liquid

    The New Zealand Kauri (Agathis Australis) Research Project: A Radiocarbon Dating Intercomparison of Younger Dryas Wood and Implications for IntCal13

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    We describe here the New Zealand kauri (Agathis australis) Younger Dryas (YD) research project, which aims to undertake Δ14C analysis of ~140 decadal floating wood samples spanning the time interval ~13.1–11.7 kyr cal BP. We report 14C intercomparison measurements being undertaken by the carbon dating laboratories at University of Waikato (Wk), University of California at Irvine (UCI), and University of Oxford (OxA). The Wk, UCI, and OxA laboratories show very good agreement with an interlaboratory comparison of 12 successive decadal kauri samples (average offsets from consensus values of –7 to +4 14C yr). A University of Waikato/University of Heidelberg (HD) intercomparison involving measurement of the YD-age Swiss larch tree Ollon505, shows a HD/Wk offset of ~10–20 14C yr (HD younger), and strong evidence that the positioning of the Ollon505 series is incorrect, with a recommendation that the 14C analyses be removed from the IntCal calibration database

    A systematic review of the effectiveness of docetaxel and mitoxantrone for the treatment of metastatic hormone-refractory prostate cancer

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    A systematic review was performed to evaluate the clinical effectiveness of docetaxel in combination with prednisolone (docetaxel is licensed in the UK for use in combination with prednisone or prednisolone for the treatment of patients with metastatic hormone-refractory prostate cancer. Prednisone is not used in the UK, but it is reasonable to use docetaxel plus prednisone data in this review of docetaxel plus prednisolone) for the treatment of metastatic hormone-refractory prostate cancer. A scoping search identified a trial of docetaxel plus prednisone vs mitoxantrone plus prednisone, but did not identify any trials comparing docetaxel plus prednisolone/prednisone with any other treatments. Therefore, we considered additional indirect evidence that would enable a comparison of docetaxel plus prednisolone/prednisone with other chemotherapy regimens and active supportive care. Systematic searching (upto April 2005) identified seven randomised controlled trials. One large well-conducted trial assessed docetaxel plus prednisone vs mitoxantrone plus prednisone; this showed statistically significant improvements with 3-weekly docetaxel in terms of overall survival, quality of life, pain response and PSA decline. Two other chemotherapy regimens that included docetaxel with estramustine also showed improved outcomes in comparison with mitoxantrone plus prednisone. Three trials that compared mitoxantrone plus corticosteroids with corticosteroids alone were identified and their results for overall survival combined, which showed very little difference between the two groups. The addition of clodronate to mitoxantrone plus prednisone showed no significant differences in comparison with mitoxantrone plus prednisone alone. The evidence suggests that chemotherapy regimens containing 3-weekly docetaxel are superior to mitoxantrone or corticosteroids alone

    Defective monocyte-derived macrophage phagocytosis is associated with exacerbation frequency in COPD

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    Background Lower airway bacterial colonisation (LABC) in COPD patients is associated with increased exacerbation frequency and faster lung function decline. Defective macrophage phagocytosis in COPD drives inflammation, but how defective macrophage function contributes to exacerbations is not clear. This study investigated the association between macrophage phagocytosis and exacerbation frequency, LABC and clinical parameters. Methods Monocyte-derived macrophages (MDM) were generated from 92 stable COPD patients, and at the onset of exacerbation in 39 patients. Macrophages were exposed to fluorescently labelled Haemophilus influenzae or Streptococcus pneumoniae for 4 h, then phagocytosis measured by fluorimetry and cytokine release by ELISA. Sputum bacterial colonisation was measured by PCR. Results Phagocytosis of H. influenzae was negatively correlated with exacerbation frequency (r = 0.440, p < 0.01), and was significantly reduced in frequent vs. infrequent exacerbators (1.9 × 103 RFU vs. 2.5 × 103 RFU, p < 0.01). There was no correlation for S. pneumoniae. There was no association between phagocytosis of either bacteria with age, lung function, smoking history or treatment with inhaled corticosteroids, or long-acting bronchodilators. Phagocytosis was not altered during an exacerbation, or in the 2 weeks post-exacerbation. In response to phagocytosis, MDM from exacerbating patients showed increased release of CXCL-8 (p < 0.001) and TNFα (p < 0.01) compared to stable state. Conclusion Impaired COPD macrophage phagocytosis of H. influenzae, but not S. pneumoniae is associated with exacerbation frequency, resulting in pro-inflammatory macrophages that may contribute to disease progression. Targeting these frequent exacerbators with drugs that improve macrophage phagocytosis may prove beneficial

    Circle talks as situated experiential learning: Context, identity, and knowledgeability in \u27learning from reflection\u27

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    This article presents research that used ethnographic and sociolinguistic methods to study ways participants learn through reflection when carried out as a “circle talk.” The data indicate that participants in the event (a) invoked different contextual frames that (b) implicated them in various identity positions, which (c) affected how they could express their knowledge. These features worked together to generate socially shared meanings that enabled participants to jointly achieve conceptualization—the ideational role “reflection” is presumed to play in the experiential learning process. The analysis supports the claim that participants generate new knowledge in reflection, but challenges individualistic and cognitive assumptions regarding how this occurs. The article builds on situated views of experiential learning by showing how knowledge can be understood as socially shared and how learning and identity formation are mutually entailing processes

    CD32<sup>+</sup> and PD-1<sup>+</sup> Lymph Node CD4 T Cells Support Persistent HIV-1 Transcription in Treated Aviremic Individuals.

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    A recent study conducted in blood has proposed CD32 as the marker identifying the "elusive" HIV reservoir. We have investigated the distribution of CD32 &lt;sup&gt;+&lt;/sup&gt; CD4 T cells in blood and lymph nodes (LNs) of HIV-1-uninfected subjects and viremic untreated and long-term-treated HIV-1-infected individuals and their relationship with PD-1 &lt;sup&gt;+&lt;/sup&gt; CD4 T cells. The frequency of CD32 &lt;sup&gt;+&lt;/sup&gt; CD4 T cells was increased in viremic compared to treated individuals in LNs, and a large proportion (up to 50%) of CD32 &lt;sup&gt;+&lt;/sup&gt; cells coexpressed PD-1 and were enriched within T follicular helper (Tfh) cells. We next investigated the role of LN CD32 &lt;sup&gt;+&lt;/sup&gt; CD4 T cells in the HIV reservoir. Total HIV DNA was enriched in CD32 &lt;sup&gt;+&lt;/sup&gt; and PD-1 &lt;sup&gt;+&lt;/sup&gt; CD4 T cells compared to CD32 &lt;sup&gt;-&lt;/sup&gt; and PD-1 &lt;sup&gt;-&lt;/sup&gt; cells in both viremic and treated individuals, but there was no difference between CD32 &lt;sup&gt;+&lt;/sup&gt; and PD-1 &lt;sup&gt;+&lt;/sup&gt; cells. There was no enrichment of latently infected cells with inducible HIV-1 in CD32 &lt;sup&gt;+&lt;/sup&gt; versus PD-1 &lt;sup&gt;+&lt;/sup&gt; cells in antiretroviral therapy (ART)-treated individuals. HIV-1 transcription was then analyzed in LN memory CD4 T cell populations sorted on the basis of CD32 and PD-1 expression. CD32 &lt;sup&gt;+&lt;/sup&gt; PD-1 &lt;sup&gt;+&lt;/sup&gt; CD4 T cells were significantly enriched in cell-associated HIV RNA compared to CD32 &lt;sup&gt;-&lt;/sup&gt; PD-1 &lt;sup&gt;-&lt;/sup&gt; (averages of 5.2-fold in treated individuals and 86.6-fold in viremics), CD32 &lt;sup&gt;+&lt;/sup&gt; PD-1 &lt;sup&gt;-&lt;/sup&gt; (2.2-fold in treated individuals and 4.3-fold in viremics), and CD32 &lt;sup&gt;-&lt;/sup&gt; PD-1 &lt;sup&gt;+&lt;/sup&gt; (2.2-fold in ART-treated individuals and 4.6-fold in viremics) cell populations. Similar levels of HIV-1 transcription were found in CD32 &lt;sup&gt;+&lt;/sup&gt; PD-1 &lt;sup&gt;-&lt;/sup&gt; and CD32 &lt;sup&gt;-&lt;/sup&gt; PD-1 &lt;sup&gt;+&lt;/sup&gt; CD4 T cells. Interestingly, the proportion of CD32 &lt;sup&gt;+&lt;/sup&gt; and PD-1 &lt;sup&gt;+&lt;/sup&gt; CD4 T cells negatively correlated with CD4 T cell counts and length of therapy. Therefore, the expression of CD32 identifies, independently of PD-1, a CD4 T cell population with persistent HIV-1 transcription and coexpression of CD32 and PD-1, the CD4 T cell population with the highest levels of HIV-1 transcription in both viremic and treated individuals.IMPORTANCE The existence of long-lived latently infected resting memory CD4 T cells represents a major obstacle to the eradication of HIV infection. Identifying cell markers defining latently infected cells containing replication-competent virus is important in order to determine the mechanisms of HIV persistence and to develop novel therapeutic strategies to cure HIV infection. We provide evidence that PD-1 and CD32 may have a complementary role in better defining CD4 T cell populations infected with HIV-1. Furthermore, CD4 T cells coexpressing CD32 and PD-1 identify a CD4 T cell population with high levels of persistent HIV-1 transcription

    Simulating temporal evolution of pressure in two-phase flow in porous media

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    We have simulated the temporal evolution of pressure due to capillary and viscous forces in two-phase drainage in porous media. We analyze our result in light of macroscopic flow equations for two-phase flow. We also investigate the effect of the trapped clusters on the pressure evolution and on the effective permeability of the system. We find that the capillary forces play an important role during the displacements for both fast and slow injection rates and both when the invading fluid is more or less viscous than the defending fluid. The simulations are based on a network simulator modeling two-phase drainage displacements on a two-dimensional lattice of tubes.Comment: 12 pages, LaTeX, 14 figures, Postscrip

    (un)Doing standards in education with actor-network theory

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    Recent critiques have drawn important attention to the depoliticized consensus and empty promises embedded in network discourses of educational policy. While acceding this critique, this discussion argues that some forms of network analysis – specifically those adopting actor-network theory (ANT) approaches - actually offer useful theoretical resources for policy studies. Drawing from ANT-inspired studies of policy processes associated with educational standards, the article shows the ambivalences and contradictions as well as the possibilities that can be illuminated by ANT analysis of standards as networks. The discussion outlines the diverse network conceptions, considerations and sensibilities afforded by ANT approaches. Then it shows four phenomena that have been highlighted by ANT studies of educational standards: ordering (and rupturing) practice through ‘immutable mobiles’, local universality, tensions among networks of prescription and networks of negotiation, and different co-existing ontological forms of the same standards. The conclusion suggests starting points, drawing from these ANT-inspired network analyses, for examining policy processes associated with educational standards
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