820 research outputs found

    Synthesized grain size distribution in the interstellar medium

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    We examine a synthetic way of constructing the grain size distribution in the interstellar medium (ISM). First we formulate a synthetic grain size distribution composed of three grain size distributions processed with the following mechanisms that govern the grain size distribution in the Milky Way: (i) grain growth by accretion and coagulation in dense clouds, (ii) supernova shock destruction by sputtering in diffuse ISM, and (iii) shattering driven by turbulence in diffuse ISM. Then, we examine if the observational grain size distribution in the Milky Way (called MRN) is successfully synthesized or not. We find that the three components actually synthesize the MRN grain size distribution in the sense that the deficiency of small grains by (i) and (ii) is compensated by the production of small grains by (iii). The fraction of each {contribution} to the total grain processing of (i), (ii), and (iii) (i.e., the relative importance of the three {contributions} to all grain processing mechanisms) is 30-50%, 20-40%, and 10-40%, respectively. We also show that the Milky Way extinction curve is reproduced with the synthetic grain size distributions.Comment: 10 pages, 6 figures, accepted for publication in Earth, Planets, and Spac

    Cross-protection against European swine influenza viruses in the context of infection immunity against the 2009 pandemic H1N1 virus : studies in the pig model of influenza

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    Pigs are natural hosts for the same influenza virus subtypes as humans and are a valuable model for cross-protection studies with influenza. In this study, we have used the pig model to examine the extent of virological protection between a) the 2009 pandemic H1N1 (pH1N1) virus and three different European H1 swine influenza virus (SIV) lineages, and b) these H1 viruses and a European H3N2 SIV. Pigs were inoculated intranasally with representative strains of each virus lineage with 6- and 17-week intervals between H1 inoculations and between H1 and H3 inoculations, respectively. Virus titers in nasal swabs and/or tissues of the respiratory tract were determined after each inoculation. There was substantial though differing cross-protection between pH1N1 and other H1 viruses, which was directly correlated with the relatedness in the viral hemagglutinin (HA) and neuraminidase (NA) proteins. Cross-protection against H3N2 was almost complete in pigs with immunity against H1N2, but was weak in H1N1/pH1N1-immune pigs. In conclusion, infection with a live, wild type influenza virus may offer substantial cross-lineage protection against viruses of the same HA and/or NA subtype. True heterosubtypic protection, in contrast, appears to be minimal in natural influenza virus hosts. We discuss our findings in the light of the zoonotic and pandemic risks of SIVs

    The Bs20x22 anti-CD20-CD22 bispecific antibody has more lymphomacidal activity than do the parent antibodies alone

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    Previous studies have shown that bispecific antibodies that target both CD20 and CD22 have in vivo lymphomacidal properties. We developed a CD20-CD22 bispecific antibody (Bs20x22) from anti-CD20 and the anti-CD22 monoclonal antibodies (mAb), rituximab and HB22.7, respectively. Bs20x22 was constructed using standard methods and was shown to specifically bind CD20 and CD22. In vitro cytotoxicity assays showed that Bs20x22 was three times more effective than either parent mAb alone and twice as effective as a combination of both parent mAb used at equimolar concentrations. Bs20x22 was also nearly four times more effective at inducing apoptosis than either mAb alone. Examination of the MAPK and SAPK signaling cascades revealed that Bs20x22 induced significantly more p38 phosphorylation than either mAb alone. In an in vivo human NHL xenograft model, treatment with Bs20x22 resulted in significantly greater tumor shrinkage and improved overall survival when compared to either mAb alone or treatment with a combination of HB22.7 and rituximab. The effect of the initial tumor volume was assessed by comparing the efficacy of Bs20x22 administered before xenografts grew versus treatment of established tumors; significantly, greater efficacy was found when treatment was initiated before tumors could become established

    Land use change effects on extreme flood in the Kelantan basin using hydrological model

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    Land use and land cover (LULC) change results in increased of flood frequency and severity. The increase of annual runoff which is caused by urban development, heavy deforestation, or other anthropogenic activities occurs within the catchment areas. Therefore, accurate and continuous LULC change information is vital in quantifying flood hydrograph for any given time. Many studies showed the effect of land use change on flood based on hydrological response (i.e., peak discharge and runoff volume). In this study, a distributed hydrological modeling and GIS approach were applied for the assessment of land use impact in the Kelantan Basin. The assessment focuses on the runoff contributions from different land use classes and the potential impact of land use changes on runoff generation. The results showed that the direct runoff from developmental area, agricultural area, and grassland region is dominant for a flood event compared with runoff from other land-covered areas in the study area. The urban areas or lower planting density areas tend to increase for runoff and for the monsoon season floods, whereas the inter-flow from forested and secondary jungle areas contributes to the normal flow

    Analysis of the Performance of a Standardized Method for the Polishing of Methacrylic Resins

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    Adhesion of micro-organisms to resin surface may be caused by inadequate polishing. Most of the studies published in literature are relative to manually prepared samples and do not take into account that test repeatability is not guaranteed a priori since skills may change from one operator to another and the quality of the work done by the same expert operator may depend on “human” factors such as the level of attention, wrist trembling, etc

    Long-term effect of respiratory training for chronic obstructive pulmonary disease patients at an outpatient clinic: a randomised controlled trial

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    Objective: To assess the effect of respiratory training (RT ) on lung function, activity tolerance and acute exacerbation frequency with chronic obstructive pulmonary disease (COPD). Design: A randomised controlled trial. Setting: Outpatient clinic and home of the COPD patients, Zhengzhou City, China. Subjects: Sixty participants with COPD were randomised into two groups: an intervention group ( n = 30) which received the RT in self-management and a control group ( n = 30) that received an education program during the study. Intervention: Pulmonary function, activity tolerance and frequency of acute exacerbation of these COPD patients were evaluated before and after the program. The intervention and control programs were delivered at monthly out - patient clinic visits over a period of 12 months. The pulmonary rehabilitation (PR) program was conducted by a physiotherapist (who delivered RT to the participant over a minimum of 1 h per visit) for the intervention group, whereas the control group received routine health education provided by physiotherapists. The intervention group patients were then instructed to perform exercises at home as taught in the RT at least 5 days per week at home. Results: After 12 months of RT, the lung function and the activity tolerance of the COPD patients in the intervention group were significantly improved and the exacerbation frequency was also decreased. Conclusion: Long-term RT can improve lung function and activity tolerance while decreasing the frequency of acute exacerbation for COPD patient

    Modeling the Adaptive Role of Negative Signaling in Honey Bee Intraspecific Competition

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    Collective decision making in the social insects often proceeds via feedback cycles based on positive signaling. Negative signals have, however, been found in a few contexts in which costs exist for paying attention to no longer useful information. Here we incorporate new research on the specificity and context of the negative stop signal into an agent based model of honey bee foraging to explore the adaptive basis of negative signaling in the dance language. Our work suggests that the stop signal, by acting as a counterbalance to the waggle dance, allows colonies to rapidly shut down attacks on other colonies. This could be a key adaptation, as the costs of attacking a colony strong enough to defend itself are significant
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