1,702 research outputs found

    A Submillimeter Burst of S255IR~SMA1 - The Rise And Fall Of Its Luminosity

    Full text link
    Temporal photometric variations at near infrared to submillimeter wavelengths have been found in low-mass young stellar objects. These phenomena are generally interpreted as accretion events of star-disk systems with varying accretion rates. There is growing evidence suggesting that similar luminosity flaring also occurs in high-mass star/cluster-forming regions. We report in this Letter the rise and fall of the 900 μ{\mu}m continuum emission and the newly found 349.1 GHz methanol maser emission in the massive star forming region S255IR~SMA1 observed with the Submillimeter Array and the Atacama Large Millimeter/submillimeter Array. The level of flux variation at a factor of \sim 2 at the submillimeter band and the relatively short 2-year duration of this burst suggest that the event is probably similar to those milder and more frequent minor bursts seen in 3D numerical simulations.Comment: 8 pages, 4 figures, Accepted for publication in The Astrophysical Journal Lette

    Biscarbamate cross-linked polyethylenimine derivative with low molecular weight, low cytotoxicity, and high efficiency for gene delivery

    Get PDF
    Polyethylenimine (PEI), especially PEI 25 kDa, has been widely studied for delivery of nucleic acid drugs both in vitro and in vivo. However, it lacks degradable linkages and is too toxic for therapeutic applications. Hence, low-molecular-weight PEI has been explored as an alternative to PEI 25 kDa. To reduce cytotoxicity and increase transfection efficiency, we designed and synthesized a novel small-molecular-weight PEI derivative (PEI-Et, Mn: 1220, Mw: 2895) with ethylene biscarbamate linkages. PEI-Et carried the ability to condense plasmid DNA (pDNA) into nanoparticles. Gel retardation assay showed complete condensation of pDNA at w/w ratios that exceeded three. The particle size of polymer/pDNA complexes was between 130 nm and 180 nm and zeta potential was 5–10 mV, which were appropriate for cell endocytosis. The morphology of PEI-Et/pDNA complexes observed by atomic force microscopy (AFM) was spherically shaped with diameters of 110–190 nm. The transfection efficiency of polymer/pDNA complexes as determined with the luciferase activity assay as well as fluorescence-activated cell-sorting analysis (FACS) was higher than commercially available PEI 25 kDa and Lipofectamine 2000 in various cell lines. Also, the polymer exhibited significantly lower cytotoxicity compared to PEI 25 kDa at the same concentration in three cell lines. Therefore, our results indicated that the PEI-Et would be a promising candidate for safe and efficient gene delivery in gene therapy

    Chinese Herbal Medicine Improves the Long-Term Survival Rate of Patients With Chronic Kidney Disease in Taiwan: A Nationwide Retrospective Population-Based Cohort Study

    Get PDF
    Background and purpose: Chinese herbal medicine (CHM) is frequently applied in conjunction with western pharmacotherapy to relieve symptoms in patients with CKD. However, evidence-based research into the effectiveness of CHM use as applied to treat CKD is limited and warrants further investigation. The aim of this study is to assess whether adjunctive treatment with CHM affected survival rate of CKD patients undergoing conventional western medical management.Methods: A total of 14,718 CKD patients, including 6,958 CHM users and 7,760 non-CHM users, were recruited from the Longitudinal Health Insurance Database 2000, a sub-dataset of the National Health Insurance Research Database, to conduct this study. Demographic characteristics, including sex, age, job type, residential area, and comorbidity were considered as covariates to adjust the analysis. A network analysis of treatments, including with herbal formulas and single herbs, was performed to investigate the core patterns of CHM use for the treatment of CKD patients. The Kaplan-Meier method was used to determine the survival rate between CHM and non-CHM groups.Results: After matching for sex and age, there were 550 subjects in both the CHM and non-CHM cohorts. Other than presence of diabetes (adjusted OR = 0.57, p < 0.001) and urinary tract infection (adjusted OR = 0.69, p < 0.05), sex, age, job type, area of residence, and other comorbidities indicated no special preference for CHM use among subjects. Salvia miltiorrhiza Bunge (SM) and Ji-Sheng-Shen-Qi-Wan (JSSQW) were the most frequent single herb and formula, respectively, prescribed for patients with CKD. The most frequent CHM combination between herbs and formulas was JSSQW, associated with Rheum officinale Baill. (RO), SM and Astragalus membranaceus (Fisch.) Bunge (AM). The long-term survival rate demonstrated significant benefits for CHM users within a 12-year follow-up period (P < 0.004).Conclusion: This nationwide retrospective cohort study provides valuable insight into the characteristics and prescription patterns of CHM usage in CKD patients. JSSQW associated with RO, SM, and AM is the most common CHM prescription. CHM improves long-term survival in patients with CKD, suggesting that CHM is an effective adjuvant therapy for CKD
    corecore