367 research outputs found
Ruling Out Bosonic Repulsive Dark Matter in Thermal Equilibrium
Self-interacting dark matter (SIDM), especially bosonic, has been considered
a promising candidate to replace cold dark matter (CDM) as it resolves some of
the problems associated with CDM. Here, we rule out the possibility that dark
matter is a repulsive boson in thermal equilibrium. We develop the model first
proposed by Goodman (2000) and derive the equation of state at finite
temperature. Isothermal spherical halo models indicate a Bose-Einstein
condensed core surrounded by a non-degenerate envelope, with an abrupt density
drop marking the boundary between the two phases. Comparing this feature with
observed rotation curves constrains the interaction strength of our model's DM
particle, and Bullet Cluster measurements constrain the scattering cross
section. Both ultimately can be cast as constraints on the particle's mass. We
find these two constraints cannot be satisfied simultaneously in any realistic
halo model---and hence dark matter cannot be a repulsive boson in thermal
equilibrium. It is still left open that DM may be a repulsive boson provided it
is not in thermal equilibrium; this requires that the mass of the particle be
significantly less than a millivolt.Comment: 13 pages, 3 figures, 1 table, accepted MNRAS August 9 201
Assessing the number of users who are excluded by domestic heating controls
This is the pre-print version of the Article. This Article is also referred to as: "Assessing the 'Design Exclusion' of Heating Controls at a Low-Cost, Low-Carbon Housing Development". - Copyright @ 2011 Taylor & FrancisSpace heating accounts for almost 60% of the energy delivered to housing which in turn accounts for nearly 27% of the total UK's carbon emissions. This study was conducted to investigate the influence of heating control design on the degree of ‘user exclusion’. This was calculated using the Design Exclusion Calculator, developed by the Engineering Design Centre at the University of Cambridge. To elucidate the capability requirements of the system, a detailed hierarchical task analysis was produced, due to the complexity of the overall task. The Exclusion Calculation found that the current design placed excessive demands upon the capabilities of at least 9.5% of the UK population over 16 years old, particularly in terms of ‘vision’, ‘thinking’ and ‘dexterity’ requirements. This increased to 20.7% for users over 60 years old. The method does not account for the level of numeracy and literacy and so the true exclusion may be higher. Usability testing was conducted to help validate the results which indicated that 66% of users at a low-carbon housing development could not programme their controls as desired. Therefore, more detailed analysis of the cognitive demands placed upon the users is required to understand where problems within the programming process occur. Further research focusing on this cognitive interaction will work towards a solution that may allow users to behave easily in a more sustainable manner
Long-Term Follow-Up of Children Treated With Peginterferon and Ribavirin for Hepatitis C Virus Infection
Objectives: The aim of the study was to describe the 5-year follow-up of children who received peginterferon and ribavirin in a global, open-label study. Methods: A 5-year follow-up study of 107 children and adolescents ages 3 to 17 years with chronic hepatitis C virus infection who received peginterferon and ribavirin for 24 or 48 weeks. No drugs were administered during follow-up. Results: Ninety-four patients were enrolled in the long-term follow-up portion of the study;the median duration of follow-up was 287 weeks (range, 73-339). Of 63 patients with sustained virologic response who were enrolled, 54 completed 5 years of follow-up;none had relapse in the 5-year follow-up period. Significant decreases in height z scores were observed during treatment. The effect of treatment on height z score was larger in patients treated for 48 weeks compared with those treated for 24 weeks (mean change from baseline to the end of treatment was -0.13 [P < 0.001] and -0.44 [P < 0.001] in the 247 and 48-week treatment groups, respectively). Among patients treated for 24 weeks, full recovery of height z scores to baseline was observed by 1 year of follow-up, whereas only partial recovery was observed during 5 years of follow-up in patients treated for 48 weeks (mean change from baseline to the final follow-up visit was -0.16 (P=NS) and 0.32 (P < 0.05) in the 24- and 48-week treatment groups, respectively). Similar patterns were observed for weight and body mass index z scores. Conclusions: Impairment of growth should be considered when assessing the risk-benefit profile of peginterferon/ribavirin therapy in children with hepatitis C virus infection. In deciding to treat children with chronic hepatitis C virus, considerations should include both deferring treatment in patients during optimal growth periods, and the possibility that interferon free regimens may be available to children in the next 5 to 10 years
Effects of Red Clover Isoflavones on Tall Fescue Seed Fermentation and Microbial Populations \u3cem\u3eIn Vitro\u3c/em\u3e
Negative impacts of endophyte-infected Lolium arundinaceum (Darbyshire) (tall fescue) are responsible for over $2 billion in losses to livestock producers annually. While the influence of endophyte-infected tall fescue has been studied for decades, mitigation methods have not been clearly elucidated. Isoflavones found in Trifolium pratense (red clover) have been the subject of recent research regarding tall fescue toxicosis mitigation. Therefore, the aim of this study was to determine the effect of ergovaline and red clover isoflavones on rumen microbial populations, fiber degradation, and volatile fatty acids (VFA) in an in vitro system. Using a dose of 1.10 mg × L-1, endophyte-infected or endophyte-free tall fescue seed was added to ANKOM fiber bags with or without 2.19 mg of isoflavones in the form of a control, powder, or pulverized tablet, resulting in a 2 × 3 factorial arrangements of treatments. Measurements of pH, VFA, bacterial taxa, as well as the disappearance of neutral detergent fiber (aNDF), acid detergent fiber (ADF), and crude protein (CP) were taken after 48 h of incubation. aNDF disappearance values were significantly altered by seed type (P = 0.003) and isoflavone treatment (P = 0.005), and ADF disappearance values were significantly different in a seed × isoflavone treatment interaction (P ≤ 0.05). A seed × isoflavone treatment interaction was also observed with respect to CP disappearance (P ≤ 0.05). Eighteen bacterial taxa were significantly altered by seed × isoflavone treatment interaction groups (P ≤ 0.05), eight bacterial taxa were increased by isoflavones (P ≤ 0.05), and ten bacterial taxa were altered by seed type (P ≤ 0.05). Due to the beneficial effect of isoflavones on tall fescue seed fiber degradation, these compounds may be viable options for mitigating fescue toxicosis. Further research should be conducted to determine physiological implications as well as microbiological changes in vivo
Adefovir Dipivoxil for the Treatment of Hepatitis B e Antigen–Positive Chronic Hepatitis B
BACKGROUND
In preclinical and phase 2 studies, adefovir dipivoxil demonstrated potent activity against hepatitis B virus (HBV), including lamivudine-resistant strains. METHODS
We randomly assigned 515 patients with chronic hepatitis B who were positive for hepatitis B e antigen (HBeAg) to receive 10 mg of adefovir dipivoxil (172 patients), 30 mg of adefovir dipivoxil (173), or placebo (170) daily for 48 weeks. The primary end point was histologic improvement in the 10-mg group as compared with the placebo group. RESULTS
After 48 weeks of treatment, significantly more patients who received 10 mg or 30 mg of adefovir dipivoxil per day than who received placebo had histologic improvement (53 percent [P CONCLUSIONS
In patients with HBeAg-positive chronic hepatitis B, 48 weeks of 10 mg or 30 mg of adefovir dipivoxil per day resulted in histologic liver improvement, reduced serum HBV DNA and alanine aminotransferase levels, and increased the rates of HBeAg seroconversion. The 10-mg dose has a favorable risk–benefit profile for long-term treatment. No adefovir-associated resistance mutations were identified in the HBV DNA polymerase gene
Prognostic value of Ishak fibrosis stage: Findings from the hepatitis C antiviral long-term treatment against cirrhosis trial
Studies of the prognostic value of Ishak fibrosis stage are lacking. We used multi-year follow-up of the Hepatitis C Antiviral Long-Term Treatment Against Cirrhosis (HALT-C) Trial to determine whether individual Ishak fibrosis stages predicted clinical outcomes in patients with chronic hepatitis C. Baseline liver biopsy specimens from 1050 patients with compensated chronic hepatitis C who had failed combination peginterferon and ribavirin were reviewed by a panel of expert hepatopathologists. Fibrosis was staged with the Ishak scale (ranging from 0 = no fibrosis to 6 = cirrhosis). Biopsy fragmentation and length as well as number of portal tracts were recorded. We compared rates of prespecified clinical outcomes of hepatic decompensation and hepatocellular carcinoma across individual Ishak fibrosis stages. Of 1050 biopsy specimens, 25% were fragmented, 63% longer than 1.5 cm, 69% larger than 10 mm 2 , and 75% had 10 or more portal tracts. Baseline laboratory markers of liver disease severity were worse and the frequency of esophageal varices higher with increasing Ishak stage ( P < 0.0001). The 6-year cumulative incidence of first clinical outcome was 5.6% for stage 2, 16.1% for stage 3, 19.3% for stage 4, 37.8% for stage 5, and 49.3% for stage 6. Among nonfragmented biopsy specimens, the predictive ability of Ishak staging was enhanced; however, no association was observed between Ishak stage and outcomes for fragmented biopsy specimens because of high rates of outcomes for patients with noncirrhotic stages. Similar results were observed with liver transplantation or liver-related death as the outcome. Conclusion : Ishak fibrosis stage predicts clinical outcomes, need for liver transplantation, and liver-related death in patients with chronic hepatitis C. Patients with fragmented biopsy specimens with low Ishak stage may be understaged histologically. (H EPATOLOGY 2010;51:585–594.)Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/64929/1/23315_ftp.pd
Telbivudine versus lamivudine in patients with chronic hepatitis B
BACKGROUND: Reducing hepatitis B virus (HBV) replication to minimal levels is emerging as a key therapeutic goal for chronic hepatitis B. METHODS: In this double-blind, phase 3 trial, 1370 patients with chronic hepatitis B were randomly assigned to receive 600 mg of telbivudine or 100 mg of lamivudine once daily. The primary efficacy end point was noninferiority of telbivudine to lamivudine for therapeutic response (i.e., a reduction in serum HBV DNA levels to fewer than 5 log 10 copies per milliliter, along with loss of hepatitis B e antigen [HBeAg] or normalization of alanine aminotransferase levels). Secondary efficacy measures included histologic response, changes in serum HBV DNA levels, and HBeAg responses. RESULTS: At week 52, a significantly higher proportion of HBeAg-positive patients receiving telbivudine than of those receiving lamivudine had a therapeutic response (75.3% vs. 67.0%, P = 0.005) or a histologic response (64.7% vs. 56.3%, P = 0.01); telbivudine also was not inferior to lamivudine for these end points in HBeAg-negative patients. In HBeAg-positive and HBeAg-negative patients, telbivudine was superior to lamivudine with respect to the mean reduction in the number of copies of HBV DNA from baseline, the proportion of patients with a reduction in HBV DNA to levels undetectable by polymerase-chain-reaction assay, and development of resistance to the drug. Elevated creatine kinase levels were more common in patients who received telbivudine, whereas elevated alanine aminotransferase and aspartate aminotransferase levels were more common in those who received lamivudine. CONCLUSIONS: Among patients with HBeAg-positive chronic hepatitis B, the rates of therapeutic and histologic response at 1 year were significantly higher in patients treated with telbivudine than in patients treated with lamivudine. In both the HBeAg-negative and the HBeAg-positive groups, telbivudine demonstrated greater HBV DNA suppression with less resistance than did lamivudine. (ClinicalTrials.gov number, NCT00057265.) Copyright © 2007 Massachusetts Medical Society.published_or_final_versio
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