This paper describes a method for model predictive control (MPC) with model maintenance. A supervisor maintains the control model in real time by providing an estimate of disturbances and noise. A ...switch is triggered when the predictions of the control model deviate from disturbance estimate by more than a pre-determined amount. The predictive control algorithm described in the paper uses the innovation representation of a Markov–Laguerre model. A Monte Carlo study and an experiment show that good models and stable control are obtained. A simulation study based on models of a boiler–turbine unit shows that the algorithm can adapt to time-varying data. The performance is assessed using the area regulation (AR) test criterion currently adopted by PJM Interconnection LLC. The proposed adaptive MPC gives an AR test score of more than 90 with pressure fluctuations less than 3% even when the coal quality changes.
Human metapneumovirus (HMPV) is a newly discovered pathogen thought to be associated with respiratory disease. We report the results of a study of 587 children hospitalized with respiratory infection ...over a 13-month period. HMPV was detected in the nasopharyngeal aspirates from 32 (5.5%) children by reverse transcription-polymerase chain reaction. HMPV infection was associated with clinical diagnoses of pneumonia (36%), asthma exacerbation (23%), or acute bronchiolitis (10%). When compared to those with respiratory syncytial virus infection, children with HMPV infection were older, and wheezing was more likely to represent asthma exacerbation rather than acute bronchiolitis. HMPV viral activity peaked during the spring-summer period in Hong Kong. Phylogenetically, all HMPV virus strains from Hong Kong belonged to one of the two genetic lineages previously described. HMPV contributed to 441.6 hospital admissions per 100,000 population <6 years of age.
► Plasma Aβ oligomers level is higher in AD patients compared to non-demented controls. ► Highest tertile of plasma Aβ oligomers independently associated with increased AD risk. ► Plasma Aβ oligomers ...level negatively correlated with cognition in AD. ► Plasma Aβ oligomers level: an useful biomarker for AD diagnosis.
Amyloid beta (Aβ), especially Aβ oligomers, is important in Alzheimer’s disease (AD) pathogenesis. We studied plasma Aβ40, Aβ42, and Aβ oligomers levels in 44 AD patients and 22 non-demented controls. Cognitive functions were assessed by Chinese version of mini-mental state examination (MMSE), Abbreviated Metal Test (AMT), Alzheimer’s Disease Assessment Scale Cognitive Subscale (ADAS-cog). Plasma Aβ monomers and oligomers levels were measured by ELISA. We found that the median plasma Aβ40 and Aβ42 levels were similar between AD and controls, and without significant correlation with cognition. Plasma Aβ oligomers level was higher in AD than controls (642.54ng/ml range 103.33–2676.93 versus 444.18ng/ml range 150.19–1311.18, p=0.047), and negatively correlated with cognition. In multivariate logistic regression analysis, the highest tertile of Aβ oligomers levels showed an increased risk of AD than the combined group of middle and lowest tertiles (OR=8.85, p=0.013), after adjustment of gender, age and APOE4 genotype. Increased plasma Aβ oligomers level was associated with decreased MMSE and AMT scores (p=0.037, p=0.043, respectively) and increased ADAS-cog score (p=0.036), suggesting negative correlation with cognitive function. We concluded that plasma Aβ oligomers level is an useful biomarker for AD diagnosis.
Abstract Background A novel swine origin influenza virus (S-OIV) (H1N1) is spreading worldwide and threatens to become pandemic. Objectives Determine analytical sensitivity of selected commercially ...available rapid influenza antigen detection tests in detecting S-OIV H1N1. Study design Serial dilutions of two S-OIV isolates, one seasonal influenza A (H1N1) isolate and a nasopharyngeal aspirate from a patient with S-OIV disease were tested in five commercially available influenza antigen detection tests and by virus isolation in cell culture. Viral M gene copy number was determined by quantitative PCR methods. Results The analytical sensitivity of the five influenza antigen detection tests for S-OIV (tissue culture infectious dose 50 (TCID50 ) log10 3.3–4.7 was comparable with that of seasonal influenza (TCID50 log10 4.0–4.5). Conclusion The analytical sensitivity of the selected influenza A antigen detection tests for detection of S-IOV was comparable with that of seasonal influenza H1N1.
Abstract Background The quality of clinical specimens is a crucial determinant for virological diagnosis. Objectives We compared the viral diagnostic yield for influenza A and respiratory syncytial ...virus (RSV) from the recently developed nasopharyngeal flocked swabs (NPFS) with nasopharyngeal aspirates (NPA) collected in parallel from 196 hospitalized children with acute respiratory infection during the peak period of influenza A and RSV activity in Hong Kong. Specimens were tested by RT-PCR for influenza A and RSV and viral load determined. They were also tested by direct immunofluorescence (DIF) for influenza A and B, RSV, parainfluenza types 1–3 and adenovirus. Results Both NPA and NPFS had excellent sensitivity (100%) for detecting influenza A by RT-PCR but NPA was slightly more sensitive than NPFS for detecting RSV by both RT-PCR (100% vs. 92.3%) and DIF (87.2% vs. 84.6%) and for detecting influenza A by DIF (90.2% vs. 82.9%). Viral load for influenza A in NPA and NPFS was not significantly different but that for RSV was higher in NPA. Conclusion NPA remains the optimal specimen for diagnosis of respiratory infections by RT-PCR and DIF. However, collection of NPFS is easier to perform in an out-patient setting, was more acceptable to parents and less likely to generate aerosols than NPA engendering potentially less infection control hazard.
The primary cause of severe acute respiratory syndrome (SARS) is a newly discovered coronavirus. Replication of this SARS coronavirus (SCV) occurs mainly in the lower respiratory tract, and causes ...diffuse alveolar damage. Lack of understanding of the pathogenesis of SARS has prevented the rational development of a therapy against this disease. Here we show extensive SCV antigen expression in type 1 pneumocytes of experimentally infected cynomolgus macaques (Macaca fascicularis) at 4 d postinfection (d.p.i.), indicating that this cell type is the primary target for SCV infection early in the disease, and explaining the subsequent pulmonary damage. We also show that prophylactic treatment of SCV-infected macaques with the antiviral agent pegylated interferon-α (IFN-α) significantly reduces viral replication and excretion, viral antigen expression by type 1 pneumocytes and pulmonary damage, compared with untreated macaques. Postexposure treatment with pegylated IFN-α yielded intermediate results. We therefore suggest that pegylated IFN-α protects type 1 pneumocytes from SCV infection, and should be considered a candidate drug for SARS therapy
For daily CyberKnife QA a Winston-Lutz-Test (Automated-Quality-Assurance, AQA) is used to determine sub-millimeter deviations in beam delivery accuracy. This test is performed using gafchromic film, ...an extensive and user-dependent method requiring the use of disposables. We therefore analyzed the usability and accuracy of high-resolution detector arrays. We analyzed a liquid-filled ionization-chamber array (Octavius 1000SRS, PTW, Germany), which has a central resolution of 2.5mm. To test sufficient sensitivity, beam profiles with robot shifts of 0.1mm along the arrays' axes were measured. The detected deviation between the shifted and central profile were compared to the real robot's position. We then compared the results to the SRS-Profiler (SunNuclear, USA) with 4.0mm resolution and to the Nonius (QUART, Germany), a single-line diode detector with 2.8mm resolution. Finally, AQA variance and usability were analyzed performing a number of AQA tests over time, which required the use of specially designed fixtures for each array, and the results were compared to film. Concerning sensitivity, the 1000SRS detected the beam profile shifts with a maximum difference of 0.11mm (mean deviation = 0.03mm) compared to the actual robot shift. The Nonius and SRS-Profiler showed differences of up to 0.15mm and 0.69mm with mean deviation of 0.05mm and 0.18mm, respectively. Analyzing the variation of AQA results over time, the 1000SRS showed a comparable standard deviation to film (0.26mm vs. 0.18mm). The SRS-Profiler and the Nonius showed a standard deviation of 0.16mm and 0.24mm, respectively. The 1000SRS seems to provide equivalent accuracy and sensitivity to the gold standard film when performing daily AQA tests. Compared to other detectors in our study the sensitivity as well as the accuracy of the 1000SRS appears to be superior and more user-friendly. Furthermore, no significant modification of the standard AQA procedure is required when introducing 1000SRS for CyberKnife AQA.
Background. Large clinical trials have demonstrated the therapeutic efficacy of oseltamivir against influenza. We assessed the indirect effectiveness of oseltamivir in reducing secondary household ...transmission in an incident cohort of influenza index patients and their household members. Methods. We recruited index outpatients whose rapid test results were positive for influenza from February through September 2007 and January through September 2008. Household contacts were followed up for 7–10 days during 3–4 home visits to monitor symptoms. Nose and throat swabs were collected and tested for influenza by reverse-transcription polymerase chain reaction or viral culture. Results. We followed up 384 index patients and their household contacts. Index patients who took oseltamivir within 24 h of symptom onset halved the time to symptom alleviation (adjusted acceleration factor, 0.56; 95% confidence interval CI, 0.42–0.76). Oseltamivir treatment was not associated with statistically significant reduction in the duration of viral shedding. Household contacts of index patients who had taken oseltamivir within 24 h of onset had a nonstatistically significant lower risk of developing laboratory-confirmed infection (adjusted odds ratio, 0.54; 95% CI, 0.11–2.57) and a marginally statistically significant lower risk of clinical illness (adjusted odds ratio, 0.52; 95% CI, 0.25–1.08) compared with contacts of index patients who did not take oseltamivir. Conclusions. Oseltamivir treatment is effective in reducing the duration of symptoms, but evidence of household reduction in transmission of influenza virus was inconclusive.
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