Correction: Steam turbine power prediction based on encode-decoder framework guided by the condenser vacuum degree.

[This corrects the article DOI: 10.1371/journal.pone.0275998.].

Steam turbine power prediction based on encode-decoder framework guided by the condenser vacuum degree.

The steam turbine is one of the major pieces of equipment in thermal power plants. It is crucial to predict its output accurately. However, because of its complex coupling relationships with other equipment, it is still a challenging task. Previous methods mainly focus on the operation of the steam turbine individually while ignoring the coupling relationship with the condenser, which we believe is crucial for the prediction. Therefore, in this paper, to explore the coupling relationship between steam turbine and condenser, we propose a novel approach for steam turbine power prediction based on the encode-decoder framework guided by the condenser vacuum degree (CVD-EDF). In specific, the historical information within condenser operation conditions data is encoded using a long-short term memory network. Moreover, a connection module consisting of an attention mechanism and a convolutional neural network is incorporated to capture the local and global information in the encoder. The steam turbine power is predicted based on all the information. In this way, the coupling relationship between the condenser and the steam turbine is fully explored. Abundant experiments are conducted on real data from the power plant. The experimental results show that our proposed CVD-EDF achieves great improvements over several competitive methods. our method improves by 32.2% and 37.0% in terms of RMSE and MAE by comparing the LSTM at one-minute intervals.

Identification and application of self-binding zipper-like sequences in SARS-CoV spike protein.

Self-binding peptides containing zipper-like sequences, such as the Leu/Ile zipper sequence within the coiled coil regions of proteins and the cross-ß spine steric zippers within the amyloid-like fibrils, could bind to the protein-of-origin through homophilic sequence-specific zipper motifs. These self-binding sequences represent opportunities for the development of biochemical tools and/or therapeutics. Here, we report on the identification of a putative self-binding ß-zipper-forming peptide within the severe acute respiratory syndrome-associated coronavirus spike (S) protein and its application in viral detection. Peptide array scanning of overlapping peptides covering the entire length of S protein identified 34 putative self-binding peptides of six clusters, five of which contained octapeptide core consensus sequences. The Cluster I consensus octapeptide sequence GINITNFR was predicted by the Eisenberg's 3D profile method to have high amyloid-like fibrillation potential through steric ß-zipper formation. Peptide C6 containing the Cluster I consensus sequence was shown to oligomerize and form amyloid-like fibrils. Taking advantage of this, C6 was further applied to detect the S protein expression in vitro by fluorescence staining. Meanwhile, the coiled-coil-forming Leu/Ile heptad repeat sequences within the S protein were under-represented during peptide array scanning, in agreement with that long peptide lengths were required to attain high helix-mediated interaction avidity. The data suggest that short ß-zipper-like self-binding peptides within the S protein could be identified through combining the peptide scanning and predictive methods, and could be exploited as biochemical detection reagents for viral infection.

Evaluation of two commercial real-time PCR kits for detection of pandemic (H1N1) 2009 virus in Beijing.

Active surveillance and diagnosis of the influenza pandemic (H1N1) 2009 (pH1N1) have played a critical role in the effective control and prevention of the pandemic in China. Although several commercially available real-time PCR kits for pH1N1 virus have been used in diagnostic laboratories in Beijing, little has been known about the performance of these kits for detecting pH1N1 virus. In this study, the performance of two commercial real-time PCR kits in Beijing was evaluated. Analysis of clinical samples showed that the positive detection rate for the AgPath-ID™ kit (38.2%) was significantly higher than that for the Da An H1N1 kit (30.0%) (McNemar's chi-square test, P=0.000). The limit of detection (LOD) of the AgPath-ID™ kit was 10(2), 10(2), and 10(3) copies/reaction for the Influenza A (set 1), H1N1 Influenza A (set 2) and H1N1 Influenza A Sub H1 (set 3) genes, respectively, whereas the LOD of the Da An kit was 10(3) copies/reaction for both H1 and N1 genes. Although the AgPath-ID™ kit exhibited a significantly higher detection rate for pH1N1 than the Da An kit, cross-reactivity to A/PR8/34 was found for the AgPath-ID™ kit for H1N1 Influenza A (set 2).

[Etiological characteristics of influenza A (H1N1) 2009 virus in Beijing].

OBJECTIVE: To analyze the results of detection on influenza A (H1N1) 2009 virus in Beijing from May 2009 to December 2009 and to understand the epidemiologic characteristics during the pandemic period. METHODS: The study was conducted from the May 1 to December 27, 2009. A total of 101 852 throat swab samples were detected with the real-time RT-PCR assay by the Beijing Network Laboratory. Data was statistically analyzed. RESULTS: 9843 samples showed influenza A (H1N1) 2009 positive, with an overall positive rate as 9.66%. In terms of the positive rates, they were 2.85% from May to June, 3.32% from July to August and 8.35% from September to October. The peak month fell in November (29.67%) and December (24.33%). The positive rates among the following subpopulations were: 8.40% among the suspected cases, 4.75% among close contact cases, 11.46% among the influenza-like illness cases and 7.33% among the cluster cases with fever. Positive cases mainly fell in age groups 5 - 14 and 15 - 24. The ratio of male to female was 1.5:1. CONCLUSION: During the pandemic period of influenza A (H1N1) 2009, positive cases gradually increased during May to November but slowly decreasing in December.

[The significance of different sample types in study of pandemic A (H1N1) influenza diagnosis].

OBJECTIVE: To explore the value of different types of samples, including throat swabs, stools, bloods in pandemic A (H1N1) influenza diagnosis and virus shedding patterns. METHODS: From May to June in 2009, 135 samples were collected from 23 confirmed cases of pandemic influenza A (H1N1) infection, including 99 throat swabs, 14 stools, 11 bloods, 1 respiratory tract washing from 13 confirmed cases and 10 blood samples from other confirmed cases. The virus was detected by real-time RT-PCR, the antibody was detected by haemagglutination inhibition assay. RESULTS: For 99 throat swabs of 13 patients, the median time of the first positive real-time RT-PCR was 1 day (ranged from 0 to 7 days) after the onset of the symptoms of illness; the median length of time duration of positive real-time RT-PCR results from throat swabs was 3 days (ranged from 1 to 15 days). Four cases intermittently released virus. One respiratory tract washing sample was positive. In 14 stools, 8 stools were real-time RT-PCR positive, the positive rate was 57.14%. The median time of the positive real-time RT-PCR was 3 days (ranged from 1 to 4 days) after the onset of the symptoms of illness. In 21 blood samples collected at 2 to 9 days of onset, 1 blood sample was real-time RT-PCR positive, the positive rate was 4.76%. All these 21 blood samples were antibody negative. CONCLUSION: Throat swabs and stools samples can be used as A (H1N1) influenza early diagnosis. The length of time duration of positive real-time RT-PCR in throat swabs was longer than stool samples and intermittently releasing of virus were found in throat swabs. Influenza A H1N1 cases showed the presence of small amount of viremia and antibody was negative in early blood samples (< 9 days).

Review of an influenza surveillance system, Beijing, People's Republic of China.

In 2007, a surveillance system for influenza-like illness (ILI) and virologic data was established in Beijing, China. The system tracked ILI and laboratory-confirmed influenza in 153 general hospitals from September 1, 2007, through April 30, 2008. To analyze the ILI surveillance data (weekly ILI rates and counts) and the effectiveness of the system, we used the US Centers for Disease Control and Prevention Early Aberration Reporting System. The data indicated that the highest rate of influenza isolation and the highest ILI count occurred in the first week of 2008. The system enabled us to detect the onset and peak of an epidemic.

Importance of SARS-CoV spike protein Trp-rich region in viral infectivity.

SARS-CoV entry is mediated by spike glycoprotein. During the viral and host cellular membrane fusion, HR1 and HR2 form 6-helix bundle, positioning the fusion peptide closely to the C-terminal region of ectodomain to drive apposition and subsequent membrane fusion. Connecting to the HR2 region is a Trp-rich region which is absolutely conserved in members of coronaviruses. To investigate the importance of Trp-rich region in SARS-CoV entry, we produced different mutated S proteins using Alanine scan strategy. SARS-CoV pseudotyped with mutated S protein was used to measure viral infectivity. To restore the aromaticity of Ala-mutants, we performed rescue experiments using phenylalanine substitutions. Our results show that individually substituted Ala-mutants substantially decrease infectivity by >90%, global Ala-mutants totally abrogated infectivity. In contrast, Phe-substituted mutants are able to restore 10-25% infectivity comparing to the wild-type. The results suggest that the Trp-rich region of S protein is essential for SARS-CoV infectivity.

Lipid rafts are involved in SARS-CoV entry into Vero E6 cells.

Lipid rafts often serve as an entry site for certain viruses. Here, we report that lipid rafts in Vero E6 cells are involved in the entry of severe acute respiratory syndrome coronavirus (SARS-CoV). Infectivity assay showed the integrity of lipid rafts was required for productive infection of pseudotyped SARS-CoV. Depletion of plasma membrane cholesterol with MbetaCD relocalized raft-resident marker caveolin-1 as well as SARS-CoV receptor ACE2 to a nonraft environment, but did not significantly change the surface expression of ACE2. MbetaCD-treatment inhibited infectivity of pseudotyped SARS-CoV by 90%. Biochemical fractionation and confocal imaging confirmed that ACE2 colocalized with raft-resident markers. Furthermore, an ectodomain of SARS-CoV S protein (S1188HA) could associate with lipid rafts after binding to its receptor, and colocalize with raft-resident marker ganglioside GM1. The binding of S1188HA was not affected by depleting plasma membrane cholesterol. Taken together, our results support that lipid rafts serve as an entry port for SARS-CoV.

[The expression of 5 immune molecules on rat peripheral leucocytes after heart transplantation].

AIM: To observe 5 kinds of immune molecule expressions on rat peripheral leucocytes at varying time points after ectopic heart transplantation and explore the mechanism of acute rejection reaction. METHODS: Donor's heart derived from SD rat was transplanted into the abdomen cavity of Wistar rat by anastomosis of donor's aorta and pulmonary artery to recipient's abdominal aorta and inferior-venacava for establishing coronary perfusion. Before and after transplantation, peripheral leucocytes were isolated from venous blood and labelled with the monoclonal antibodies(mAbs) against CD4, CD8, IL-2R, ICAM-I and MHC-II molecules, respectively. The these molecule levels were assessed by flowcytometry. Simultaneity, graft's pathological changes and their survival rate were observed. RESULTS: At 24 hours after transplantation, MHC-II molecule expression was increased, while expressions of CD4, IL-2R and ICAM-I were significantly decreased, but CD8 expression had no change. At 72 hours after operation, the expressions of CD4, CD8 and IL-2R increased and expressions of CD8 and IL-2R reached to peak. At 7-10 days after operation, except that CD4 expression increased continuously, the expressions of 4 other molecules decreased gradually. The survival rate of graft at varying times after operation were 100%( 24 h), 85.7%(3 days), 16.7%(7 days) and, 0 (10 and 12 days), respectively. Pathological examination showed that there was no notable pathological change in cardiac muscle tissue. At the third day after operation, 4 out of 7 transplanted hearts had only grade I A pathological change. Grade II and above grade II pathological changes were observed in all 6 grafts at the 7th day after operation. CONCLUSION: These data indicate that graft rejection reaction begin to appear in first 72 hours, and effector phase of the reaction appear mainly within 3-7 days after heart transplantation.