Seroprevalence of dengue IgG antibodies in symptomatic and asymptomatic individuals three years after an outbreak in Zhejiang Province, China.

BACKGROUND: Cross-reacting antibodies enhanced dengue infection in humans and antibody dependent enhancement (ADE) have been proposed as early mechanisms underlying DHF/DSS. However, the duration of dengue IgG antibodies in the body as well as factors associated with said duration remain unclear. METHODS: Blood samples from 59 dengue symptomatic persons and 48 asymptomatic individuals were collected. Study participant demographic information (including age in 2009, gender, and place of residence) were also collected. Serum samples were tested for dengue specific IgG by Panbio dengue IgG indirect enzyme-linked immunosorbent assay (ELISA). Chi-square tests and logistic regression analysis of dengue IgG antibodies seroprevalence divided by gender, age groups, and symptomatic or asymptomatic infection were conducted using the Statistical Package for the Social Sciences. RESULTS: Overall, 70 (65.42%) blood samples were seropositive for dengue IgG antibodies with similar seroprevalences found when dividing by gender and different age groups. However, seroprevalence of dengue IgG antibodies in samples from dengue symptomatic persons was significantly higher than that in samples from asymptomatic individuals (96.61% vs 27.08%) according to multivariable logistic regression analysis, the odds ratio (OR) of the factor was 76.731. CONCLUSIONS: Dengue IgG antibodies were detectable in samples from most individuals three years after infection. Dengue symptomatic persons had a higher dengue IgG prevalence compared to asymptomatic individuals.

Full-length sequence analysis of hepatitis E virus isolates: showing potential determinants of virus genotype and identity.

The complete genome sequence of a genotype 4 strain of hepatitis E virus (CH-YT-HEV02) from a patient (in Yantai, China) has been determined. Phylogenetic analysis showed that CH-YT-HEV02 belongs to genotype 4, subtype 4a. However, the phylogenetic analysis indicated that it was most closely related to JKO-CHiSai98C (AB197673) strain, sharing only 91.6% sequence identity with it. Judging from the phylogenetic tree based on the full-length nucleotide sequences of all 70 genotype 4 HEV isolates retrieved from GenBank up to May, 2013, the CH-YT-HEV02 isolates could serve as a Yantai-indigenous strain. A broader comparison with other genotype isolates revealed that there are a few conserved amino acids in the HVR region of different HEV genotypes, and two amino acid motifs in ORF2 and ORF3 might serve as signatures of genotype diversity of HEV.

Important evidence of constant low CO2 windows and impacts on the non-closure of the greenhouse effect.

The CO2 distribution in the atmosphere remains unclear for the complexity of the long-range vertical transport process and other influencing factors. In this work, regression analysis was used to verify the accuracy of CO2 concentrations datasets. Geostatistical analyses were used to investigate the spatiotemporal distributions of CO2 at 7 levels from near the surface to the mid-troposphere (0~5 km). Spatial correlation and time series analyses were used to further determine the diffusion characteristics of the CO2 concentration based on the horizontal wind (NCEP R2), which is one of the main driving factors. The results showed that the horizontal, not vertical, diffusion of CO2 becomes increasingly more prominent with the decrease in atmospheric pressure to the mid-troposphere, whereas many regions, such as the Rocky Mountains and Qinghai-Tibet Plateau, have constant low values throughout the year due to the influence of high topography (up to 10.756 ppmv lower than that near the surface). These areas form low CO2 concentration 'windows' keeping letting thermal infrared energy out into space. This study is the first to question the existing view of the closure of the 'greenhouse effect'. Future research studies should more precisely determine the closure threshold and the uncertainties about the surface fluxes.

Competitive O-H and C-H oxidative addition of CH3OH to rhodium(II) porphyrins.

Rhodium(II) porphyrins react with CH(3)OH in benzene by alternate mechanisms that give H-CH(2)OH and H-OCH(3) bond activation in different methanol concentration regimes which is a rare example of transition metal reactivity with methanol.

Hepatitis E seroprevalence and related risk factors among seafood processing workers: a cross-sectional survey in Shandong Province, China.

OBJECTIVE: This study aimed to assess the seroprevalence of hepatitis E virus (HEV) infection and the potential risk factors for acquiring HEV infection in the seafood processing factories in Yantai City of Shandong Province, China. METHODS: A cross-sectional study was conducted in five randomly selected seafood processing factories in Yantai City. Subjects were 15-66 years of age and were raw seafood processing workers, semi-finished products processing workers, and administrative staff, etc. Each participant completed a structured questionnaire and agreed to blood drawing. Anti-HEV IgG antibody was detected in the blood samples by ELISA method. RESULTS: A total of 1028 of 1044 eligible workers were tested for HEV IgG antibody (response rate 98.5%). The prevalence of HEV IgG seropositivity was found to be 22.20%. Occupation was significantly associated with anti-HEV IgG antibody seropositivity (p<0.05). Subjects who had direct contact with raw seafood had a higher anti-HEV IgG antibody prevalence (32.54%) than the semi-finished products processing workers (24.74%) and less exposed group (11.85%). HEV seroprevalence in the workers showed an increasing trend with the increase in working years, and this phenomenon was most obvious in raw seafood processing workers. CONCLUSIONS: There is a higher risk of HEV infection in those who have direct contact with raw seafood. This study will help identify the risk factors for HEV infection and provide guidance on controlling HEV infection in the seafood processing occupations.

Seroprevalence and evolutionary dynamics of genotype 4 hepatitis E virus in Shandong Province, China.

AIM: To investigate the seroprevalence and evolutionary dynamics of hepatitis E virus (HEV) and assess the ancestor of HEVs in China's Shandong Province. METHODS: A total of 2028 serum, 60 fecal and 82 bile samples were collected from the general human population, patients and swine, respectively. This seroepidemiological study was conducted using an immunnosorbent assay and HEV RNA was detected by the reverse transcription-nested polymerase chain reaction (RT-nPCR) method. Complete genome sequences of the prevalent strains (CH-YT-HEV01, CH-YT-HEV02 and CH-YT-sHEV01) were determined, and the sequences were analyzed phylogenetically. In addition, the evolutionary dynamics of three HEV isolates were determined using the framework of coalescent analysis in the program package BEAST, and the time of the most recent common ancestors (TMRCAs) of China-indigenous genotype 4 HEV isolates was calculated. RESULTS: The overall viral burden in the general human population was 0.1%, and the positive rates of anti-HEV IgG and IgM in the serum specimens were 25.1% (509/2028) and 2.3% (51/2028), respectively. In addition, IgG positivity increased with age. The phylogenetic analysis based on the full-length nucleotide sequences showed that the strain CH-YT-HEV02 was directly related to CH-YT-sHEV01 with a 94% identity, suggesting that they were involved in cross-species transmission. The isolate CH-YT-HEV01 was close to HB-3 and CHN-SD-sHEV with a bootstrap value of 100%, sharing a 96.1%-96.4% identity with each other. Surprisingly, the HB-3 strain was a representative strain prevalent in swine in Hubei, and the isolate CHN-SD-sHEV was obtained from swine in Shandong in a previous report. TMRCA for the clade of CH-YT-HEV01 and HB-3 was 2003, which was consistent with the TMRCA for the clade of CHN-SD-sHEV and HB-3, and they were both earlier than the TMRCA for the clade of CH-YT-HEV01 and CHN-SD-sHEV (2004). CONCLUSION: The strains CH-YT-HEV01, CHN-SD-sHEV and HB-3 are involved in trans-regional transmission, and the ancestors of HEVs in Shandong come from Hubei Province.

[The coastal areas of Yantai human and swine hepatitis E virus genotyping analysis].

OBJECTIVE: Survey of the coastal city of Yantai, from human and swine hepatitis E virus (HEV) genotype correlation. METHOD: Application of reverse transcription nested polymerase chain reaction (RT-nPCR) method for local acute sporadic hepatitis E patients,normal population of HEV-IgM positive and local pig farm pigs were HEV RNA detection. And HEV RNA positive samples for cloning sequencing and sequence analysis. RESULTS: In 16 patients with acute sporadic hepatitis E in 7 cases of RNA positive stool specimens of HEV; 51 IgM positive sera of normal people in specimens with 1 HEV RNA positive; 34 pig bile specimens with 1 HEV RNA positive. Sequence analysis revealed the region HEV strains and swine strains in the ORF2 region of nucleotide sequence homology is 87%-98.1%. 7 strains of hepatitis E virus genotype in patients and 1 strains of swine hepatitis E virus genotypes are type IV, gene sequence homology between the 87%-98.1%; there were 6 patients and porcine gene sequence homology in 93.9%-98.1% between,for type a subtype; 1 patients and porcine gene sequence homology in 87%, for the type D subtype. Normal population of 1 cases of hepatitis E virus genotype for I type D subtype. Human and porcine HEV ORF2 gene fragment and HEV part I-IV representative strains were compared, and the nucleotide sequence homology were 82.5%-100%, 81.7%-92.9%, 81.4%-93.9%, 84.9%-100%. CONCLUSION: The area population prevalence of HEV in the presence of 2 genotype 3 subtype genes, mainly to IV A, in pigs with popular HEV gene with a high homology; HEV type I in the crowd disperses in the presence of.

[Epidemiological study on risk factors of hepatitis E in Yantai, Shandong province].

OBJECTIVE: To study the prevalent characteristics and risk factors of viral hepatitis E in Yantai and the relative for strategy on viral hepatitis E control in the area. METHODS: Data on viral hepatitis E incidence reported by the Notifiable Infectious Disease Reporting System in 2005-2009 was analyzed. 2028 persons were chosen for hepatitis E virus (HEV) antibody detection by enzyme linked immunosorbent assay method. RT-nPCR method was applied to obtain the sequence of HEV in HEV cases. A case-control study was used to identify the risk factors of HEV infection. RESULTS: The distribution of HEV cases was sporadic in Yantai, and the annual incidence rate was 5.70/100 000, with spring as the prevalent season. Farmers were the main population involved and with those over the age of 40. Regional distribution was mainly along the coastline. Data from the sequential analysis showed that gene type of local patients was type 4 and healthy person whose HEV-IgM was positive was type l. Finding from the case-control study suggested that eating seafoods, living condition in the households and unhealthy habits played important roles in the infection of HEV. Results from multiple logistic regression showed that eating seafood, with eat-out history, drinking alcohol and un-boiled water were the main risk factors in the infection of HEV. CONCLUSION: The level of HE in Yantai will maintain in a high level, but there is no chance of epidemic outbreak of HE in large range. Population of incidence mainly concentrates on farmers.

Superoxo, peroxo, and hydroperoxo complexes formed from reactions of rhodium porphyrins with dioxygen: thermodynamics and kinetics.

Rhodium(II) porphyrin complexes react with dioxygen to form terminal superoxo and bridged mu-peroxo complexes. Equilibrium constants for dioxygen complex formation with rhodium(II) tetramesitylporphyrin ((TMP)Rh*) and a m-xylyl-tethered dirhodium(II) diporphyrin complex (*Rh(m-xylyl)Rh*) are reported. (TMP)Rh-H reacts with oxygen to form a transient hydroperoxy complex ((TMP)Rh-OOH), which reacts on to form the rhodium(II) complex ((TMP)Rh*) and water. Kinetic studies for reactions of (TMP)Rh-H with O2 suggest a near concerted addition of dioxygen to the (TMP)Rh-H unit. Reactivity studies for mixtures of H2/O2 and CH4/O2 with the dirhodium(II) complex (*Rh(m-xylyl)Rh*) are reported.

Activation of C-H / H-H bonds by rhodium(II) porphyrin bimetalloradicals.

Reactivity, kinetic, and thermodynamic studies are reported for reactions of a rhodium(II) bimetalloradical with H(2), and with the methyl C-H bonds for a series of substrates CH(3)R (R = H, CH(3), OH, C(6)H(5)) using a m-xylyl diether tethered diporphyrin ligand. Bimolecular substrate reactions involving the intramolecular use of two metalloradical centers and preorganization of the four-centered transition state (M*...X...Y*...M) result in large rate enhancements as compared to termolecular reactions of monometalloradicals. Activation parameters and deuterium kinetic isotope effects for the substrate reactions are reported. The C-H bond reactions become less thermodynamically favorable as the substrate steric requirements increase, and the activation free energy (DeltaG++) decreases regularly as DeltaG degrees becomes more favorable. An absolute Rh-H bond dissociation enthalpy of 61.1 +/- 0.4 kcal mol(-1) is directly determined, and the derived Rh-CH(2)R BDE values increase regularly with the increase in the C-H BDE.

Bimetallo-radical carbon-hydrogen bond activation of methanol and methane.

Carbon-hydrogen bond cleavage reactions of CH3OH and CH4 by a dirhodium(II) diporphyrin complex with a m-xylyl tether (.Rh(m-xylyl)Rh.(1)) are reported. Kinetic-mechanistic studies show that the substrate reactions are bimolecular and occur through the use of two Rh(II) centers in the molecular unit of 1. Second-order rate constants (T = 296 K) for the reactions of 1 with methanol (k(CH3OH) = 1.45 x 10-2 M-1 s-1) and methane (k(CH4) = 0.105 M-1 s-1) show a clear kinetic preference for the methane activation process. The methanol and methane reactions with 1 have large kinetic isotope effects (k(CH3OH)/k(CD3OD) = 9.7 +/- 0.8, k(CH4)/k(CD4) = 10.8 +/- 1.0, T = 296 K), consistent with a rate-limiting step of C-H bond homolysis through a linear transition state. Activation parameters for reaction of 1 with methanol (DeltaH = 15.6 +/- 1.0 kcal mol-1; DeltaS = -14 +/- 5 cal K-1 mol-1) and methane (DeltaH = 9.8 +/- 0.5 kcal mol-1; DeltaS = -30 +/- 3 cal K-1 mol-1) are reported.