12 results on '"Xiao-lei, Guo"'
Search Results
2. Nationwide prevalence of human papillomavirus infection and viral genotype distribution in 37 cities in China.
- Author
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Rong Wang, Xiao-lei Guo, Wisman, G. Bea. A., Schuuring, Ed, Wen-feng Wang, Zheng-yu Zeng, Hong Zhu, and Shang-wei Wu
- Subjects
HIV infection epidemiology ,DISEASE prevalence ,DIAGNOSIS of HIV infections ,TRANSMISSION of papillomavirus diseases ,VIRUS diseases ,GENE therapy - Abstract
Background: Type-specific high-risk HPV (hrHPV) infection is related to cervical carcinogenesis. The prevalence of hrHPV infection varies geographically, which might reflect the epidemiological characteristics of cervical cancer among different populations. To establish a foundation for HPV-based screening and vaccination programs in China, we investigated the most recent HPV prevalence and genotypic distributions in different female age groups and geographical regions in China. Methods: In 2012, a total of 120,772 liquid-based cytological samples from women enrolled for population- or employee-based cervical screening in 37 Chinese cities were obtained by the Laboratory of Molecular Infectious Diseases of Guangzhou KingMed. A total of 111,131 samples were tested by Hybrid Capture II and the other 9,641 were genotyped using the Tellgenplex™ HPV DNA Assay. Results: The total positive rate for hrHPV was 21.07 %, which ranged from 18.42 % (Nanchang) to 31.94 % (Haikou) and varied by region. The regions of Nanchang, Changsha, Hangzhou, Chengdu, Fuzhou, Guangdong, and Guiyang could be considered the low prevalence regions. Age-specific prevalence showed a "two-peak" pattern, with the youngest age group (15-19 years) presenting the highest hrHPV infection rate (30.55 %), followed by a second peak for the 50-60-year-old group. Overall, the most prevalent genotypes were HPV16 (4.82 %) and HPV52 (4.52 %), followed by HPV58 (2.74 %). Two genotypes HPV6 (4.01 %) and HPV11 (2.29 %) were predominant in the low-risk HPV (lrHPV) type, while the mixed genotypes HPV16 + 52 and HPV52 + 58 were most common in women with multiple infections. Conclusions: This study shows that HPV infection in China has increased to the level of an "HPV-heavy-burden" zone in certain regions, with prevalence varying significantly among different ages and regions. Data from this study represent the most current survey of the nationwide prevalence of HPV infection in China, and can serve as valuable reference to guide nationwide cervical cancer screening and HPV vaccination programs. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
3. Nationwide prevalence of human papillomavirus infection and viral genotype distribution in 37 cities in China.
- Author
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Rong Wang, Xiao-lei Guo, A. Wisman, G. Bea., Schuuring, Ed, Wen-feng Wang, Zheng-yu Zeng, Hong Zhu, and Shang-wei Wu
- Abstract
Background: Type-specific high-risk HPV (hrHPV) infection is related to cervical carcinogenesis. The prevalence of hrHPV infection varies geographically, which might reflect the epidemiological characteristics of cervical cancer among different populations. To establish a foundation for HPV-based screening and vaccination programs in China, we investigated the most recent HPV prevalence and genotypic distributions in different female age groups and geographical regions in China. Methods: In 2012, a total of 120,772 liquid-based cytological samples from women enrolled for population- or employee-based cervical screening in 37 Chinese cities were obtained by the Laboratory of Molecular Infectious Diseases of Guangzhou KingMed. A total of 111,131 samples were tested by Hybrid Capture II and the other 9,641 were genotyped using the Tellgenplex™ HPV DNA Assay. Results: The total positive rate for hrHPV was 21.07 %, which ranged from 18.42 % (Nanchang) to 31.94 % (Haikou) and varied by region. The regions of Nanchang, Changsha, Hangzhou, Chengdu, Fuzhou, Guangdong, and Guiyang could be considered the low prevalence regions. Age-specific prevalence showed a “two-peak” pattern, with the youngest age group (15–19 years) presenting the highest hrHPV infection rate (30.55 %), followed by a second peak for the 50–60-year-old group. Overall, the most prevalent genotypes were HPV16 (4.82 %) and HPV52 (4.52 %), followed by HPV58 (2.74 %). Two genotypes HPV6 (4.01 %) and HPV11 (2.29 %) were predominant in the low-risk HPV (lrHPV) type, while the mixed genotypes HPV16 + 52 and HPV52 + 58 were most common in women with multiple infections. Conclusions: This study shows that HPV infection in China has increased to the level of an “HPV-heavy-burden” zone in certain regions, with prevalence varying significantly among different ages and regions. Data from this study represent the most current survey of the nationwide prevalence of HPV infection in China, and can serve as valuable reference to guide nationwide cervical cancer screening and HPV vaccination programs. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
4. Prevalence of overweight and obesity and their associations with blood pressure among children and adolescents in Shandong, China.
- Author
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Jing Dong, Xiao-Lei Guo, Zi-Long Lu, Xiao-Ning Cai, Hui-Cheng Wang, Ji-Yu Zhang, Liu-Xia Yan, and Ai-Qiang Xu
- Subjects
CHILDHOOD obesity ,DISEASE prevalence ,CHILDREN ,SCHOOL children ,BODY mass index ,STATISTICAL sampling - Abstract
Background: Obesity and high blood pressure (BP) are public health problems all over the world. Some studies have reported a positive association between them in children and adolescents. The purpose of this study was to assess the prevalence of overweight and obesity and their associations with BP among school children and adolescents in Shandong, an important province in eastern China. Methods: In 2011, we conducted a cross-sectional population-representative survey in Shandong, China. A total of 4 898 children and adolescents aged 6-17 years were randomly selected from 140 counties/districts using a multistage random cluster sampling. Weight, height and BP were measured by a trained physician or pediatrician, and information about age, gender and place of residence was obtained using questionnaires. Obesity and high BP were defined according to age- and gender-specific Chinese reference data for children. Results: A total of 4 898 (100%) children and adolescents provided complete information. The prevalence of overweight, obesity and overweight plus obesity were 10.9%, 8.7% and 19.6%, respectively. Boys were more likely to be overweight or obese than girls (P < 0.05 for overweight; P < 0.001 for obesity). The prevalence of overweight plus obesity was highest among children aged 6-11 years (22.3%). BP and the prevalence of high BP increased with increasing body mass index (BMI). With age and sex adjusted, odds ratios (ORs) for high BP were [OR 2.2;95% CI 1.7-2.8) in overweight and [OR 3.6;95% CI 2.6-4.9] in obese children. Conclusion: The representative survey confirms high prevalence of overweight and obesity among children and adolescents in Shandong. Childhood obesity is a strong risk factor for high BP. Intervention programs should be implemented to combat the growing obesity epidemic. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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- View/download PDF
5. Estimating daily salt intake based on 24 h urinary sodium excretion in adults aged 18–69 years in Shandong, China.
- Author
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Ji-yu Zhang, Liu-xia Yan, Jun-li Tang, Ji-xiang Ma, Xiao-lei Guo, Wen-hua Zhao, Xiao-fei Zhang, Jian-hong Li, Jie Chu, and Zhen-qiang Bi
- Abstract
Objective: 24 h urinary sodium extretion was used to estimate the daily salt intake of shandong residents aged from 18 to 69 years in China. Setting: 20 selected counties/districts in Shandong stratified by geographic region (Eastern, Central Southern and North Western) and residence type (urban vs rural). Participants: Among 2184 randomly selected adults, 2061 provided usable 24 h urine samples. Urine volume <500 mL or male creatinine <3.81 (female creatinine <4.57) are not included in the analysis. Results: The mean sodium level excreted over 24 h was 237.61 mmol (95% CI 224.77 to 250.44) mmol. Overall, the estimated mean salt intake was 13.90 g/day (95% CI 13.15 to 14.65). The mean salt intake among rural residents was higher than that among urban residents (14.00 vs 13.68 g; p<0.01). Salt intake in men was higher than that in women (14.40 vs 13.37 g; p<0.01). Approximately 96% of the survey participants had a dietary salt intake of ≥6 g/day. Conclusions: The salt intake in Shandong is alarmingly higher than the current recommended amount (6 g/day). Thus, effective interventions to reduce salt intake levels to combat the increasing burden of non-communicable diseases need to be developed and implemented. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
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6. Synthesis and properties of organic-inorganic hybrid P(NIPAM- co-AM- co-TMSPMA) microgels.
- Author
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Zheng Cao, Tian-you Chen, Xiao-lei Guo, Xian-jing Zhou, Jing-jing Nie, Jun-ting Xu, Zhi-qiang Fan, and Bin-yang Du
- Subjects
HYDROLYSIS ,CONDENSATION ,COLLOIDS ,LOW temperatures ,POLYMERIZATION - Abstract
Utilizing the hydrolysis and condensation of the methoxysilyl moieties, organic-inorganic hybrid poly( N-isopropylacrylamide- co-acrylamide- co-3-(trimethoxysilyl)propylmethacrylate) P(NIPAM- co-AM- co-TMSPMA) microgels were prepared via two different methods. The first method was that the microgels were post-fabricated from the crosslinkable linear P(NIPAM- co-AM- co-TMSPMA) terpolymer aqueous solutions above the lower critical solution temperature (LCST) of the terpolymer. For the second method, the microgels were directly synthesized by conventional surfactant free emulsion copolymerization of NIPAM, AM, and TMSPMA. The hydrodynamic diameter and stability of the resultant P(NIPAM- co-AM- co-TMSPMA) microgels strongly depend on the pH and temperature of the microgel aqueous solution. The hydrodynamic diameters of the microgels decreased with increasing the measuring temperature. The phase transition temperature of the microgels was found to be around 34°C, which was independent of the initial terpolymer concentration and shifted to lower temperature with increasing the preparation temperature. Increasing the initial amount of AM will enhance the instability of the microgels at high pH values. Moreover, the P(NIPAM- co-AM- co-TMSPMA) microgels obtained from the linear terpolymer had more homogeneous microstructures as compared with the corresponding NIPAM/AM/TMSPMA microgels prepared by one step emulsion copolymerization as revealed by light scattering measurements. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
7. The Circinus Galaxy Revisited with 10 yr Fermi-LAT Data.
- Author
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Xiao-Lei Guo, Yu-Liang Xin, Neng-Hui Liao, and Yi-Zhong Fan
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COSMIC rays ,PHOTON flux ,GALAXY clusters ,ACTIVE galactic nuclei ,BL Lacertae objects ,GALAXIES - Abstract
The Circinus galaxy is a nearby composite starburst/active galactic nucleus (AGN) system. In this work we re-analyze the GeV emission from Circinus with 10 yr of Fermi-LAT Pass 8 data. In the energy range of 1–500 GeV, the spectrum can be well fitted by a power-law model with a photon index of Γ = 2.20 ± 0.14, and its photon flux is (5.90 ± 1.04) × 10
−10 photons cm−2 s−1 . Our 0.1–500 GeV flux is several times lower than that reported in previous literature, which is roughly in compliance with the empirical relation for star-forming and Local Group galaxies and might be reproduced by the interaction between cosmic rays and the interstellar medium. The ratio between the γ-ray luminosity and the total infrared luminosity is near the proton calorimetric limit, indicating that Circinus may be a proton calorimeter. However, marginal evidence for variability of the γ-ray emission is found in the timing analysis, which may indicate the activity of an AGN jet. More Fermi-LAT data and future observation of CTA are required to fully reveal the origin of its γ-ray emission. [ABSTRACT FROM AUTHOR]- Published
- 2019
- Full Text
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8. HESS J1640-465: A Gamma-Ray Emitting Pulsar Wind Nebula?
- Author
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Yu-Liang Xin, Neng-Hui Liao, Xiao-Lei Guo, Qiang Yuan, Si-Ming Liu, Yi-Zhong Fan, and Da-Ming Wei
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SUPERNOVA remnants ,PHOTONS ,TELESCOPES ,FERMI energy ,LUMINOSITY - Abstract
HESS J1640-465 is an extended TeV γ-ray source, and whether its γ-ray emission is from the shell of a supernova remnant (SNR) or a pulsar wind nebula (PWN) is still under debate. We reanalyze the GeV γ-ray data in the field of HESS J1640-465 using eight years of Pass 8 data recorded by the Fermi Large Area Telescope. An extended GeV γ-ray source positionally coincident with HESS J1640-465 is found. Its photon spectrum can be described by a power law with an index of 1.42 ± 0.19 in the energy range of 10–500 GeV and smoothly connects with the TeV spectrum of HESS J1640-465. The broadband spectrum of HESS J1640-465 can be well fit by a leptonic model with a broken power-law spectrum of electrons with an exponential cut off at ∼300 TeV. The spectral properties of HESS J1640-465 are broadly consistent with the characteristics of other sources identified as PWNe, such as the correlations between high-energy luminosity ratios and the physical parameters of pulsar, including the spin-down luminosity and the characteristic age τ
c . All of these pieces of evidence support that the γ-ray emission of HESS J1640-465 may originate from the PWN powered by PSR J1640-4631 rather than the shell of the SNR G338.3-0.0. [ABSTRACT FROM AUTHOR]- Published
- 2018
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9. Detection of GeV Gamma-Ray Emission in the Direction of HESS J1731-347 with Fermi-LAT.
- Author
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Xiao-Lei Guo, Yu-Liang Xin, Neng-Hui Liao, Qiang Yuan, Wei-Hong Gao, and Yi-Zhong Fan
- Subjects
GAMMA ray astronomy ,SUPERNOVA remnants ,TELESCOPES ,LEPTONS (Nuclear physics) ,STANDARD model (Nuclear physics) - Abstract
We report the detection of GeV γ-ray emission from supernova remnant HESS J1731-347 using 9 yr of Fermi Large Area Telescope data. We find a slightly extended GeV source in the direction of HESS J1731-347. The spectrum above 1 GeV can be fitted by a power law with an index of Γ = 1.77 ± 0.14, and the GeV spectrum connects smoothly with the TeV spectrum of HESS J1731-347. Either a hadronic–leptonic or a pure leptonic model can fit the multiwavelength spectral energy distribution of the source. However, the hard GeV γ-ray spectrum is more naturally produced in a leptonic (inverse Compton scattering) scenario, under the framework of diffusive shock acceleration. We also searched for the GeV γ-ray emission from the nearby TeV source HESS J1729-345. No significant GeV γ-ray emission is found, and upper limits are derived. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
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10. Revisiting SNR Puppis A with Seven Years of Fermi Large Area Telescope Observations.
- Author
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Yu-Liang Xin, Xiao-Lei Guo, Neng-Hui Liao, Qiang Yuan, Si-Ming Liu, and Da-Ming Wei
- Subjects
GAMMA rays ,SUPERNOVA remnants ,SUPERNOVAE ,INTERSTELLAR medium ,GALACTIC cosmic rays - Abstract
Puppis A is a very famous and extensively studied supernova remnant that shows strong evidence of shock-cloud interaction. We reanalyze its GeV γ-ray emission using seven years of Pass 8 data recorded by the Fermi Large Area Telescope. The morphology of the γ-ray emission is more compatible with that of the thermal X-ray and IR emissions than the radio image, which suggests a possible correlation between the gamma-ray-emitting region and dense clouds. The γ-ray spectrum in the energy range of 1–500 GeV shows a break at 7.92 ± 1.91 GeV, with photon indices of 1.81 ± 0.08 below the break and 2.53 ± 0.12 above the break, which can naturally explain the lack of TeV γ-ray emission from Puppis A. The multi-wavelength observations favor a hadronic origin for the γ-ray emission. [ABSTRACT FROM AUTHOR]
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- 2017
- Full Text
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11. HESS J1427−608: AN UNUSUAL HARD, UNBROKEN γ-RAY SPECTRUM IN A VERY WIDE ENERGY RANGE.
- Author
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Xiao-Lei Guo, Yu-Liang Xin, Neng-Hui Liao, Qiang Yuan, Wei-Hong Gao, Hao-Ning He, Yi-Zhong Fan, and Si-Ming Liu
- Subjects
PARTICLES (Nuclear physics) ,HESS'S Law ,X-ray spectroscopy ,GAMMA ray astronomy ,GAMMA ray measurement ,MATHEMATICAL models - Abstract
We report the detection of a GeV γ-ray source that spatially overlaps and is thus very likely associated with the unidentified very high energy (VHE) γ-ray source HESS J1427−608 with the Pass 8 data recorded by the Fermi Large Area Telescope. The photon spectrum of this source is best described by a power law with an index of 1.85 ± 0.17 in the energy range of 3–500 GeV, and the measured flux connects smoothly with that of HESS J1427−608 at a few hundred gigaelectronvolts. This source shows no significant extension and time variation. The broadband GeV to TeV emission over four decades of energies can be well fitted by a single power-law function with an index of 2.0, without obvious indication of spectral cutoff toward high energies. Such a result implies that HESS J1427−608 may be a PeV particle accelerator. We discuss the possible nature of HESS J1427−608 according to the multiwavelength spectral fittings. Given the relatively large errors, either a leptonic or a hadronic model can explain the multiwavelength data from radio to VHE γ-rays. The inferred magnetic field strength is a few micro-Gauss, which is smaller than the typical values of supernova remnants (SNRs) and is consistent with some pulsar wind nebulae (PWNe). On the other hand, the flat γ-ray spectrum is slightly different from typical PWNe but is similar to that of some known SNRs. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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12. Backlog balancing flow control in high-speed data networks.
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Xiao-Lei Guo and Lee, T.T.
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- 1995
- Full Text
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