130 research outputs found

    The impact of maternal pre-pregnancy impaired fasting glucose on preterm birth and large for gestational age: a large population-based cohort study

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    Background The impact of maternal pre-pregnancy impaired fasting glucose on preterm birth and large for gestational age has been poorly understood. Objectives We aimed to estimate the impact of pre-pregnancy impaired fasting glucose defined by the WHO cut-point on the risk of preterm birth and large for gestational age, and to investigate whether the WHO cut-point of impaired fasting glucose was appropriate for identifying women at the risk of preterm birth and large for gestational age among the Chinese population. Study Design This was a retrospective cohort study of women from the National Free Preconception Health Examination Project with singleton birth from 121 counties/districts in 21 cities of Guangdong Province, China, from 1st January 2013 to 31st December 2017. Women were included if pre-pregnancy fasting glucose was less than 7.0mmol/L. The primary outcomes were preterm birth (gestational age 90th percentile based on the international standards in the INTERGROWTH-21st) and severe large for gestational age (birth weight by gestational age >97th percentile). We calculated the adjusted risk ratio for impaired fasting glucose, and a 1 standard deviation increase in fasting glucose. Results We included 640469 women. Of these, 31006 (4.84%) met the WHO cut-point for impaired fasting glucose, 32640 (5.10%) had preterm birth and 7201 (1.12%) had early preterm birth, 45532 (7.11%) had large for gestational age birth and 16231 (2.53%) had severe large for gestational age birth. Compared with women with normoglycaemia, women with pre-pregnancy impaired fasting glucose had a 7.0% higher risk of preterm birth (adjusted risk ratio 1.07, 95%CI 1.02-1.12), 10.0% higher risk of large for gestational age (1.10, 1.06-1.14) and 17.0% higher risk of severe large for gestational age (1.17, 1.10-1.26). No significant association of pre-pregnancy impaired fasting glucose with early preterm birth was found. The association of pre-pregnancy impaired fasting glucose with preterm birth and large for gestational age were similar in subgroups of women with various baseline characteristics. Adjusted risk ratio for preterm birth per standard deviation fasting glucose (0.7mmol/L) was 0.99 (95% CI 0.98-1.00), for early preterm birth 0.99 (0.97-1.02), for large for gestational age 1.04 (1.03-1.05) and for severe large for gestational age 1.03 (1.01-1.04). Conclusions Our data suggest that maternal pre-pregnancy impaired fasting glucose increases the risk of preterm birth, large for gestational age and severe large for gestational age. Data also suggest that the WHO cut-point of impaired fasting glucose is too restrictive and lesser levels of fasting glucose also increase the risk of large gestational age and severe for severe gestational age in the Chinese population. Further investigation is warranted to determine whether and how counselling and interventions for women with pre-pregnancy impaired fasting glucose could reduce the risk of preterm birth and large for gestational age.This work was supported by grants National Natural Science Foundation of China (81773457 & 81302445 to JJT)Published versio

    Antibody Dynamics of 2009 Influenza A (H1N1) Virus in Infected Patients and Vaccinated People in China

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    BACKGROUND: To evaluate the risk of the recurrence and the efficiency of the vaccination, we followed-up antibody responses in patients with the 2009 pandemic H1N1 influenza and persons who received the pandemic H1N1 vaccine in Guangzhou China. METHODS: We collected serum samples from 129 patients and 86 vaccinated persons at day 0, 15, 30, 180 after the disease onset or the vaccination, respectively. Antibody titers in these serum samples were determined by haemagglutination inhibition (HI) assay using a local isolated virus strain A/Guangdong Liwan/SWL1538/2009(H1N1). RESULTS: HI antibody positive rate of the patients increased significantly from 0% to 60% at day 15 (Ο‡(2)β€Š=β€Š78, P<0.001) and 100% at day 30 (Ο‡(2)β€Š=β€Š23, P<0.001), but decreased significantly to 52% at day 180 (Ο‡(2)β€Š=β€Š38, P<0.001), while that of vaccinated subjects increased from 0% to 78% at day 15 (Ο‡(2)β€Š=β€Š110, P<0.001) and 81% at day 30 (Ο‡(2)β€Š=β€Š0.32, Pβ€Š=β€Š0.57), but decreased significantly to 34% at day 180 (Ο‡(2)β€Š=β€Š39, P<0.001). Geometric mean titers (GMT) of HI antibodies in positive samples from the patients did not change significantly between day 15 and day 30 (Tβ€Š=β€Š0.92, Pβ€Š=β€Š0.36), but it decreased significantly from 80 at day 30 to 52 at day 180 (Tβ€Š=β€Š4.5, P<0.001). GMT of vaccinated persons increased significantly from 100 at day 15 to 193 at day 30 (Tβ€Š=β€Š4.5, P<0.001), but deceased significantly to 74 at day 180 (Tβ€Š=β€Š5.1, P<0.001). Compared to the patients, the vaccinated subjects showed lower seroconversion rate (Ο‡(2)β€Š=β€Š11, P<0.001; Ο‡(2)β€Š=β€Š5.9, Pβ€Š=β€Š0.015), but higher GMT (Tβ€Š=β€Š6.0, P<0.001; Tβ€Š=β€Š3.6, Pβ€Š=β€Š0.001) at day 30 and day 180, respectively. CONCLUSION: Vaccination of 2009 influenza A (H1N1) was effective. However, about half or more recovered patients and vaccinated persons might have lost sufficient immunity against the recurrence of the viral infection after half a year. Vaccination or re-vaccination may be necessary for prevention of the recurrence

    Tumor-Initiating Cells Are Enriched in CD44hi Population in Murine Salivary Gland Tumor

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    Tumor-initiating cells (T-ICs) discovered in various tumors have been widely reported. However, T-IC populations in salivary gland tumors have yet to be elucidated. Using the established Pleomorphic Adenoma Gene-1 (Plag1) transgenic mouse model of a salivary gland tumor, we identified CD44high (CD44hi) tumor cells, characterized by high levels of CD44 cell surface expression, as the T-ICs for pleomorphic adenomas. These CD44hi tumor cells incorporated 5-bromo-2-deoxyuridine (BrdU), at a lower rate than their CD44negative (CD44neg) counterparts, and also retained BrdU for a long period of time. Cell surface maker analysis revealed that 25% of the CD44hi tumor cells co-express other cancer stem cell markers such as CD133 and CD117. As few as 500 CD44hi tumor cells were sufficient to initiate pleomorphic adenomas in one third of the wildtype mice, whereas more than 1Γ—104 CD44neg cells were needed for the same purpose. In NIH 3T3 cells, Plag1 was capable of activating the gene transcription of Egr1, a known upregulator for CD44. Furthermore, deletion of sequence 81–96 in the Egr1 promoter region abolished the effect of Plag1 on Egr1 upregulation. Our results establish the existence of T-ICs in murine salivary gland tumors, and suggest a potential molecular mechanism for CD44 upregulation

    Nonlinear

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    Let A be a unital *-algebra with the unit I and a nontrivial projection P∈A. Suppose that A satisfies XAP=0 implies X=0 and XA(I-P)=0 implies X=0. In this paper, we prove that Ο• is a nonlinear A*B+B*A type derivation on A if and only if Ο• is an additive *-derivation. This is then applied to prime *-algebra, von Neumann algebras with no central summands of type I1, factor von Neumann algebras and standard operator algebras

    Modeling the Evolution of Major Storm-Disaster-Induced Accidents in the Offshore Oil and Gas Industry

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    Storm disasters are the most common cause of accidents in offshore oil and gas industries. To prevent accidents resulting from storms, it is vital to analyze accident propagation and to learn about accident mechanism from previous accidents. In this paper, a novel risk analysis framework is proposed for systematically identifying and analyzing the evolution of accident causes. First, accident causal factors are identified and coded based on grounded theory (GT). Then, decision making trial and evaluation laboratory (DEMATEL) is integrated with interpretative structural modeling (ISM) to establish accident evolution hierarchy. Finally, complex networks (CN) are developed to analyze the evolution process of accidents. Compared to reported works, the contribution is threefold: (1) the demand for expert knowledge and personnel subjective influence are reduced through the data induction of accident cases; (2) the method of establishing influence matrix and interaction matrix is improved according to the accident frequency analysis; (3) a hybrid algorithm that can calculate multiple shortest paths of accident evolution under the same node pair is proposed. This method provides a new idea for step-by-step assessment of the accident evolution process, which weakens the subjectivity of traditional methods and achieves quantitative assessment of the importance of accident evolution nodes. The proposed method is demonstrated and validated by a case study of major offshore oil and gas industry accidents caused by storm disasters. Results show that there are five key nodes and five critical paths in the process of accident evolution. Through targeted prevention and control of these nodes and paths, the average shortest path length of the accident evolution network is increased by 35.19%, and the maximum global efficiency decreases by 20.12%. This indicates that the proposed method has broad applicability and can effectively reduce operational risk, so that it can guide actual offshore oil and gas operations during storm disasters

    Satellite In-Orbit Secondary Collision Risk Assessment

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    The massive mega constellation of satellites will have a significant impact on global space safety. With Starlink as an example, this paper is aimed at assessing the risk of in-orbit collision, analyzing the probability of collision in orbit in its natural operating state, and forecasting the probability of secondary collision between the collision-generated short-term debris cloud and satellites in the same orbit. The mass, size, velocity, and direction of space debris in a particular orbit of Starlink satellite are calculated based on the MASTER-8 model, and the shape characteristics of the Starlink satellite are added to the model to determine the probability of a Starlink satellite colliding with space debris in that orbit. A modified spacecraft impact disintegration model then is used to calculate the collision results and estimate the collision threat level of the short-term debris cloud formed by the Starlink satellite after its destruction to satellites in the same orbit. The results indicate that the collision probability of Starlink satellite in orbit natural operation exceeds the red warning threshold 10-4 that the satellite disintegration after the first collision will generate 14088 pieces of debris over 1 cm, of which 4092 debris are potentially dangerous to other spacecraft, and that the collision probability to a satellite in the same orbit exceeds the red warning threshold of 10-4 within 30 minutes, implying that collision avoidance needs to be improved

    Exploring associations between eHealth literacy, cyberchondria, online health information seeking and sleep quality among university students: A cross-section study

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    Background: University students are increasingly inclined to use the Internet for health-related purposes, and their sleep problems are becoming increasingly prominent. Currently, the relationship between sleep quality and online health-related searches is poorly understood. The aim of this study was to exam the associations of sleep quality, Internet use, eHealth literacy, online health information seeking and cyberchondria in the sample of Chinese university students. Methods: A total of 2744 students completed self-reported questionnaires online containing the Pittsburgh Sleep Quality Index (PSQI), eHealth Literacy Scale, Online Health Information Seeking, Cyberchondria Severity Scale (CSS) and questions regarding sleep duration, Internet use, health status, and demographic information. Results: The prevalence of poor sleep quality (PSQI >7) among the university students was 19.9% and 15.6% students slept less than 7Β h per day. As time spent on online daily and playing phone before bed increased, the prevalence of sleep disturbance gained. Sleep disturbance was significantly associated with cyberchondria (ORΒ =Β 1.545, pΒ =Β 0.001), health status [good (ORΒ =Β 0.625, pΒ =Β 0.039), poor (ORΒ =Β 3.128, pΒ =Β 0.010), and fair (ORΒ =Β 1.932, pΒ =Β 0.001)]. Sleep quality, online health information seeking and eHealth literacy positively influenced with cyberchondria. Compared to 7–8Β h sleep duration, online health information seeking (ORΒ =Β 0.750, pΒ =Β 0.012) was significantly associated with β‰₯8Β h sleep duration. Conclusion: Our findings highlighted poor health status, too much time spent on online daily and high cyberchondria level might decrease sleep quality in the sample of Chinese university students, further suggesting the need for developing interventions based on online health-related searches for improving sleep quality among university students

    Laser Inter-Satellite Link Visibility and Topology Optimization for Mega Constellation

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    In this paper, we begin by describing the Starlink constellation’s configuration plan, treating each satellite as a network node, naming and numbering the various nodes, and then classifying the laser interstellar links (LISLs) according to their orbital alignment and whether they are permanently visible. Whereupon, the method for calculating the respective theoretical interstellar distances required for establishing LISLs under two distinct orbital scenarios, co-orbital and hetero-orbital are analyzed, and the optimal phasing factors are proposed by solving an optimization algorithm for the shortest distance. The OneWeb and Starlink constellations, as well as the constellation states of various phasing factors are simulated, respectively. The Starlink constellation with F = 11 obtains the best coverage between 60Β° north and south latitudes predicated upon the analysis of the constellation N Asset Coverage. Following that, the first phase of the Starlink constellation deployment was modeled in order to analyze and count the number of permanent LISLs in orbit, adjacent to, and nearby. Subsequently, the characteristics of azimuthal, elevation, and range (AER) were subsequently analyzed to ascertain their variation law and to compile the number of permanent and temporary LISLs that could be established at various inter-distance ranges. Finally, predicated on the simulation results, the optimal LISLs connection strategy for the Starlink constellation is evaluated and a static topology for the constellation is constructed

    Laser Inter-Satellite Link Visibility and Topology Optimization for Mega Constellation

    No full text
    In this paper, we begin by describing the Starlink constellation&rsquo;s configuration plan, treating each satellite as a network node, naming and numbering the various nodes, and then classifying the laser interstellar links (LISLs) according to their orbital alignment and whether they are permanently visible. Whereupon, the method for calculating the respective theoretical interstellar distances required for establishing LISLs under two distinct orbital scenarios, co-orbital and hetero-orbital are analyzed, and the optimal phasing factors are proposed by solving an optimization algorithm for the shortest distance. The OneWeb and Starlink constellations, as well as the constellation states of various phasing factors are simulated, respectively. The Starlink constellation with F = 11 obtains the best coverage between 60&deg; north and south latitudes predicated upon the analysis of the constellation N Asset Coverage. Following that, the first phase of the Starlink constellation deployment was modeled in order to analyze and count the number of permanent LISLs in orbit, adjacent to, and nearby. Subsequently, the characteristics of azimuthal, elevation, and range (AER) were subsequently analyzed to ascertain their variation law and to compile the number of permanent and temporary LISLs that could be established at various inter-distance ranges. Finally, predicated on the simulation results, the optimal LISLs connection strategy for the Starlink constellation is evaluated and a static topology for the constellation is constructed

    Simulation and assessment of gas dispersion above sea from a subsea release: A CFD-based approach

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    This paper presents a comprehensive simulation and assessment of gas dispersion above sea from a subsea release using a Computational Fluid Dynamics (CFD) approach. A 3D CFD model is established to evaluate the behavior of flammable gas above sea, and a jack-up drilling platform is included to illustrate the effect of flammable gas cloud on surface vessels. The simulations include a matrix of scenarios for different surface release rates, distances between surface gas pool and offshore platform, and wind speeds. Based on the established model, the development process of flammable gas cloud above sea is predicted, and the dangerous area generated on offshore platform is assessed. Additionally, the effect of some critical factors on flammable gas dispersion behavior is analyzed. The simulations produce some useful outputs including the detailed parameters of flammable gas cloud and the dangerous area on offshore platform, which are expected to give an educational reference for conducting a prior risk assessment and contingency planning. Keywords: CFD simulation, Risk assessment, Gas dispersion, Dangerous area, Offshore platfor
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