254 research outputs found

    Correlation between diopters and refractive parameters among 5 to 12 years old school-age children of Lanzhou city

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    AIM: To investigate the epidemiological status of refractive state among school-age children of 5 to 12 years in Chengguan district of Lanzhou city, and to analyze the correlation with axial length(AL), horizontal and vertical corneal refractive power(K1, K2), anterior chamber depth(ACD)and corneal diameter(W-W). <p>METHODS: The value of AL, K1, K2, ACD and W-W of 813 school-age children(1626 eyes)aged 8.46±2.30 years old(5-12 years)were measured by IOL-Master, refractive error was measured by computer refractor. The eyes were divided into 5 groups according to different mean spherical equivalent(SE)diopter: high myopia, moderate myopia, low myopia, emmetropia and hyperopia. The correlation between diopter and different refractive parameters of different ages and different diopter groups were analyzed respectively, the SPSS 19.0 was used for the statistical analysis.<p>RESULTS: There were statistically significant difference(<i>P</i><0.05)in uncorrected visual acuity and refractive state among the different groups of 5-12 years school-age children, the prevalence of myopia tended to increase with the age. There were statistically significant difference in AL and ACD among the different age groups(<i>P</i><0.05), AL and ACD increased with the age. There were statistically significant difference in AL among three myopic groups(<i>P</i><0.05). There were statistically significant difference in ACD between low myopia and moderate myopia, low myopia and high myopia(<i>P</i><0.05). There were statistically significant difference in corneal refractive power and corneal diameter between low myopia and high myopia, moderate myopia and high myopia(<i>P</i><0.05). SE was negatively correlated with AL(<i>r</i>=-0.764, <i>P</i><0.01)and ACD(<i>r</i>=-0.498, <i>P</i><0.01), but had week correlation with corneal refractive power or corneal diameter.<p>CONCLUSION: The increase of AL plays an important role in the changes of refractive among school-age children of 5-12 years, AL is the main morphological variable related to myopia. Meanwhile, refractive changes may be affected by corneal refractive power(K1, K2), ACD and corneal diameter(W-W). 7-8 years old can be regarded as the main phase from emmetropization to myopization of school-age children

    Survey on Online Adversarial Planning for Real-time Strategy Game

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    Real-time strategy game online adversarial planning is a challenging problem in the field of multi-agent learning.In the process of game confrontation,in the face of an uncertain threat environment and non-stationary opponents,the agent needs to reason about the opponent’s actions within a limited time according to the game situation,make your own action plan quickly and perform adversarial planning in the huge state space and action space.The real-time strategy game platform is an ideal testbed for studying online adversarial planning problems.This paper firstly uses a typical real-time strategy game model to elicit the real-time strategy game confrontation problems,and classifies them into three levels and two operation control methods,and sorts out the five challenges faced from five sub-directions.Secondly,the current online adversarial planning methods are comprehensively reviewed and analyzed from three perspectives of tactical adversarial planning,strategic adversarial planning and mixed adversarial planning.Finally,the key issues that need to be studied in the future are pointed out from three key aspects:opponent and player modeling,human-machine collaborative online ad hoc planning,and learning-based planning

    Distribution and behaviour of dissolved selenium in tropical peatland-draining rivers and estuaries of Malaysia

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    Selenium (Se) is an essential micronutrient for aquatic organisms. Despite its importance, our current knowledge of the biogeochemical cycling of dissolved Se in tropical estuaries is limited, especially in Southeast Asia. To gain insights into Se cycling in tropical peat-draining rivers and estuaries, samples were collected from the Rajang, Maludam, Sebuyau, Simunjan, Sematan, Samunsam and Lunda rivers and estuaries in western Sarawak, Malaysia, in March and September 2017 and analysed for various forms of Se (dissolved inorganic and organic). Mean total dissolved Se (TDSe), dissolved inorganic Se (DISe) and dissolved organic Se concentrations (DOSe) were 2.2 nmol L−1 (range: 0.7 to 5.7 nmol L−1 ), 0.18 nmol L−1 (range: less than the detection limit to 0.47 nmol L−1 ) and 2.0 nmol L−1 (range: 0.42 to 5.7 nmol L−1 ), respectively. In acidic, low-oxygen, organicrich blackwater (peatland-draining) rivers, the concentrations of DISe were extremely low (near or below the detection limit, i.e. 0.0063 nmol L−1 ), whereas those of DOSe were high. In rivers and estuaries that drained peatland, DOSe / TDSe ratios ranged from 0.67 to 0.99, showing that DOSe dominated. The positive relationship between DISe and salinity and the negative relationship between DOSe and salinity indicate marine and terrestrial origins of DISe and DOSe, respectively. The positive correlations of DOSe with the humification index and humic-like chromophoric dissolved organic matter components in freshwater river reaches suggest that peat soils are probably the main source of DOSe The DOSe fractions may be associated with high molecular weight peatland-derived aromatic and black carbon compounds and may photodegrade to more bioavailable forms once transported to coastal waters. The TDSe flux delivered by the peat-draining rivers exceeded those reported for other small rivers and is quantitatively more significant than previously thought

    Gender Differences and Effect of Air Pollution on Asthma in Children with and without Allergic Predisposition: Northeast Chinese Children Health Study

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    BACKGROUND: Males and females exhibit different health responses to air pollution, but little is known about how exposure to air pollution affects juvenile respiratory health after analysis stratified by allergic predisposition. The aim of the present study was to assess the relationship between air pollutants and asthmatic symptoms in Chinese children selected from multiple sites in a heavily industrialized province of China, and investigate whether allergic predisposition modifies this relationship. METHODOLOGY/PRINCIPAL FINDINGS: 30139 Chinese children aged 3-to-12 years were selected from 25 districts of seven cities in northeast China in 2009. Information on respiratory health was obtained using a standard questionnaire from the American Thoracic Society. Routine air-pollution monitoring data was used for particles with an aerodynamic diameter ≀10 ”m (PM(10)), sulfur dioxide (SO(2)), nitrogen dioxides (NO(2)), ozone (O(3)) and carbon monoxide (CO). A two-stage regression approach was applied in data analyses. The effect estimates were presented as odds ratios (ORs) per interquartile changes for PM(10), SO(2), NO(2), O(3), and CO. The results showed that children with allergic predisposition were more susceptible to air pollutants than children without allergic predisposition. Amongst children without an allergic predisposition, air pollution effects on asthma were stronger in males compared to females; Current asthma prevalence was related to PM(10) (ORs = 1.36 per 31 ”g/m(3); 95% CI, 1.08-1.72), SO(2) (ORs = 1.38 per 21 ”g/m(3); 95%CI, 1.12-1.69) only among males. However, among children with allergic predisposition, more positively associations between air pollutants and respiratory symptoms and diseases were detected in females; An increased prevalence of doctor-diagnosed asthma was significantly associated with SO(2) (ORs = 1.48 per 21 ”g/m(3); 95%CI, 1.21-1.80), NO(2) (ORs = 1.26 per 10 ”g/m(3); 95%CI, 1.01-1.56), and current asthma with O(3) (ORs = 1.55 per 23 ”g/m(3); 95%CI, 1.18-2.04) only among females. CONCLUSION/SIGNIFICANCE: Ambient air pollutions were more evident in males without an allergic predisposition and more associations were detected in females with allergic predisposition

    2D Black Phosphorus: from Preparation to Applications for Electrochemical Energy Storage

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    Black phosphorus (BP) is rediscovered as a 2D layered material. Since its first isolation in 2014, 2D BP has triggered tremendous interest in the fields of condensed matter physics, chemistry, and materials science. Given its unique puckered monolayer geometry, 2D BP displays many unprecedented properties and is being explored for use in numerous applications. The flexibility, large surface area, and good electric conductivity of 2D BP make it a promising electrode material for electrochemical energy storage devices (EESDs). Here, the experimental and theoretical progress of 2D BP is presented on the basis of its preparation methods. The structural and physiochemical properties, air instability, passivation, and EESD applications of 2D BP are discussed systemically. Specifically, the latest research findings on utilizing 2D BP in EESDs, such as lithium‐ion batteries, supercapacitors, and emerging technologies (lithium–sulfur batteries, magnesium‐ion batteries, and sodium‐ion batteries), are summarized. On the basis of the current progress, a few personal perspectives on the existing challenges and future research directions in this developing field are provided

    Microbial polysaccharides: An emerging family of natural biomaterials for cancer therapy and diagnostics

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