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Aim: The aim of this study was to determine reference values for oxygen saturation (SpO2 ) in neonates at mild and moderate altitudes.Methods: Our study included 41 097 consecutively born, asymptomatic neonates from 35 hospitals, located in Yunnan, China, with altitudes ranging from 267 to 2202 m. Pre-and post-ductal SpO2 of each neonate was measured at 24 hours of age and before hospital discharge. All study participants, according to the altitude of birth, were categorised into three groups: low (0-500 m), mild (500-1500 m) and moderate altitude (1500-2500 m).Results: Every 1000-m increase in altitude was associated with a 1.54 per cent decrease in mean SpO2 . The means of pre-ductal SpO2 at low, mild and moderate groups were 97.9%, 96.4% and 95.5%, respectively. We used the 2.5th percentile of SpO2 distribution as the cut-off for neonatal SpO2 screening and defined new cut-off values of ≤93% for mild altitudes, ≤92% for moderate altitudes and no adjustment for low altitudes.Conclusion: We recommend revised cut-off values for neonatal SpO2 at mild and moderate altitudes and provide new values for paediatricians to refer to when screening neonates for severe congenital heart or lung diseases. [ABSTRACT FROM AUTHOR]

ABSTRACT Biological images with significant intensity inhomogeneity are considerably difficult for the tissue segmentation. To overcome the difficulties caused by the intensity inhomogeneity, this study presents a variational level set method to simultaneous bias field estimation and tissue segmentation for images in the presence of intensity inhomogeneity. An energy function is defined in terms of two data fitting terms which incorporate the local clustering properties into the global region information. First, depended on the observed image mode, the local cluster property based on the observed signal is simplified to a criterion function which is similar to the Mumford-Shah model. The local criterion energy is then integrated with a global region measure, which is based on intensity difference of the true signal. The energy is minimized in a variational level set formulation with a regularity term, thus avoiding the expensive computation of the level set reinitialization and keeping the curve close to the signal distance function. Experiment results on biological images show desirable performance and demonstrate the effectiveness of the proposed algorithm. [ABSTRACT FROM AUTHOR]

Introduction: HIV and syphilis testing rates remain low among men who have sex with men (MSM) in low- and middle-income countries (LMICs). Community engagement has been increasingly used to promote HIV testing among key populations in high-income countries, often in settings with stronger civil society. This study aimed to assess socio-demographic, behavioural, and community engagement factors associated with HIV and syphilis testing among MSM in China. Methods: MSM ≥16 years old who had condomless sex in the past three months were recruited nationwide to complete a cross-sectional online survey in November 2015. Data were collected on socio-demographics, sexual behaviours, HIV testing, syphilis testing, and community engagement in sexual health. We defined community engagement in sexual health using six items assessing awareness and advocacy of sexual health programmes. The underlying factor structure of a 6-item community engagement scale was determined through exploratory factor analysis. Univariate and multivariable logistic regressions identified correlates of HIV and syphilis testing. Results: 1189 MSM were recruited. 54% (647/1189) of men had ever tested for HIV and 30% (354/1189) had ever tested for syphilis. Factor analysis suggested three levels of community engagement (minimal, moderate, and substantial) and this model explained 79.5% of observed variance. A quarter (26%, 312/1189) reported none to minimal engagement, over one half (54%, 644/1189) reported moderate engagement, and a fifth (20%, 233/1189) reported substantial engagement. Multivariable logistic regression showed that MSM with greater community engagement in sexual health were more likely to have ever tested for HIV (substantial vs. no engagement: aOR 7.91, 95% CI 4.98–12.57) and for syphilis (substantial vs. no engagement: aOR 5.35, 95% CI 3.16–9.04). Conclusions: HIV and syphilis testing are suboptimal among MSM in China. Community engagement may be useful for promoting testing in China and should be considered in intervention development and delivery. Further research is needed to better understand the role of LMIC community engagement in HIV interventions. [ABSTRACT FROM AUTHOR]