The multidirectional auxeticity and negative linear compressibility of a 3D mechanical metamaterial

In this work, through the use of a theoretical model, we analyse the potential of a specific three-dimensional mechanical metamaterial composed of arrowhead-like structural units to exhibit a negative Poisson’s ratio for an arbitrary loading direction. Said analysis allows us to assess its suitability for use in applications where materials must be able to respond in a desired manner to a stimulus applied in multiple directions. As a result of our studies, we show that the analysed system is capable of exhibiting auxetic behaviour for a broad range of loading directions, with isotropic behaviour being shown in some planes. In addition to that, we show that there are also certain loading directions in which the system manifests negative linear compressibility. This enhances its versatility and suitability for a number of applications where materials exhibiting auxetic behaviour or negative linear compressibility are normally implemented.peer-reviewe

Long-term visual and treatment outcomes of whole-population pre-school visual screening (PSVS) in children:a longitudinal, retrospective, population-based cohort study

BACKGROUND: This study reports the long-term visual and treatment outcomes in a whole-population, orthoptic-delivered pre-school visual screening (PSVS) programme in Scotland and further examines their associations with socioeconomic backgrounds and home circumstances. METHODS: Retrospective case review was conducted on 430 children who failed PSVS. Outcome measures included best corrected visual acuity (BCVA), severity of amblyopia (mild, moderate and severe), binocular vision (BV) (normal, poor and none), ophthalmic diagnosis and treatment modalities. Parameters at discharge were compared to those at baseline and were measured against the Scottish index of multiple deprivation (SIMD) and Health plan indicator (HPI), which are indices of deprivation and status of home circumstances. RESULTS: The proportion of children with amblyopia reduced from 92.3% (373/404) at baseline to 29.1% (106/364) at discharge (p < 0.001). Eighty percent (291/364) had good BV at discharge compared to 29.2% (118/404) at baseline (p < 0.001). Children from more socioeconomically deprived areas (OR 2.19, 95% CI 1.01–4.30, p = 0.003) or adverse family backgrounds (OR 3.94, 95% CI 1.99–7.74, p = 0.002) were more likely to attend poorly and/or become lost to follow-up. Children from worse home circumstances were five times more likely to have residual amblyopia (OR 5.37, 95% CI 3.29–10.07, p < 0.001) and three times more likely to have poor/no BV (OR 3.41, 95% CI 2.49–4.66, p < 0.001) than those from better home circumstances. CONCLUSIONS: Orthoptic-delivered PSVS is successful at screening and managing amblyopia. Children from homes requiring social care input are less likely to attend and are more likely to have poorer visual outcomes

Neurobehavioral consequences of chronic intrauterine opioid exposure in infants and preschool children: a systematic review and meta-analysis

&lt;b&gt;Background&lt;/b&gt;&lt;p&gt;&lt;/p&gt; It is assumed within the accumulated literature that children born of pregnant opioid dependent mothers have impaired neurobehavioral function as a consequence of chronic intrauterine opioid use.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Methods&lt;/b&gt;&lt;p&gt;&lt;/p&gt; Quantitative and systematic review of the literature on the consequences of chronic maternal opioid use during pregnancy on neurobehavioral function of children was conducted using the Meta-analysis of Observational Studies in Epidemiology (MOOSE) and the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. We searched Cinahl, EMBASE, PsychINFO and MEDLINE between the periods of January 1995 to January 2012.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Results&lt;/b&gt;&lt;p&gt;&lt;/p&gt; There were only 5 studies out of the 200 identified that quantitatively reported on neurobehavioral function of children after maternal opioid use during pregnancy. All 5 were case control studies with the number of exposed subjects within the studies ranging from 33–143 and 45–85 for the controls. This meta-analysis showed no significant impairments, at a non-conservative significance level of p &#60; 0.05, for cognitive, psychomotor or observed behavioural outcomes for chronic intra-uterine exposed infants and pre-school children compared to non-exposed infants and children. However, all domains suggested a trend to poor outcomes in infants/children of opioid using mothers. The magnitude of all possible effects was small according to Cohen’s benchmark criteria.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Conclusions&lt;/b&gt;&lt;p&gt;&lt;/p&gt; Chronic intra-uterine opioid exposed infants and pre-school children experienced no significant impairment in neurobehavioral outcomes when compared to non-exposed peers, although in all domains there was a trend to poorer outcomes. The findings of this review are limited by the small number of studies analysed, the heterogenous populations and small numbers within the individual studies. Longitudinal studies are needed to determine if any neuropsychological impairments appear after the age of 5 years and to help investigate further the role of environmental risk factors on the effect of ‘core’ phenotypes