Investigating the mechanical response of paediatric bone under bending and torsion using finite element analysis

Fractures of bone account 25% of all paediatric injuries (Cooper et al. in J Bone Miner Res 19:1976–1981, 2004.  https://doi.org/10.1359/JBMR.040902). These can be broadly categorised into accidental or inflicted injuries. The current clinical approach to distinguish between these two is based on the clinician’s judgment, which can be subjective. Furthermore, there is a lack of studies on paediatric bone to provide evidence-based information on bone strength, mainly due to the difficulties of obtaining paediatric bone samples. There is a need to investigate the behaviour of children’s bones under external loading. Such data will critically enhance our understanding of injury tolerance of paediatric bones under various loading conditions, related to injuries, such as bending and torsional loads. The aim of this study is therefore to investigate the response of paediatric femora under two types of loading conditions, bending and torsion, using a CT-based finite element approach, and to determine a relationship between bone strength and age/body mass of the child. Thirty post-mortem CT scans of children aged between 0 and 3 years old were used in this study. Two different boundary conditions were defined to represent four-point bending and pure torsional loads. The principal strain criterion was used to estimate the failure moment for both loading conditions. The results showed that failure moment of the bone increases with the age and mass of the child. The predicted failure moment for bending, external and internal torsions were 0.8–27.9, 1.0–31.4 and 1.0–30.7 Nm, respectively. To the authors’ knowledge, this is the first report on infant bone strength in relation to age/mass using models developed from modern medical images. This technology may in future help advance the design of child, car restrain system, and more accurate computer models of children.     

To sleep, to strive, or both: how best to optimize memory

While numerous studies have shown that a night of sleep profits memory relative to wake, we still have little understanding about what factors mediate this effect of sleep. A clear understanding of the dynamics of this effect of sleep beyond the initial night of sleep is also lacking. Here, we examined the effect of extrinsic rewards on sleep-dependent declarative memory processing across 12 and 24 hr training-retest intervals. Subjects were either paid based on their performance at retest ($1 for each correct answer), or received a flat fee for participation. After a 12 hr interval we observed pronounced benefits of both sleep and reward on memory. Over an extended 24 hr interval we found 1) that an initial night of sleep partially protects memories from subsequent deterioration during wake, and 2) that sleep blocks further deterioration, and may even have a restorative effect on memory, when it follows a full day of wake. Interestingly, the benefit imparted to rewarded (relative to unrewarded) stimuli was equal for sleep and wake subjects, suggesting that the sleeping brain may not differentially process rewarded information, relative to wake. However, looking at the overall impact of sleep relative to reward in this protocol, it was apparent that sleep both imparted a stronger mnemonic boost than reward, and provided a benefit to memory regardless of whether it occurred in the first or the second 12 hrs following task training.     

Microbiome of the larvae of Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) from maize plants

Fall armyworm (FAW), Spodoptera frugiperda, is an invasive insect pest with a diverse host range threatening food security in the African continent by causing severe economic damage to staple maize crop. FAW like all other insects are associated with various microbiota that influence their several characteristics and activities. The microbiota of insects plays important roles in their growth, development and environmental adaptation to their host plants or animals and not much is known about microbiota of FAW in Nigeria. In this study, the microbial community of FAW larvae from maize plants in Nigeria was investigated using Illumina PE250 NovaSeq of 16S rRNA V3-V4 gene region. A total of 1,160,133 sequence reads that ranged from 83,794 to 145,475 were obtained. They span through 2 kingdoms: bacteria (99.59%) and archaea (0.37%), 37 phyla, 59 classes, 78 orders, 145 families and 285 genera. The dominant taxonomic group of bacteria across the larval samples were Proteobacteria (58.32%), Firmicutes (35.87%) and Bacteroidetes (4.02%). There were no significant differences in bacteria species diversity and richness among the individual fall armyworm larva and samples from different geographical regions. The relative abundance of Bacteria phyla and classes also showed no significant differences among the larval samples. Significant differences were documented in bacteria orders Acidobacteriales and Aeromonadales, family Acidobacteriaceae_ (Subgroup_1) and genera Novosphingobium and Pedobacter. The results indicate that the gut of FAW larvae harbours a diverse set of bacteria and archaea biota. Understanding their ecological and functional relevance would provide novel insight on potential approaches for their exploitation in the integrated management of FAW in the tropics.