Investigation of a drag reduction on a circular cylinder in rotary oscillation

Drag reduction in two-dimensional flow over a circular cylinder, achieved using rotary oscillation, was investigated with computational simulations. In the experiments of Tokumaru & Dimotakis (1991), this mechanism was observed to yield up to 80% drag reduction at Re = 15 000 for certain ranges of frequency and amplitude of sinusoidal rotary oscillation. Simulations with a high-resolution viscous vortex method were carried out over a range of Reynolds numbers (150–15 000) to explore the effects of oscillatory rotational forcing. Significant drag reduction was observed for a rotational forcing which had been very effective in the experiments. The impact of the forcing is strongly Reynolds number dependent. The cylinder oscillation appears to trigger a distinctive shedding pattern which is related to the Reynolds number dependence of the drag reduction. It appears that the source of this unusual shedding pattern and associated drag reduction is vortex dynamics in the boundary layer initiated by the oscillatory cylinder rotation. The practical efficiency of the drag reduction procedure is also discussed

Lens ER-stress response during cataract development in Mip-mutant mice

AbstractMajor intrinsic protein (MIP) is a functional water-channel (AQP0) that also plays a key role in establishing lens fiber cell architecture. Genetic variants of MIP have been associated with inherited and age-related forms of cataract; however, the underlying pathogenic mechanisms are unclear. Here we have used lens transcriptome profiling by microarray-hybridization and qPCR to identify pathogenic changes during cataract development in Mip-mutant (Lop/+) mice. In postnatal Lop/+ lenses (P7) 99 genes were up-regulated and 75 were down-regulated (>2-fold, p=<0.05) when compared with wild-type. A pathway analysis of up-regulated genes in the Lop/+ lens (P7) was consistent with endoplasmic reticulum (ER)-stress and activation of the unfolded protein response (UPR). The most up-regulated UPR genes (>4-fold) in the Lop/+ lens included Chac1>Ddit3>Atf3>Trib3>Xbp1 and the most down-regulated genes (>5-fold) included two anti-oxidant genes, Hspb1 and Hmox1. Lop/+ lenses were further characterized by abundant TUNEL-positive nuclei within central degenerating fiber cells, glutathione depletion, free-radical overproduction, and calpain hyper-activation. These data suggest that Lop/+ lenses undergo proteotoxic ER-stress induced cell-death resulting from prolonged activation of the Eif2ak3/Perk-Atf4-Ddit3-Chac1 branch of the UPR coupled with severe oxidative-stress

Sirtuins, bioageing, and cancer

The Sirtuins are a family of orthologues of yeast Sir2 found in a wide range of organisms from bacteria to man. They display a high degree of conservation between species, in both sequence and function, indicative of their key biochemical roles. Sirtuins are heavily implicated in cell cycle, cell division, transcription regulation, and metabolism, which places the various family members at critical junctures in cellular metabolism. Typically, Sirtuins have been implicated in the preservation of genomic stability and in the prolongation of lifespan though many of their target interactions remain unknown. Sirtuins play key roles in tumourigenesis, as some have tumour-suppressor functions and others influence tumours through their control of the metabolic state of the cell. Their links to ageing have also highlighted involvement in various age-related and degenerative diseases. Here, we discuss the current understanding of the role of Sirtuins in age-related diseases while taking a closer look at their roles and functions in maintaining genomic stability and their influence on telomerase and telomere function

"Functional electrical stimulation (FES) impacted on important aspects of my life" - A qualitative exploration of chronic stroke patients' and carers' perceptions of FES in the management of dropped foot.

Our purpose was to explore the impact of functional electrical stimulation (FES), as applied in the management of dropped foot, on patients with chronic stroke and their carers. A qualitative phenomenological study was undertaken. Participants were recruited from the Lothian FES clinic. Data were collected by using semistructured face-to-face interviews and analysed by using the framework of interpretative phenomenological analysis (IPA). Thirteen patients and nine carers consented to participate in the study. The overarching theme that emerged from the data was that "FES impacted on important aspects of my life." Four subthemes were identified: 1) "Walking with FES is much better"; 2) "FES helped regain control of life"; 3) "Feeling good comes with using FES"; and 4) "FES is not perfect but it is of value." This study provides insights into the perceptions of patients and carers of the impact of FES. These results have implications for clinicians delivering an FES service for the management of dropped foot after stroke. © Informa Healthcare. USA, Inc

Extracellular vesicles, ageing, and therapeutic interventions

A more comprehensive understanding of the human ageing process is required to help mitigate the increasing burden of age-related morbidities in a rapidly growing global demographic of elderly individuals. One exciting novel strategy that has emerged to intervene involves the use of extracellular vesicles to engender tissue regeneration. Specifically, this employs their molecular payloads to confer changes in the epigenetic landscape of ageing cells and ameliorate the loss of functional capacity. Understanding the biology of extracellular vesicles and the specific roles they play during normative ageing will allow for the development of novel cell-free therapeutic interventions. Hence, the purpose of this review is to summarise the current understanding of the mechanisms that drive ageing, critically explore how extracellular vesicles affect ageing processes and discuss their therapeutic potential to mitigate the effects of age-associated morbidities and improve the human health span

Queen Elizabeth in Germany: It is important to remember the dangers of a divided Europe

The Queen recently gave a speech in Germany where she said that “division in Europe is dangerous”. This remark met with controversy in the UK, where advocates of a Brexit accused the monarch of meddling in politics. Insofar as her speech contained any political message, writes David Shiels, it was directed at the leaders of all countries in Europe who sometimes seem to forget the original purpose behind the European project – the reconciliation of the peoples and nations of a divided continent

‘What would Maggie do?’ Had she been given the chance, we probably wouldn’t be asking

The question of how Margaret Thatcher would have voted in the forthcoming EU referendum has exercised a number of Conservative politicians. Her former adviser, Lord Powell, has argued that she was a pragmatist who would have at least considered supporting the Remain side. David Shiels says the ex-PM was always a Eurosceptic whose views hardened during her premiership. Had she stayed in office longer, we might well already have left the EU

How Enoch Powell helped to shape modern Tory Euroscepticism

The name of Enoch Powell provokes consternation in many on both the left and right of British politics. But the sometime Conservative was a powerful influence on Tory Euroscepticism – probably greater than most would want to acknowledge, writes David Shiels. His views on Europe chime with recurring themes in the referendum campaign