The physical basis of self-organization of the mammalian oocyte spindle

To prepare gametes with the appropriate number of chromosomes, mammalian oocytes undergo two sequential cell divisions. During each division, a large, long-lived, microtubule-based organelle called the meiotic spindle assembles around condensed chromosomes. Although meiotic spindles have been intensively studied for several decades, as force-generating mechanical objects, they remain very poorly understood. In materials physics, coarse-grained theories have been essential in understanding the large-scale behavior of systems composed of many interacting particles. It is unclear, however, if this approach can succeed in capturing the properties of active, biochemically complex, living materials like the spindle. Here, we show that a class of models based on nematic liquid crystal theory can describe important aspects of the organelle-scale structure and dynamics of spindles in living mouse oocytes. Using our models to interpret quantitative polarization microscopy data, we measure for the first time material properties relating to stress propagation in living oocytes, including the nematic diffusivities corresponding to splay and bend deformations. Unlike the reconstituted amphibian spindles that were previously studied in vitro, nematic elastic stress is exponentially screened in the microtubule network of living mammalian oocytes, with a screening length of order one micron. This observation can be explained by the relatively high volume fraction of embedded chromosomes in mammalian meiotic spindles, which cause long voids in the microtubule network and so disrupt orientational stress propagation

Patient involvement to explore research prioritisation and self-care management in people with periodontitis and diabetes

Aim To investigate, firstly, research priorities for people with periodontitis and those with periodontitis and diabetes. Secondary aims were to explore disease self-management barriers, difficulties and enhancers for people with periodontitis and/or diabetes, mutual learning in patient groups regarding self-care and views of academic researchers on patient-derived research prioritisation. Materials and methods Research prioritisation and self-care management was based on the James Lind Alliance workshop methodology. Participants generated and ranked research priorities and enhancers and barriers to self-care management. Semi-structured interviews were undertaken to explore the views of academic staff about patient and public involvement (PPI) and the findings from this research. Results Periodontitis patients ranked preventive educational interventions highest, whereas the top priority for those with both periodontitis and diabetes was increasing public awareness about periodontitis and systemic health links. Regarding self-care, both periodontitis and diabetes groups highly ranked the importance of being able to self-assess their condition and efficacy of management. Important barriers for the diabetes patients were psychological issues, while for periodontitis patients, the main barrier was receiving conflicting or lacking information. Both groups reported that shared learning helped to develop a better understanding of their conditions and improved management. Academics believed it was essential to involve patients in developing research and most felt the findings would influence their institutions' research priorities; however, they would not change their own research only based on patients' perspectives. Conclusions The workshops led to new insights for research priorities and approaches for health self-management. PPI should be further investigated across oral health applications

Developing the role of the sports dentist

Sports dentistry has traditionally focused on orofacial trauma. There is now increasing evidence that participation in sport, particularly at elite level, may significantly increase the risks to oral health. The negative impact of poor oral health on athlete-reported wellbeing and performance is clear. The risks to athlete oral health can and should be mitigated and the role of the sports dentist is evolving to meet these new challenges. Custom-made mouthguards provide protection against orofacial trauma and potentially, concussion. Oral health screening should be included in athlete pre-season preparation. As integrated members of the athlete support team, dentists and dental care professionals can provide sport-specific oral health advice, encouraging athletes to take ownership of their oral health. The potential for translational health and wellbeing benefits to the wider population is also substantial, particularly with youth groups and recreational athletes. Sports dentistry requires distinctive skills. A UK-wide network of dentists and other oral health professionals with an interest in sport is important, to ensure that both appropriate advice and treatment is evidence-based and to further develop the research and clinical foundations

Oral health-related behaviours reported by elite and professional athletes

Background In elite sport, the protection of an athlete's health is a priority. However, research indicates a substantial prevalence of oral disease in elite and professional athletes. The challenges to oral health from participation in sport require investigation to identify effective strategies and mitigate risk. Aim To explore athlete-reported oral health behaviours, risks and potential for behaviour change in a representative sample of elite athletes based in the UK. Method This was a cross-sectional study. We provided oral health screening for 352 elite and professional athletes from June 2015 to September 2016; 344 athletes also completed a questionnaire. Results The median age was 25 years (range 18-39) and 236 (67%) were male; 323 (94.2%) said they brush twice daily while 136 (40%) said their most recent dental attendance was within the previous six months. Ninety-seven (28%) would be assessed as high consumers of sugar in their regular diet. The use of sports nutrition products was common with 288 (80%) reporting the use of sports drinks during training or competition but were positive about behaviour changes. Conclusion Despite reporting positive oral health-related behaviours, athletes have substantial amounts of oral disease. Athletes are willing to consider behaviour change related to daily plaque removal, increased fluoride availability and regular dental visits to improve oral health

A finite strain, finite band method for modeling ductile fracture

We present a finite deformation generalization of the finite thickness embedded discontinuity formulation presented in our previous paper [A.E. Huespe, A. Needleman, J. Oliver, P.J. Sánchez, A finite thickness band method for ductile fracture analysis, Int. J. Plasticity 25 (2009) 2349–2365]. In this framework the transition from a weak discontinuity to a strong discontinuity can occur using a single constitutive relation which is of importance in a range of applications, in particular ductile fracture, where localization typically precedes the creation of new free surface. An embedded weak discontinuity is introduced when the loss of ellipticity condition is met. The resulting localized deformation band is given a specified thickness which introduces a length scale thus providing a regularization of the post-localization response. The methodology is illustrated through several example problems emphasizing finite deformation effects including the development of a cup-cone failure in round bar tensio

Assessing the Device-performance Impacts of Structural Defects with TCAD Modeling

Advanced solar cell architectures like passivated emitter and rear (PERC) and heterojunction with intrinsic thin layer (HIT) are increasingly sensitive to bulk recombination. Present device models consider homogeneous bulk lifetime, which does not accurately reflect the effects of heterogeneously distributed defects. To determine the efficiency potential of multicrystalline silicon (mc-Si) in next-generation architectures, we present a higher-dimensional numerical simulation study of the impacts of structural defects on solar cell performance. We simulate these defects as an interfacial density of traps with a single mid-gap energy level using Shockley-Read-Hall (SRH) statistics. To account for enhanced recombination at the structural defects, we apply a linear scaling to the majority-carrier capture cross-section and scale the minority-carrier capture cross-section with the inverse of the line density of traps. At 300 K, our simulations of carrier occupation and recombination rate match literature electron-beam-induced current (EBIC) data and first-principles calculations of carrier capture, emission, and recombination for all the energy levels associated with dislocations decorated with metal impurities. We implement our model in Sentaurus Device, determining the losses across different device architectures for varying impurity decoration of grain boundaries.American Society for Engineering Education. National Defense Science and Engineering Graduate FellowshipNational Science Foundation (U.S.). Engineering Research Centers Program (Cooperative Agreement EEC-1041895

Self-Reported Outcome Measures of the Impact of Injury and Illness on Athlete Performance: A Systematic Review

BACKGROUND: Self-reported outcome measures of athlete health, wellbeing and performance add information to that obtained from clinical measures. However valid, universally accepted outcome measures are required. OBJECTIVE: To determine which athlete-reported outcome measures of performance have been used to measure the impact of injury and illness on performance in sport and assess evidence to support their validity. METHODS: The authors searched Ovid MEDLINE, Ovid EMBASE, CINAHL Plus, SPORTDiscus with Full Text and Cochrane library to January 2016. Predefined inclusion and exclusion criteria were applied and papers included if an outcome measure of performance, assessed in relation to illness, injury or a related intervention, was reported by an elite, adult, able-bodied athlete. A checklist was used to assess eligible outcome measures for aspects of validity. Reporting of this study was guided by PRISMA guidelines for systematic reviews. RESULTS: Twenty athlete-reported outcome measures in 21 papers were identified. Of these 20, only four cited validation. Of these four, three reported evidence to support validity in elite athlete groups as defined by the predetermined checklist. Fifteen patient-reported outcome measures were identified, of which four demonstrated validity in young athletic populations. CONCLUSIONS: Most athlete-reported outcome measures of performance have been designed for individual studies with no reported assessment of validity. Despite some limitations, the Oslo Sports Trauma Centre overuse injury questionnaire demonstrates validity and potential utility to investigate the self-reported impact of pre-defined conditions on athletic performance across different sports

Assessing the Device-performance Impacts of Structural Defects with TCAD Modeling

Advanced solar cell architectures like passivated emitter and rear (PERC) and heterojunction with intrinsic thin layer (HIT) are increasingly sensitive to bulk recombination. Present device models consider homogeneous bulk lifetime, which does not accurately reflect the effects of heterogeneously distributed defects. To determine the efficiency potential of multicrystalline silicon (mc-Si) in next-generation architectures, we present a higher-dimensional numerical simulation study of the impacts of structural defects on solar cell performance. We simulate these defects as an interfacial density of traps with a single mid-gap energy level using Shockley-Read-Hall (SRH) statistics. To account for enhanced recombination at the structural defects, we apply a linear scaling to the majority-carrier capture cross-section and scale the minority-carrier capture cross-section with the inverse of the line density of traps. At 300 K, our simulations of carrier occupation and recombination rate match literature electron-beam-induced current (EBIC) data and first-principles calculations of carrier capture, emission, and recombination for all the energy levels associated with dislocations decorated with metal impurities. We implement our model in Sentaurus Device, determining the losses across different device architectures for varying impurity decoration of grain boundaries.DoD/National Defense Science & Engineering Graduate Fellowship (NDSEG

Oral health of elite athletes and association with performance: a systematic review.

We aimed to systematically review the epidemiology of oral disease and trauma in the elite athlete population and to investigate the impact of oral health on sporting performance