Deformable self-propelled particles

A theory of self-propelled particles is developed in two dimensions assuming that the particles can be deformed from a circular shape when the propagating velocity is increased. A coupled set of equations in terms of the velocity and a tensor variable to represent the deformation is introduced to show that there is a bifurcation from a straight motion to a circular motion of a single particle. Dynamics of assembly of the particles is studied numerically where there is a global interaction such that the particles tend to cause an orientational order.Comment: 4pages, 4figure

Sex differences in the association between diabetes and cancer: a systematic review and meta-analysis of 121 cohorts including 20 million individuals and one million events

Aims/hypothesis: Diabetes has been shown to be a risk factor for some cancers. Whether diabetes confers the same excess risk of cancer, overall and by site, in women and men is unknown. Methods: A systematic search was performed in PubMed for cohort studies published up to December 2016. Selected studies reported sex-specific relative risk (RR) estimates for the association between diabetes and cancer adjusted at least for age in both sexes. Random-effects meta-analyses with inverse-variance weighting were used to obtain pooled sex-specific RRs and women-to-men ratios of RRs (RRRs) for all-site and site-specific cancers. Results: Data on all-site cancer events (incident or fatal only) were available from 121 cohorts (19,239,302 individuals; 1,082,592 events). The pooled adjusted RR for all-site cancer associated with diabetes was 1.27 (95% CI 1.21, 1.32) in women and 1.19 (1.13, 1.25) in men. Women with diabetes had ~6% greater risk compared with men with diabetes (the pooled RRR was 1.06, 95% CI 1.03, 1.09). Corresponding pooled RRRs were 1.10 (1.07, 1.13) for all-site cancer incidence and 1.03 (0.99, 1.06) for all-site cancer mortality. Diabetes also conferred a significantly greater RR in women than men for oral, stomach and kidney cancer, and for leukaemia, but a lower RR for liver cancer. Conclusions/interpretation: Diabetes is a risk factor for all-site cancer for both women and men, but the excess risk of cancer associated with diabetes is slightly greater for women than men. The direction and magnitude of sex differences varies by location of the cancer

Diabetes as a risk factor for heart failure in women and men: a systematic review and meta-analysis of 47 cohorts including 12 million individuals

Aims/hypothesis: The prevalence of diabetes and heart failure is increasing, and diabetes has been associated with an increased risk of heart failure. However, whether diabetes confers the same excess risk of heart failure in women and men is unknown. The aim of this study was to conduct a comprehensive systematic review with meta-analysis of possible sex differences in the excess risk of heart failure consequent to diabetes. Our null hypothesis was that there is no such sex difference. Methods: A systematic search was conducted in PubMed for population-based cohort studies published between January 1966 and November 2018. Studies were selected if they reported sex-specific estimates of RRs for heart failure associated with diabetes, and its associated variability, which were adjusted at least for age. Random-effects meta-analyses with inverse variance weighting were used to obtain pooled sex-specific RRs and women-to-men ratio of RRs (RRRs) for heart failure associated with diabetes. Results: Data from 47 cohorts, involving 12,142,998 individuals and 253,260 heart failure events, were included. The pooled multiple-adjusted RR for heart failure associated with type 1 diabetes was 5.15 (95% CI 3.43, 7.74) in women and 3.47 (2.57, 4.69) in men, leading to an RRR of 1.47 (1.44, 1.90). Corresponding pooled RRs for heart failure associated with type 2 diabetes were 1.95 (1.70, 2.22) in women and 1.74 (1.55, 1.95) in men, with a pooled RRR of 1.09 (1.05, 1.13). Conclusions/interpretation: The excess risk of heart failure associated with diabetes is significantly greater in women with diabetes than in men with diabetes. PROSPERO registration: CRD42019135246

Dynamics of a deformable self-propelled domain

We investigate the dynamical coupling between the motion and the deformation of a single self-propelled domain based on two different model systems in two dimensions. One is represented by the set of ordinary differential equations for the center of gravity and two tensor variables characterizing deformations. The other is an active cell model which has an internal mechanism of motility and is represented by the partial differential equation for deformations. Numerical simulations show a rich variety of dynamics, some of which are common to the two model systems. The origin of the similarity and the difference is discussed.Comment: 6 pages, 6 figure