Mitochondria in human reproduction: novel paradigm in the onset of neurodegenerative disorders.

The disease progression of neurodegenerative disorders (NDD), including Alzheimer's, Parkinson's and Huntington's disease, is inextricably tied to mitochondrial dysfunction. However, although the contribution by nuclear gene mutations is recognised for familial onset of NDD, the degree to which cytoplasmic inheritance serves as a predetermining factor for the predisposition and onset of NDD is not yet fully understood. We review the reproductive mechanisms responsible for ensuring a healthy mitochondrial population within each new generation and elucidate how advanced maternal age can constitute an increased risk for the onset of NDD in the offspring, through the increased heteroplasmic burden. On the one hand, this review draws attention to how assisted reproductive technologies (ART) can impair mitochondrial fitness in offspring. On the other hand, we consider qualified ART approaches as a significant tool for the prevention of NDD pathogenesis.

Emerging scale invariance in a model of turbulence of vortices and waves.

This note is devoted to broken and emerging scale invariance of turbulence. Pumping breaks the symmetry: the statistics of every mode explicitly depend on the distance from the pumping. And yet the ratios of mode amplitudes, called Kolmogorov multipliers, are known to approach scale-invariant statistics away from the pumping. This emergent scale invariance deserves an explanation and a detailed study. We put forward the hypothesis that the invariance of multipliers is due to an extreme non-locality of their interactions (similar to the appearance of mean-field properties in the thermodynamic limit for systems with long-range interaction). We analyse this phenomenon in a family of models that connects two very different classes of systems: resonantly interacting waves and wave-free incompressible flows. The connection is algebraic and turns into an identity for properly discretized models. We show that this family provides a unique opportunity for an analytic (perturbative) study of emerging scale invariance in a system with strong interactions. This article is part of the theme issue 'Scaling the turbulence edifice (part 1)'.

Second-harmonic generation as a minimal model of turbulence.

When two resonantly interacting modes are in contact with a thermostat, their statistics is exactly Gaussian and the modes are statistically independent despite strong interaction. Considering a noise-driven system, we show that when one mode is pumped and another dissipates, the statistics of such cascades is never close to Gaussian, no matter what is the relation between interaction and noise. One finds substantial phase correlation in the limit of strong interaction or weak noise. Surprisingly, the mutual information between modes increases and entropy decreases when interaction strength decreases. We use the model to elucidate the fundamental problem of far-from equilibrium physics: where the information, or entropy deficit, is encoded, and how singular measures form. For an instability-driven system, such as laser, even a small added noise leads to large fluctuations of the relative phase near the stability threshold, while far from the equilibrium the conversion into the second harmonic is weakly affected by noise.

Termination of pregnancy due to fetal central nervous system abnormalities performed after 24 weeks' gestation: survey of 57 fetuses from a single medical center.

PURPOSE: To assess fetal central nervous system (CNS) abnormalities presenting as major findings leading to late termination of pregnancy (late TOP) performed ≥ 24 weeks' gestation. METHOD: The study population included 2789 pregnant women that underwent late TOP in our institute between the years 1998 and 2015. RESULTS: Fifty-seven cases (2.0%) underwent late TOP because of fetal CNS indications and are the subjects of the current study. Those cases were subdivided into four categories (1) no routine prenatal screening with an incidental finding discovered ≥ 24 weeks' gestation (25 patients, 43.8%); (2) developmental or acquired findings detected during late second and third trimester (22 patients, 38.6%); (3) apparently normal routine screening with abnormal findings that could have been detected earlier (six patients, 10.6%); (4) routine prenatal care raised suspicion of abnormalities, and the final diagnosis was established only following additional tests (four patients, 7.0%). CONCLUSIONS: Combining the two categories of CNS abnormalities, i.e., pregnant women who did not undergo any fetal evaluation (group 1) and those that could have been detected earlier (group 3) consists 54% from our cohort in which late TOP could have been avoided. On contrary, 39% fetuses from our study population had CNS developmental findings which could be detected only at advanced stage of gestation.