Activity and autonomous motion are fundamental aspects of many living and engineering systems. Here, the scale of biological agents covers a wide range, from nanomotors, cytoskeleton, and cells, to insects, fish, birds, and people. Inspired by biological active systems, various types of autonomous synthetic nano- and micromachines have been designed, which provide the basis for multifunctional, highly responsive, intelligent active materials.
View Article and Find Full Text PDFNumerical analysis of conserved field dynamics has been generally performed with pseudospectral methods. Finite differences integration, the common procedure for nonconserved field dynamics, indeed struggles to implement a conservative noise in the discrete spatial domain. In this work we present a method to generate a conservative noise in the finite differences framework, which works for any discrete topology and boundary conditions.
View Article and Find Full Text PDFMosquito copulation is a crucial determinant of its capacity to transmit malaria-causing Plasmodium parasites as well as underpinning several highly-anticipated vector control methodologies such as gene drive and sterile insect technique. For the anopheline mosquitoes responsible for African malaria transmission, mating takes place within crepuscular male swarms which females enter solely to mate. However, the mechanisms that regulate swarm structure or that govern mate choice remain opaque.
View Article and Find Full Text PDFLiving groups move in complex environments and are constantly subject to external stimuli, predatory attacks and disturbances. An efficient response to such perturbations is vital to maintain the group's coherence and cohesion. Perturbations are often local, i.
View Article and Find Full Text PDFFlocking in d=2 is a genuine nonequilibrium phenomenon for which irreversibility is an essential ingredient. We study a class of minimal flocking models whose only source of irreversibility is self-propulsion and use the entropy production rate (EPR) to quantify the departure from equilibrium across their phase diagrams. The EPR is maximal in the vicinity of the order-disorder transition, where reshuffling of the interaction network is fast.
View Article and Find Full Text PDFDiscretization of continuous stochastic processes is needed to numerically simulate them or to infer models from experimental time series. However, depending on the nature of the process, the same discretization scheme may perform very differently for the two tasks, if it is not accurate enough. Exact discretizations, which work equally well at any scale, are characterized by the property of invariance under coarse-graining.
View Article and Find Full Text PDFSpeed fluctuations of individual birds in natural flocks are moderate, due to the aerodynamic and biomechanical constraints of flight. Yet the spatial correlations of such fluctuations are scale-free, namely they have a range as wide as the entire group, a property linked to the capacity of the system to collectively respond to external perturbations. Scale-free correlations and moderate fluctuations set conflicting constraints on the mechanism controlling the speed of each agent, as the factors boosting correlation amplify fluctuations, and vice versa.
View Article and Find Full Text PDFThe recent inflow of empirical data about the collective behaviour of strongly correlated biological systems has brought field theory and the renormalization group into the biophysical arena. Experiments on bird flocks and insect swarms show that social forces act on the particles' velocity through the generator of its rotations, namely the spin, indicating that mode-coupling field theories are necessary to reproduce the correct dynamical behaviour. Unfortunately, a theory for three coupled fields-density, velocity and spin-has a prohibitive degree of intricacy.
View Article and Find Full Text PDFHuman implantation is a highly complex and multifactorial process. Successful implantation requires the presence of a healthy embryo, a receptive endometrium, and a synchronized molecular dialogue between the two, as well as immune tolerance/protection from the host. The endometrial receptivity refers to a hormonally limited period in which the endometrial tissue acquires a transient functional status allowing blastocyst implantation and pregnancy initiation.
View Article and Find Full Text PDFPre-eclampsia (PE) is a systemic maternal syndrome affecting 2-8% of pregnancies worldwide and involving poor placental perfusion and impaired blood supply to the foetus. It manifests after the 20 week of pregnancy as new-onset hypertension and substantial proteinuria and is responsible for severe maternal and newborn morbidity and mortality. Identifying biomarkers that predict PE onset prior to its establishment would critically help treatment and attenuate outcome severity.
View Article and Find Full Text PDFBackground: COVID-19 is a pandemic disease caused by the SARS-CoV-2 and it spread globally in the last few months. The complete lack of specific treatment forced clinicians to use old drugs, chosen for their efficacy against similar viruses or their activity. Trials on patients are ongoing but the majority of information comes from small case series and single center reports.
View Article and Find Full Text PDFBackground: Prematurity, low birth weight (LBW), very low birth weight (VLBW), and intrauterine growth restriction (IUGR) are risk factors of long-term poor neuro-development outcomes and associate with reduction of regional brain volumes.
Objective: To evaluate the possible role of 3D ultrasound sonography (3DUS) regional brain volumes, measured at 30-40 days of postnatal period, as early predictors of long-term risk of neuro-behavioral disorders.
Methods: A highly selected population, which included: full-term, preterm, IUGR, and preterm-IUGR born individuals, was followed longitudinally from 30 to 40 days of postnatal period to the second year of life.
J Matern Fetal Neonatal Med
February 2022
Objectives: High temperature requirement A1 (HtrA1) is a serine protease detected in maternal plasma and in placental tissues during normal gestation and in various pathological conditions. The purpose of this study was to determine whether the maternal plasma concentration of HtrA1 in first trimester, alone or combined with other maternal factors, can be used to identify women at risk for spontaneous preterm birth (SPTB).
Study Design: This is a cohort study on pregnant women at 12 weeks of gestation recruited between 2014 and 2016 and prospectively followed until delivery.
Motivated by the collective behavior of biological swarms, we study the critical dynamics of field theories with coupling between order parameter and conjugate momentum in the presence of dissipation. Under a fixed-network approximation, we perform a dynamical renormalization group calculation at one loop in the near-critical disordered region, and we show that the violation of momentum conservation generates a crossover between an unstable fixed point, characterized by a dynamic critical exponent z=d/2, and a stable fixed point with z=2. Interestingly, the two fixed points have different upper critical dimensions.
View Article and Find Full Text PDFWe study the critical behavior of a model with nondissipative couplings aimed at describing the collective behavior of natural swarms, using the dynamical renormalization group under a fixed-network approximation. At one loop, we find a crossover between an unstable fixed point, characterized by a dynamical critical exponent z=d/2, and a stable fixed point with z=2, a result we confirm through numerical simulations. The crossover is regulated by a length scale given by the ratio between the transport coefficient and the effective friction, so that in finite-size biological systems with low dissipation, dynamics is ruled by the unstable fixed point.
View Article and Find Full Text PDFJ Matern Fetal Neonatal Med
October 2021
Background: Maternal tetanus, diphtheria, and acellular pertussis (Tdap) and influenza immunization for women during pregnancy (the so-called "maternal immunization") has been introduced in several countries, and recently also in Italy, to protect mother and fetus during pregnancy, infant in his first months of life and mother during postpartum period. However, very low vaccination coverage rates have been reached due to several variables.
Methods: A literature search was conducted on PubMed and Embase, including any experimental or observational studies, to assesses existing evidence on the effectiveness, efficacy, safety and optimal timing of administration of Tdap and influenza immunization in pregnancy for mothers and their infants.
Objective: To assess and compare fetal cardiac parameters of fetuses listening to music before and during nonstress test, only during the test or never.
Study Design: Thirty healthy mother-fetus dyads were randomized in a 1:1:1 ratio to one of three groups: group A in which fetuses were submitted to (33rd + 0 to 36th + 3 week) and during 4 nonstress tests, group B in which fetuses were submitted to during 4 nonstress tests, and group C receiving 4 nonstress tests without any listening. We assessed mean fetal heart rate, fetal heart rate accelerations, fetal heart rate decelerations, fetal movements and uterine contractility.
J Matern Fetal Neonatal Med
April 2021
Aim: To identify risk factors for maternity blues (MB) and to evaluate the impact of obstetric factors on MB prevalence.
Materials And Methods: 194 mothers have completed the Edinburgh Postnatal Depression Scale (EPDS) 2 days after delivery. Bivariate and multivariate logistic regression models were used to identify the predictors of MB.
The purpose of the present study was to search for associations between spontaneous preterm birth (sPTB), single nucleotide polymorphisms (SNPs) associated with the apoptotic pathway as triggered by oxidative stress, maternal lifestyle and health status. SNP genotyping [rs7560 for c-Jun N-terminal kinase (JNK), rs9517320 for mammalian STE20-like protein kinase 3 (MST3), rs1049216 for caspase 3 (CASP3)] in the placenta and maternal blood of 300 controls with at-term birth and 43 cases of sPTB was performed. No association was identified in genotype frequencies or combinations of foetal/maternal genotypes between single SNPs and sPTB.
View Article and Find Full Text PDFBackground: The aim of this study was to assess the efficacy of PAMG-1 test (placental alpha microglobulin-1) in cervicovaginal secretions collected immediately following transvaginal ultrasound (TVUS) of women with signs and symptoms of preterm labor (PTL), clinically intact membranes and cervical length between 15 and 30 mm for the prediction of imminent spontaneous delivery (within 7 days of testing), as well as delivery <34 weeks of gestation.
Methods: Performing PAMG-1 test in 79 women with singleton pregnancy (240/7 -336/7 weeks' gestation) reporting signs and symptoms indicative of PTL and cervical length <30 mm.
Results: For PTB prediction risk within 7 days of testing in pregnant women with cervicale length between 15-30 mm sensitivity is 100% and specificity is 94%.
Best Pract Res Clin Obstet Gynaecol
October 2018
The time of birth is a critical determinant of perinatal and long-term outcomes. Preterm birth is still the first cause of infant mortality and morbidity; unfortunately, rates of preterm birth remain high in both high- and low-resource countries, ranging from 5% to 18%. Preterm parturition is a syndrome, which can be induced by various factors such as infection, cervical pathology, uterine overdistension, progesterone deficiency, vascular alterations (utero-placental ischemia, decidual hemorrhage), maternal and fetal stress, allograft reaction, allergic phenomena, and probably other several unknown factors.
View Article and Find Full Text PDFJ Matern Fetal Neonatal Med
December 2018
Purpose: The purpose of this study was to evaluate the potential improvement of introducing an intrapartum test for the detection of Group B Streptococcus (GBS) during labor and to estimate its cost-effectiveness versus antepartum GBS screening culture.
Materials And Methods: Three hundred and thirteen women at beginning of labor, with unknown GBS status or with antepartum GBS screening culture were enrolled. A vaginal-rectal specimen was collected from each woman for GBS detection by real-time PCR.