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Collective migration-the directed, coordinated motion of many self-propelled agents-is a fascinating emergent behavior exhibited by active matter with functional implications for biological systems. However, how migration can persist when a population is confronted with perturbations is poorly understood. Here, we address this gap in knowledge through studies of bacteria that migrate via directed motion, or chemotaxis, in response to a self-generated nutrient gradient. We find that bacterial populations autonomously smooth out large-scale perturbations in their overall morphology, enabling the cells to continue to migrate together. This smoothing process arises from spatial variations in the ability of cells to sense and respond to the local nutrient gradient-revealing a population-scale consequence of the manner in which individual cells transduce external signals. Altogether, our work provides insights to predict, and potentially control, the collective migration and morphology of cellular populations and diverse other forms of active matter. eLife digest Flocks of birds, schools of fish and herds of animals are all good examples of collective migration, where individuals co-ordinate their behavior to improve survival. This process also happens on a cellular level; for example, when bacteria consume a nutrient in their surroundings, they will collectively move to an area with a higher concentration of food via a process known as chemotaxis. Several studies have examined how disturbing collective migration can cause populations to fall apart. However, little is known about how groups withstand these interferences. To investigate, Bhattacharjee, Amchin, Alert et al. studied bacteria called Escherichia coli as they moved through a gel towards nutrients. The E. coli were injected into the gel using a three-dimensional printer, which deposited the bacteria into a wiggly shape that forces the cells apart, making it harder for them to move as a collective group. However, as the bacteria migrated through the gel, they smoothed out the line and gradually made it straighter so they could continue to travel together over longer distances. Computer simulations revealed that this smoothing process is achieved by differences in how the cells respond to local nutrient levels based on their position. Bacteria towards the front of the group are exposed to more nutrients, causing them to become oversaturated and respond less effectively to the nutrient gradient. As a result, they move more slowly, allowing the cells behind them to eventually catch-up. These findings reveal a general mechanism in which limitations in how individuals sense and respond to an external signal (in this case local nutrient concentrations) allows them to continue migrating together. This mechanism may apply to other systems that migrate via chemotaxis, as well as groups whose movement is directed by different external factors, such as temperature and light intensity.

BACKGROUND: 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

The Global Health Security Initiative (GHSI) established a laboratory network within the GHSI community to develop their collective surge capacity for radionuclide bioassay in response to a radiological or nuclear emergency. A recent exercise was conducted to test the participating laboratories for their capabilities in screening and in vitro assay of biological samples, performing internal dose assessment and providing advice on medical intervention, if necessary, using a urine sample spiked with a single radionuclide, 241Am. The laboratories were required to submit their reports according to the exercise schedule and using pre-formatted templates. Generally, the participating laboratories were found to be capable with respect to rapidly screening samples for radionuclide contamination, measuring the radionuclide in the samples, assessing the intake and radiation dose, and providing advice on medical intervention. However, gaps in bioassay measurement and dose assessment have been identified. The network may take steps to ensure that procedures and practices within this network be harmonised and a follow-up exercise be organised on a larger scale, with potential participation of laboratories from the networks coordinated by the International Atomic Energy Agency and theWorld Health Organization. © The Author 2015. Published by Oxford University Press.

The clinic use of alpha Lipoic Acid (ALA) is linked to its capability to exert antioxidant effects and, more interestingly, to counteract the pathologic changes of complex networks of cytokines, chemokines and growth factors, restoring their physiological state. The aim of this randomized controlled clinical trial was to test the contribution of oral supplementation of ALA to the standard treatment with Progesterone vaginal suppositories, in healing subchorionic hematomas in patients with threatened miscarriage. Controls were administered only Progesterone suppositories.Nineteen pregnant women in the first trimester of gestation, with threatened miscarriage and ultrasound evidence of subchorionic hematoma, were included in the trial and randomly divided in two groups: controls, treated with 400 mg Progesterone (200 mg 2 times per day), given by vaginal suppositories, and case study treated with the same Progesterone dosage, plus ALA, given orally at the dose of 600 mg (300 mg 2 times per day, DAV®, Lo.Li. Pharma srl, Italy). Sixteen patients completed the trial. Treatment was performed until complete resolution of the clinical picture.In both groups, the subjects improved significantly but, in general, a better and faster evolution in the major signs of threatened miscarriage was observed in the subjects treated with ALA and Progesterone. In these patients, the speed of resorption of subchorionic hematoma was significantly (p ≤ 0.05) superior compared to controls. The ALA and Progesterone group showed a faster decrease or disappearance of all symptoms than that observed in the control group, however the difference was not significant.These preliminary results suggest that ALA supplementation significantly contributes to speed up the process of restoration of physiological conditions in threatened miscarriage and ameliorates the medical conditions of both the mothers and the foetus, probably modulating the networks of cytokines, growth factors and other molecules.

The aim of this study was to evaluate the effectiveness of the fetal fibronetcin (fFN) test and ultrasonographic cervical length measurement used alone or in combination with each other in order to further improve the identification of patients in preterm labor.Prospective multicenter observational study on patients between 24 and 32 weeks of gestation with symptoms of preterm labor (total patients = 132). The endpoint was the delivery at 34 weeks or more. The screening methods used were: the fFN test (group 1), the cervical length measurement by transvaginal ultrasound (group 2) or a combination of both tests (group 3) according to an established protocol. The statistical analysis was performed using the χ2 test using the SPSS software.Group 1: positive fFN test in 25.7% of cases, incidence of preterm birth (34 weeks) of 18%. Group 2: cervical length25 mm in 56.2% of cases, incidence of preterm birth (34 weeks) of 18.5%. The negative predictive value is equivalent to 99.0% for the fFN test and 95.2% for cervicometry; combined use reaches 100%, compared to 54% positive predictive value.The identification of women at high risk of preterm delivery carried out with the fFN test or with transvaginal ultrasound cervicometry is clinically valid. The study also showed that the contextual use of biochemical and biophysical tests reaches a high negative predictive value (100%), making it a very useful method to identify patients truly at risk and to further reduce the incidence of non adequate treatment.

Objective The aim of this study was to identify maternal risk factors for spontaneous preterm birth (PTB) compared to delivery at term, in order to recognize high risk women and to provide a global overview of the Italian situation. Study design A multicenter, observational and retrospective, cross-sectional study was designed. The study population comprised 7634 women recruited in 9 different University Maternity Hospitals in Italy. The main criteria for inclusion were: women having had vaginal preterm or term spontaneous delivery in each participating centre during the study period. The records related to deliveries occurring between April and December 2008. A multivariable logistic regression was employed to identify independent predictors of spontaneous preterm birth. Odds ratios (ORs) and 95% confidence intervals (95% CI) were reported with two-tailed probability ( p ) values. Statistical calculations were carried out using SAS version 9.1. A two-tailed p -value of 0.05 was used to define statistical significant results. Results A significant increased risk of PTB was found in women with BMI>25 (OR=1.662; 95% CI=1.033–2.676; p -value=0.0365) and in women employed in heavy work (OR=1.947; 95% CI=1.182–3.207; p -value=0.0089). Moreover there was a significant association between PTB and previous reproductive history. In fact a history of previous abortion (OR=1.954; 95% CI=1.162–3.285; p -value=0.0116) or previous cesarean section (OR=2.904; 95% CI=1.066–7.910; p -value=0.0371) was positively correlated to the increased risk of PTB and an important statistically significant association was calculated between PTB and previous pre-term delivery (OR=3.412; 95% CI=1.342–8.676; p -value=0.0099). All the other covariates examined as potential risk factors for PTB were not found to be statistically significantly related ( p -value>0.05). Conclusions The present study, applied to a substantial sample of Italian population, demonstrates that there are peculiar risk factors for spontaneous PTB in the Italian population examined. It shows an association between preterm delivery and certain maternal factors as: BMI, employment, previous abortions, previous PTBs and previous cesarean section.

Numerical models indicate that collective animal behaviour may emerge from simple local rules of interaction among the individuals. However, very little is known about the nature of such interaction, so that models and theories mostly rely on aprioristic assumptions. By reconstructing the three-dimensional position of individual birds in airborne flocks of few thousands members, we prove that the interaction does not depend on the metric distance, as most current models and theories assume, but rather on the topological distance. In fact, we discover that each bird interacts on average with a fixed number of neighbours (six-seven), rather than with all neighbours within a fixed metric distance. We argue that a topological interaction is indispensable to maintain flock's cohesion against the large density changes caused by external perturbations, typically predation. We support this hypothesis by numerical simulations, showing that a topological interaction grants significantly higher cohesion of the aggregation compared to a standard metric one., Comment: To be submitted to PNAS - 25 pages

Fast monitoring of water quality is a fundamental part of environmental management and protection, in particular, the possibility of qualitatively and quantitatively determining its contamination at levels that are dangerous for human health, fauna and flora. Among the techniques currently available, Raman spectroscopy and its variant, Surface-Enhanced Raman Spectroscopy (SERS), have several advantages, including no need for sample preparation, quick and easy operation and the ability to operate on the field. This article describes the application of the Raman and SERS technique to liquid samples contaminated with different classes of substances, including nitrates, phosphates, pesticides and their metabolites. The technique was also used for the detection of the air pollutant polycyclic aromatic hydrocarbons and, in particular, benzo(a)pyrene, considered as a reference for the carcinogenicity of the whole class of these compounds. To pre-concentrate the analytes, we applied a methodology based on the well-known coffee-ring effect, which ensures preconcentration of the analytes without any pretreatment of the sample, providing a versatile approach for fast and in-situ detection of water pollutants. The obtained results allowed us to reveal these analytes at low concentrations, close to or lower than their regulatory limits.

Economically motivated adulterations of food, in general, and spices, in particular, are an emerging threat to world health. Reliable techniques for the rapid screening of counterfeited ingredients in the supply chain need further development. Building on the experience gained with CO2 lasers, the Diagnostic and Metrology Laboratory of ENEA realized a compact and user-friendly photoacoustic laser system for food fraud detection, based on a quantum cascade laser. The sensor has been challenged with saffron adulteration. Multivariate data analysis tools indicated that the photoacoustic laser system was able to detect adulterants at mass ratios of 2% in less than two minutes.

The results obtained in a measurement campaign concerning internal contamination by the gamma-emitting radionuclides of a large number of individuals are presented in this work. The aim is to assess the effectiveness of the spectrometric method in an emergency response following a nuclear power plant accident or a spread of radionuclides in the atmosphere due to an act of terrorism. An HPGe portable spectrometer, deployed in a collective protection apparatus, was used for both whole-body and thyroid measurements. An adult bottle mannequin absorption (BOMAB) and thyroid phantoms were used to evaluate the detector performance. The BOMAB phantom was provided by the Italian Institute of Ionizing Radiation Metrology (INMRI) for the ENEA intercomparison exercise. Thyroid phantoms were provided by the Belgian Nuclear Research Centre for the 'Child and Adult Thyroid Monitoring After Reactor Accident' European intercomparison exercise. The instrument performance was further evaluated by collecting spectral data from healthy volunteers, using acquisition times of 180 s and 100 s, respectively, for the whole-body and thyroid measurements. The detector showed good accuracy in quantifying radionuclide activities in the adult BOMAB and in the thyroids of persons of all ages. The proposed method allows us to detect in vivo activity leading to a committed effective dose E(50) and committed thyroid equivalent doses H T greater than 2 mSv due to all gamma-emitting fission products, if the scan is performed within five days after intake. Assuming, for instance, an acute inhalation of 137Cs and 131I, the obtained detection limit values for adults lead to a E(50) value equal to 0.08 mSv and an H T value of 0.27 mSv. The E(50) and H T values show that the proposed method can be successfully used when the dose assessment must be rapidly performed for a large number of individuals in the eventuality of the scenarios previously mentioned.

A set of measurements have been conducted to determine the activity-level of natural and artificial radionuclides in some baby foods commercialized in Italy. The measurements have been carried out using liquid scintillation, gamma, alpha and mass spectrometry. The activity concentrations ranged from 0.005 to 0.238, from 0.0082 to 1.65, from 0.0003 to 0.015 and from

Activity concentration of natural radionuclides and 137Cs were estimated in 28 honeys purchased from large supermarket chains in Italy. Uranium, polonium and thorium were measured by alpha spectrometry, 40 K and 137Cs by gamma spectrometry and 226Ra by liquid scintillation. The concentrations were 50.6 ± 46.3, 0.023 ± 0.010, 0.019 ± 0.017, 0.27 ± 0.40 Bqkg−1 for 40 K, 238U, 234U and 210Po respectively. 235U, 228Th, 232Th were consistently

In order to properly respond to an emergency caused by an accident in a nuclear power plant with a spread of radionuclides in the atmosphere, we propose a field procedure to perform a large-scale individual thyroid monitoring of internal contamination due to inhalation of 131I, by means of non-spectrometric equipment, in particular dose rate meters. Specific attention is paid to the individual monitoring of children, because of the very high radiosensitivity of the child's thyroid to the carcinogenic effects of ionising radiation. The device performance was evaluated by measuring mock iodine sources provided in the Child and Adult Thyroid Monitoring After Reactor Accident (CAThyMARA) intercomparison and, just for a scintillator dose rate meter, by means of 60 s acquisitions of healthy volunteers' thyroids. All the devices showed a remarkable accuracy in quantification of equivalent 131I activity in the thyroids of persons of all ages. The selected scintillator dose rate meter showed detection limit values resulting in a maximum committed equivalent dose to thyroid HT, assuming an acute 131I inhalation occurred five days before the measurement, equal to 10 mSv (related to five-year-old children). Considering the level of HT values associated with the calculated detection limit activities, the proposed procedure has a significant sensitivity to be used for fast internally thyroid monitoring in nuclear or radiological emergencies, allowing daily monitoring a large amount of individuals.