193 research outputs found

    Observed frequency-independent torque in flagellar bacterial motors optimizes space exploration

    Get PDF
    A surprising feature of many bacterial motors is the apparently conserved form of their torque-frequency relation. Experiments indicate that the torque provided by the bacterial rotary motor is approximately constant over a large range of angular speeds. This is observed in both monotrichous and peritrichous bacteria, independently of whether they are propelled by a proton flux or by a Na+ ion flux. If the relation between angular speed ω and swimming speed is linear, a ω-independent torque implies that the power spent in active motion is proportional to the instantaneous bacterial speed. Using realistic values of the relevant parameters, we show that a constant torque maximizes the volume of the region explored by a bacterium in a resource-depleted medium. Given that nutrients in the ocean are often concentrated in separate, ephemeral patches, we propose that the observed constancy of the torque may be a trait evolved to maximize bacterial survival in the ocean.Fil: Di Salvo, Mario Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Condat, Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentin

    First record of brown long-eared bat Plecotus auritus (Chiroptera: Vespertilionidae) for Sicily island (Italy)

    Get PDF
    The knowledge of the bat fauna of Sicily (Southern Italy) is scarce, fragmentary or sometimes even confusing. A recent review mentioned 20 species for the region, but it is likely that the checklist of bats of Sicily is still far from being exhaustive. To help fill this gap, in the past few years specific studies were carried out on the distribution of bat species in Sicily, especially in the woodlands of the Nebrodi Mountains. In the municipality of Caronia (Messina province) has captured a young female brown long-eared bat Plecotus auritus (Linneaus, 1758). The capture of P. auritus in Sicily represents the first record of brown long-eared bat Plecotus auritus for Sicily island, an interesting biogeographical record, as this bat is mostly known for the north and centre of the Italian peninsul

    Long-term evaluation of patient satisfaction and quality of life in pectus excavatum repair

    Get PDF
    Abstract Background: The aim of our study was to evaluate long-term patient satisfaction and quality-of-life improvement in grown-up patients treated for pectus excavatum with the Nuss procedure in the pediatric age, searching for correlation between preoperative characteristics and long-term outcomes. Methods: At first, we performed a retrospective analysis of pediatric patients undergoing the Nuss procedure in a 5-year period. We administered, at least 5 years after bar removal, a single-step questionnaire to focus on the assessment of patient satisfaction with operative results. Results: Most patients stated general health and exercise tolerance were improved after the operation. High levels of overall satisfaction were reported after Nuss repair, with 95.6% of patients being either satisfied or very satisfied. Overall, 87.0% of patients stated they would have the operation again. The high overall satisfaction after surgery was not correlated with the deformity severity and the presence of physical symptoms before correction. Conclusions: Patients expressed high levels of satisfaction in terms of self-image and quality of life. Improvement in cosmetic appearance and health in general translated in most patients in an improvement of social life. The degree of postoperative pain after the Nuss procedure is the overriding factor in the patient’s perception of the quality of the postoperative course

    Peritoneal dialysis catheters in pediatric patients: 10 years of experience in a single centre

    Get PDF
    Peritoneal Dialysis (PD) is one of the numerous options for chronic dialysis and in many cases when access for acute dialysis is required early in a hospital course, at any age. PD catheter can be inserted with an open or laparoscopic approach. The complication rate after catheter insertion is still high, as reported in published literature. We present the experience matured at our Centre in the last 10 years on implantation of peritoneal dialysis catheters in children, emphasising surgical complications. We conducted a retrospective study on patients who underwent PD at our Centre in a range period of 10 years. We analysed patients \u2019demographic data, past and present medical, perioperative and post-operative data, permanence of the catheter, duration of dialysis, the gap between placement and use, outcomes and complications. We compared the data, dividing patients in 2 groups: patients operated with a traditional open technique and patients operated laparoscopically. We retrospectively reviewed 29 children with an average age of 3years and 6 months. Mean age was 42 months (1 month; 8 years) for the VLS group, 18 months (11 days, 4 years) for the OT group. Mean operative time was 106 min for the VLS group; 44 min for the OT group. The Catheter permanence period was 17 days (12h-64 days). Duration of dialysis was between 48 hours and 23 days (average 8 days). In the total population, we registered 8 complications (5 minor, 3 major), the overall complication rate being 33 % (minor complication rate 21%, major complication rate 12,5 %). 6 complications occurred in patients operated laparoscopically (6/14 = 36 %); 2 complications in the OT group (2/10 = 20 %). The complication rate after PD catheter insertion is still high. Advantages and disadvantages of the open and laparoscopic approach must be known. Both minor and major complications, such as bowel perforations and occlusions, must be understood and differentiated

    Robotic removal of MĂĽllerian duct remnants in pediatric patients: our experience and a review of the literature.

    Get PDF
    Persistent MĂĽllerian duct syndrome is a disorder of sexual development, which features a failure of involution of MĂĽllerian structures. An enlarged prostatic utricle is a kind of MĂĽllerian duct remnant (MDR) with a tubular shaped structure communicating with the prostatic urethra. Treatment is aimed at relieving symptoms when present, preserve fertility and prevent neoplastic degeneration. We describe 3 cases of successful robot assisted-removal of symptomatic MDRs. The first case came to our attention for pseudo-incontinence; the other two for recurrent urinary tract infections. The patients have not presented such symptoms anymore on follow-up. We then reviewed existent literature on authors who have recently investigated the main issues concerning MDRs and have attempted a roboticassisted approach on them. Robot-assisted laparoscopy can be considered a valid, safe and effective minimally-invasive technique for the primary treatment of prostatic utricle

    Biochemical data from the characterization of a new pathogenic mutation of human pyridoxine-5'-phosphate oxidase (PNPO)

    Get PDF
    PNPO deficiency is responsible of severe neonatal encephalopathy, responsive to pyridoxal-5’-phosphate (PLP) or pyridoxine. Recent studies widened the phenotype of this condition and detected new genetic variants on PNPO gene, whose pathogenetic role and clinical expression remain to be established. One of these mutations, Arg116Gln, is of particular interest because of its later onset of symptoms (beyond the first months of life) and its peculiar epileptic manifestations in patients. This protein variant was expressed as recombinant protein in E coli, purified to homogeneity, and characterized with respect to structural and kinetic properties, stability, binding constants of cofactor flavin mononucleotide (FMN) and product (PLP) in order to define the molecular and structural bases of its pathogenicity. For interpretation and discussion of reported data, together with the description of clinical studies, refer to the article [7][1] (doi: 10.1016/j.ymgme.2017.08.003)

    A Configurable 64-Channel ASIC for Cherenkov Radiation Detection from Space

    Get PDF
    This work presents the development of a 64-channel application-specific integrated circuit (ASIC), implemented to detect the optical Cherenkov light from sub-orbital and orbital altitudes. These kinds of signals are generated by ultra-high energy cosmic rays (UHECRs) and cosmic neutrinos (CNs). The purpose of this front-end electronics is to provide a readout unit for a matrix of silicon photo-multipliers (SiPMs) to identify extensive air showers (EASs). Each event can be stored into a configurable array of 256 cells where the on-board digitization can take place with a programmable 12-bits Wilkinson analog-to-digital converter (ADC). The sampling, the conversion process, and the main digital logic of the ASIC run at 200 MHz, while the readout is managed by dedicated serializers operating at 400 MHz in double data rate (DDR). The chip is designed in a commercial 65 nm CMOS technology, ensuring a high configurability by selecting the partition of the channels, the resolution in the interval 8–12 bits, and the source of its trigger. The production and testing of the ASIC is planned for the forthcoming months

    Paediatric surgery in the robotic era: early experience and comparative analysis

    Get PDF
    The aim of this study is to present our preliminary experience in robotics and a comparative analysis with conventional Minimally- Invasive Surgery (MIS). Cases operated by da Vinci Xi® System from February 2016 to October 2017 are reviewed retrospectively through demographics, diagnosis-procedure and short-term outcome parameters. A comparison with a matching conventional MIS population was also conducted. 40 robotic procedures were carried out and 112 (out of 3705) non-robotic procedures met inclusion criteria for comparison. Among robotic patients we observed: an average age of 143.5 months, weight of 42.9 Kg, operative and anaesthesia induction time respectively of 116.8 and 34.8 minutes. Furthermore, we observed a 6.1-day length of stay, 2.5% conversion rate and no complications. From the comparison between the groups, no statistical difference emerged in the length of stay, in conversion rates or in complications. A statistical significance was observed in terms of operative time in favour of non-Robotic- System. Our experience has meant to introduce the System in our surgical environment, comparing to the conventional MIS (an already established approach routinely performed at our center). Results have shown comparable safety and feasibility
    • …
    corecore