Hypersonic flight regime is conventionally defined for Mach> 5; in these conditions, the flying object becomes enveloped in a plasma. This plasma is densest in thin surface layers, but in typical ...situations of interest it impacts electromagnetic wave propagation in an electrically large volume. We address this problem with a hybrid approach. We employ Equivalence Theorem to separate the inhomogeneous plasma region from the surrounding free space via an equivalent (Huygens) surface, and the Eikonal approximation to Maxwell equations in the large inhomogeneous region for obtaining equivalent currents on the separating surface. Then, we obtain the scattered field via (exact) free space radiation of these surface equivalent currents. The method is extensively tested against reference results and then applied to a real-life re-entry vehicle with full 3D plasma computed via Computational Fluid Dynamic (CFD) simulations. We address both scattering (RCS) from the entire vehicle and radiation from the on-board antennas. From our results, significant radio link path losses can be associated with plasma spatial variations (gradients) and collisional losses, to an extent that matches well the usually perceived blackout in crossing layers in cutoff. Furthermore, we find good agreement with existing literature concerning significant alterations of the radar response (RCS) due to the plasma envelope.
Biofilm-related infections represent a recurrent problem in the orthopaedic setting. In recent years, great interest was directed towards the identification of novel molecules capable to interfere ...with pathogens adhesion and biofilm formation on implant surfaces. In this study, two stable forms of α-tocopherol, the hydrophobic acetate ester and the water-soluble phosphate ester, were tested in vitro as coating for titanium prosthesis. Antimicrobial activity against microorganisms responsible of prosthetic and joints infections was assessed by broth microdilution method. In addition, α-tocopherol esters were evaluated for both their ability to hamper bacterial adhesion to and biofilm formation on sandblasted titanium surfaces. Results showed that only α-tocopheryl phosphate displayed antimicrobial activity against the tested strains. Both esters were able to significantly interfere with bacterial adhesion and to prevent biofilm formation, especially by Staphylococcus aureus and Staphylococcus epidermidis. The activity of α-tocopheryl phosphate was greater than that of α-tocopheryl acetate. Alterations at membrane levels have been reported in literature and may be likely responsible for the interference on bacterial adhesion and biofilm formation shown by α-tocopherol esters. Although further studies are needed to better investigate the mechanisms of action and the spectrum of activity of α-tocopherol esters, these characteristics together with the positive effect on wound healing and immune response, make these molecules promising candidate for coating in order to prevent implant-associated infections.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Dravet syndrome (DS) is a rare and severe form of genetic epilepsy characterized by cognitive and behavioural impairments and progressive gait deterioration. The characterization of gait parameters ...in DS needs efficient, non-invasive quantification. The aim of the present study is to apply nonlinear indexes calculated from inertial measurements to describe the dynamics of DS gait. Twenty participants (7 M, age 9-33 years) diagnosed with DS were enrolled. Three wearable inertial measurement units (OPAL, Apdm, Portland, OR, USA; Miniwave, Cometa s.r.l., Italy) were attached to the lower back and ankles and 3D acceleration and angular velocity were acquired while participants walked back and forth along a straight path. Segmental kinematics were acquired by means of stereophotogrammetry (SMART, BTS). Community functioning data were collected using the functional independence measure (FIM). Mean velocity and step width were calculated from stereophotogrammetric data; fundamental frequency, harmonic ratio, recurrence quantification analysis, and multiscale entropy (τ = 1...6) indexes along anteroposterior (AP), mediolateral (ML), and vertical (V) axes were calculated from trunk acceleration. Results were compared to a reference age-matched control group (112 subjects, 6-25 years old). All nonlinear indexes show a disruption of the cyclic pattern of the centre of mass in the sagittal plane, quantitatively supporting the clinical observation of ataxic gait. Indexes in the ML direction were less altered, suggesting the efficacy of the compensatory strategy (widening the base of support). Nonlinear indexes correlated significantly with functional scores (i.e., FIM and speed), confirming their effectiveness in capturing clinically meaningful biomarkers of gait.
Male fertility is progressively declining in many developed countries, but the relationship between male infertility and environmental factors is still unclear.
To assess the influence of ...environmental temperature and air pollution on semen parameters, using a big-data approach.
A big data analysis of parameters related to 5131 men, living in a province of Northern Italy and undergoing semen analyses between January 2010 and March 2016 was performed. Ambient temperature was recorded on the day of analysis and the 90 days prior to the analysis and the average value of particulate matter (PM) and NO2 in the year of the test. All data were acquired by geocoding patients residential address. A data warehouse containing 990,904,591 data was generated and analysed by multiple regressions.
5573 semen analyses were collected. Both maximum and minimum temperatures registered on the day of collection were inversely related to total sperm number (p < .001), non-progressive motility (NPrM) (p < .005) and normal forms (p < .001). Results were confirmed considering temperature in the 30 and 60 days before collection, but not in the 90 days before collection. Total sperm number was lower in summer/autumn (p < .001) and was inversely related with daylight duration (p < .001). PM10 and PM2.5 were inversely related to PrM (p < .001 and p < .005) and abnormal forms (p < .001).
This is the first evaluation of the relationship between male fertility-related parameters and environment using a big-data approach. A seasonal change in semen parameters was found, with a fluctuation related to both temperature and daylight duration. A negative correlation between air pollution and semen quality is suggested. Such seasonal and environmental associations should be considered when assessing changes of male fertility-related parameters over time.
Display omitted
•This represents the first big-data approach on the complex relationship between environment and male fertility.•Semen parameters show a seasonal change, with a fluctuation during the year related to temperature and daylight duration.•Air pollution exerts a negative effect on semen quality.
Semen parameters show seasonal changes, with fluctuations during the year related to both temperature and daylight duration. Air pollution is inversely related to semen quality.
The treatment of bone and joint infections is challenging due to the presence of bacterial biofilm and the increasing emergence of multiresistant strains. BAG-S53P4 is a bone substitute that is ...characterized by osteoconductive and antimicrobial properties. The aim of this study was to assess the effectiveness of BAG-S53P4 against biofilm produced in vitro by multiresistant bacterial strains.
Multiresistant Staphylococcus epidermidis, Acinetobacter baumannii and Klebsiella pneumoniae isolated from bone and joint infections were used in this study. Titanium discs covered by bacterial biofilm were incubated with BAG-S53P4 or inert glass as a control. The amount of biofilm on each titanium disc was evaluated after 48 h of incubation by means of confocal laser scanning microscopy.
Significantly lower total biomass volumes were observed for all strains after treatment with BAG-S53P4 when compared with controls. Moreover, the percentage of dead cells was significantly higher in treated samples than in controls for all the tested strains.
BAG-S53P4 is able to reduce the biofilm produced by multiresistant S. epidermidis, A. baumannii and K. pneumoniae on titanium substrates in vitro, probably by interfering with cell viability. Owing to its osteoconductive, antibacterial and antibiofilm properties, the use of BAG-S53P4 may be a successful strategy for the treatment of bone and prosthetic joint infections.
The paper builds on the case of the design and implementation of the National Information System for School Buildings in Italy. The project is one of digitalisation of the public sector and involves ...several layers of territorial governments (the State Department for Education, regional and local governments) and ICT experts, and is becoming a tool for policy making in the field. Nonetheless, the programme was initially designed with a top-down approach immediately stuck. Its effective implementation only took place some years later by downsizing policy design and allowing regions to implement those digital solutions which, in the meanwhile, had been designed and implemented from the bottom-up. The paper draws from the case study theoretical considerations about the importance of where policy learning happens and the strategies that policy makers may adopt in case of policy failure in order to re-establish the conditions for effectiveness.
Background:
Videocapsule endoscopy (VCE) and double-balloon enteroscopy (DBE) are part of the diagnostic and therapeutic work-up of indications other than suspected small bowel bleeding (OSBB). The ...literature is currently lacking studies describing these procedures in this particular setting.
Objectives:
We assessed the clinical impact of VCE and DBE in a large monocentric cohort of OSBB patients, as compared to a control group of suspected small bowel bleeding (SSBB) patients who underwent enteroscopy over the same period.
Design:
Monocentric, retrospective, cohort study.
Methods:
We collected the data of consecutive patients with OSBB undergoing VCE and/or DBE from March 2001 to July 2020. The demographic and clinical parameters of the patients, technical characteristics, and adverse events for each procedure were collected. The impact of VCE and DBE was defined in terms of diagnostic yield (DY). The patients were subdivided according to the main indication into four groups: celiac disease, Crohn’s disease (CD), neoplasia, and persistent gastrointestinal symptoms.
Results:
A total of 611 VCEs and 387 DBEs were performed for OSBB. The main indications were complicated celiac disease and CD. The DYs of VCE and DBE overall were 53 and 61.7%, respectively, with some variance among the four groups. We report no statistical differences in the DY of VCE and DBE in SSBB vs OSBB (57.7% vs 53%, p = 0.0859 and 68.8% vs 61.7%, p = 0.0582, respectively). OSBB patients were significantly younger than those with SSBB. However, similarly to SSBB (k = 0.059), poor agreement between the enteroscopic techniques was found in the OSBB population (k = 0.109). The safety of both procedures in OSBB was comparable to that in SSBB patients.
Conclusion:
VCE and DBE are effective and safe in suspected OSBB, where their role is similar to that in SSBB, their main indication.
We establish two new characterizations of magnetic Sobolev spaces for Lipschitz magnetic fields in terms of nonlocal functionals. The first one is related to the BBM formula, due to Bourgain, Brezis ...and Mironescu. The second one is related to the work of the first author on the classical Sobolev spaces. We also study the convergence almost everywhere and the convergence in
appearing naturally in these contexts.
PDF
