Two-peaked and flat-top perfect bright solitons in epsilon-near-zero nonlinear metamaterials: novel Kerr self-trapping mechanisms

We analytically investigate transverse magnetic (TM) spatial bright solitons, as exact solutions of Maxwell's equations, propagating through nonlinear metamaterials whose linear dielectric permittivity is very close to zero and whose effective nonlinear Kerr parameters can be tailored to achieve values not available in standard materials. Exploiting the fact that, in the considered medium, linear and nonlinear polarization can be comparable at feasible and realistic optical intensities, we identify two novel self-trapping mechanisms able to support two-peaked and flat-top solitons, respectively. Specifically, these two novel mechanisms are based on the occurrence of critical points at which the effective nonlinear permittivity vanishes, the two mechanisms differing in the way the compensation between linear and nonlinear polarization is achieved through the non-standard values of the nonlinear parameters.Comment: 7 pages, 4 figure

Pancreatic cystosis in cystic fibrosis. Sometimes a bike ride can help you decide

Pancreatic cystosis (PC) is an uncommon manifestation of pancreas involvement in cystic fibrosis (CF), characterized by the presence of multiple macrocysts partially or completely replacing pancreas. Only few reports are available from literature and management (surgery vs follow up) is commonly based on the presence of symptoms or complications due to local mass effect, although evidence-based recommendations are still not available. We here report the case of a young adult CF patient with PC, in which cardiopulmonary exercise testing (CPET) provided important information to be integrated to the radiological finding of inferior vena cava compression by the multicystic pancreas complex. Through the analysis of oxygen kinetic cardiodynamic phase pattern, CPET may be helpful to safely exclude significant mass effects on blood venous return and to improve the decision-making process on whether to consider surgery or not in patients with PC

Bandwidth Optimisation and Frequency Tuning of Plasmonic Functionalised Metasurfaces for Optical Sensing of Chemical and Biological Substances

This paper reports on a method to optimise the sensitivity of plasmonics sensors based on functionalised metasurfaces of 2D-array of Al NanoAntennas (NA) deposited on a SiO2 substrate operating in the visible region of the electromagnetic spectrum. Moreover, we analysed the characteristics of a double layer metasurface configuration where two different NA 2D-arrays are separated by a dielectric spacer. The optical properties of both the metasurface configurations have been studied analysing how their maximum transmittance and Full-Width-at-Half-Maximum (FWHM) of the transmission curve are related to the variations of the NA geometrical parameters and dielectric spacer thickness. The tailoring of the FWHM is particular important for improving the plasmonic sensors sensitivity in probing the presence of chemical/biological substances absorbed on the NA surface when their absorption curve is superimposed with the metasurface transmission curve. In particular, better is this superposition better will be the plasmonic sensor sensitivity in probing variations of small concentrations of the adsorbed substances. The simulation results of the optical response of the designed plasmonic sensors suggest a methodology in choosing the NA parameters able to modify the bandwidth of the metasurface transmittance so fitting the absorption curve of chemical/biological substances absorbed on them. As a case-example, we simulated the response of a plasmonic sensor on which has been deposited a 3nm-thick layer of Rhodamine-6G (R6G) proving that is possible to increase the sensor detection sensitivity of about two orders of magnitude in the measurement of the R6G absorbance. Furthermore we proved the capability of the double layer plasmonic sensors to tune the transmission curve peak wavelength without changing the main optical characteristics

Multistability at arbitrary low optical intensities in a metallo-dielectric layered structure

We show that a nonlinear metallo-dielectric layered slab of subwavelength thickness and very small average dielectric permittivity displays optical multistable behavior at arbitrary low optical intensities. This is due to the fact that, in the presence of the small linear permittivity, one of the multiple electromagnetic slab states exists no matter how small is the transmitted optical intensity. We prove that multiple states at ultra-low optical intensities can be reached only by simultaneously operating on the incident optical intensity and incidence angle. By performing full wave simulations, we prove that the predicted phenomenology is feasible and very robust.Comment: 4 pages, 4 figure

Respiratory Effects of Exposure to Traffic-Related Air Pollutants During Exercise

Traffic-related air pollution (TRAP) is increasing worldwide. Habitual physical activity is known to prevent cardiorespiratory diseases and mortality, but whether exposure to TRAP during exercise affects respiratory health is still uncertain. Exercise causes inflammatory changes in the airways, and its interaction with the effects of TRAP or ozone might be detrimental, for both athletes exercising outdoor and urban active commuters. In this Mini-Review, we summarize the literature on the effects of exposure to TRAP and/or ozone during exercise on lung function, respiratory symptoms, performance, and biomarkers. Ozone negatively affected pulmonary function after exercise, especially after combined exposure to ozone and diesel exhaust (DE). Spirometric changes after exercise during exposure to particulate matter and ultrafine particles suggest a decrease in lung function, especially in patients with chronic obstructive pulmonary disease. Ozone frequently caused respiratory symptoms during exercise. Women showed decreased exercise performance and higher symptom prevalence than men during TRAP exposure. However, performance was analyzed in few studies. To date, research has not identified reliable biomarkers of TRAP-related lung damage useful for monitoring athletes' health, except in scarce studies on airway cells obtained by induced sputum or bronchoalveolar lavage. In conclusion, despite partly counteracted by the positive effects of habitual exercise, the negative effects of TRAP exposure to pollutants during exercise are hard to assess: outdoor exercise is a complex model, for multiple and variable exposures to air pollutants and pollutant concentrations. Further studies are needed to identify pollutant and/or time thresholds for performing safe outdoor exercise in cities

|\epsilon|-Near-Zero materials in the near-infrared

We consider a mixture of metal coated quantum dots dispersed in a polymer matrix and, using a modified version of the standard Maxwell-Garnett mixing rule, we prove that the mixture parameters (particles radius, quantum dots gain, etc.) can be chosen so that the effective medium permittivity has an absolute value very close to zero in the near-infrared, i.e. |Re(epsilon)|<<1 and |Im (epsilon)|<<1 at the same near-infrared wavelength. Resorting to full-wave simulations, we investigate the accuracy of the effective medium predictions and we relate their discrepancy with rigorous numerical results to the fact that |epsilon|<<1 is a critical requirement. We show that a simple method for reducing this discrepancy, and hence for achieving a prescribed value of |\epsilon|, consists in a subsequent fine-tuning of the nanoparticles volume filling fraction.Comment: 3 pages, 3 figure

A case of SLE with pancreatitis

Systemic lupus erythematosus (SLE) is a chronic, autoimmune inflammatory disease characterized by the presence of autoantibodies, immune complex formation, and multiple organ system involvement. Gastrointestinal manifestations are common in SLE patients, but acute pancreatitis is rare. Here we present a case of a 23 yrs. old male who came to the medicine OPD with the chief complaints of pain in abdomen, swelling all over the body since, 8 days and multiple joint pain for 1 and half months. On examination he was febrile pallor present with anasarca, periorbital edema with heliotrope around both eyes. Dry and xerotic ski over the face, butterfly rash present. Blood investigations, USG and CECT suggestive of acute panceatitis. Patient was treated in ICU for pancreatitis. Patient was found to be hypothyroid and treated with thyroid supplements. ANA BLOT was suggestive of SLE. Renal biopsy showed diffuse proliferative lupus nephritis. Hence our patient had pancreatitis possibly due to SLE induced hypertriglyceridemia.