Electronically reconfigurable parasitic antenna array for pattern selectivity

Antenna arrays are commonly used to achieve high gains and beam steering, but they require complex feeding networks. For applications demanding moderate antenna gains (≃6 dB) and planar radiating structures, printed Yagi-Uda antennas can offer many advantages, but clearly, they cannot cover the whole azimuth plane. A symmetric structure made of two Yagi-Uda antennas with two active elements, a shared reflector and two directors of variable length is here presented and demonstrated to have switched beams that cover all the azimuth plane. By lengthening the physical lengths of the directors, they turn to act as reflectors: as a result, this antenna system has the ability to switch between broadside, bidirectional end-fire and two opposite end-fire patterns. The feeding is provided by a balanced parallel strip-slot line without the need for a balun section and thus reducing the overall size of the antenna. A modified design is also presented, obtained by adding a reflector board which allows for higher gains and focused radiation reconfigurability in the half-space. Simulated and measured results of both designs are reported showing good agreement. The antenna has a compact size, wideband characteristics and directive pattern reconfigurability

Veno-Venous ECMO: An Alternative Strategy for Acute Respiratory Failure After High-Voltage Electrocution. The Utility of Point-of-Care Tests

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Beam-forming capabilities of a plasma circular reflector antenna

A gaseous plasma antenna array (PAA) is an aggregate of plasma discharges and possibly conventional metallic radiating elements, and it constitutes a promising alternative to metallic antennas for applications in which fast reconfiguration of radiation pattern, and gain is desired; such properties can be achieved by exploiting the electronic switch on/off condition of plasma discharges, and tuning of the plasma parameters. Here, the authors present a reconfigurable PAA that features a central metallic half-wavelength dipole working around 1.45\u2005GHz, surrounded by a planar circular lattice of cylindrical plasma discharges. Customised plasma discharges have been realised, and filled with argon gas at 2\u2005mbar so as to have a complete control on the plasma discharge properties (e.g. plasma frequency, collisional frequency). The magnitude of the reflection coefficient, and the gain pattern on the H-plane have been investigated numerically and experimentally; numerical and experimental results exhibit a good agreement and show that the central intrinsically omnidirectional antenna can provide simple beamforming capabilities upon turning on a subset of plasma discharges; as these plasma discharges are turned on, the authors have observed a maximum gain of 3c5\u2005dBi, a half-power beam width of 80 18, and an angular steering resolution of 3c15 18

Graphene sustained nonlinear modes in dielectric waveguides

We discuss the existence of nonlinear modes sustained by graphene layers in dielectric waveguides. Taking advantage of the almost two dimensional nature of graphene, we introduce the nonlinear effect as a parameter in the continuity equations. We then apply our modeling to a simple slab waveguide to enlighten how graphene can be used to induce huge nonlinear phase shifts at easily accessible power levels

Non-Aβ-dependent factors associated with global cognitive and physical function in alzheimer's disease: a pilot multivariate analysis

Recent literature highlights the importance of identifying factors associated with mild cognitive impairment (MCI) and Alzheimer's Disease (AD). Actual validated biomarkers include neuroimaging and cerebrospinal fluid assessments; however, we investigated non-Aβ-dependent factors associated with dementia in 12 MCI and 30 AD patients. Patients were assessed for global cognitive function (Mini-Mental state examination-MMSE), physical function (Physical Performance Test-PPT), exercise capacity (6-min walking test-6MWT), maximal oxygen uptake (VO₂max), brain volume, vascular function (flow-mediated dilation-FMD), inflammatory status (tumor necrosis factor-α ,TNF- α, interleukin-6, -10 and -15) and neurotrophin receptors (p75NTR and Tropomyosin receptor kinase A -TrkA). Baseline multifactorial information was submitted to two separate backward stepwise regression analyses to identify the variables associated with cognitive and physical decline in demented patients. A multivariate regression was then applied to verify the stepwise regression. The results indicated that the combination of 6MWT and VO₂max was associated with both global cognitive and physical function (MMSE = 11.384 + (0.00599 × 6MWT) - (0.235 × VO₂max)); (PPT = 1.848 + (0.0264 × 6MWT) + (19.693 × VO₂max)). These results may offer important information that might help to identify specific targets for therapeutic strategies (NIH Clinical trial identification number NCT03034746)

The application of scanning near field optical imaging to the study of human sperm morphology

BackgroundThe morphology of spermatozoa is a fundamental aspect to consider in fertilization, sperm pathology, assisted reproduction and contraception. Head, neck, midpiece, principal and terminal part of flagellum are the main sperm components to investigate for identifying morphological features and related anomalies. Recently, scanning near-field optical microscopy (SNOM), which belongs to the wide family of nanoscopic techniques, has opened up new routes for the investigation of biological systems. SNOM is the only technique able to provide simultaneously highly resolved topography and optical images with a resolution beyond the diffraction limit, typical of conventional optical microscopy. This offers the advantage to obtain complementary information about cell surface and cytoplasmatic structures.ResultsIn this work human spermatozoa both healthy and with morphological anomalies are analyzed by SNOM, to demonstrate the potentiality of such approach in the visualization of sperm morphological details. The combination of SNOM topography with optical (reflection and transmission) images enables to examine typical topographic features of spermatozoa together with underlying cytoplasmic structures. Indeed the head shape and inner components as acrosome and nucleus, and the organization of mitochondria in the midpiece region are observed. Analogously for principal tract of the tail, the ridges and the columns are detected in the SNOM topography, while their internal arrangement can be observed in the corresponding SNOM optical transmission images, without requiring specific staining procedures or invasive protocols.ConclusionsSuch findings demonstrate that SNOM represents a versatile and powerful tool to describe topographical and inner structural details of spermatozoa simultaneously. This analysis could be helpful for better characterizing several morphological anomalies, often related to sperm infertility, which cannot be examined by conventional techniques all together

Effects of remote monitoring on clinical outcomes and use of healthcare resources in heart failure patients with biventricular defibrillators: results of the MORE-CARE multicentre randomized controlled trial

Aims: The aim of this study was to evaluate the clinical efficacy and safety of remote monitoring in patients with heart failure implanted with a biventricular defibrillator (CRT-D) with advanced diagnostics. Methods and results: The MORE-CARE trial is an international, prospective, multicentre, randomized controlled trial. Within 8 weeks of de novo implant of a CRT-D, patients were randomized to undergo remote checks alternating with in-office follow-ups (Remote arm) or in-office follow-ups alone (Standard arm). The primary endpoint was a composite of death and cardiovascular (CV) and device-related hospitalization. Use of healthcare resources was also evaluated. A total of 865 eligible patients (mean age 66 \ub1 10 years) were included in the final analysis (437 in the Remote arm and 428 in the Standard arm) and followed for a median of 24 (interquartile range = 15\u201326) months. No significant difference was found in the primary endpoint between the Remote and Standard arms [hazard ratio 1.02, 95% confidence interval (CI) 0.80\u20131.30, P = 0.89] or in the individual components of the primary endpoint (P > 0.05). For the composite endpoint of healthcare resource utilization (i.e. 2-year rates of CV hospitalizations, CV emergency department admissions, and CV in-office follow-ups), a significant 38% reduction was found in the Remote vs. Standard arm (incidence rate ratio 0.62, 95% CI 0.58\u20130.66, P < 0.001) mainly driven by a reduction of in-office visits. Conclusions: In heart failure patients implanted with a CRT-D, remote monitoring did not reduce mortality or risk of CV or device-related hospitalization. Use of healthcare resources was significantly reduced as a result of a marked reduction of in-office visits without compromising patient safety. Trial registration: NCT00885677