A Methodology for Remote Microwave Sterilization Applicable to the Coronavirus and Other Pathogens Using Retrodirective Antenna Arrays.

This paper describes an innovative remote surface sterilization approach applicable to the new coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The process is based on the application of a liquid film on the surface or object under sterilization (OUS). A beacon signal is used to self-steer the transmitted power from the designed retrodirective antenna array (RDA) towards the OUS using circularly polarized fields; then, the sterilization is completed by raising and maintaining the required temperature for a certain time. Results suggest that the process takes 5 minutes or less for an angular coverage range over 60 degrees whilst abiding by the relevant safety protocols. This paper also models the power incident onto the OUS, providing consistent results with full-wave simulations. A practical RDA system is developed using a 2 × 1 microstrip patch array operating at 2.5 GHz and tested through the positioning of a representative target surface. Measurements, developed by sampling the power transmitted by the heterodyne RDA, are reported for various distances and angles, operating in the near-field of the system. To further validate the methodology, an additional experiment investigating virus deactivation through microwave heating was also developed. Measurements have been performed with an open cavity microwave oven on the Coronavirus (strain 229E) and egg white protein in a cuvette. This demonstrates that the temperature increases of aqueous films up to 70 [Formula: see text]C by remote microwave-induced heat can denature proteins and deactivate viruses. Possible applications of the method include sterilization of ambulances, medical equipment, and internet of things (IoT) devices.

Analysis and Design of a Compact Leaky-Wave Antenna for Wide-Band Broadside Radiation.

A low-cost compact planar leaky-wave antenna (LWA) is proposed offering directive broadside radiation over a significantly wide bandwidth. The design is based on an annular metallic strip grating (MSG) configuration, placed on top of a dual-layer grounded dielectric substrate. This defines a new two-layer parallel-plate open waveguide, whose operational principles are accurately investigated. To assist in our antenna design, a method-of-moments dispersion analysis has been developed to characterize the relevant TM and TE modes of the perturbed guiding structure. By proper selection of the MSG for a fabricated prototype and its supporting dielectric layers as well as the practical TM antenna feed embedded in the bottom ground plane, far-field pencil-beam patterns are observed at broadside and over a wide frequency range, i.e., from 21.9 GHz to 23.9 GHz, defining a radiating percentage bandwidth of more than 8.5%. This can be explained by a dominantly excited TM mode, with low dispersion, employed to generate a two-sided far-field beam pattern which combines to produce a single beam at broadside over frequency. Some applications of this planar antenna include radar and satellite communications at microwave and millimeter-wave frequencies as well as future 5G communication devices and wireless power transmission systems.

Seroepidemiologic study of toxocariasis and strongyloidiasis in institutionalized mentally retarded adults.

Serologic surveys for Toxocara canis and Strongyloides sp., as well as stool examinations for intestinal parasites, were conducted in a home for mentally retarded adults. Evidence of parasitic infection was found in 30 (28.3%) of 106 residents; nine (8.5%) had positive toxocaral serology (enzyme-linked immunosorbent assay[ELISA]), 1 (0.9%) had positive serology for Stronglyoides sp. (ELISA), and 21 (19.8%) had parasites in stool (including Stronglyoides stercoralis in the patient with positive serology). Most of the residents with positive toxocaral serology lived in the same apartment and used to play with dogs. Parameters found to be significantly associated with positive toxocaral serology were pica behavior and eosinophilia (P less than 0.05). Mental retardation requiring institutionalization appears to be a risk factor for toxocariasis and other parasitic infections in adults as it is for children.

The effect of a milk diet on the retention of 74As labelled arsenic in mice.

The effect of 3 diets with different proportion of milk proteins on retention of arsenic was studied in mice. Arsenic was administered via drinking water in concentration 50 mg As [III] per litre labelled with 74As in amount 2.96 MBq per 100 ml. After 2, 4, 8, 16 and 32 days of exposure the mice in groups of 6 each from all 3 experimental cohorts were decapitated and the content of 74As was determined in whole body, blood, liver, kidneys, spleen, lungs and heart by measuring of the activity in Gamma Scintillation Counter Tesla. From the intake of drinking water and amount of arsenic found in the experimental animals was calculated retention of arsenic in mice at different exposure intervals in all three diets. The values of arsenic found at the exposure intervals in examined materials of all three experimental cohorts were compared. The results obtained indicate that a milk diet has no adverse effect at exposure to arsenic in the sense of enhancing of its retention in mice at given experimental conditions. The found data seemed to suggest that the milk protein rich diet caused retardation of the increase of arsenic concentrations in blood, liver and kidneys that might lead at a lower exposure rate to a decrease in arsenic content in tissues of exposed animals.

Rate of malignant tumor mortality among coal burning power plant workers occupationally exposed to arsenic.

The mortality pattern was retrospectively analyzed among the workers of a power plant A (exposure group) combusting coal with high arsenic levels and among the workers of power plants B, C and D (control group), where arsenic concentrations in coal were by one order of magnitude lower. The exposed group consisted of 88 and the control group of 159 male subjects deceased over the period of the last 15--18 years. The rate of tumor mortality among the exposed subjects who died during their productive age was 38% (in the control group 23%), among those died after 60 it was 51% (in the controls 43%). This increase in the tumor mortality rates was not statistically significant. What was, however, statistically proved to be significant is the fact that malignancy-caused deaths in the exposed group occurred in younger age categories and after a statistically shorter exposure time (in both cases p < 0.05). Combusted coal is known to contain a variety of biologically active microelements, but the amount of arsenic alone (950--1500 g/1 tonne of coal) most probably fully justifies the suspected link between the tumor incidence and the overexposure to arsenic.

Test of environmental exposure to arsenic and hearing changes in exposed children.

Arsenic determination was carried out on hair, urine, and blood samples taken from groups of 10-year-old boys, each numbering 20 to 25 individuals, residing in a region polluted by arsenic. In all the examined materials considerably elevated concentrations of arsenic were found. The relation of the observed levels of arsenic to the distance of the place of residence up to a distance of more than 30 km from the source of the emissions was studied. On the basis of the results obtained, the most advantageous material for estimation of nonoccupational exposure to arsenic seems to be hair, in spite of some problems with the decontamination procedure involved. Considerable variability among individual arsenic values in the hair makes group examination a necessity. Hearing changes were analyzed in a group of 56 10-year old children residing near a power plant burning local coal of high arsenic content. The results of both audiometric and clinical examination were compared with those of control group numbering 51 children of the same age living outside the polluted area. The highly standardized audiometric and clinical examination were completed with a questionnaire analysis concerning the personal medical histories of the children. The obtained data were elaborated statistically by means of the chi(2)- test. In the case of air conduction, important hearing losses were found at frequencies of 125, 250 and 8000 Hz, especially at the lowest frequency range. Significant degrees of hearing loss were found in bone conduction as well as in the corresponding ranges of frequencies. The high statistical significance of the hearing impairments found points to very low probability of their being only an "accidental" finding. The possibility of toxic damage to the ear cannot yet be excluded.