The global spread of bacterial resistance to antibiotics promotes a search for alternative approaches to eradication of pathogenic bacteria. One alternative is using photosensitizers for inhibition of Gram-positive and Gram-negative bacteria under illumination. Due to low penetration of visible light into tissues, applications of photosensitizers are currently limited to treatment of superficial local infections. Excitation of photosensitizers in the dark can be applied to overcome this problem. In the present work, dark antibacterial activity of the photosensitizer Rose Bengal alone and in combination with antibiotics was studied. The minimum inhibitory concentrations (MIC) value of Rose Bengal against S. aureus dropped in the presence of sub-MIC concentrations of ciprofloxacin, levofloxacin, methicillin, and gentamicin. Free Rose Bengal at sub-MIC concentrations can be excited in the dark by ultrasound at 38 kHz. Rose Bengal immobilized onto silicon showed good antibacterial activity in the dark under ultrasonic activation, probably because of Rose Bengal leaching from the polymer during the treatment. Exposure of bacteria to Rose Bengal in the dark under irradiation by electromagnetic radio frequency waves in the 9 to 12 GHz range caused a decrease in the bacterial concentration, presumably due to resonant absorption of electromagnetic energy, its transformation into heat and subsequent excitation of Rose Bengal.

A quasi-optical multi-ray model for a short-range millimeter wave radar is presented. The model considers multi-path effects emerging while multiple rays are scattered from the target and reflected to the radar receiver. Among the examined scenarios, the special case of grazing ground reflections is analyzed. Such a case becomes relevant when short range anti-collision radars are employed in vehicles. Such radars operate at millimeter wavelengths, and are aimed at the detection of targets located several tens of meters from the transmitter. Reflections from the road are expected to play a role in the received signal strength, together with the direct line-of-sight beams illuminated and scattered from the target. The model is demonstrated experimentally using radar operating in the W-band. Controlled measurements were done to distinguish between several scattering target features. The experimental setup was designed to imitate vehicle near-ground millimeter wave radars operating in vehicles. A comparison between analytical calculations and experimental results is made and discussed.

Non‑thermal millimeter‑wave (MMW) irradiation (75–110 GHz) represents a promising non‑invasive strategy for cancer therapy. Lung cancer remains the leading cause ‎of cancer‑related mortality worldwide, highlighting the need for alternative therapeutic modalities that can overcome resistance and minimize toxicity. Yet the effects ‎of MMW exposure in physiologically relevant 3D systems remain insufficiently ‎characterized. Here, we evaluated the anti‑cancer efficacy of MMW exposure in 3D ‎lung cancer spheroids (NCI‑H1299, A549) alongside noncancerous WI‑38 fibroblasts. ‎Cells were irradiated using two antenna types—a waveguide (WG; localized, ‎high-power density) and a pyramidal horn (PH; broader coverage, lower power ‎density)—with or without a frequency multiplier to modulate local energy delivery. ‎Acute responses were assessed by XTT viability assays (day 2) and apoptosis (flow ‎cytometry), while chronic effects were evaluated using clonogenic survival (day 10) ‎and senescence markers. ‎ MMW exposure reduced cancer cell survival in a time‑ and power‑dependent manner ‎and induced sustained growth inhibition. Apoptosis was markedly higher in cancer ‎cells than in non‑cancerous WI‑38 cells and was further amplified under power-enhanced conditions. WG irradiation produced strong localized antiproliferative ‎effects, whereas the PH antenna enabled broader coverage while maintaining selective cytotoxicity toward NCI‑H1299 cells. Notably, p53‑deficient NCI‑H1299 cells ‎exhibited up to ~64% apoptosis after 60 min of exposure, whereas WI‑38 fibroblasts ‎remained below ~20%, demonstrating robust cancer selectivity. These findings high-‎light the selective, non‑thermal anticancer potential of MMW irradiation in 3D tumor ‎models and provide a mechanistic and experimental foundation for further preclinical ‎optimization of MMW‑based therapeutic strategies.

Non-thermal millimeter-wave (MMW) irradiation represents a promising non-invasive strategy for cancer therapy, yet its effects in physiologically relevant 3D systems remain poorly defined. Here, we evaluated the biological impact of MMW exposure in 3D non-small-cell lung cancer (NSCLC) spheroids (NCI-H1299, A549) and normal WI-38 fibroblasts under active cooling to suppress bulk heating. We demonstrate that cellular responses are governed primarily by power density (PD), irradiation geometry, and genotype-dependent susceptibility. High-PD pyramidal horn (PH) irradiation (~4.9 mW/cm²) induced rapid apoptosis, metabolic collapse, and near-complete loss of clonogenic survival, whereas lower-PD waveguide (WG) irradiation (~0.6 mW/cm²) produced depth-limited, cumulative cytotoxicity. Surviving cancer cells exhibited robust senescence-associated growth arrest, particularly in p53-deficient NCI-H1299 cells, indicating a dual apoptotic–senescent anti-proliferative response. In contrast, WI-38 fibroblasts showed minimal apoptosis and only transient stress-associated senescence, confirming selective tumor vulnerability. Mechanistic modeling suggests that MMW energy couples to glycan-rich membrane domains, generating localized electromagnetic hotspots that trigger calcium influx, mitochondrial dysfunction, and depth-dependent apoptosis. These findings establish a mechanistic basis for selective, non-thermal MMW-induced cytotoxicity in 3D NSCLC models and support further preclinical development of MMW-based therapeutic strategies.