Effective transmission of sound from water to air is crucial for the enhancement of the detection sensitivity of underwater sound. However, only 0.1% of the acoustic energy is naturally transmitted at such a boundary. At audio frequencies, quarter-wave plates or multilayered antireflection coatings are too bulky for practical use for such enhancement. Here we present an acoustic metasurface of a thickness of only ∼λ/100, where λ is the wavelength in air, consisting of an array of meta-atoms that each contain a set of membranes and an air-filled cavity. We experimentally demonstrate that such a meta-atom increases the transmission of sound at ∼700 Hz by 2 orders of magnitude, allowing about 30% of the incident acoustic power from water to be transmitted into air. Applications include underwater sonic sensing and communication.
ObjectiveTo evaluate the clinical impact of prostate peripheral zone thickness (PZT), based on presumed circle area ratio (PCAR) theory, on urinary symptoms in men with lower urinary tract symptoms/benign prostatic hyperplasia (LUTS/BPH) as a novel prostate parameter.
Patients and methodsMedical records were obtained from a prospective database of first-visit men with LUTS/BPH. Age, international prostate symptom score (IPSS), overactive bladder symptom score (OABSS), maximum urinary flow rate (Q max ), and post-void residual urine volume (PVR) were assessed. Total prostate volume (TPV), transition zone volume (TZV), transition zone index (TZI), and PZT were measured by transrectal ultrasonography. Reliability analysis was also performed.
ResultsIn all, 1009 patients were enrolled for the analysis. The mean (SD) PZT was 11.10 (2.50) mm, and patients were classified into three groups PZT thickness groups; PZT <9.5 mm, ≥9.5 to <13 mm, and ≥13 mm. As the PZT became smaller, all urinary symptom scores including IPSS, quality of life (QoL), and OABSS significantly increased. Uroflowmetry variables, such as Q max and PVR, also showed significant differences. PZT showed a high intra-class correlation coefficient (0.896). Multivariate analysis revealed that the PZT was independently associated with IPSS (P < 0.001), QoL (P = 0.003), OABSS (P = 0.001), and PVR (P = 0.001), but PZT influence on Q max was only of borderline significance (P = 0.055).
ConclusionPZT is a novel, easy-to-measure prostate parameter that is significantly associated with urinary symptoms. Our present findings suggest that clinical usefulness of PZT should be further validated for managing men with LUTS/BPH.
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