RESUMO
A new class of Radio Frequency IDentification (RFID) tags, namely the three-dimensional (3D)-printed chipless RFID one, is proposed, and their performance is assessed. These tags can be realized by low-cost materials, inexpensive manufacturing processes and can be mounted on metallic surfaces. The tag consists of a solid dielectric cylinder, which externally appears as homogeneous. However, the information is hidden in the inner structure of the object, where voids are created to encrypt information in the object. The proposed chipless tag represents a promising solution for anti-counterfeiting or security applications, since it avoids an unwanted eavesdropping during the reading process or information retrieval from a visual inspection that may affect other chipless systems. The adopted data-encoding algorithm does not rely on On-Off or amplitude schemes that are commonly adopted in the chipless RFID implementations but it is based on the maximization of available states or the maximization of non-overlapping regions of uncertainty. The performance of such class of chipless RFID tags are finally assessed by measurements on real prototypes.
RESUMO
Background: Obstructive sleep apnea syndrome and is characterized by recurrent episodes of partial or complete upper airway collapse during sleep with consequent oxygen desaturations and cardiovascular, neurological, and metabolic impairment. Clinical presentation: The authors report the case of a 66-year-old male presenting "metabolic syndrome" (obesity, impaired glucose tolerance, dyslipidemia, multi-drug treated arterial hypertension), atopy, mouth breathing due to turbinate hypertrophy, and pathological daytime sleepiness. As patient's compliance to standard continuous positive airway pressure (CPAP) therapy was poor, he was treated using low-pressure CPAP combined with a mandibular advancement device (MAD). Conclusion: In selected patients, a treatment combining CPAP and MAD might be a more tolerable alternative to CPAP alone. The improved pharyngeal patency, promoted by mandibular advancement and stretching of the pharyngeal muscles, allows operating the CPAP at lower pressures when the MAD alone is not sufficient to induce a safe sleep profile.
