A miniaturized triple-band antenna based on square split ring for IoT applications

YesThis article presents a miniaturized triple-band antenna for Internet of Things (IoT) applications. The miniaturization is achieved by using a split square ring resonator and half ring resonator. The antenna is fabricated on an FR4 substrate with dimensions of (33 × 22 × 1.6) mm3. The proposed antenna resonates at the frequencies 2.4 GHz, 3.7 GHz, and 5.8 GHz for WLAN and WiMax applications. The obtained −10 dB bandwidth for the three bands of the proposed antenna are 300 MHz, 360 MHz, and 900 MHz, respectively. The measured reflection coefficient values of the proposed antenna corresponding to each resonant frequency are equal to −14.772 dB, −20.971 dB, and −28.1755 dB, respectively. The measured gain values are 1.43 dBi, 0.89 dBi, and 1 dBi, respectively, at each resonant frequency. There is a good agreement between the measured and simulated results, and both show an omnidirectional radiation pattern at each of the antenna resonant frequencies that is suitable for IoT portable devices

The effect of pulp inflammation and premature extraction of primary molars on the successor permanent teeth. A retrospective study

Background: Untreated caries on primary molars often leads to pulp inflammation and extraction. Aim: To retrospectively investigate the effect of pulp inflammation and extraction of primary molars on their successors regarding alignment in the dental arch and developmental enamel defects (DED). Design: The participants in this study were children at public schools in Petropolis (Brazil), who participated in a 3-year longitudinal clinical trial. Children (N = 44) were selected for the present study if they had at least one erupted premolar of which the predecessor primary molar presented pulp inflammation at baseline or during any of the 6-month follow-up assessments. All premolars were examined for DED and misalignment. Distinction was made between extraction performed before (E <8) or after the age of 8 years (E ≥8). Distinction was also made between pulp inflammation occurred before (P < 7) or after the age of 7 years (P ≥ 7). A logistic regression analysis was performed, and the odds ratio was calculated. Results and conclusions: Misalignment occurred more frequently in E <8 as compared to E ≥8 (OR = 2.85; P =.03). There was no significant difference in DED between P < 7 and P ≥ 7. Conclusion: Misalignment of premolars occurs more frequently when the predecessor primary molars are extracted before the age of 8 years