3D Smith charts scattering parameters frequency-dependent orientation analysis and complex-scalar multi-parameter characterization applied to Peano reconfigurable vanadium dioxide inductors.

Recently, the field of Metal-Insulator-Transition (MIT) materials has emerged as an unconventional solution for novel energy efficient electronic functions, such as steep slope subthermionic switches, neuromorphic hardware, reconfigurable radiofrequency functions, new types of sensors, terahertz and optoelectronic devices. Employing radiofrequency (RF) electronic circuits with a MIT material like vanadium Dioxide, VO2, requires appropriate characterization tools and fabrication processes. In this work, we develop and use 3D Smith charts for devices and circuits having complex frequency dependences, like the ones resulting using MIT materials. The novel foundation of a 3D Smith chart involves here the geometrical fundamental notions of oriented curvature and variable homothety in order to clarify first theoretical inconsistencies in Foster and Non Foster circuits, where the driving point impedances exhibit mixed clockwise and counter-clockwise frequency dependent (oriented) paths on the Smith chart as frequency increases. We show here the unique visualization capability of a 3D Smith chart, which allows to quantify orientation over variable frequency. The new 3D Smith chart is applied as a joint complex-scalar 3D multi-parameter modelling and characterization environment for reconfigurable RF design exploiting Metal-Insulator-Transition (MIT) materials. We report fabricated inductors with record quality factors using VO2 phase transition to program multiple tuning states, operating in the range 4 GHz to 10 GHz.

Sweat Biomarker Sensor Incorporating Picowatt, Three-Dimensional Extended Metal Gate Ion Sensitive Field Effect Transistors.

Ion sensitive field effect transistors (ISFETs) form a very attractive solution for wearable sensors due to their capacity for ultra-miniaturization, low power operation, and very high sensitivity, supported by complementary metal oxide semiconductor (CMOS) integration. This paper reports for the first time, a multianalyte sensing platform that incorporates high performance, high yield, high robustness, three-dimensional-extended-metal-gate ISFETs (3D-EMG-ISFETs) realized by the postprocessing of a conventional 0.18 µm CMOS technology node. The detection of four analytes (pH, Na+, K+, and Ca2+) is reported with excellent sensitivities (58 mV/pH, -57 mV/dec(Na+), -48 mV/dec(K+), and -26 mV/dec(Ca2+)) close to the Nernstian limit, and high selectivity, achieved by the use of highly selective ion selective membranes based on postprocessing integration steps aimed at eliminating any significant sensor hysteresis and parasitics. We are reporting simultaneous time-dependent recording of multiple analytes, with high selectivities. In vitro real sweat tests are carried out to prove the validity of our sensors. The reported sensors have the lowest reported power consumption, being capable of operation down to 2 pW/sensor. Due to the ultralow power consumption of our ISFETs, we achieve and report a final four-analyte passive system demonstrator including the readout interface and the remote powering of the ISFET sensors, all powered by an radio frequency (RF) signal.

Effects of hyperbaric oxygen therapy on rapid tissue expansion in rabbits.

BACKGROUND: Tissue expansion has been widely used to provide additional soft tissue for clinical reconstruction. Rapid expansion requires a much shorter clinical period than conventional expansion; however, less natural skin growth occurs resulting in a larger stretch-back ratio and insufficient extra soft tissue for clinical use. In this study, hyperbaric oxygen therapy (HBOT) was used in the inflation phase of rapid expansion to increase natural skin growth. METHODS: Twelve rabbits were divided into two groups. Each group received rapid expander inflation every day. One group received HBOT and the other did not. Blood flow in the expanded skin of each rabbit was assayed in the 10-day inflation phase. After the inflation phase, a rectangular expanded flap of each rabbit was harvested. The instant stretch-back ratio, tension, weight and histological characteristics of the flaps were evaluated. RESULTS: (1) After the second inflation day, the mean blood flow of the HBOT group became significantly higher than that of the control with each day (P < 0.05). At the last day, the blood flow of the HBOT group increased to 131 ± 17 pu, while the control group decreased to 35 ± 5 pu. (2) The mean instant stretch-back ratio of the HBOT group under no-tension conditions was 29 ± 4%, which was significantly less than that of the control group, 46 ± 3% (P < 0.01). (3) The mean flap tension of the HBOT group was 15.3000 ± 1.47648 g and 12.9833 ± 0.73598 g in the transverse and longitudinal axis, respectively, both significantly smaller than that of the control group (33.9167 ± 4.78390 g and 26.5000 ± 2.45031 g, respectively) (P < 0.01). (4) Mean per unit flap weight of the HBOT group was 0.221 ± 0.005 g cm(-2), significantly heavier (P < 0.01) than that of the control group (0.143 ± 0.010 g cm(-2)). (5) Histologically, the epidermal layer and thickness of the expanded skin of the HBOT group were much thicker than those of the control group, and more vessels were visible in the subcutaneous tissue. CONCLUSIONS: The use of HBOT in the inflation phase of rapid expansion can effectively promote blood flow in the expanded skin, increase its natural skin growth and reduce the instant stretch-back ratio and tension of expanded skin.