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This letter discusses the fabrication, wireless performance, and reliability of graphene-based passive UHF RFID tags on a fabric substrate. The conductive ink comprising of functionalized graphene nanoplatelets is deposited directly on a cotton fabric substrate to fabricate the tag antennas. After attaching the chips, the tag performance is evaluated through wireless tag measurements before and after high humidity conditions, bending, and stretching. Initially the peak read range of the tag is about 1.6 meters, which increases to 3.2 meters in 100% humidity conditions. Additionally, after drying, the performance of the tag returns back to normal. In a bending test, the read range of a bent tag decreases below 1 meter. Further, the read range of the tag in a non-bended state decreases gradually and is about 1.1 meters after 100 bending cycles. According to our measurements, stretching has a serious detrimental effect on these tags and they cannot be considered stretchable. However, these initial results show that this low-cost and eco-friendly graphene RFID tag has a remarkable and unique response to moisture and high reliability in harsh bending conditions. Overall, it also has a strong potential to be used in future wearable sensor applications.

This work describes a facile, mild and general wet chemical method to change the material and the geometry of inkjet-printed interdigitated electrodes (IDEs) thus drastically enhancing the sensitivity of chemiresistive sensors. A novel layer-by-layer chemical method was developed and used to uniformly deposit semiconducting single-wall carbon nanotube (SWCNT)-based sensing elements on a Kapton® substrate. Flexible chemiresistive sensors were then fabricated by inkjet-printing fine-featured silver IDEs on top of the sensing elements. A mild and facile two-step process was employed to convert the inkjet-printed dense silver IDEs into their highly porous gold counterparts under ambient conditions without losing the IDE-substrate adhesion. A proof-of-concept gas sensor equipped with the resulting porous gold IDEs featured a sensitivity to diethyl ethylphosphonate (DEEP, a simulant of the nerve agent sarin) of at least 5 times higher than a similar sensor equipped with the original dense silver IDEs, which suggested that the electrode material and/or the Schottky contacts between the electrodes and the SWCNTs might have played an important role in the gas sensing process.

PurposeTo compare the recurrence rate and surgical outcomes of amniotic membrane transplantation (AMT) and free conjunctival autograft (CAT) for pterygium surgery.MethodsIn this prospective study, 60 patients with primary pterygium were randomly assigned to two groups of CAT or AMT and were compared in terms of recurrence rate, mean healing time of corneal epithelial defects, the mean level of inflammation, and complications.ResultsThe mean ± SD age of patients was 48.98 ± 9.8 years (range, 27–71 years). 73.3% were men, and 26.7% were women. The groups did not differ with respect to demographic characteristics (P > 0.05). Patients were followed for an average of 12.6 ± 1.3 months. The recurrence rates were 6.7% and 3.3% in the AMT and CAT groups, respectively (P > 0.05). Comparison of mean inflammation score showed higher inflammation in the AMT group in the first, third, and sixth postoperative month (P < 0.05). Mean healing times of corneal epithelial defects were 2.5 ± 0.572 and 2.67 ± 0.479 days in the CAT and AMT groups, respectively (P = 0.173).ConclusionsNo significant complication was observed during or after both surgical methods. No statistically significant difference was seen in visual acuity changes and epithelial healing in CAT and AMT groups, but more inflammation and recurrence rate were seen in AMT group.