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The Influence of sintering temperature on the physical, electrochemical and sensing properties of α-Fe2O3-SnO2 nanocomposite sensing electrode for a mixed-potential type NOx sensor is investigated. The α-Fe2O3-SnO2 nanocomposite was synthesized by a solution combustion route and sintered at temperatures 900, 1000, 1100 and 1200 °C to form the sensing electrodes of a stabilized-zirconia based mixed-potential type NOx sensor. The influence of sintering temperatures on the physical properties was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and N2 adsorption-desorption isotherm measurements. The gas sensing measurements were conducted at an operating temperature of 650 °C. A systematic increase in the response/recovery times was observed with an increase in the sintering temperature from 900 to 1200 °C. An optimum microstructure with a low surface area and large pore size leading to high electrochemical reactions at the interface and low heterogenous gas-phase decomposition of NO2 resulted in the maximum response magnitude (ΔV) and sensitivity for the electrode sintered at 1000 °C. Furthermore, the effect of sintering temperature on the electrochemical activity of the sensing electrode and its co-relation with the sensing properties was studied by dc polarization curve measurement. Moreover, the microstructure, sensing response, sensitivity, dynamics and O2 conc. dependence of the presented mixed-potential type NOx sensor is critically dependent upon the sintering temperature of the sensing electrodes.

Target analyte detection using whole-cell microbial biosensors can benefit from a microchemostat platform owing to the reduced reagent consumption, a finely controllable environment, and multi-parallel processing. However, the use of the previous microchemostat still has limitations for practical applications, e.g., its single-use design, long time requirements for cell and device preparation, low portability, slow and weak response signals, and the lack of ready-to-use in situ devices. In the present study, we developed a novel microchemostat platform that resolves these issues and enhances the performance of microbial biosensors via its abilities to actively control the cell population and to form a uniform culture environment using a nanoscale hydrodynamic film (NHF). The combination of the microchemostat platform and the microbial biosensors yielded fast and strong signals on demand in response to heavy metal ions (e.g., Pb2+). In addition, the platform enables the long-term on-chip storage of microbial biosensors for over 1 month, without deterioration of growth and detection ability. Lastly, we demonstrated that microbial biosensors can consecutively measure multiple samples by a regeneration process in which the microchemostat platform continuously subcultures the microbial biosensors until the complete recovery of their sensing capabilities. Thus, the microchemostat offers whole-cell microbial biosensors that are fast, ready-to-use, reusable, and storable. It also shows good potential for user-friendly, portable on-site environmental monitoring, particularly where expensive analytical tools and/or instruments for heavy metal ion detection are unavailable.

In this study, Polygonum aviculare L. extract, which has superior antioxidative and cellular membrane protective activity, was loaded onto cell penetrating peptide (CPP) conjugated liposomes to enhance transdermal delivery. The physical characteristics of typical liposomes and CPP-conjugated liposomes containing P. aviculare extract were evaluated. The particle sizes of both liposomes were approximately 150 nm. Whereas the zeta potential of typical liposomes was -45 mV, that of CPP-conjugated liposomes was +42 mV. The loading efficiency of P. aviculare extract in both liposomes was calculated to be about 83%. Fluorescent-labeled liposomes were prepared to evaluate cellular uptake and skin permeation efficiency. Using flow cytometry, we found that CPP-conjugated liposomes improved cellular uptake of the fluorescent dye as compared with the typical liposomes. In addition, the skin permeation of CPP-conjugated liposomes was proved higher than that of typical liposomes by confocal laser scanning microscopy studies and Franz diffusion cell experiments. The improved cellular uptake and skin permeation of the CPP-conjugated liposomes were due to the cationic arginine-rich peptide. In vivo studies also determined that the CPP-conjugated liposomes were more effective in depigmentation and anti-wrinkle studies than typical liposomes. These results indicate that the CPP-conjugated liposomes could be effective for transdermal drug delivery of antioxidant and anti-aging therapeutics.

Reporter-gene-based microbial biosensors have high potential for detecting small molecules, including heavy metal ions (HMIs), in a sensitive and selective manner by involving low costs. However, the sensitivity and dynamic range of the sensing mechanism are largely limited by the conventional culture environment that relies on the batch-type addition of the small molecules in nutrients and the subsequent genetic induction of sensing microbes. Here, we describe a high-throughput, chemostat-like microfluidic platform that can continuously supply both nutrients and inducers (HMIs) using microfabricated ratchet structures and a mixing microchannel network. We found that the microfluidic platform not only allowed microbial biosensors to be highly concentrated in a detection microchamber array but also enabled them to continuously grow and control synthetic genetic circuits in response to heavy metals. We also demonstrated that the combination of the platform and microbial biosensors enhanced the sensitivity for detecting divalent lead and cadmium ions by approximately three orders of magnitude relative to conventional batch-type methods. Because the platform is portable and only requires small sample volumes and fluorescent detection, the chemostat-like microfluidic platform in conjunction with microbial biosensors could be widely utilized to facilitate the specific and sensitive detection of molecular analytes on a chip.

To describe the clinical implications of outer foveolar defects on optical coherence tomography (OCT) in eyes treated surgically for macular hole (MH).Retrospective observational case series.Ninety-six eyes of 93 subjects who had undergone surgery for the treatment of idiopathic MH were included. Clinical data, including OCT prior to and at follow-up visits ranging from 3 to 32 months after surgery, were analyzed. Incidence, risk factors, and clinical outcomes of outer foveolar defect were evaluated.Outer foveolar defects were noted on postoperative OCT in 44 of the 96 eyes (45.8%). The mean preoperative diameter of MH in the eyes (333.5 ± 126.3 μm) evidencing outer foveolar defects was significantly smaller than those that did not (504.2 ± 155.6 μm) (P.0001). The mean disappearance time of the defect was estimated to be 182 days after surgery. The mean postoperative visual acuity (logMAR) improved to 0.40 ± 0.26 from 0.58 ± 0.23 after the disappearance of outer foveolar defects.Outer foveolar defects were detected predominantly after surgery for small MHs. The defect decreases gradually in size and eventually disappears completely approximately 6 months after surgery.