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A robust organic hydrogen sensor for distributed monitoring applications

Hydrogen is an abundant and clean energy source that could help to decarbonize difficult-to-electrify economic sectors. However, its safe deployment relies on the availability of cost-effective hydrogen detection technologies. We describe a hydrogen sensor that uses an organic semiconductor as the active layer. It can operate over a wide temperature and humidity range. Ambient oxygen p-dopes the organic semiconductor, which improves hole transport, and the presence of hydrogen reverses this doping process, leading to a drop in current and enabling reliable and rapid hydrogen detection. The sensor exhibits a high responsivity (more than 10,000), fast response time (less than 1 s), low limit of detection (around 192 ppb) and low power consumption (less than 2 μW). It can operate continuously for more than 646 days in ambient air at room temperature. We show that the sensor outperforms a commercial hydrogen detector in realistic sensing scenarios, illustrating its suitability for application in distributed sensor networks for early warning of hydrogen leaks and preventing explosions or fires.

A tip-tilt-piston electrothermal micromirror array with integrated position sensors

A tip-tilt-piston 3 × 3 electrothermal micromirror array (MMA) integrated with temperature field-based position sensors is designed and fabricated in this work. The size of the individual octagonal mirror plates is as large as 1.6 mm × 1.6 mm. Thermal isolation structures are embedded to reduce the thermal coupling among the micromirror units. Results show that each micromirror unit has a piston scan range of 218 μm and a tip-tilt optical scan angle of 21° at only 5 Vdc. The micromirrors also exhibit good dynamic performance with a rise time of 51.2 ms and a fall time of 53.6 ms. Moreover, the on-chip position sensors are proven to be capable for covering the full-range movement of the mirror plate, with the measured sensitivities of 1.5 mV/μm and 8.8 mV/° in piston sensing and tip-tilt sensing, respectively. Furthermore, the thermal crosstalk in an operating MMA has been experimentally studied. The measured results are promising thanks to the embedded thermal isolation structures.

Inverted pyramid 3-axis silicon Hall-effect magnetic sensor with offset cancellation

Microelectronic magnetic sensors are essential in diverse applications, including automotive, industrial, and consumer electronics. Hall-effect devices hold the largest share of the magnetic sensor market, and they are particularly valued for their reliability, low cost and CMOS compatibility. This paper introduces a novel 3-axis Hall-effect sensor element based on an inverted pyramid structure, realized by leveraging MEMS micromachining and CMOS processing. The devices are manufactured by etching the pyramid openings with TMAH and implanting the sloped walls with n-dopants to define the active area. Through the use of various bias-sense detection modes, the device is able to detect both in-plane and out-of-plane magnetic fields within a single compact structure. In addition, the offset can be significantly reduced by one to three orders of magnitude by employing the current-spinning method. The device presented in this work demonstrated high in-plane and out-of-plane current- and voltage-related sensitivities ranging between 64.1 to 198 V A−1 T1 and 14.8 to 21.4 mV V−1 T−1, with crosstalk below 4.7%. The sensor exhibits a thermal noise floor which corresponds to approximately (0.5,mu text{T}/sqrt{text{Hz}}) at 1.31 V supply. This novel Hall-effect sensor represents a promising and simpler alternative to existing state-of-the-art 3-axis magnetic sensors, offering a viable solution for precise and reliable magnetic field sensing in various applications such as position feedback and power monitoring.

sLZIP functions as a key modulator of bone remodeling by regulating the crosstalk between osteoblasts and osteoclasts

Human small leucine zipper protein (sLZIP) regulates the differentiation of both osteoblasts (OBs) and osteoclasts (OCs). However, the regulatory role of sLZIP in bone remodeling and its involvement in bone disorders remain unclear. Here we investigated the role of sLZIP in bone remodeling and its importance in the development of cell therapies for bone diseases. sLZIP increased bone mass in an osteoporosis mouse model. Moreover, bone mass was lower in mesenchymal stem cell-specific murine LZIP-1/2 knockout (Osx-LZIP-1/2fl/fl) mice than in control LZIP-1/2fl/fl mice. Compared with control mice, Osx-LZIP-1/2fl/fl mice presented delayed bone fracture healing in osteoporosis. Conditioned medium from OBs differentiated from adipose-derived stem cells from Osx-LZIP-1/2fl/fl mice attenuated OC formation and the migration of bone marrow-derived macrophages. However, conditioned medium from OCs from sLZIP transgenic mice induced OB differentiation and migration. sLZIP regulates the secretion of OC-derived sphingosine-1-phosphate, which induces OB differentiation. sLZIP also regulates OB-derived WNT16, which inhibits OC differentiation. Therefore, sLZIP is a key modulator of the crosstalk between OBs and OCs and promotes bone remodeling and fracture healing in osteoporosis. In addition, sLZIP-overexpressing adipose-derived stem cells promote bone formation and repair in osteoporosis. sLZIP is an excellent target for stem cell-based treatment of osteoporosis.

Pilot-scale partial nitrification and anaerobic ammonium oxidation system for nitrogen removal from municipal wastewater

Partial nitrification has the advantages of saving energy and reducing the need for carbon sources in municipal wastewater treatment. However, for municipal wastewater with low ammonia, start-up and maintenance of partial nitrification is a worldwide challenge. Here we developed a pilot-scale double sludge system consisting of two sequencing batch reactors for partial nitrification (12 m2) and denitrification/anaerobic ammonium oxidation (denitrification/anammox, 8.4 m2) to treat municipal wastewater. Partial nitrification was maintained at no ammonium remaining with a nitrite accumulation rate of 87.7%. This study found that partial nitrification system effluent chemical oxygen demand increased from 24.8 mg L−1 to 64.9 mg L−1 accompanied by transformation from complete nitrification to partial nitrification. In the denitrification/anammox system, the reduction of nitrite to nitrogen required about 40% less carbon consumption than nitrate. High nitrogen removal was achieved with effluent total inorganic nitrogen of 2.7 mg L−1 without carbon addition. This work provided a pilot-scale demonstration of low-carbon high-nitrogen removal.

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