Traditional GaAs-based frequency multipliers still exhibit great challenges to meet the demand for solid-state high-power THz sources due to low breakdown voltage and heat dissipation of the Schottky barrier diode (SBD). In this study, a GaN SBD chain was fabricated with n⁻/n⁺-GaN structure. As a consequence, the breakdown voltage of 54.9 V at 1 μA and cut-off frequency of 587.5 GHz at zero bias were obtained. A 120 GHz frequency-doubler module based on the GaN SBD chain was designed and fabricated. When driven with 500 mW input power in a continuous wave, the output power of the frequency-doubler module was 15.1 mW at 120 GHz. Moreover, the experiments show that the frequency-doubler module can endure an input power of 2 W. In addition, it is worth noting that the SBD chain works well at an anode temperature of 337.2 °C.

Fibrosis is characterised by excessive deposition of the extracellular matrix (ECM) and develops because of fibroblast differentiation during the process of inflammation. There are few effective treatment options for this diseases due to the aetiology of fibrosis is not completely clarified. Long non-coding RNAs (lncRNAs), a type of ncRNA with a length of greater than 200 nucleotides without evident protein coding function, are important regulators of most biological and pathological processes, including participation, regulation or mediation of disease development. Among them, H19 is recently discovered as a class of lncRNAs which is related to fibrotic disease and inflammation. These observations implied a potential role for H19 as a promising therapeutic targets for treatment of fibrotic diseases. In this review, we will describe the characteristics of H19 and summarise recent advances in the mechanisms of H19 in the process of fibrosis. Finally, we will succinctly discuss the recent progress of the involvement of H19 in the development and pathogenesis of fibrosis diseases.

Optrodes, which are single shaft neural probes integrated with microelectrodes and optical light sources, offer a remarkable opportunity to simultaneously record and modulate neural activities using light within an animal’s brain; however, a common problem with optrodes is that stimulation artifacts can be observed in the neural recordings of microelectrodes when the light source on the optrode is activated. These stimulation artifacts are undesirable contaminants, and they cause interpretation complexity when analyzing the recorded neural activities. In this paper, we tried to mitigate the effects of the stimulation artifacts by developing a low-noise, double-sided optrode integrated with multiple Electromagnetic Shielding (EMS) layers. The LED and microelectrodes were constructed separately on the top epitaxial and bottom substrate layers, and EMS layers were used to separate the microelectrodes and LED to reduce signal cross-talks. Compared with conventional single-sided designs, in which the LED and microelectrodes are constructed on the same side, our results indicate that double-sided optrodes can significantly reduce the presence of stimulation artifacts. In addition, the presence of stimulation artifacts can further be reduced by decreasing the voltage difference and increasing the rise/fall time of the driving LED pulsed voltage. With all these strategies, the presence of stimulation artifacts was significantly reduced by ~76%. As well as stimulation suppression, the sapphire substrate also provided strong mechanical stiffness and support to the optrodes, as well as improved electronic stability, thus making the double-sided sapphire optrodes highly suitable for optogenetic neuroscience research on animal models.

Integrated optrodes for optogenetics have been becoming a significant tool in neuroscience through the combination of offering accurate stimulation to target cells and recording biological signals simultaneously. This makes it not just be widely used in neuroscience researches, but also have a great potential to be employed in future treatments in clinical neurological diseases. To optimize the integrated optrodes, this paper aimed to investigate the influence of surface material and illumination upon the performance of the microelectrode/electrolyte interface and build a corresponding evaluation system. In this work, an integrated planar optrode with a blue LED and microelectrodes was designed and fabricated. The charge transfer mechanism on the interface was theoretically modeled and experimentally verified. An evaluation system for assessing microelectrodes was also built up. Using this system, the proposed model of various biocompatible surface materials on microelectrodes was further investigated under different illumination conditions. The influence of illumination on the microelectrode/electrolyte interface was the cause of optical artifacts, which interfere the biological signal recording. It was found that surface materials had a great effect on the charge transfer capacity, electrical stability and recoverability, photostability, and especially optical artifacts. The metal with better charge transfer capacity and electrical stability is highly possible to have a better performance on the optical artifacts, regardless of its electrical recoverability and photostability under the illumination conditions of optogenetics. Among the five metals used in our investigation, iridium served as the best surface material for the proposed integrated optrodes. Thus, optimizing the surface material for optrodes could reduce optical interference, enhance the quality of the neural signal recording for optogenetics, and thus help to advance the research in neuroscience.

Human epidermal growth factor receptor-3 (HER-3) plays a key role in the growth and metastasis of cancer cells. The detection of HER-3 is very important for early screening and treatment of cancer. The AlGaN/GaN-based ion-sensitive heterostructure field effect transistor (ISHFET) is sensitive to surface charges. This makes it a promising candidate for the detection of HER-3. In this paper, we developed a biosensor for the detection of HER-3 with AlGaN/GaN-based ISHFET. The AlGaN/GaN-based ISHFET biosensor exhibits a sensitivity of 0.53 ± 0.04 mA/dec in 0.01 M phosphate buffer saline (1× PBS) (pH = 7.4) solution with 4% bovine serum albumin (BSA) at a source and drain voltage of 2 V. The detection limit is 2 ng/mL. A higher sensitivity (2.20 ± 0.15 mA/dec) can be achieved in 1× PBS buffer solution at a source and drain voltage of 2 V. The AlGaN/GaN-based ISHFET biosensor can be used for micro-liter (5 μL) solution measurements and the measurement can be performed after incubation of 5 min.

The AlGaN/GaN Schottky barrier diodes (SBDs) working as high-power mixer and multiplier show great potential in millimeter wave (MMW) field owing to their high breakdown voltage. Nevertheless, its further application is severely limited by large reverse leakage current (J_r) since the two-dimensional electron gas (2DEG) channel is hard to be pinched off at low voltage. To address this limitation, a graded AlGaN/GaN heterostructure is introduced to extend the 2DEG channel into a quasi-three-dimensional electron slab. By comparing the fixed Al composition AlGaN/GaN SBD, J_r of the graded AlGaN/GaN SBD is significantly reduced due to the extension of channel carriers, confirming the effective J_r suppression effect of this structure. Furthermore, on this basis, a recessed anode structure is utilized to expect a smaller J_r. The results indicated that the graded AlGaN/GaN SBDs with air-bridge structure have achieved a pretty low J_r value (1.6×10⁻¹³ A at -15V), and its cutoff frequency is as high as 60.6GHz. It is expected that such SBDs with low J_r have significant advantages in future applications.