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Objectives: Oral squamous cell carcinoma (OSCC) is often diagnosed with cervical lymph node metastasis. Mesenchymal stem cells (MSCs) and interleukin‐6 (IL‐6) signalling are considered to play important roles in promoting tumour malignancy. The detailed biological interaction of MSCs and IL‐6 and the subsequent effect on OSCC metastasis remain largely unclear. This study aimed to determine the effects and molecular mechanism of MSCs‐derived IL‐6 on tumour invasion and metastasis. Subjects and Methods: The effects of MSC‐derived IL‐6 and tocilizumab on the proliferation, mobility, and epithelial‐mesenchymal transition (EMT) of OSCC cells and potential pathways were detected in vitro. In addition, a murine xenograft model was generated to verify the biological mechanism in vivo. Results: The results showed that the expression of MSCs and EMT‐related signals was increased in poorly differentiated OSCC tissues. MSCs released a higher level of IL‐6 and promoted the proliferation, invasion, and metastasis of OSCC cells and solid neoplasms, which were activated by the downstream molecules JAK and STAT3. Conclusions: The results indicated that MSCs‐derived IL‐6‐promoted tumour invasion and metastasis via JAK–STAT3 signalling. Blockade of this pathway by tocilizumab may be a potential treatment to improve the prognosis and survival rate of patients with OSCC. [ABSTRACT FROM AUTHOR]

The hot-electron-related reliability is an important issue for GaN power devices under harsh operation condition or environment. These high-energy electrons can scatter toward the device surface or buffer layer, introducing newly generated traps/defects and resulting in the degradation of dynamic ON-resistance (RON). This work investigates the dynamic characteristics in active-passivation p-GaN gate HEMTs (AP-HEMTs) after hot-electron stress (HES). Unlike the dielectric passivation whose dynamic RON performance is often reported to severely worsen as hot-electron-induced defects/traps accumulate, the active passivation is found to have a superior robustness against hot-electron stress. In this study, after an HES of 30 min with VD = 200 V and IS = 10 mA/mm, the dynamic RON/static RON of a conventional HEMT increases dramatically from 3.63 to 9.35 for VDS-OFF = 650 V, whereas that of AP-HEMT only shows a slight increase from 1.51 to 1.85. Two mechanisms have been experimentally proved for the improved hot-electron robustness in AP-HEMT. (i) The mobile holes in active passivation layer can effectively screen the preexisting and/or newly generated surface defects/traps from affecting the 2DEG channel. (ii) The recovery of buffer trapping is accelerated by hole injection from gate and active passivation. [ABSTRACT FROM AUTHOR]

PbSn solders are used in semiconductor devices for aerospace or military purposes with high levels of reliability requirements. Microalloying has been widely adopted to improve the reliability for Pb-free solders, but its application in PbSn solders is scarce. In this article, the optimization of PbSn solder reliability with Ge microalloying was investigated using both experimental and calculation methods. Intermetallic compounds (IMC) growth and morphologies evolution during reliability tests were considered to be the main factors of device failure. Through first-principle calculation, the growth mechanism of interfacial Ni3Sn4 was discussed, including the formation of vacancies, the Ni-vacancies exchange diffusion and the dominant Ni diffusion along the [1 0 0] direction. The doping of Ge in the cell increased the exchange energy barrier and thus inhibited the IMC development and coarsening trend. In three reliability tests, only 0.013 wt% Ge microalloying in Pb60Sn40 was able to reduce IMC thickness by an increment of 22.6~38.7%. The proposed Ge microalloying method in traditional PbSn solder could yield a prospective candidate for highly reliable applications. [ABSTRACT FROM AUTHOR]

A thermal-based acoustic vector sensor consisting of three heated wires can detect acoustic particle velocity instead of pressure. This paper proposes an analytical model for calculating the temperature distribution and acoustic-caused temperature perturbation of the sensor with a three-hot-wire configuration. In this model, the nonlinear effect caused by non-uniform thermal conductivity is considered. The nonlinear effects will not only affect the temperature of the three hot wires, but also the frequency response of the sensor. Based on the stationary temperature distribution calculated by the nonlinear model, we correct the heat diffusion coefficient in the acoustic perturbation model. The nonlinear stationary model and the corrected perturbation model are found to be in good agreement with the numerical results. Furthermore, we design a chip to measure the temperature distribution of the three heated wires and compare the sensitivity of the sensor with the corrected model. The experimental results can verify the proposed model. This study provides a theoretical basis for sensor performance optimization. [ABSTRACT FROM AUTHOR]

Acoustic dyadic sensors (ADSs) are a new type of acoustic sensor with higher directivity than microphones and acoustic vector sensors, which has great application potential in the fields of sound source localization and noise cancellation. However, the high directivity of an ADS is seriously affected by the mismatches between its sensitive units. In this article, (1) a theoretical model of mixed mismatches was established based on the finite-difference approximation model of uniaxial acoustic particle velocity gradient and its ability to reflect the actual mismatches was proven by the comparison of theoretical and experimental directivity beam patterns of an actual ADS based on MEMS thermal particle velocity sensors. (2) Additionally, a quantitative analysis method based on directivity beam pattern was proposed to easily estimate the specific magnitude of the mismatches, which was proven to be useful for the design of ADSs to estimate the magnitudes of different mismatches of an actual ADS. (3) Moreover, a correction algorithm based on the theoretical model of mixed mismatches and quantitative analysis method was successfully demonstrated to correct several groups of simulated and measured beam patterns with mixed mismatches. [ABSTRACT FROM AUTHOR]

The article presents the discussion on Oral lichen planus (OLP) being a T-cell-mediated chronic inflammatory disease clinically manifested as striated lacy hyperkeratosis. Topics include lymphocytes showing cytotoxicity leading to apoptosis of keratinocytes; and Langerhans cells presenting the MHC class II-associated antigen to CD4+helper T cells secreting large amounts of IL-2 and interferon-c.

We extract the electric properties of border traps with long time constant in low-pressure chemical vapor deposition (LPCVD) Si3N4/GaN/AlGaN/GaN metalâ€"insulatorâ€"semiconductor (MIS) structure using quasi-static capacitance voltage method. The energy and depth distribution of the border traps is calculated based on the analysis of energy band diagram and charging dynamic of border traps in the MIS structures. With this method, it is found that LPCVD Si3N4/GaN/AlGaN/GaN MIS structure have a high density of border traps in the order up to 1021 cmâˆ'3 eVâˆ'1 located at energy level between E C,GaN âˆ' 0.04 eV and E C,GaN âˆ' 0.66 eV with distance of 1.0â€"4.2 nm from the Si3N4/GaN interface. Microstructure analysis suggests that the high density of border traps is possibly correlated to the oxygen content at the Si3N4/GaN interface. Meanwhile, the proposed method is also suitable for MIS or metal-oxide-semiconductor structure on other semiconductors, providing another powerful tool to analysis the physical properties of border traps. [ABSTRACT FROM AUTHOR]

Junction termination extension (JTE) is a mature edge termination structure in Si and SiC power devices, but remains a technical challenge in GaN due to lack of mature selective area doping technique. In this work, GaN vertical p-n diodes with Hydrogen-Modulated Step Graded JTE (HMSG-JTE) are realized by gradually enlarging photolithography windows for hydrogen plasma treatment and controlled thermal diffusion of hydrogen in p-GaN. HMSG-JTE leads to a gradually decreasing hole distribution outwards from the main junction, which laterally spreads the electric field and mitigates the electric field peak under reverse bias. Consequently, the breakdown voltage of vertical GaN p-n diode is successfully boosted from 661 V (with hydrogen-plasma-based edge termination) to 1489 V with HMSG-JTE. [ABSTRACT FROM AUTHOR]

Vascular smooth muscle cells (VSMCs) in the normal arterial media continually express contractile phenotypic markers which are reduced dramatically in response to injury. Tripartite motif‐containing proteins are a family of scaffold proteins shown to regulate gene silencing, cell growth, and differentiation. We here investigated the biological role of tripartite motif‐containing 28 (TRIM28) and tripartite motif‐containing 27 (TRIM27) in VSMCs. We observed that siRNA‐mediated knockdown of TRIM28 and TRIM27 inhibited platelet‐derived growth factor (PDGF)‐induced migration in human VSMCs. Both TRIM28 and TRIM27 can regulate serum response element activity and were required for maintaining the contractile gene expression in human VSMCs. At the same time, TRIM28 and TRIM27 knockdown reduced the expression of PDGF receptor‐β (PDGFRβ) and the phosphorylation of its downstream signaling components. Immunoprecipitation showed that TRIM28 formed complexes with TRIM27 through its N‐terminal RING‐B boxes‐Coiled‐Coil domain. Furthermore, TRIM28 and TRIM27 were shown to be upregulated and mediate the VSMC contractile marker gene and PDGFRβ expression in differentiating human bone marrow mesenchymal stem cells. In conclusion, we identified that TRIM28 and TRIM27 cooperatively maintain the endogenous expression of PDGFRβ and contractile phenotype of human VSMCs. [ABSTRACT FROM AUTHOR]

AlGaN/GaN high-electron-mobility transistor (HEMT) based pH sensors have the advantages of fast response and high stability, and can be used in harsh environments. This paper presents a pH sensor based on a planar dual-gate AlGaN/GaN HEMT cascode amplifier, which can increase the pH sensitivity for about 45 times from 45 mV/pH to 2.06 V/pH with linearity of 1.27%. The results indicate that it is possible to improve the pH sensitivity at the origin of detecting instead of the subsequent complex amplifier circuits. The proposed device has also shown the capacity to adjust the sensor’s sensitivity by changing the gate voltage and the resistance values for various pH ranges of different measuring requirements. [ABSTRACT FROM AUTHOR]

In this letter, we report a quasi-vertical GaN Schottky barrier diode (SBD) fabricated on a hetero-epitaxial layer on silicon with low dislocation density and high carrier mobility. The reduction of dislocation is realized by inserting a thin layer with high density of Ga vacancies to promote the dislocation bending. The dislocation density is ${1.6}\times {10}^{{8}}$ cm−2 with a GaN drift layer thickness of $4.5~\mu \text{m}$. The fabricated prototype GaN SBD delivers a high on/off current ratio of $10^{{10}}$ , a high forward current density of 1.6 kA/cm2@3 V, a low specific on-resistance of 1.1 $\text{m}\Omega \cdot \text {cm}^{{2}}$ , and a low ideality factor of 1.23. [ABSTRACT FROM AUTHOR]

A novel gate and passivation dielectric stack consisting of a thin metal-organic chemical vapor deposition (MOCVD) grown in-situ Si3N4 (3 nm) and a thick low-pressure chemical vapor deposition (LPCVD) grown Si3N4 (30 nm) in AlGaN/GaN metal–insulator–semiconductor high-electron-mobility transistor (MIS-HEMT) is proposed. The quality of the Si3N4/(Al)GaN interface and the effect on threshold voltage (${V}_{\text {TH}}$) instability and dynamic ${R}_{ \mathrm{\scriptscriptstyle ON}}$ in the MIS-HEMTs with/without the in-situ Si3N4 layer are investigated by high-frequency capacitance-voltage (HFCV), quasi-static (QS) ${C}$ – ${V}$ (QSCV), time-of-fly (TOF) stress/measure, and QS ${I}_{\text {D}}$ – ${V}_{\text {DS}}$ methods. It is founded that the in-situ Si3N4 interfacial layer is effective in improving the dielectric/III-N interface morphology. As a result, better ${V}_{\text {TH}}$ stability and lower ${R} _{ \mathrm{\scriptscriptstyle ON},\text {D}}/{R} _{ \mathrm{\scriptscriptstyle ON},\text {S}}$ ratio are observed in devices with the in-situ Si3N4 interfacial layer due to the reduced density of traps close to the dielectric/III-N interface. Time-dependent dielectric breakdown and Weibull performance further verified that the proposed bilayer gate dielectric stack is a promising structure for the high-reliability power transistors. [ABSTRACT FROM AUTHOR]

In this letter, a distributed network model describing the effects of the border traps and distributed channel resistance on the impedance frequency dispersion of lateral MOS devices is proposed. The proposed model is verified using a gate recessed, normally-off Al2O3/GaN MOSFET structure operating as a MOS diode. The measured frequency-dependent capacitance and conductance curves of the MOS diode over a wide frequency range are found to be in good agreement with the proposed model. According to the intrinsic property of border traps to the ac signal, the proposed model is further modified to get the spatial distribution of border traps. The new insight derived from the impedance dispersion characteristics of lateral MOS devices is critical for quantitative analysis of the quality of III-V lateral MOS structures. [ABSTRACT FROM AUTHOR]

Oral lichen planus (OLP) is a chronic mucosal inflammatory disease. The World Health Organization has described it as a potentially malignant condition. The pathogenesis of OLP remains to be fully elucidated, but extensive evidence suggests that immunologic and inflammatory factors have important roles. MicroRNAs (miRs), which are small non-coding RNAs, have been reported to be involved in OLP. In particular, miR-155 is significantly upregulated in patients with OLP. miR-155 has numerous functions and is closely linked to inflammation and immune system regulation. However, in-depth studies of the mechanisms via which miR-155 is involved in OLP are currently insufficient. Considering the close association between miR-155 and immune regulation as well as the importance of immune factors in OLP, the role of miR-155 in the immune system was herein summarized with a focus on OLP. The present review provides a basis for further study of the molecular mechanisms underlying the development and progression of OLP. [ABSTRACT FROM AUTHOR]

A novel early gate dielectric AlGaN/GaN metal–insulator–semiconductor high-electron-mobility transistors (MIS-HEMTs) process is reported. With the high-quality Si3N4 dielectric by low-pressure chemical vapor deposition and damage free, self-terminating passivation layer etching at the gate area, the MIS-HEMTs on 150-mm Si substrate demonstrate excellent output performance and good uniformity. The interface trap density between the gate insulator and the barrier layer is as low as $2 \times 10^{{12}}{\mathrm {cm}}^{- {2}}\,\,\cdot \,\,{\mathrm {eV}}^{- {1}}$ extracted by the conductance method. The MIS-HEMT fabricated on the wafer delivers an extremely small gate leakage current of 10−9 mA/mm and a high ${I}_{\mathrm{\scriptscriptstyle {ON}}}/{I}_{{\mathrm{\scriptscriptstyle {OFF}}}}$ ratio of 1011. The subthreshold swing (SS) is around 80 mV/dec, and the saturated output current density is 750 mA/mm. The dynamic on-resistance increases about 42% at a quiescent drain bias of 600 V. The ${V}_{ {th}}$ shift is −0.63 and −0.89 V at a high temperature of 200 °C and negative gate-bias stress of −25 V, respectively, indicating a comparable stability with the state-of-the-art MIS-HEMTs. An excellent threshold voltage and SS uniformity ($ {1} - \sigma /\mu)$ with the value of 94.5% and 95.2% are achieved on the 150-mm wafer. [ABSTRACT FROM AUTHOR]