Eight In. Wafer-Scale Epitaxial Monolayer MoS2.

Large-scale, high-quality, and uniform monolayer molybdenum disulfide (MoS2) films are crucial for their applications in next-generation electronics and optoelectronics. Epitaxy is a mainstream technique for achieving high-quality MoS2 films and is demonstrated at a wafer scale up to 4-in. In this study, the epitaxial growth of 8-in. wafer-scale highly oriented monolayer MoS2 on sapphire is reported as with excellent spatial homogeneity, using a specially designed vertical chemical vapor deposition (VCVD) system. Field effect transistors (FETs) based on the as-grown 8-in. wafer-scale monolayer MoS2 film are fabricated and exhibit high performances, with an average mobility and an on/off ratio of 53.5 cm2 V-1 s-1 and 107, respectively. In addition, batch fabrication of logic devices and 11-stage ring oscillators are also demonstrated, showcasing excellent electrical functions. This work may pave the way of MoS2 in practical industry-scale applications.

Electron/infrared-phonon coupling in ABC trilayer graphene.

Stacking order plays a crucial role in determining the crystal symmetry and has significant impacts on electronic, optical, magnetic, and topological properties. Electron-phonon coupling, which is central to a wide range of intriguing quantum phenomena, is expected to be intricately connected with stacking order. Understanding the stacking order-dependent electron-phonon coupling is essential for understanding peculiar physical phenomena associated with electron-phonon coupling, such as superconductivity and charge density waves. In this study, we investigate the effect of stacking order on electron-infrared phonon coupling in graphene trilayers. By using gate-tunable Raman spectroscopy and excitation frequency-dependent near-field infrared nanoscopy, we show that rhombohedral ABC-stacked trilayer graphene has a significant electron-infrared phonon coupling strength. Our findings provide novel insights into the superconductivity and other fundamental physical properties of rhombohedral ABC-stacked trilayer graphene, and can enable nondestructive and high-throughput imaging of trilayer graphene stacking order using Raman scattering.

Epitaxy of wafer-scale single-crystal MoS2 monolayer via buffer layer control.

Monolayer molybdenum disulfide (MoS2), an emergent two-dimensional (2D) semiconductor, holds great promise for transcending the fundamental limits of silicon electronics and continue the downscaling of field-effect transistors. To realize its full potential and high-end applications, controlled synthesis of wafer-scale monolayer MoS2 single crystals on general commercial substrates is highly desired yet challenging. Here, we demonstrate the successful epitaxial growth of 2-inch single-crystal MoS2 monolayers on industry-compatible substrates of c-plane sapphire by engineering the formation of a specific interfacial reconstructed layer through the S/MoO3 precursor ratio control. The unidirectional alignment and seamless stitching of MoS2 domains across the entire wafer are demonstrated through cross-dimensional characterizations ranging from atomic- to centimeter-scale. The epitaxial monolayer MoS2 single crystal shows good wafer-scale uniformity and state-of-the-art quality, as evidenced from the ~100% phonon circular dichroism, exciton valley polarization of ~70%, room-temperature mobility of ~140 cm2v-1s-1, and on/off ratio of ~109. Our work provides a simple strategy to produce wafer-scale single-crystal 2D semiconductors on commercial insulator substrates, paving the way towards the further extension of Moore's law and industrial applications of 2D electronic circuits.

MoS2-Thin Film Transistor Based Flexible 2T1C Driving Circuits for Active-Matrix Displays.

Two-dimensional (2D) semiconductors offer great potential as high-performance materials for thin film transistors (TFTs) in displays. Their thin, stable, and flexible nature, along with excellent electrical properties, makes them suitable for flexible displays. However, previous demonstrations lacked clear superiority in pixel resolution and TFT performance. Here we present the flexible 2T1C pixel driving circuit for active-matrix displays based on high-quality large-scale monolayer MoS2. A gate-first fabrication process was developed for flexible MoS2-TFTs, showing a remarkable carrier mobility (average at 52.8 cm2 V-1 s-1), high on/off ratio (average at 1.5 × 108), and negligible hysteresis. The driving current can be modulated by pulsed input voltages and demonstrates a stable and prompt response to both frequency and amplitude. We also demonstrated a 10 × 10 active-matrix with high resolution of 508 pixels per inch, exhibiting 100% yield and high uniformity. The driving circuit works well under bending up to ∼0.91% strain, highlighting its normal functions in flexible displays.

Low power flexible monolayer MoS2 integrated circuits.

Monolayer molybdenum disulfide (ML-MoS2) is an emergent two-dimensional (2D) semiconductor holding potential for flexible integrated circuits (ICs). The most important demands for the application of such ML-MoS2 ICs are low power consumption and high performance. However, these are currently challenging to satisfy due to limitations in the material quality and device fabrication technology. In this work, we develop an ultra-thin high-κ dielectric/metal gate fabrication technique for the realization of thin film transistors based on high-quality wafer scale ML-MoS2 on both rigid and flexible substrates. The rigid devices can be operated in the deep-subthreshold regime with low power consumption and show negligible hysteresis, sharp subthreshold slope, high current density, and ultra-low leakage currents. Moreover, we realize fully functional large-scale flexible ICs operating at voltages below 1 V. Our process could represent a key step towards using energy-efficient flexible ML-MoS2 ICs in portable, wearable, and implantable electronics.

Scaling of MoS2 Transistors and Inverters to Sub-10 nm Channel Length with High Performance.

Two-dimensional (2D) semiconductors such as monolayer molybdenum disulfide (MoS2) are promising building blocks for ultrascaled field effect transistors (FETs), benefiting from their atomic thickness, dangling-bond-free flat surface, and excellent gate controllability. However, despite great prospects, the fabrication of 2D ultrashort channel FETs with high performance and uniformity remains a challenge. Here, we report a self-encapsulated heterostructure undercut technique for the fabrication of sub-10 nm channel length MoS2 FETs. The fabricated 9 nm channel MoS2 FETs exhibit superior performances compared with sub-15 nm channel length including the competitive on-state current density of 734/433 µA/µm at VDS = 2/1 V, record-low DIBL of ∼50 mV/V, and superior on/off ratio of 3 × 107 and low subthreshold swing of ∼100 mV/dec. Furthermore, the ultrashort channel MoS2 FETs fabricated by this new technique show excellent homogeneity. Thanks to this, we scale the monolayer inverter down to sub-10 nm channel length.

The effect of water-insoluble dietary fiber from star anise on water retention of minced meat gels.

The mechanism of star anise dietary fiber (SADF) in improving the water-holding capacity (WHC) of meat batter during chilled storage was investigated. In the 0-day storage group, the cooking loss (CL) decreased from 11.93% to 9.38% with the increased content of SADF, indicating that the physical filling of SADF could improve the WHC of cooked meat batter. After 7 days of chilled storage, the CL of meat batter without SADF increased from 11.93% to 17.65%, while the addition of SADF significantly reduced the CL, especially 2% SADF showing the lowest CL. Additionally, adding SADF could significantly improve the color stability and increase the hardness of cooked meat batter. According to the results of TBARS and carbonyls, SADF significantly inhibited lipid oxidation and alleviated oxidative damage of protein, resulting in an increase in the level of ß-sheet, which was confirmed by the result of FT-IR. Therefore, the water mobility of meat batter was restricted, which was confirmed by the T2 relaxation time. In general, the water retention of meat batter during chilled storage was improved via antioxidant and physical filling of SADF.

ZmPP2C26 Alternative Splicing Variants Negatively Regulate Drought Tolerance in Maize.

Serine/threonine protein phosphatase 2C (PP2C) dephosphorylates proteins and plays crucial roles in plant growth, development, and stress response. In this study, we characterized a clade B member of maize PP2C family, i.e., ZmPP2C26, that negatively regulated drought tolerance by dephosphorylating ZmMAPK3 and ZmMAPK7 in maize. The ZmPP2C26 gene generated ZmPP2C26L and ZmPP2C26S isoforms through untypical alternative splicing. ZmPP2C26S lost 71 amino acids including an MAPK interaction motif and showed higher phosphatase activity than ZmPP2C26L. ZmPP2C26L directly interacted with, dephosphorylated ZmMAPK3 and ZmMAPK7, and localized in chloroplast and nucleus, but ZmPP2C26S only dephosphorylated ZmMAPK3 and localized in cytosol and nucleus. The expression of ZmPP2C26L and ZmPP2C26 was significantly inhibited by drought stress. Meanwhile, the maize zmpp2c26 mutant exhibited enhancement of drought tolerance with higher root length, root weight, chlorophyll content, and photosynthetic rate compared with wild type. However, overexpression of ZmPP2C26L and ZmPP2C26S significantly decreased drought tolerance in Arabidopsis and rice with lower root length, chlorophyll content, and photosynthetic rate. Phosphoproteomic analysis revealed that the ZmPP2C26 protein also altered phosphorylation level of proteins involved in photosynthesis. This study provides insights into understanding the mechanism of PP2C in response to abiotic stress.

Isolation and characterization of maize ZmPP2C26 gene promoter in drought-response.

The clade A members of serine/threonine protein phosphatase 2Cs (PP2Cs) play crucial roles in plant growth, development, and stress response via the ABA signaling pathway. But little is known about other PP2C clades in plants. Our previous study showed that maize the ZmPP2C26, a clade B member of ZmPP2Cs, negatively regulated drought tolerance in transgenic Arabidopsis. However, the upstream regulatory mechanism of ZmPP2C26 remains unclear. In the present study, the expression of ZmPP2C26 gene in maize was analyzed by quantitative real time PCR (qRT-PCR). The results showed that the expression of ZmPP2C26 in shoot and root was both significantly inhibited by drought stress. Subsequently, a 2175 bp promoter of ZmPP2C26 was isolated from maize genome (P 2175). To validate whether the promoter possess some key cis-element and negatively drive ZmPP2C26 expression in drought stress, three 5´-deletion fragments of 1505, 1084 and 215 bp was amplified from P 2175 and were fused to ß-glucuronidase (GUS) and luciferase gene (LUC) to produce promoter::GUS and promoter::LUC constructs, and transformed into tobacco, respectively. Transient expression assays indicated that all promoters could drive GUS and LUC expression. The GUS and LUC activity were both significantly inhibited by PEG-6000 treatment. Notably, the - 1084 to - 215 bp promoter possess one MBS element and inhibits the expression of GUS and LUC under drought stress. Meanwhile, we found that the 215 bp length is enough to drive ZmPP2C26 expression. These findings will provide insights into understanding the transcription-regulatory mechanism of ZmPP2C26 negatively regulating drought tolerance.

Comparison of the Hepatoprotective Effects of the Three Main Stilbenes from Mulberry Twigs.

The purpose of this study was to compare the hepatoprotective effects of Oxy (oxyresveratrol), Res (resveratrol), and MulA (mulberroside A) (80 mg/kg body weight/d, i.g.) on acute liver injury (ALI) induced by lipopolysaccharide (LPS)/d-galactosamine (d-GalN) in mice. After 7 h of LPS (50 µg/kg body weight, i.p.) and d-GalN (500 mg/kg body weight, i.p.) exposure, the activities of serum transaminases and antioxidant enzymes were determined. The expressions of the Kelch-like ECH-associated protein 1 (Keap1)-nuclear factor erythroid 2-related factor 2 (Nrf2) signal pathway, the nuclear factor-kappa B (NF-κB) signal pathway, and the mitogen-activated protein kinase (MAPK) signal pathway related proteins were evaluated by Western blot assays. Histopathological analysis was performed by hematoxylin-eosin (H&E) staining on the separated livers of mice. The results showed that treatment with Oxy, Res, and MulA could significantly decreases the levels of alanine transaminase (ALT) and aspartate transaminase (AST) ( P < 0.01). MulA was the most effective ingredient among the three, and the ALT and AST levels were reduced at 90.3 ± 1.3% and 93.9 ± 1.1% compared with the LPS/D-GalN treated group ( P < 0.01). Meanwhile, the stilbenes curbed the expression of inflammatory factors, NF-κB pathway activation, and MAPKs phosphorylation and upregulated antioxidant enzymes, Nrf2, NAD (P) H:quinone oxidoreductase (NQO1), and heme oxygenase-1 (HO-1) expression levels. Stilbenes might protect the ALI caused by LPS/d-GalN through inhibiting the negative effectiveness of oxidation stress and inflammation. The protective performance of MulA was better than those of Oxy and Res, and we hypothesize that it might be due to the mediation of the specific metabolic pathway of the MulA in vivo. All of these results implied that stilbenes in mulberry twigs might be promising as natural additives.

Oxyresveratrol prevents lipopolysaccharide/d-galactosamine-induced acute liver injury in mice.

Oxyresveratrol (Oxy) is a natural polyhydroxystilbene abundant in mulberry that has anti-inflammation and anti-oxidant activities. We evaluated the protective effect of Oxy in the context of the lipopolysaccharide and d-galactosamine (LPS/d-GalN) induced acute liver injury. Oxy restricted the development of histopathological changes, markedly reduced the activity of alanine transaminase (ALT) and aspartate transaminase (AST), which are indicators of impaired liver function. Oxy significantly regulated the contents of oxidative stress related enzymes and products, and inhibited expressions of inflammatory mediators and cytokines. Oxy treatment diminished the Toll-like receptor 4/nuclear factor-kappa B (TLR4/NF-κB) signaling pathway in liver, activated the Kelch-like ECH-associated protein 1(Keap1)-nuclear factor erythroid 2-related factor 2 (Nrf2) pathway, and increased expressions of heme oxygenase 1 (HO-1) and quinine oxidoreductase 1(NQO1). Pretreatment with Oxy decreased LPS/d-GalN stimulated hepatocyte apoptosis by efficaciously raising the B-cell lymphoma 2 (Bcl-2)/Bcl-2 associated X (Bax) ratio, inhibiting the expression and activation of caspases, and activating the phosphoinoside-3-kinase (PI3K)-Akt pathway. Our results demonstrate the hepatoprotective efficacy of Oxy. The protection is mainly due to the prevention of TLR4/NF-κB pathway activation, induced activation of Keap1-Nrf2 signaling pathway, and decreased hepatocyte apoptosis. Oxy warrants further study as a potential therapeutic agent candidate for the management of acute liver injury.

Oxyresveratrol, a Stilbene Compound from Morus alba L. Twig Extract Active Against Trichophyton rubrum.

Morus alba L. (mulberry) twig is known to have an inhibitory effect on pathogens in traditional Chinese medicine. In the present study, the dermophytic fungus, Trichophyton rubrum, was used to evaluate the inhibitory effect of total M. alba twig extract and extracts obtained using solvents with different polarities by the method of 96-well MTT colorimetry. The main active substance was isolated and identified by tracking its activity. In addition, the inhibitory effects of active extracts and a single active substance were investigated in combination with miconazole nitrate. Our data indicated that ethyl acetate extracts of mulberry twig (TEE) exhibited a desired inhibitory activity on T. rubrum with the minimum inhibitory concentration (MIC) of 1.000 mg/mL. With activity tracking, the main substance showing antimicrobial activity was oxyresveratrol (OXY), which was isolated from TEE. Its MIC for inhibiting the growth of T. rubrum was 0.500 mg/mL. The combined use of miconazole nitrate and OXY showed a synergistic inhibitory effect, as shown by a significant decrease in the MIC of both components. Based on the OXY content in TEE, the contribution rate of OXY to the inhibitory effect of TEE on T. rubrum was 80.52%, so it was determined to be the main antimicrobial substance in M. alba twig. Copyright © 2017 John Wiley & Sons, Ltd.

[Comparison of three methods for evaluating acrosome reaction in human spermatozoa].

OBJECTIVE: To find a convenient and exact method for evaluating acrosome reaction in human spermatozoa. METHODS: The semen of the normal male was mixed and then divided into 6 groups. Coomassie brilliant blue (CBB) staining, chlortetracycline (CTC) fluorescence staining and acid phosphatase (ACP) detection were used for morphological observation and data analysis of the acrosome status of the human sperm treated with or without progesterone. RESULTS: There were obvious morphological differences between the acrosome-reaction and acrosome-intact spermatozoa in CBB staining and CTC fluorescence staining, and significant differences were observed between the experimental and control spermatozoa by the three methods (P < 0.05). CONCLUSION: All the three methods can be used to assess acrosome reaction in human spermatozoa, but Coomassie brilliant blue (CBB) staining is much more convenient and stable.