Self-aligned stitching growth of centimeter-scale quasi-single-crystalline hexagonal boron nitride monolayers on liquid copper.

Two-dimensional hexagonal boron nitride (hBN) atomic crystals are excellent charge scattering screening interlayers for advanced electronic devices. Although wafer-scale single crystalline hBN monolayer films have been demonstrated on liquid Au and solid Cu (110) and (111) vicinal surfaces, their reproducible growth still remains challenging. Here, we report the facile self-aligned stitching growth of centimeter-scale quasi-single-crystalline hBN monolayer films through synergistic chemical vapor deposition growth kinetics and liquid Cu rheological kinetics control. The sublimation temperature of the ammonia borane precursor, H2 content and melting temperature of the Cu substrate are revealed to be the dominant factors that regulate hBN nucleation, growth and alignment. The flowing liquid Cu catalytic surface promotes efficient rotation of floating triangular hBN domains and provokes uniform self-alignment upon merging at a critical high temperature of 1105 °C. Identical aligned grains are constantly observed at multiple regions, which corroborate the homogeneous in-plane orientation and uniform stitching over the whole growth area. Continuous quasi-single-crystalline hBN monolayer films are produced by seamless stitching of aligned domains with the same polarity. The quasi-single-crystalline hBN monolayers are successfully included as charge scattering and trap site screening interlayers in the hBN/SiO2 gate insulator stack to build high performance InGaZnO field-effect transistors (FETs). Full suppression of hysteresis and twofold enhancement of field-effect mobility are realized for InGaZnO FETs built with hBN as the interface dielectric. The facile growth of large quasi-single-crystalline hBN monolayers on liquid Cu paves the way for future high-performance electronics.

Graded Channel Junctionless InGaZnO Thin-Film Transistors with Both High Transporting Properties and Good Bias Stress Stability.

InGaZnO (IGZO) is currently the most prominent oxide semiconductor complement to low-temperature polysilicon for thin-film transistor (TFT) applications in flat panel displays. However, the compromised transport performance and bias stress instability are critical issues inhibiting its application in ultrahigh-resolution optoelectronic displays. Here, we report the fabrication of graded channel junctionless IGZO:O|N TFTs with both high transporting properties and good bias stress stability by systematic manipulation of oxygen vacancy (VO) defects through sequential O antidoping and O/N codoping of the continuous IGZO framework. The transporting properties and bias stress stability of the graded channel IGZO:O|N TFTs, which exhibited high field-effect mobilities close to 100 cm2 V-1 s-1, negligible performance degradations, and trivial threshold voltage shifts against gate bias stress and photobias stress, are simultaneously improved compared to those of the controlled single-channel uniformly doped IGZO:O TFTs, IGZO:N TFTs, and double-channel barrier-confined IGZO:O/IGZO:N TFTs. The synergistic improvements are attributed to the sequential mobility and stability enhancement effects of O antidoping and O/N codoping where triple saturation currents are induced by O antidoping of the front-channel regime while the trapped electrons and photoexcited holes in the back-channel bulk and surface regions are suppressed by O/N codoping. More importantly, fast accumulation and barrier-free full depletion are rationally realized by eliminating the junction interface within the graded channel layer. Our observation identifies that graded channel doping could be a powerful way to synergistically boost up the transport performance and bias stress stability of oxide TFTs for new-generation ultrahigh-definition display applications.

HOXC10 promotes proliferation and attenuates lipid accumulation of sheep bone marrow mesenchymal stem cells.

Homeodomain-containing gene C10 (HOXC10), known to regulate cell differentiation and proliferation, is a key negative regulator in the browning of white adipose tissue in mice. Sheep is an important farm animal that provides meat for human consumption, with fat content being an important meat quality determinant; however, there is no report about the role of HOXC10 in sheep adipocytes or adipogenesis. In this study, we investigated the effect of HOXC10 on proliferation and adipogenic differentiation in sheep bone marrow mesenchymal stem cells (sBMSCs). In sBMSCs, HOXC10 overexpression promoted cell proliferation and upregulated the expression of p-PI3K, p-AKT, p-p70S6K, p-MEK, and p-ERK, whereas HOXC10 knockdown was associated with the opposite effects. These results suggested that HOXC10 may promote cell proliferation by activating the MEK/ERK and PI3K/AKT/mTOR/p70S6K signaling pathways. In addition, we found that HOXC10 expression was negatively associated with lipid accumulation in adipogenic-differentiated sBMSCs. HOXC10 overexpression in sBMSCs significantly decreased lipid droplet accumulation and suppressed the expression of adipogenic-specific genes, including ACC, LPL, PPARG, and FABP4, while HOXC10 knockdown was associated with the opposite effects. Furthermore, our study suggested a new regulatory mechanism of the effect of HOXC10 on lipid accumulation and metabolism; HOXC10 may negatively regulate lipid accumulation in adipogenic-differentiated sBMSCs, at least in part, by suppressing LPL expression. Overall, our research not only contributes to a better understanding of the mechanism of lipid accumulation and metabolism in sheep, but also shed light on meat quality control in the future.

Facile Preparation of Self-Assembled Polydopamine-Modified Electrospun Fibers for Highly Effective Removal of Organic Dyes.

Polydopamine (PDA) nanoparticles can be used as an adsorbent with excellent adsorption capacity. However, nanosized adsorbents are prone to aggregation and thus are severely limited in the field of adsorption. In order to solve this problem, we utilized polydopamine in-situ oxidation self-polymerization on the surface of polycaprolactone (PCL)/polyethylene oxide (PEO) electrospun fiber after solvent vapor annealing (SVA) treatment, and successfully designed and prepared a PCL/PEO@PDA composite membrane. The SVA treatment regulated the microscopic morphology of smooth PCL/PEO electrospun fibers that exhibited a pleated microstructure, increasing the specific surface area, and providing abundant active sites for the anchoring of PDA nanoparticles. The PCL/PEO@PDA composite obtained by chemical modification of PDA demonstrated numerous active sites for the adsorption of methylene (MB) and methyl orange (MO). In addition, the PCL/PEO@PDA composites were reusable several times with good reutilization as adsorbents. Therefore, we have developed a highly efficient and non-agglomerated dye adsorbent that exhibits potential large-scale application in dye removal and wastewater purification.

Self-Assembled Hydrogels Based on Poly-Cyclodextrin and Poly-Azobenzene Compounds and Applications for Highly Efficient Removal of Bisphenol A and Methylene Blue.

The excellent physical and chemical properties of cyclodextrin polymer (poly-CD)/azobenzene-modified polyacrylic acid (PAA-Azo) binary composite hydrogels have been designed and prepared. The prepared hydrogels were subjected to a variety of characterizations, including scanning electron microscopy, ultraviolet spectroscopy, circular dichroism spectroscopy, infrared spectroscopy, rheological properties, and specific surface area tests. It was found that the obtained hydrogels have the cross-linked three-dimensional porous network nanostructures, and the formed composite poly-CD/PAA-Azo hydrogel can basically be shear thinned and have good recovery performance. A process of gel-sol transition can occur when the gel has a stimulatory response under UV light irradiation. In addition, such excellent properties of hydrogels exhibit different mechanisms in the adsorption of organic molecules that are harmful to the environment, such as bisphenol A (BPA) and methylene blue (MB). The polymeric hydrogel serves as novel adsorbent agents to adsorb BPA via host-guest interaction and anchor MB via electrostatic interaction and hydrogen bonding.