Thionyl Chloride Corrodes Hexagonal Boron Nitride to Generate Reactive Functional Groups.

Two-dimensional hexagonal boron nitride (h-BN) has received much attention owing to its unique properties and wide range of applications. However, the lack of sufficient active functional groups on the surface coupled with the extremely stable structure restricts the wide application of h-BN. We find that thionyl chloride can corrode commercially available h-BN and generate many through-holes in the thickness direction. Both X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) show that the corroded h-BN contains reactive hydroxyl and a lot of amino groups. The corrosion mechanism is proposed and we conclude that H+ and OH- will affect the defect structure of the corroded h-BN by affecting the generation of boric acid. The thionyl chloride corroded h-BN could improve the thermal conductivity and DC breakdown strength of the composites because of the improved interface. This novel method about corroding h-BN through thionyl chloride is promising for the modification research of h-BN due to its simplicity and efficiency.

BMP2/7 heterodimer enhances osteogenic differentiation of rat BMSCs via ERK signaling compared with respective homodimers.

Bone morphogenetic protein (BMP)2/7 heterodimer shows greater efficacy in enhancing bone regeneration. However, the precise mechanism and the role of mitogen-activated protein kinase (MAPK) signaling network in BMP2/7-driven osteogenesis remain ambiguous. In this study, we evaluated the effects of BMP2/7 heterodimers on osteoblastic differentiation in rat bone marrow mesenchymal stem cells (BMSCs), with the aim to elaborate how MAPKs might be involved in this cellular process by treatment of rat BMSCs with BMP2/-7 with a special signal-pathway inhibitor. We found that BMP2/7 heterodimer induced a much stronger osteogenic response in rat BMSCs compared with either homodimer. Most interestingly, extracellular signal-regulated kinase (ERK) demonstrated a highly sustained phosphorylation and activation in the BMP2/7 heterodimer treatment groups, and inhibition of ERK cascades using U0126 special inhibitor that significantly reduced the activity of ALP and calcium mineralization to a substantial degree in rat BMSCs treated with BMP2/7 heterodimers. Collectively, we demonstrate that BMP2/7 heterodimer shows a potent ability to stimulate osteogenesis in rat BMSCs. The activated ERK signaling pathway involved in this process may contribute partially to an increased osteogenic potency of heterodimeric BMP2/7 growth factors.

Synthesis and Photoluminescence of Red to Near-Infrared-Emitting CdTe( x) Se(1−x) /CdZnS Core/Shell Quantum Dots.

Red to near-infrared (NIR)-emitting ternary-alloyed CdTe (x) Se(1−x) (x = 0­0.3) quantum dots (QDs) with tetrapod and dot morphologies have been synthesized by a facile method using oleic acid (OA) as single capping agent. The controlled dot-shaped and tetrapod-shaped CdTe( x) Se(1−x) QDs can be successfully obtained by adjusting the content of Te element. It is clear that CdTe (x) Se(1−x) QDs display the tunable emission peaks from the visible light (613.4 nm) to the NIR range (791.6 nm). With an inorganic CdZnS shell coated on the surface of CdTe(0.1)Se(0.9) cores, the stability and PL efficiency of the resulting core/shell QDs can be improved dramatically, accompanied with the red-shift of emission peaks to longer wavelength (795.6 nm). Peculiarly, a large blue shift of emission spectrum of CdTe(0.3)Se(0.7)/CdZnS core/shell QDs is observed, which is mainly ascribed to the shrink of the size of QDs by the fracture of tetrapod arms.

Growth of CdS Nanorods and Deposition of Silver Nanoparticles.

Systematic investigations have been done to deposit silver nanoparticles on seeded CdS nanorods. The CdS nanorods were synthesized by using CdS nanocrystals as seeds being indexed to the cubic structure (zinc-blende) and tetradecylphosphonic acid as surfactants to enable preferential growth on the reactive {001} facets. Ostwald ripening process occurred during the growth of CdS nanorods. Ag/CdS heterostructures were obtained through a facile method in which oleylamine was employed as reducing agents under an elevated temperature. Exposing CdS nanorods to Ag+ ions resulted in Ag domains depositing on the tips of the nanorods or defected sites embedding in the nanorod surfaces. Ag domains formed separate nuclei and grew quickly at a high concentration of AgNO3 solution. We further focused on discussing the morphology formation mechanism and optical properties of the heterostructures and the nanorods. The as-synthesized Ag/CdS heterostructures can facilitate charge separation at the metal-semiconductor interface. Herein, it opens up an application possibility of enhancing photocatalytic processes and other devices.

Hydrothermal synthesis of high-quality thiol-stabilized CdTe(x)Se(1-x) alloyed quantum dots.

Alloyed semiconductor quantum dots (QDs) enriched the synthetic routes for engineering materials with unique structural and optical properties. High-quality thiol-stabilized CdTe(x)Se(1-x) alloyed QDs were synthesized through a facile and economic hydrothermal method at 120 °C, a relatively low temperature. These water-soluble QDs were prepared using different capping agents including 3-mercaptopropionic acid (MPA) and L-cysteine (L-Cys). The photoluminescence (PL) intensity and stability of L-Cys-capped CdTe(x)Se(1-x) QDs were found to be higher than that of MPA-stabilized ones. The molar ratios of Se-to-Te upon preparation were adjusted for investigating the effect of composition on the properties of the resulting QDs. We also investigated the effect of the pH value of the reaction solution on the growth kinetics of the alloyed CdTe(x)Se(1-x) QDs. The resulting CdTe(x)Se(1-x) QDs were characterized by UV-vis absorbance and PL spectroscopy, powder X-ray diffraction, and transmission electron microscopy. Being coated with a CdS inorganic shell, the PL intensity and stability of the CdTe(x)Se(1-x)/CdS core-shell QDs were drastically enhanced, accompanied by the red-shift of the PL peak wavelength. Owing to the unique optical properties, the QDs hold great potential for application and have to be further exploited.

Synthesis of near-infrared-emitting CdTeSe and CdZnTeSe quantum dots.

We exploited the synthesis of near-infrared (NIR) emitting ternary-alloyed CdTeSe and quaternary-alloyed CdZnTeSe quantum dots (QDs) with rod and tetrapod morphologies, which have tunable emission in the NIR electromagnetic spectrum. The morphologies of the QDs depended strongly on their growth kinetics, probably due to the coordinating ligands used in the preparation. Using oleic acid, stearic acid and hexadecylamine as ligands and keeping the same reaction parameters, QDs with tetrapod and rod morphologies were created. Not only had the capping ligands influenced the morphologies of QDs, but also they influenced the optical properties of QDs. The molar ratios of Cd/Zn and Te/Se upon preparation were adjusted for investigating the effect of composition on the properties of resulting QDs. By varying the composition of QDs, the photoluminescence (PL) wavelength of QDs was tuned from 650 nm to 800 nm. To enhance PL efficiency and stability, QDs were coated with a CdZnS shell. As NIR PL has numerous advantages in biological imaging detection, these QDs hold great potential for application.

Polyphosphoric acid-promoted one-pot synthesis and neuroprotective effects of flavanones against NMDA-induced injury in PC12 cells.

We report herein an efficient polyphosphoric acid (PPA) promoted one-pot protocol for the synthesis of flavanone derivatives from 2-hydroxyacetophenones and benzaldehydes. A variety of flavanones were produced in moderate to excellent yields and evaluated for their neuroprotective effects against N-methyl-d-aspartate (NMDA)-induced excitotoxicity in PC12 cells. Derivatives bearing electron-donating groups exhibited better neuroprotective activity. Compound 3m demonstrated the best protective potency and reversed the intracellular calcium (Ca2+) influx caused by NMDA, suggesting that flavanones protected the PC12 cells against NMDA-induced neurotoxicity via inhibition of Ca2+ overload.

The Pathogenic Effects of Fusobacterium nucleatum on the Proliferation, Osteogenic Differentiation, and Transcriptome of Osteoblasts.

As one of the most common oral diseases, periodontitis is closely correlated with tooth loss in middle-aged and elderly people. Fusobacterium nucleatum (F. nucleatum) contributes to periodontitis, but the evidence in alveolar bone loss is still unclear. In this study, cytological experiments and transcriptome analyses were performed to characterize the biological process abnormalities and the molecular changes of F. nucleatum-stimulated osteoblasts. F. nucleatum could inhibit cell proliferation, promote cell apoptosis, and elevate pro-inflammatory cytokine production of osteoblasts, and it also inhibited osteoblast differentiation and mineralized nodule formation and decreased the expression of osteogenetic genes and proteins. Whole-transcriptome analyses identified a total of 235 transcripts that were differentially expressed in all six time points, most of which were inflammation-related genes. The genes, Ccl2, Ccl20, Csf1, Cx3cl1, Cxcl1, Cxcl3, Il6, Birc3, Map3k8, Nos2, Nfkb2, Tnfrsf1b, and Vcam1, played core roles in a PPI network, and interacted closely with other ones in the infection. In addition, 133 osteogenesis-related differential expression genes (DEGs) were time-serially dynamically changed in a short time-series expression miner (STEM) analysis, which were enriched in multiple cancer-related pathways. The core dynamic DEGs (Mnda, Cyp1b1, Comp, Phex, Mmp3, Tnfrsf1b, Fbln5, and Nfkb2) had been reported to be closely related to the development and metastasis in tumor and cancer progress. This study is the first to evaluate the long-term interaction of F. nucleatum on osteoblasts, which might increase the risk of cell carcinogenesis of normal osteoblasts, and provides new insight into the pathogenesis of bacterial-induced bone destruction.

Osteogenic Differentiation Capacity of In Vitro Cultured Human Skeletal Muscle for Expedited Bone Tissue Engineering.

Expedited bone tissue engineering employs the biological stimuli to harness the intrinsic regenerative potential of skeletal muscle to trigger the reparative process in situ to improve or replace biological functions. When genetically modified with adenovirus mediated BMP2 gene transfer, muscle biopsies from animals have demonstrated success in regenerating bone within rat bony defects. However, it is uncertain whether the human adult skeletal muscle displays an osteogenic potential in vitro when a suitable biological trigger is applied. In present study, human skeletal muscle cultured in a standard osteogenic medium supplemented with dexamethasone demonstrated significant increase in alkaline phosphatase activity approximately 24-fold over control at 2-week time point. More interestingly, measurement of mRNA levels revealed the dramatic results for osteoblast transcripts of alkaline phosphatase, bone sialoproteins, transcription factor CBFA1, collagen type I, and osteocalcin. Calcified mineral deposits were demonstrated on superficial layers of muscle discs after an extended 8-week osteogenic induction. Taken together, these are the first data supporting human skeletal muscle tissue as a promising potential target for expedited bone regeneration, which of the technologies is a valuable method for tissue repair, being not only effective but also inexpensive and clinically expeditious.

CdS Nanowires with Large Aspect Ratio and Their Composite with CuS and Au Nanoparticles.

We prepared CdS nanowires with small diameter (2.9 nm) and a large aspect ratio (more than 60) via a seed growth method. Wurtzite CdS seeds were firstly obtained via an organic synthesis at 310 degrees C. CdS nanowires with a single-crystal wurtzite structure and grown along the [0001] (c-axis) were further created through controlling the growth process. The injection of precursors plays an important role for getting a large respect ratio. The average size of the seeds is 2.9 nm. The growth along c-axis occurred during the preparation of the nanowires. The diameter of 2.9 nm remained unchanged within short reaction time. The heterostructures of the nanowires were fabricated by depositing CuS and Au nanoparticles (NPs). CuS monomers firstly deposited on the top of the nanowire and then to form a CuS shell on the top. In contrast, Au NPs deposited firstly on the top part of the nanowire. With increasing time or the amount of precursors, small Au NPs on side part of the nanowire was observed. The possible deposition kinetics was discussed. Because of homogeneous and uniform morphology, the heterostructures may be utilizable for applications.

MiRNA-139 regulates oral cancer Tca8113 cells apoptosis through Akt signaling pathway.

Oral cancer threats people's life and health seriously. Traditional treatment (surgery, radiotherapy, chemotherapy and traditional Chinese medicine treatment) is lack of pertinence that affects curative effect and prognosis. Therefore, it is necessary to explore the specific targets for oral cancer treatment. MiRNA-139 was transfected into oral cancer Tca8113 cells. Methyl thiazolyl tetrazolium (MTT) was applied to test cell proliferation. Flow cytometry was used to detect oral cancer Tca8113 cells apoptosis. miR-139 significantly inhibits oral cancer Tca8113 cells proliferation and induces cell apoptosis. SH-5 obviously weakened the cell apoptosis caused by miR-139. miR-139 could induce Tca8113 cell apoptosis through Akt signaling pathway. It may develop a more effective method for oral cancer treatment by this target.