α1-Antitrypsin Binds to the Glucocorticoid Receptor with Anti-Inflammatory and Antimycobacterial Significance in Macrophages.

α1-Antitrypsin (AAT), a serine protease inhibitor, is the third most abundant protein in plasma. Although the best-known function of AAT is irreversible inhibition of elastase, AAT is an acute-phase reactant and is increasingly recognized to have a panoply of other functions, including as an anti-inflammatory mediator and a host-protective molecule against various pathogens. Although a canonical receptor for AAT has not been identified, AAT can be internalized into the cytoplasm and is known to affect gene regulation. Because AAT has anti-inflammatory properties, we examined whether AAT binds the cytoplasmic glucocorticoid receptor (GR) in human macrophages. We report the finding that AAT binds to GR using several approaches, including coimmunoprecipitation, mass spectrometry, and microscale thermophoresis. We also performed in silico molecular modeling and found that binding between AAT and GR has a plausible stereochemical basis. The significance of this interaction in macrophages is evinced by AAT inhibition of LPS-induced NF-κB activation and IL-8 production as well as AAT induction of angiopoietin-like 4 protein, which are, in part, dependent on GR. Furthermore, this AAT-GR interaction contributes to a host-protective role against mycobacteria in macrophages. In summary, this study identifies a new mechanism for the gene regulation, anti-inflammatory, and host-defense properties of AAT.

A method to improve positioning of denture teeth on denture bases for CAD-CAM complete dentures: A dental technique.

In the digital workflow of complete denture fabrication, one solution for producing computer-aided design and computer-aided manufacturing dentures has been to mill the denture teeth and base separately and then bond them together. The correct bonding of the denture teeth and base is important to reproduce the designed occlusion in the definitive prosthesis. A novel technique is described to assist in the accurate positioning of denture teeth on the denture base by constructing auxiliary positioning slots on the denture base and auxiliary positioning posts on the denture teeth. The technique can assist in accurately assembling CAD-CAM milled complete dentures and may shorten chairside time by reducing clinical occlusal adjustment.

128-pixel arrays of 4H-SiC UV APD with dual-frequency PECVD SiNx passivation.

In this paper, high-performance 1×128 linear arrays of 4H-SiC ultraviolet (UV) avalanche photodiode (APD) with dual-frequency plasma enhanced chemical vapor deposition (PECVD) passivation are demonstrated for the first time. The results show that SiNx dielectric deposited by dual-frequency PECVD can effectively reduce the leakage current at high bias voltages. Due to the improved 4H-SiC epi-layer material and SiNx passivation, the fabricated 22 mm-long 1×128 4H-SiC APD linear arrays exhibit an excellent performance with a high pixel yield of 100% and a small breakdown voltage variation of 0.2 V, which is the best result ever reported. At room temperature, the pixels have a gain of over 105 and a maximum quantum efficiency of 53.5% @ 285 nm. Besides the high uniformity of breakdown voltage for 128 pixels, the dark currents at 95% of breakdown voltage are all below 1 nA.

Ultra-extraordinary optical transmission induced by cascade coupling of surface plasmon polaritons in composite graphene-dielectric stack.

Surface plasmon polaritons have been extensively studied owing to the promising characteristics of near fields. In this paper, the cascade coupling of graphene surface plasmon polaritons (GSPPs) originating from cascading excitation and multiple coupling within a composite graphene-dielectric stack is presented. GSPPs confined to graphene layers are distributed in the entire stack as waveguide modes. Owing to the near-field enhancement effect and large lifetime of the GSPPs, the terahertz wave-graphene interaction is significantly enhanced, which induces an ultra-extraordinary optical transmission (UEOT) together with the reported negative dynamic conductivity of graphene. Furthermore, owing to cascade coupling, the UEOT exhibits considerable transmission enhancement, up to three orders of magnitude, and frequency and angle selections. Based on the key characteristics of cascade coupling, the mode density and coupling intensity of GSPPs, the dependences of the number of graphene layers in the stack, the thickness of dielectric buffers, and the effective Fermi levels of the graphene on the UEOT are also analyzed. The proposed mechanism can pave the way for using layered plasmonic materials in electric devices, such as amplifiers, sensors, detectors, and modulators.

High-Speed Efficient Terahertz Modulation Based on Tunable Collective-Individual State Conversion within an Active 3 nm Two-Dimensional Electron Gas Metasurface.

Terahertz (THz) modulators are always realized by dynamically manipulating the conversion between different resonant modes within a single unit cell of an active metasurface. In this Letter, to achieve real high-speed THz modulation, we present a staggered netlike two-dimensional electron gas (2DEG) nanostructure composite metasurface that has two states: a collective state with massive surface resonant characteristics and an individual state with meta-atom resonant characteristics. By controlling the electron transport of the nanoscale 2DEG with an electrical grid, collective-individual state conversion can be realized in this composite metasurface. Unlike traditional resonant mode conversion confined in meta-units, this state conversion enables the resonant modes to be flexibly distributed throughout the metasurface, leading to a frequency shift of nearly 99% in both the simulated and experimental transmission spectra. Moreover, such a mechanism can effectively suppress parasitic modes and significantly reduce the capacitance of the metasurface. Thereby, this composite metasurface can efficiently control the transmission characteristics of THz waves with high-speed modulations. As a result, 93% modulation depth is observed in the static experiment and modulated sinusoidal signals up to 3 GHz are achieved in the dynamic experiment, while the -3 dB bandwidth can reach up to 1 GHz. This tunable collective-individual state conversion may have great application potential in wireless communication and coded imaging.

Three-Dimensionally-Printed Polyether-Ether-Ketone Implant with a Cross-Linked Structure and Acid-Etched Microporous Surface Promotes Integration with Soft Tissue.

Polyether-ether-ketone (peek) is one of the most common materials used for load-bearing orthopedic devices owing to its radiolucency and favorable mechanical properties. However, current smooth-surfaced peek implants can lead to fibrous capsule formation. To overcome this issue, here, peek specimens with well-defined internal cross-linked structures (macropore diameters of 1.0-2.0 mm) were fabricated using a three-dimensional (3D) printer, and an acid-etched microporous surface was achieved using injection-molding technology. The cell adhesion properties of smooth and microporous peek specimens was compared in vitro through a scanning electron microscope (SEM), and the soft tissue responses to the both microporous and cross-linked structure of different groups were determined in vivo using a New Zealand white rabbit model, and examined through histologic staining and separating test. The results showed that the acid-etched microporous surface promoted human skin fibroblasts (HSF) adherence, while internal cross-linked structure improved the ability of the peek specimen to form a mechanical combination with soft tissue, especially with the 1.5 mm porous specimen. The peek specimens with both the internal cross-linked structure and external acid-etched microporous surface could effectively promote the close integration of soft tissue and prevent formation of fibrous capsules, demonstrating the potential for clinical application in surgical repair.

High-Contrast SEM Imaging of Supported Few-Layer Graphene for Differentiating Distinct Layers and Resolving Fine Features: There is Plenty of Room at the Bottom.

For supported graphene, reliable differentiation and clear visualization of distinct graphene layers and fine features such as wrinkles are essential for revealing the structure-property relationships for graphene and graphene-based devices. Scanning electron microscopy (SEM) has been frequently used for this purpose where high-quality image contrast is critical. However, it is surprising that the effect of key imaging parameters on the image contrast has been seriously undermined by the graphene community. Here, superior image contrast of secondary electron (SE) images for few-layer graphene supported on SiC and SiO2 /Si is realized through simultaneously tuning two key parameters-acceleration voltage (Vacc ) and working distance (WD). The overlooked role of WD in characterizing graphene is highlighted and clearly demonstrated. A unified model of Vacc and WD dependence of three types of SE collected by the standard side-attached Everhart-Thornley (E-T) SE detector is conceptually developed for mechanistically understanding the improved mass thickness contrast for supported few-layer graphene. The findings reported here will have important implications for effective characterizations of atomically thick 2D materials and devices.

Endothelial progenitor cells improve the therapeutic effect of mesenchymal stem cell sheets on irradiated bone defect repair in a rat model.

BACKGROUND: The reconstruction of bone defects is often impaired by radiotherapy since bone quality is compromised by radiation. This study aims to investigate the therapeutic efficacy of the composite cell sheets-bone marrow mesenchymal stem cell (BMSC) sheets cocultured with endothelial progenitor cells (EPCs)-in the healing of irradiated bone defects and the biological effects of EPCs on the osteogenic properties of BMSC sheets. METHODS: BMSCs and EPCs were isolated from rat bone marrow. BMSCs were used to form cell sheets by the vitamin C inducing method. EPCs were seeded on BMSC sheets to make EPCs-BMSC sheets. Osteogenesis of EPCs-BMSC sheets and BMSC sheets were tested. In vitro osteogenesis tests included ALP, Alizarin Red S, Sirius Red staining, qRT-PCR and Western blot analysis after 3 and 7 days of osteogenic incubation. Subcutaneous osteogenesis was tested by H&E staining and immunohistochemical staining 8 weeks after transplantation. EPCs-BMSC sheets and BMSC sheets were used in the 3 mm defects of non-irradiated and irradiated rat tibias. Micro-CT and histological analysis were used to test the healing of bone defects 4 and 8 weeks after transplantation. RESULTS: EPCs-BMSC sheets showed enhanced osteogenic differentiation in vitro with increased expression of osteoblastic markers and osteogenesis related staining compared with BMSC sheets. In subcutaneous osteogenesis test, EPCs-BMSC sheets formed larger areas of new bone and blood vessels. The EPCs-BMSC group had the highest volume of newly formed bone in the defect area of irradiated tibias. CONCLUSIONS: EPCs improved the osteogenic differentiation of BMSC Sheets and enhanced the ectopic bone formation. EPCs-BMSC sheets promoted bone healing in irradiated rat tibias. EPCs-BMSC sheets are potentially useful in the reconstruction of bone defect after radiotherapy.

Volatile organic compounds discrimination based on dual mode detection.

We report on a volatile organic compound (VOC) sensor that can provide concentration-independent signals toward target gases. The device is based on a dual-mode detection mechanism that can simultaneously record the mechanical (resonant frequency, f r) and electrical (current, I) responses of the same gas adsorption event. The two independent signals form a unique I-f r trace for each target VOC as the concentration varies. The mechanical response (frequency shift, Δf r) resulting from mass load on the device is directly related to the amount of surface adsorptions, while the electrical response (current variation, ΔI) is associated with charge transfer across the sensing interface and changes in carrier mobility. The two responses resulting from independent physical processes reflect intrinsic physical properties of each target gas. The ΔI-Δf r trace combined with the concentration dependent frequency (or current) signals can therefore be used to achieve target both recognition and quantification. The dual-mode device is designed and fabricated using standard complementary metal oxide semiconductor (CMOS) compatible processes. It exhibits consistent and stable performance in our tests with six different VOCs including ethanol, methanol, acetone, formaldehyde, benzene and hexane.

The effect of air stable n-doping through mild plasma on the mechanical property of WSe2 layers.

Two-dimensional transition metal dichalcogenides have been widely applied to electronic and optoelectronic device owing to their remarkable material properties. Many studies present the platform for regulating the contact resistance via various doping schemes. Here, we report the alteration of mechanical properties of few top layers of the WSe2 flake which are processed by air stable n-doping of N2O with a constant gas flow through mild plasma and present better manufacturability and friability. The single-line nanoscratching experiments on the WSe2 flakes with different doping time reveal that the manufacturable depths are positively correlated with the exposure time at a certain range and tend to be stable afterwards. Meanwhile, material characterization by x-ray photoelectron spectroscopy confirms that the alteration of mechanical properties is owing to the creation of Se vacancies and substitution of O atoms, which breaks the primary molecular structure of the WSe2 flakes. The synchronous Kelvin probe force microscopy and topography results of ROI nanoscratching of a stepped WSe2 sample confirmed that the depth of the degenerate doping is five layers, which was consistent with the single-line scratching experiments. Our results reveal the interrelationship of the mechanical property, chemical bonds and work function changes of the doped WSe2 flakes.

Advanced biomaterials and their potential applications in the treatment of periodontal disease.

Periodontal disease is considered as a widespread infectious disease and the most common cause of tooth loss in adults. Attempts for developing periodontal disease treatment strategies, including drug delivery and regeneration approaches, provide a useful experimental model for the evaluation of future periodontal therapies. Recently, emerging advanced biomaterials including hydrogels, films, micro/nanofibers and particles, hold great potential to be utilized as cell/drug carriers for local drug delivery and biomimetic scaffolds for future regeneration therapies. In this review, first, we describe the pathogenesis of periodontal disease, including plaque formation, immune response and inflammatory reactions caused by bacteria. Second, periodontal therapy and an overview of current biomaterials in periodontal regenerative medicine have been discussed. Third, the roles of state-of-the-art biomaterials, including hydrogels, films, micro/nanofibers and micro/nanoparticles, developed for periodontal disease treatment and periodontal tissue regeneration, and their fabrication methods, have been presented. Finally, biological properties, including biocompatibility, biodegradability and immunogenicity of the biomaterials, together with their current applications strategies are given. Conclusive remarks and future perspectives for such advanced biomaterials are discussed.

Enhanced non-volatile resistive switching in suspended single-crystalline ZnO nanowire with controllable multiple states.

Resistive switching nanostructures are a promising candidate for next-generation non-volatile memories. In this report, we investigate the switching behaviors of single-crystalline ZnO nanowires suspended in air. They exhibit significantly higher current density, lower switching voltage, and more pronounced multiple conductance states compared to nanowires in direct contact with substrate. We attribute the effect to enhanced Joule heating efficiency, reduced surface scattering, and more significantly, the positive feedback established between the current density and local temperature in the suspended nanowires. The proposed mechanism has been quantitatively examined by finite element simulations. We have also demonstrated an innovative approach to initiating the current-temperature mutual enhancement through illumination by ultraviolet light, which further confirmed our hypothesis and enabled even greater enhancement. Our work provides further insight into the resistive switching mechanism of single-crystalline one-dimensional nanostructures, and suggests an effective means of performance enhancement and device optimization.

Gbps terahertz external modulator based on a composite metamaterial with a double-channel heterostructure.

The past few decades have witnessed a substantial increase in terahertz (THz) research. Utilizing THz waves to transmit communication and imaging data has created a high demand for phase and amplitude modulation. However, current active THz devices, including modulators and switches, still cannot meet THz system demands. Double-channel heterostructures, an alternative semiconductor system, can support nanoscale two-dimensional electron gases (2DEGs) with high carrier concentration and mobility and provide a new way to develop active THz devices. In this Letter, we present a composite metamaterial structure that combines an equivalent collective dipolar array with a double-channel heterostructure to obtain an effective, ultrafast, and all-electronic grid-controlled THz modulator. Electrical control allows for resonant mode conversion between two different dipolar resonances in the active device, which significantly improves the modulation speed and depth. This THz modulator is the first to achieve a 1 GHz modulation speed and 85% modulation depth during real-time dynamic tests. Moreover, a 1.19 rad phase shift was realized. A wireless free-space-modulation THz communication system based on this external THz modulator was tested using 0.2 Gbps eye patterns. Therefore, this active composite metamaterial modulator provides a basis for the development of effective and ultrafast dynamic devices for THz wireless communication and imaging systems.

A quick, easy, cheap, effective, rugged, and safe sample pretreatment and liquid chromatography with tandem mass spectrometry method for the simultaneous quantification of 33 mycotoxins in Lentinula edodes.

Lentinula edodes, one of the most cultivated edible fungi in the world, are usually neglected for mycotoxins contamination due to the initial thinking of its resistance to mycotoxingenic molds. In the present study, a sensitive and reliable liquid chromatography with tandem mass spectrometry method was developed for the simultaneous quantification of 33 mycotoxins in L. edodes. Targeted mycotoxins were extracted using a quick, easy, cheap, effective, rugged, and safe procedure without any further clean-up step, and analyzed by liquid chromatography with tandem mass spectrometry on an Agilent Poroshell 120 EC-C18 column (100 × 3 mm, 2.7 µm) with a linear gradient elution program using water containing 5 mM ammonium acetate and methanol as the mobile phase. After validation by determining linearity (R(2) > 0.99), sensitivity (LOQ ≤ 20 ng/kg), recovery (73.6-117.9%), and precision (0.8-19.5%), the established method has been successfully applied to reveal the contamination states of various mycotoxins in L. edodes. Among the 30 tested samples, 22 were contaminated by various mycotoxins with the concentration levels ranging from 3.3-28,850.7 µg/kg, predicting that the edible fungus could be infected by the mycotoxins-producing fungi. To the best of our knowledge, this is the first report about real mycotoxins contamination in L. edodes.

Low-Temperature Thermal Transport Characteristics in Epitaxial Bilayer Graphene Microbridges.

In this paper, we present a study of the thermal transport of epitaxial bilayer graphene microbridges. The thermal conductance of three graphene microbridges with different lengths was measured at different temperatures using Johnson noise thermometry. We find that with the decrease of the temperature, the thermal transport in the graphene microbridges switches from electron-phonon coupling to electron diffusion, and the switching temperature is dependent on the length of the microbridge, which is in good agreement with the simulation based on a distributed hot-spot model. Moreover, the electron-phonon thermal conductance has a temperature power law of T3 as predicted for pristine graphene and the electron-phonon coupling coefficient σep is found to be approximately 0.18 W/(m2 K4), corresponding to a deformation potential D of 55 eV. In addition, the electron diffusion in the graphene microbridges adheres to the Wiedemann-Franz law, requiring no corrections to the Lorentz number.

Treatment of malignant triton tumor in zygomatic region.

Malignant triton tumor (MTT) is extremely rare and supposed to be highly aggressive because of high propensity for local recurrence and metastasis. To date, only about 170 cases were reported in various body locations including trunks, maxillary sinus, neck, extremities, retroperitoneal, and so on. We present a case of MTT in the zygoma with good outcome. A 27-year-old male patient with progressive swelling and pain in the right zygoma was proved to have an MTT by biopsy. Radical resection accompanying postoperative radiotherapy was adopted, and then the soft and hard tissue defects were repaired by prosthesis. The patient recovered well and was satisfied with the facial contour. At 45-month follow-up, there was no recurrence or metastasis that occurred. According to literature review, one third of MTTs appeared in the head and neck regions and seem to have a better prognosis. Radical resection is the most important remedy, and adjuvant radiotherapy could be helpful. With early finding and effective treatments, satisfactory outcome could be achieved.

Finite Element Study of PEEK Materials Applied in Post-Retained Restorations.

BACKGROUND: This study aimed to investigate the biomechanical behaviors of polyether ether ketone (PEEK) and traditional materials (titanium and fiber) when used to restore tooth defects in the form of prefabricated post or customized post via computational modelling. METHODS: First, the prototype of natural tooth, and the prototypes of prefabricated post and customized post were established, respectively, whilst the residual root was restored with dentin ferrule using reverse engineering methods. Then, the stress and strain of CFR-PEEK (PEEK reinforced by 30% carbon fiber) and pure PEEK (PEEK without any reprocessing) post were compared with those made in traditional materials using the three-dimensional finite element method. RESULTS: From the stress point of view, compared with metal and fiber posts, CFR-PEEK and pure PEEK prefabricated post both demonstrated reduced post-core interface stress, post stress, post-root cement stress and root cement stress; moreover, CFR-PEEK and pure PEEK customized post demonstrated reduced post stress, post-root cement stress and root cement stress, while the strain of CFR-PEEK post was the closest to that of dentin. CONCLUSIONS: Compared with the traditional posts, both the CFR-PEEK and pure PEEK posts could reduce the risk of debonding and vertical root fracture, whether they were used as prefabricated posts or customized posts, but the biomechanical behavior of carbon fiber-reinforced CFR-PEEK restorations was the closest to dentin, no matter if they were used as prefabricated post or customized post. Therefore, the CFR-PEEK post could be more suitable to restore massive tooth defects. Pure PEEK needs filler reinforcement to be used for post-retained restoration.

Chitosan/Hyaluronic Acid/MicroRNA-21 Nanoparticle-Coated Smooth Titanium Surfaces Promote the Functionality of Human Gingival Fibroblasts.

Purpose: Forming a compact biological seal between the gingiva and the implant interface around the percutaneous parts of an implant is one of the key issues in preventing peri-implantitis. Methods: In this study, since microRNA-21 (miR-21) has been approved to promote fibroblast proliferation and collagen formation in skin fibrosis, we prepared miR-21-loaded chitosan (CS)/tripolyphosphate (TPP)/hyaluronic acid (HA) nanoparticles (CTH NPs) and cross-linked them to smooth Ti surfaces with 0.2% gel solution for reverse transfection, after which isolated human gingival fibroblasts were cultured on the miR-21-functionalized Ti substrates. Results: An optimal CS:TPP:HA ratio (1:0.15:0.1) and N/P ratio (20:1) were chosen to produce appropriate nanoparticles. Finally, the CTH/miR-21 nanoparticle-coated smooth Ti surfaces demonstrated increased fibroblast adhesion, proliferation and expression of extracellular matrix-related genes along with similar cytotoxicity and cell spreading on the miR-21-functionalized Ti surface and the unmodified smooth Ti surface. Conclusion: The chitosan-based nanoparticles might be an efficient nonviral miRNA vector to form a stable biological seal in percutaneous areas of Ti for clinical use.

Reconstruction of mandibular defects using a custom-made titanium tray in combination with autologous cancellous bone.

PURPOSE: To esthetically and functionally restore a 40-mm canine mandibular discontinuity defect using a custom-made titanium bone-grafting tray packed with autologous iliac bone. MATERIALS AND METHODS: Individualized titanium bone-grafting trays were made using a reverse engineering, computer-aided design, and rapid prototyping technique. A 40-mm discontinuity defect in the right mandibular body was created in 10 hybrid dogs. The defect was restored immediately using the tray that was densely packed with autologous cancellous iliac particles and covered with trimmed iliac chips. Sequential radionuclide bone imaging was performed postoperatively at 2, 4, 8, 12, and 24 weeks. The ratio of activity between the grafted mandible and the contralateral native mandible on each transaxial slice was calculated. The mean activity ratio was analyzed at each time point to evaluate the bone metabolism and reconstitution of the grafts. The subjects were sacrificed at 4, 12, and 24 weeks after grafting. The specimens were evaluated by postmortem gross dissection, biomechanical testing, 3-dimensional microcomputed tomographic scanning, and histologic examination. RESULTS: All the subjects tolerated the grafting operation well. Over an observation period of 24 weeks, tray extrusion occurred in 3 of the 10 subjects. Bony continuities were reconstructed in 9 of the 10 subjects. Radionuclide bone imaging revealed that the tracer uptake increased in the grafted mandible, and the radionuclide ratio between the graft and the native mandible decreased with time. Gross evaluation, microcomputed tomographic examination, biomechanical testing, and histologic examination demonstrated corticalization of the grafts. CONCLUSIONS: The use of a customized technique using reverse engineering, computer-aided design, and rapid prototyping tray containing autologous cancellous bone is a potentially powerful grafting technique for the reconstruction of mandibular discontinuity defects.

Surgical treatment of a giant neurofibroma.

Neurofibromatosis type 1, an autosomal dominant inherited disease, presents pathologic symptoms of multiple systems, including neurofibromatosis, skeletal dysplasia, café-au-lait spots in skins, and so on. A 45-year-old man with neurofibromatosis type 1 was reported in this article. The patient presented a giant neurofibroma in his head and neck, dysplasia of skull, facial bones and spinal columns, and multiple café-au-lait spots in systematic skins. Satisfactory curative effects were obtained in this case after tumor resection and prosthesis implantation.