Organic-based pollutants are extensively released from various industries and they potentially harm the environment and human health. Photocatalysis is regarded as one of the most promising techniques for removal of organic contaminants from wastewater. Therefore, in this study, iron oxide-based nanocomposites were synthesized by an emerging green and sustainable method using Ethiopian endemic plant extract, Echinops kebericho M. as a capping and stabilizing agent. The phytoextract-assisted synthesized nanoparticles (NPs) α-Fe 2 O 3 and nanocomposites (NCs) α-Fe 2 O 3 /MgO calcinated at a temperature of 400°C were characterized and used for their photocatalytic activities toward gentian violet (GV) dye degradation using ultraviolet–visible spectroscopy (UV-vis) at optimized catalyst dose, initial GV concentration, pH, and time conditions. The X-ray diffraction (XRD) analysis result revealed that the mean crystal size of α-Fe 2 O 3 and α-Fe 2 O 3 /MgO is 11.2 and 15.4 nm, respectively. Characterization results of scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS) clearly showed the successful deposition of MgO on α-Fe 2 O 3 . The maximum degradation of GV, 96.2%, was observed by using α-Fe 2 O 3 /MgO after 60 min under visible light irradiation. Thus, synthesized NCs were shown to have better GV degradation efficiency in a shorter time as compared to the previously reported nanomaterials. The results revealed photocatalytic degradation using endemic plant extract-assisted synthesized NCs, α-Fe 2 O 3 /MgO, is considered a greener, simple, and more efficient method for the removal of organic dyes.
Magnetoplasmonic nanoparticles (Fe3O4@Au NPs) have been proven to be effective theranostic agents in genetic transmission and drug targeted delivery system as well as in photothermal treatment. Herein, two spiky magnetoplasmonic NPs with different branch lengths and numbers (short- and long-branched spiky Fe3O4@Au NPs) were specifically designed to determine theirs in vivo behaviors. The biocompatibility, biodistribution, and clearance of spiky Fe3O4@Au NPs were examined in mice. Organ distributions showed that intravenously administered spiky Fe3O4@Au NPs cumulated mainly in liver and spleen, and particle shape significantly affected their in vivo behaviors. The higher tendency in bioaccumulation of short-branched rather than long-branched spiky Fe3O4@Au NPs was observed in the spleen because long-branched spiky Fe3O4@Au NPs with a high aspect ratio were internalized more slowly than short-branched spiky Fe3O4@Au NPs. Serum biochemistry and transmission electron microscopy of ultrahistological structures indicated that spiky Fe3O4@Au NPs did not exhibit distinct toxicity in vivo and posed no potential risk of causing liver and kidney dysfunction. These findings lay the foundation for the design of future theragnostic agents.
One-dimensional hybrid nanostructures composed of a plasmonic gold nanowire core covered by a shell of magnetic oxide nanoparticles (Au@FexOy NWs) were synthesized by a one-pot solvothermal synthesis process. The effects of reaction temperature, time, reducing agent, and precursor as well as postsynthesis treatment were optimized to produce highly uniform NWs with a diameter of 226 ± 25 nm and a plasmonic core aspect ratio of 25 to 82. By exploiting the interaction of NWs with an external magnetic field, precise arrangements into highly periodic photonic structures were achieved, which can generate distinctive structural colors that are vividly iridescent and polarization-sensitive. Furthermore, a Bouligand-type chiral nematic film consisting of multistacked unidirectional layers of achiral NWs was fabricated using a modified layer-by-layer deposition method, which displays circular dichroism (CD) and chiral sensing capability. The addition of bovine serum albumin (BSA) as a model protein analyte induced a concentration-dependent wavelength shift of CD peaks. These intriguing properties of magnetoplasmonic anisotropic NWs and their self-assemblies could be consequently valuable for developing nature-inspired structural color imprints as well as solid-state chiral sensing devices.
Canal wall down (CWD) mastoidectomy is a surgical procedure that is essential to eradicate chronic ear diseases but results into bone defects due to the resulting mastoid cavity. This study investigated the ability of human tonsil-derived mesenchymal stem cells (hTMSCs) combined with a hydroxyapatite (HAp)-chitosan patch to promote osteogenesis in the treatment of postoperative temporal bone defects using an animal model. At 12 weeks postsurgery, the obliteration ratio and bone formation in the tympanic bulla of rats that were grafted with hTMSCs and a hydroxyapatite (HAp)-chitosan patch or not were compared using histopathological observation and computed tomography (CT) imaging. The group of rats that was administered the Patch group and the group of rats that was administered hTMSCs + Patch group both showed significantly remarkable obliteration ratios and bone formation compared with the Sham and hTMSCs groups. Moreover, the hTMSCs + Patch group showed bone formation in both the periphery and the central region of the tympanic bulla cavity, indicating prominently enhanced osteogenesis compared to the Patch group. Altogether, the results showed that combining hTMSCs with a HAp-chitosan patch accelerated osteogenesis for reconstruction of postoperative temporal bone defects. These findings demonstrate that the hTMSCs + Patch scaffolds are promising for treatment of the bone defects in the tissue engineering.
In this paper, we derive an optimal rate control algorithm for shape coding as defined in the forthcoming MPEG-4 international standard. The current MPEG-4 shape coding scheme consists of two steps: first, distortion is introduced by down and up scaling; then, context-based arithmetic encoding is applied. Since arithmetic coding is "lossless", the down up scaling step is considered as a virtual quantizer. We first formulate the buffer-constrained adaptive quantization problem for shape coding, and then propose an algorithm for the optimal solution under buffer constraints. Experimental results are given using an MPEG-4 shape codec.
VC-1 is now one of the three video coding standards for high definition DVD that include MPEG-2 and H.264. The coded is expected to be used in consumer electronic devices such as DVD and camcorders. The H.264 format has begun to see strong acceptance and is used in mobile devices such as iPod and mobile phones. While multi-format DVD players are expected to support the three high definition video coding formats, H.264 is expected to have broader support in devices and video download services. The need to move data among devices with different capabilities creates a need for transcoding. In this paper we present a P-frame transcoder for VC-1 to H.264 transcoding. The transcoder exploits the variable size transform used in VC-1 to select the variable block size for motion compensation in H.264. The transcoder reduces the complexity substantially without significant loss in quality.
Whitlockite (WH; Ca18Mg2(HPO4)2(PO4)12) is a calcium phosphate based ceramic that contains magnesium ions. As the second most abundant mineral in living bone, WH occupies 25-35 wt % of the inorganic portion of human bone. Compared to hydroxyapatite (HAp, Ca10(PO4)6(OH)2), WH possesses better mechanical properties, faster resorbability, and promotion behavior on the osteogenesis. In this article, we introduced a fabrication method of interconnected porous WH granules through vacuum filtration, followed by sintering treatment based on the thermal stability of WH synthesized using the tri-solvent system. This study presents a histological, radiological, and immunohistochemical evaluation of the bone healing potential of these WH granules in a 5 mm diameter calvarial bone defect in rats. The histological evaluation shows no inflammation or foreign body reaction in the WH group. The WH group displays newly formed bone at the same thickness as the original bone. On the contrary, bone formation is not observed in the nontreated (NT) group. Besides, immunohistochemistry (IHC) confirmed that WH granules promoted bone regeneration with the significantly higher expression of bone morphogenetic proteins-2 (BMP-2), alkaline phosphatase (ALP), osteopontin (OPN), and osteocalcin (OCN) compared to the NT group without the addition of exogenous cells or growth factors. These results suggest that WH has excellent potential for application in bone tissue regeneration.
Recognition of enantiomeric molecules is essential in pharmaceutical and biomedical applications. In this Article, a novel approach is introduced to monitor chiral molecules via a helical magnetic field (hB), where chiral-inactive magnetoplasmonic nanoparticles (MagPlas NPs, Ag@Fe3O4 core-shell NPs) are assembled into helical nanochain structures to be chiral-active. An in-house generator of hB-induced chiral NP assembly, that is, a plasmonic chirality enhancer (PCE), is newly fabricated to enhance the circular dichroism (CD) signals from chiral plasmonic interaction of the helical nanochain assembly with circularly polarized light, reaching a limit of detection (LOD) of 10-10 M, a 1000-fold enhancement as compared to that of conventional CD spectrometry. These enhancements were successfully observed from enantiomeric molecules, oligomers, polymers, and drugs. Computational simulation studies also proved that total chiroptical properties of helical plasmonic chains could be readily changed by modifying the chiral structure of the analytes. The proposed PCE has the potential to be used as an advanced tool for qualitative and quantitative recognition of chiral materials, enabling further application in pharmaceutical and biomedical sensing and imaging.
The second-harmonic generation (SHG) phenomenon, which readily supports the characteristic advantages of promising laser-based display systems, brings a new concept to advanced displays. Here, we demonstrate a laser projection display that utilizes the fabrication and design principles in individual micron-scale pixel arrays by depositing colloidal Se nanowires, a nonlinear optical nanomaterial for full-color light emission. Our system reveals the manufacturing process of planar light-emitting elements without the use of complex color segments, and the layout represents a full-color laser display with high-resolution pixels extracted from the combination of a pulsed femtosecond laser scanning process to access the frequency up-conversion technique based on a wavelength-tunable manner. The work presents attractive features for newly emerging multifunctional optical components composed of unique nanomaterials that can be applied for displays, bioimaging, and other optoelectronic devices.
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