Endoscope-Assisted Extracapsular Resection of Benign Parotid Tumors Via Temporal and Retroauricular Approach.

OBJECTIVE: To evaluate the feasibility of endoscope-assisted extracapsular resection of benign parotid tumors via temporal and retroauricular approach. MATERIALS AND METHODS: A total of 12 patients with parotid gland tumors had endoscope-assisted extracapsular resection performed via temporal and retroauricular approach (4 versus 8) between January 2018 and January 2019. RESULTS: All tumors were benign with a median diameter of 2.32 ± 0.49 cm. The mean length of the skin incision was 3.5 ±0.35 cm. The mean operating time 86.7 ± 10.8 minutes. The median blood loss was 30.4 ± 5.94 ml. The median volume of drainage was 27.1 ± 8.88 ml and the duration of drainage was 2 ± 0.71 days. The mean aesthetics scoring assigned by patients was 9.67 ± 0.51. Two patients had numbness of the earlobe and 1 patient developed a transient salivary sialocele. No facial nerve paresis was observed and no tumor recurrence occurred during the follow-up period. CONCLUSIONS: The minimally invasive endoscope-assisted extracapsular resection of benign parotid tumors provide both a safe and reliable technique for benign parotid tumors with excellent cosmetic results.

Modulating the Crystallinity of a Circular Plastic towards Packaging Material with Outstanding Barrier Properties.

Chemically recyclable polymers have attracted increasing attention since they are promising materials in a circular economy, but such polymers appropriate for packaging applications are scarce. Here a combined thermal, mechanical, and transport (permeability and sorption) study is presented of a circular polymer system based on biobased trans-hexahydrophthalide which, upon polymerization, can lead to amorphous, homochiral crystalline, and nanocrystalline stereocomplex materials. This study uncovers their largely different transport properties of the same polymer but with different stereochemical arrangements and synergistic or conflicting effects of crystallinity on transport properties versus thermal and mechanical properties. Overall, the homocrystalline chiral polymer shows the best performance with an outstanding barrier character to gases and vapors, outperforming commercial poly(ethylene terephthalate) and polyethylene. The results presented herein show that it is possible to modify the crystalline structure of the same polymer to tune the mechanical and transport properties and generate multiple materials of different barrier characters.

Production of Hydroxyl Radicals from Oxygenation of Simulated Acid Mine Drainage in Presence of Extracellular Polymers Substances.

The reaction mechanisms Fe(II) abiotic oxidation produce ·OH by CaCO3-induced in acid mine drainage (AMD) are well-documented, but little is known about the influence of extracellular polymeric substances (EPS) secreted by microorganisms on Fe(II) oxidation in AMD. In this study, ·OH production was experimently measured from oxygenation of simulated AMD in the presence of EPS. The cumulative ·OH increased from 56.75 to 158.70 µM within 24 h at pH 3 with the increase in EPS concentration from 0 to 12 mg/L. An appropriate pH (about 6) and EPS (6 mg/L) concentration were required for the moderate rate of Fe(II) oxidation. Besides, the yield of ·OH increased remarkably with the addition of Fe3+. In the presence of EPS, ·OH production is attributed mainly the complexation of Fe(II) with EPS, of which is rich of carboxyl and hydroxyl groups. The findings provide fundamental supplement of ·OH production from Fe(II) oxidation by microorganisms in natural AMD.

A Metallic Ion-Induced Self-Assembly Enabling Nanowire-Based Aerogels.

The controlled assembly of nanowires is one of the key challenges in the development of a range of functional 3D aerogels with unique physicochemical properties for practical applications. However, the deep understanding of the dynamic assemble process for fabricating nanowire aerogels remains elusive. Herein, a facile strategy is presented for the metallic ion-induced assembly of nanowires into macroscopic aerogels via a solution-based process. This method enables the interconnecting between polymer-decorated nanowires via metallic coordination, resulting in plenty of nanowire bundles with the same orientation. Besides, the coordinated binding strength of nanowires with different metallic ions is also discussed. The assembly mechanism that the metallic ions induced dynamic behavior of nanowires is revealed via molecular dynamics theoretical evaluation. These findings benefit for constructing nanowire-based aerogels with unique structural features and multi-function, which pave new opportunities for other material systems.

Visual Ozone Sensor: Structural Color Change of Pendant Selenium-Containing Maleimide Polymers via Oxidation.

Pendant selenium-containing maleimide polymers with different selenium contents are synthesized via a radical copolymerization of styrene and N-butylmaleimide phenyl selenide. The polymer structures are characterized by nuclear magnetic resonance, gel permeation chromatography, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, and scanning electron microscopy with an energy-dispersive spectrometer, which results in the desired structures and selenium contents. The refractive indices of the polymers, which change as a function of different contents of selenium and oxidative stimuli by H2 O2 or O3 , are investigated. Finally, a photonic crystal (PC) is prepared based on the selenium-containing polymer. The visible color changes of the PC are investigated as a function of different concentrations and contact times of O3 .

Amplification of oxidative stress with lycorine and gold-based nanocomposites for synergistic cascade cancer therapy.

BACKGROUND: Despite advances of surgery and neoadjuvant chemotherapy during the past few decades, the therapeutic efficacy of current therapeutic protocol for osteosarcoma (OS) is still seriously compromised by multi-drug resistance and severe side effects. Amplification of intracellular oxidative stress is considered as an effective strategy to induce cancer cell death. The purpose of this study was to develop a novel strategy that can amplify the intracellular oxidative stress for synergistic cascade cancer therapy. METHODS AND RESULTS: A novel nanocomposite, composed of folic acid (FA) modified mesoporous silica-coated gold nanostar (GNS@MSNs-FA) and traditional Chinese medicine lycorine (Ly), was rationally designed and developed. Under near-infrared (NIR) irradiation, the obtained GNS@MSNs-FA/Ly could promote a high level of ROS production via inducing mitochondrial dysfunction and potent endoplasmic reticulum (ER) stress. Moreover, glutathione (GSH) depletion during ER stress could reduce ROS scavenging and further enable efficient amplification of intracellular oxidative stress. Both in vitro and in vivo studies demonstrated that GNS@MSNs-FA/Ly coupled with NIR irradiation exhibited excellent antitumor efficacy without noticeable toxicity in MNNG/HOS tumor-bearing mice. CONCLUSION: All these results demonstrated that GNS@MSNs-FA/Ly coupled with NIR irradiation could dramatically amplify the intra-tumoral oxidative stress, exhibiting excellent antitumor ability without obvious systemic toxicity. Taken together, this promising strategy provides a new avenue for the effective cancer synergetic therapy and future clinical translation.

Plastic pollution in croplands threatens long-term food security.

Plastic pollution is a global concern given its prevalence in aquatic and terrestrial ecosystems. Studies have been conducted on the distribution and impact of plastic pollution in marine ecosystems, but little is known on terrestrial ecosystems. Plastic mulch has been widely used to increase crop yields worldwide, yet the impact of plastic residues in cropland soils to soil health and crop production in the long term remained unclear. In this paper, using a global meta-analysis, we found that the use of plastic mulch can indeed increase crop yields on average by 25%-42% in the immediate season due to the increase of soil temperature (+8%) and moisture (+17%). However, the unabated accumulation of film residues in the field negatively impacts its physicochemical properties linked to healthy soil and threatens food production in the long term. It has multiple negative impacts on plant growth including crop yield (at the mean rate of -3% for every additional 100 kg/ha of film residue), plant height (-2%) and root weight (-5%), and soil properties including soil water evaporation capacity (-2%), soil water infiltration rate (-8%), soil organic matter (-0.8%) and soil available phosphorus (-5%) based on meta-regression. Using a nationwide field survey of China, the largest user of plastic mulch worldwide, we found that plastic residue accumulation in cropland soils has reached 550,800 tonnes, with an estimated 6%-10% reduction in cotton yield in some polluted sites based on current level of plastic residue content. Immediate actions should be taken to ensure the recovery of plastic film mulch and limit further increase in film residue loading to maintain the sustainability of these croplands.

High-Throughput Phosphorylation Screening and Validation through Ti(IV)-Nanopolymer Functionalized Reverse Phase Phosphoprotein Array.

Protein phosphorylation is one of the most important and widespread molecular regulatory mechanisms that controls almost all aspects of cellular functions in animals and plants. Here, we introduce a novel chemically functionalized reverse phase phosphoprotein array (RP3A) to capture and measure phosphoproteomes. RP3A uses polyamidoamine (PAMAM) dendrimer immobilized with Ti(IV) ions to functionalize nitrocellulose membrane, facilitating specific chelation of phosphoproteins from complex protein samples on the array. Globular, water-soluble Ti(IV)-dendrimer allows the RP3A surface to be highly accessible to phosphoproteins multidimensionally, and the captured phosphoproteins were subsequently detected using the same validated antibodies as in regular reverse-phase protein arrays. The novel chemical strategy demonstrated superior specificity (1:10 000), high sensitivity (fg level), and good quantitative nature ( R2 = 0.99) for measuring phosphoproteins. We further applied quantitative phosphoproteomics followed by RP3A to validate the phosphorylation status of a panel of phosphoproteins in response to environmental stresses in Arabidopsis.

Zinc phthalocyanine encapsulated in polymer micelles as a potent photosensitizer for the photodynamic therapy of osteosarcoma.

Zinc phthalocyanine (ZnPc) is a highly potent second-generation photosensitizer for cancer photodynamic therapy (PDT) with attractive photo-physical and photo-chemical properties. However, poor solubility and strong trend of crystallization prevent it from loading in most of drug delivery systems and hamper its further application. Herein, to overcome this problem, an amphiphilic block copolymer poly(ethylene glycol)-poly[2-(methylacryloyl)ethylnicotinate] (PEG-PMAN) with aromatic nicotinate is used to load ZnPc for their π-π interactions. The formed PEG-PMAN/ZnPc nanoparticle (PPZ) dramatically increases reactive oxygen species production in osteosarcoma cells after light irradiation, causes mitochondrial injury and promotes cell cycle arrest at G2/M, leading to a 100-fold cytotoxicity improvement comparing with free ZnPc. The excellent therapeutic effectiveness and safety of PPZ are also proved by in vivo experiments operating on osteosarcoma model. The finding above indicates that PPZ has promising clinical applications as a next-generation photosensitizer in PDT of osteosarcoma.

Self-Rolled Porous Hollow Tubes Made up of Biodegradable Polymers.

A tubular highly porous scaffold of polylactide (PLA) and poly-ε-caprolactone (PCL) is fabricated by self-rolling of a 2D fibrous bilayer of PLA and PCL in water without use of any classical thermo-/pH-responsive polymers. The self-rolling and diameter of the tube are dependent upon the bilayer thickness and temperature. A 75 µm thick 2D bilayer (PLA = 25 µm; PCL = 50 µm) rolls to a hollow tube of diameter around 0.41 mm with multilayered wall at 40 °C within 5 min. The tubes keep their form and size in water at all temperatures once they are formed. The interesting properties of the hollow tubes, that is, permeation of gases through the walls and flow of water without leakage under tested conditions in combination with good mechanical stability, use of only biodegradable polymers, and easy and reproducible fabrication method, allow them to be promising candidates for future studies as scaffolds for tissue engineering.

Branched Aramid Nanofibers.

Interconnectivity of components in three-dimensional networks (3DNs) is essential for stress transfer in hydrogels, aerogels, and composites. Entanglement of nanoscale components in the network relies on weak short-range intermolecular interactions. The intrinsic stiffness and rod-like geometry of nanoscale components limit the cohesive energy of the physical crosslinks in 3DN materials. Nature realizes networked gels differently using components with extensive branching. Branched aramid nanofibers (BANFs) mimicking polymeric components of biological gels were synthesized to produce 3DNs with high efficiency stress transfer. Individual BANFs are flexible, with the number of branches controlled by base strength in the hydrolysis process. The extensive connectivity of the BANFs allows them to form hydro- and aerogel monoliths with an order of magnitude less solid content than rod-like nanocomponents. Branching of nanofibers also leads to improved mechanics of gels and nanocomposites.

Diselenide-Labeled Cyclic Polystyrene with Multiple Responses: Facile Synthesis, Tunable Size, and Topology.

Diselenide-containing polymers have attracted more and more attention due to their redox sensitivity and bioapplication. In this work, a bifunctional diselenocarbonate is prepared and used to mediate the reversible addition-fragmentation chain transfer (RAFT) polymerization, producing α,ω-selenocarbonate-labeled telechelic polystyrene. Based on effective aminolysis of the terminal selenocarbonates and the followed spontaneous oxidation coupling reaction of diselenols, monoblock cyclic polystyrene linked by one diselenide bond and multiblock cyclic copolymer linked by several diselenide bonds are prepared by manipulating the concentration of α,ω-telechelic polystyrene in solution. The progress of aminolysis and the subsequent spontaneous oxidation of selenols to diselenides are monitored by UV-vis, gel permeation chromatography (GPC), and NMR characterizations, confirming the cyclic topologies of the resultant polymers (monocyclic or multiblock cyclic polymer). The monoblock cyclic or multiblock polymers show redox sensitivity, which can be converted to linear polymer by reducing or oxidizing agent. Moreover, the obtained monoblock cyclic polymer or multiblock cyclic copolymer can be transformed to each other under UV irradiation by adjusting the concentration of the cyclic polystyrene. For the first time, this work provides an alternative and promising approach to realize the topological transformation of polymers by installing multiresponsive diselenide moities into the backbone of cyclic polymer.

Human Basic Fibroblast Growth Factor Inhibits Tau Phosphorylation via the PI3K/Akt-GSK3ß Signaling Pathway in a 6-Hydroxydopamine-Induced Model of Parkinson's Disease.

BACKGROUND: Basic fibroblast growth factor (bFGF) has been increasingly investigated due to its neuroprotection in neurodegenerative disorders. Because there are still no cures for any of these disorders, it is crucial to identify new therapeutic targets and screen potential drugs. The increased phosphorylation of tau at Ser396 leads to intracellular tau accumulation, which forms neurofibrillary tangles in Parkinson's disease (PD). In this study, neuroprotection by bFGF was observed, and the mechanisms related to its regulation of phosphorylated tau were investigated. METHODS: bFGF-loaded liposome carriers were intranasally administered to rats. The neuroprotective effects of bFGF were assessed in a PD model induced by 6-hydroxydopamine (6-OHDA) in vivo and in vitro. The phosphorylation of tau was measured, and the PI3K/Akt-GSK3ß signaling pathway was investigated. RESULTS: Our study demonstrated that liposomes markedly assisted in the delivery of bFGF to the striatum and substantia nigra of rats and enhanced the neuroprotective effects of bFGF on dopaminergic neurons. bFGF treatment significantly ameliorated the behavioral deficits induced by 6-OHDA, rescued the loss of tyrosine hydroxylase-positive neurons and increased the number of Nissl bodies. bFGF reduced the phosphorylation of tau and GSK3ß and increased the phosphorylation of PI3K/Akt. CONCLUSION: Liposomes markedly assisted in the delivery of bFGF to the brain and enhanced the neuroprotective effects of bFGF by inhibiting the phosphorylation of tau. bFGF down-regulated the phosphorylation of tau by increasing the phosphorylation of GSK3ß via the PI3K/Akt signaling pathway. These findings provide a new vision of bFGF as a potential therapy for PD.

Rhizobacterial Strain Bacillus megaterium BOFC15 Induces Cellular Polyamine Changes that Improve Plant Growth and Drought Resistance.

Plant-growth-promoting rhizobacteria can improve plant growth, development, and stress adaptation. However, the underlying mechanisms are still largely unclear. We investigated the effects of Bacillus megaterium BOFC15 on Arabidopsis plants. BOFC15 produced and secreted spermidine (Spd), a type of polyamine (PA) that plays an important role in plant growth. Moreover, BOFC15 induced changes in the cellular PAs of plants that promoted an increase of free Spd and spermine levels. However, these effects were remarkably abolished by the addition of dicyclohexylamine (DCHA), a Spd biosynthetic inhibitor. Additionally, the inoculation with BOFC15 remarkably increased plant biomass, improved root system architecture, and augmented photosynthetic capacity. Inoculated plants also displayed stronger ability to tolerate drought stress than non-inoculated (control) plants. Abscisic acid (ABA) content was notably higher in the inoculated plants than in the control plants under drought stress and polyethylene glycol (PEG)-induced stress conditions. However, the BOFC15-induced ABA synthesis was markedly inhibited by DCHA. Thus, microbial Spd participated in the modulation of the ABA levels. The Spd-producing BOFC15 improved plant drought tolerance, which was associated with altered cellular ABA levels and activated adaptive responses.

Prospects of Robot-Assisted Mandibular Reconstruction with Fibula Flap: Comparison with a Computer-Assisted Navigation System and Freehand Technique.

Background Function and aesthetics have a significant impact on the quality of life in patients undergoing mandibular reconstructive surgery, but achieving satisfactory results remain challenging. The aim of the study is to investigate the feasibility and accuracy of robot-assisted mandibular reconstruction with fibula flap in comparison to that with a computer-assisted navigation system and the freehand technique. Methods Experimental procedures (15 phantom studies and 6 animal experiments) were performed with a custom three-arm robotic system automatically, under the guidance of a computer-assisted navigation system, and by the freehand technique, respectively. The accuracy of the reconstruction was assessed by comparison between the preoperative and postoperative three-dimensional surface virtual models. Results All procedures were successfully performed. In the phantom study, the mean deviation of the fibula implant was 1.221, 1.581, and 2.313 mm, respectively, with the robotic system, the navigation system, and the freehand technique; in the animal experiment the corresponding figures were 1.7697, 1.7847, and 2.0815 mm, respectively. The mean deviation of the proximal mandibular ramus was 1.0420, 1.0532, 1.8800 mm with the robotic system, computer-assisted navigation system, and freehand technique, respectively, and the mean deviation of the distal mandibular segment was 1.1645, 2.7198, and 2.8445 mm, respectively. Conclusions The robotic system is feasible, efficient, and reliable for mandibular reconstruction. The accuracy of the fibula implant orientation with the robotic system was comparable to that with navigation system and superior to that with the freehand technique.

From meso-Lactide to Isotactic Polylactide: Epimerization by B/N Lewis Pairs and Kinetic Resolution by Organic Catalysts.

B/N Lewis pairs have been discovered to catalyze rapid epimerization of meso-lactide (LA) or LA diastereomers quantitatively into rac-LA. The obtained rac-LA is kinetically polymerized into poly(L-lactide) and optically resolved D-LA, with a high stereoselectivity k(L)/k(D) of 53 and an ee of 91% at 50.6% monomer conversion, by newly designed bifunctional chiral catalyst 4 that incorporates three key elements (ß-isocupreidine core, thiourea functionality, and chiral BINAM) into a single organic molecule. The epimerization and enantioselective polymerization can be coupled into a one-pot process for transforming meso-LA directly into poly(L-lactide) and D-LA.

Photocatalyst-Free and Blue Light-Induced RAFT Polymerization of Vinyl Acetate at Ambient Temperature.

Vinyl acetate is polymerized in the living way under the irradiation of blue light-emitting diodes (LEDs) or sunlight without photocatalyst at ambient temperature. 2-(Ethoxycarbonothioyl)sulfanyl propanoate is exclusively added and acts as initiator and chain transfer agent simultaneously in the current system. Poly(vinyl acetate) with well-regulated molecular weight and narrow molecular weight distribution (D < 1.30) is synthesized. Near quantitative end group fidelity of polymer is demonstrated by nuclear magnetic resonance (NMR) and matrix-assisteed laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS).

An electronically tunable duct silencer using dielectric elastomer actuators.

A duct silencer with tunable acoustic characteristics is presented in this paper. Dielectric elastomer, a smart material with lightweight, high elastic energy density and large deformation under high direct current/alternating current voltages, was used to fabricate this duct silencer. The acoustic performances and tunable mechanisms of this duct silencer were experimentally investigated. It was found that all the resonance peaks of this duct silencer could be adjusted using external control signals without any additional mechanical part. The physics of the tunable mechanism is further discussed based on the electro-mechanical interactions using finite element analysis. The present promising results also provide insight into the appropriateness of the duct silencer for possible use as next generation acoustic treatment device to replace the traditional acoustic treatment.

Preparation of malathion MIP-SPE and its application in environmental analysis.

Malathion is an organophosphorous insecticide for controlling insects on fruits and vegetables, miscellaneous household insects, and animal parasites. It is important to develop highly efficient and selective pre-treatment method for analyzing malathion residues in environment and samples from agricultural products based on the molecularly imprinted polymers (MIPs). In this study, we developed a tailor-made MIP method with highly specific recognization to the template. The MIPs were prepared using malathion as a template, methacrylic acid (MAA) as a functional monomer, ethylene glycol dimethacrylate (EGDMA) as a crosslinker, azodiisobutyronitrile (AIBN) as an initiator, and the acetonitrile-chloroform (1:1, v/v) as a porogen. The molecular recognization mechanism of malathion and MAA was evaluated by molecular simulation, ultraviolet spectrometry (UV), and (1)H-nuclear magnetic resonance ((1)H-NMR). MAA interacted specifically with malathion by hydrogen bond with a ratio of 2:1. The MIPs exhibit a high affinity, recognition specificity, and efficient adsorption performance for malathion. The Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), surface area and porosimeter analyzer, thermogravimetric/differential thermal analyzer (TG/DTA) were used to characterize the properties of MIP. The malathion residues in soil, tap water, and cabbage were cleaned up by MIP-SPE, detected quantitatively using GC-FPD, and confirmed by GC-MS/MS. The limits of tap water, soil, and cabbage were confined to 0.001 mg L(-1), 0.004 and 0.004 mg kg(-1), respectively. The spiked recoveries of malathion were 96.06-111.49% (with RSD being 5.7-9.2%), 98.13-103.83% (RSD, 3.5-8.7%), and 84.94-93.69% (RSD, 4.7-5.8%) for tap water, soil, and cabbage samples, respectively. Thus, the method developed here can be used effectively in assessing malathion residues in multiple environmental samples. The aim of the study was to provide an efficient, selective, and accurate method for analyzing malathion at trace levels in multiple media.

The plant cuticle is required for osmotic stress regulation of abscisic acid biosynthesis and osmotic stress tolerance in Arabidopsis.

Osmotic stress activates the biosynthesis of abscisic acid (ABA). One major step in ABA biosynthesis is the carotenoid cleavage catalyzed by a 9-cis epoxycarotenoid dioxygenase (NCED). To understand the mechanism for osmotic stress activation of ABA biosynthesis, we screened for Arabidopsis thaliana mutants that failed to induce the NCED3 gene expression in response to osmotic stress treatments. The ced1 (for 9-cis epoxycarotenoid dioxygenase defective 1) mutant isolated in this study showed markedly reduced expression of NCED3 in response to osmotic stress (polyethylene glycol) treatments compared with the wild type. Other ABA biosynthesis genes are also greatly reduced in ced1 under osmotic stress. ced1 mutant plants are very sensitive to even mild osmotic stress. Map-based cloning revealed unexpectedly that CED1 encodes a putative α/ß hydrolase domain-containing protein and is allelic to the BODYGUARD gene that was recently shown to be essential for cuticle biogenesis. Further studies discovered that other cutin biosynthesis mutants are also impaired in osmotic stress induction of ABA biosynthesis genes and are sensitive to osmotic stress. Our work demonstrates that the cuticle functions not merely as a physical barrier to minimize water loss but also mediates osmotic stress signaling and tolerance by regulating ABA biosynthesis and signaling.