Search

Few studies have reported the application of vacuum‐sealing drainage of infected dialysis vascular access wounds. Herein, we present a case of buttonhole‐related arteriovenous fistula infection treated with vacuum‐sealing drainage. A 53‐year‐old female hemodialysis patient was hospitalized with an inflamed arteriovenous fistula. The patient underwent non‐tunneled catheterization for dialysis and was treated with moxifloxacin and vancomycin for staphylococcal infection. On Day 3, the skin overlying the inflamed fistula was ulcerated, resulting in severe hemorrhage. Emergency surgery was performed along with vacuum‐sealing drainage for fistula reconstruction. Vacuum‐sealing drainage accelerated the recovery of the wound without complications. No further access complications occurred during over a 3‐year follow‐up. [ABSTRACT FROM AUTHOR]

A series of conjugated polymers bearing thiophene‐based donors and pyromellitic diimide (PMDI) acceptor were prepared, and their electrochromic (EC) properties were studied via using fabricated thin‐film EC devices. It was observed that structurally regular alternating polymers with fewer (1 and 2) thiophene donors do not exhibit any EC properties while increasing the number of donors eventually led to the emergence of orange‐red‐to‐green colour switching. On this basis, two more random co‐polymers containing higher donor‐to‐acceptor ratios were synthesized to further improve EC switching properties. The two polymers, which bear a PMDI‐to‐thiophene ratio of ca. 1 : 7 and 1 : 8, revealed orange red‐to‐blue colour switching and generally improved optical contrasts and switching speeds in both the visible and near infra‐red (NIR) region. In addition, the subtle modulation of polymer colour and hue via variation of the number of thiophene donors was evident through colorimetric study. This work therefore demonstrates the potential and possibility of using the PMDI acceptor unit to construct EC‐active conjugated polymers, and considerations for future tuning of colour and switching performances. [ABSTRACT FROM AUTHOR]

Fe–N–C catalysts are emerging as promising alternatives to Pt‐based catalysts for the oxygen reduction reaction (ORR), while they still suffer from sluggish reaction kinetics due to the discontented binding affinity between the Fe‐N4 sites and oxygen‐containing intermediates, and unsatisfactory stability. Herein, a flexible multichannel carbon fiber membrane immobilized with atomically dispersed Fe‐N4 sites and neighboring Fe nanoclusters/nanoparticles (FeN4‐FeNCP@MCF) is synthesized. The optimized geometric and electronic structures of the Fe atomic sites brought by adjacent Fe nanoclusters/nanoparticles and hierarchically porous structure of the carbon matrix endow FeN4‐FeNCP@MCF with outstanding ORR activity and stability, considerably outperforming its counterpart with FeN4 sites only and the commercial Pt/C catalyst. Liquid and solid‐state flexible zinc–air batteries employing FeN4‐FeNCP@MCF both exhibit outstanding durability. Theoretical calculation reveals that the Fe nanoclusters can trigger remarkable electron redistribution of the FeN4 sites and modulate the hybridization of central Fe 3d and O 2p orbitals, facilitating the activation of O2 molecules and optimizing the adsorption capacity of oxygen‐containing intermediates on FeN4 sites, and thus accelerating the ORR kinetic. This work offers an effective approach to constructing coupling catalysts that have single atoms coexisting with nanoclusters/nanoparticles for efficient ORR catalysis. [ABSTRACT FROM AUTHOR]

Bio‐based and biodegradable polymer composites, most notably poly(l‐lactic acid) (PLLA) and poly(3‐hydroxybutyrate) (PHB), represent a promising solution to replace conventional petroleum‐based plastics. However, the brittleness and low miscibility of PLLA and PHB remain two major obstacles to practical applications. In this work, first PLLA/PHB blends are reported by melt mixing with a rigid component, poly(methyl methacrylate) (PMMA). Driven by favorable entropy, PMMA forms an interfacial nanolayer, which transforms the morphology of resultant blends. The ternary blends show 55‐fold increase in elongation, 50‐fold in toughness, and metal‐like malleability (≈180° bending and twisting), while retaining its high stiffness (3.4 GPa) and strength (≈50 MPa). The mechanical improvement arises from numerous craze fibrils and shear deformation of the matrix, induced by the incorporated PMMA. Furthermore, this generic strategy can be applied to design other mechanically robust biocomposites for advanced green devices. [ABSTRACT FROM AUTHOR]

The development of earth‐abundant oxygen reduction reaction (ORR) catalysts with high catalytic activity and good stability for practical metal‐air batteries remains an enormous challenge. Herein, a highly efficient and durable ORR catalyst is reported, which consists of atomically dispersed Co single atoms (Co‐SAs) in the form of Co‐N4 moieties and small Co nanoparticles (Co‐SNPs) co‐anchored on nitrogen‐doped porous carbon nanocage (Co‐SAs/SNPs@NC). Benefiting from the synergistic effect of Co‐SAs and Co‐SNPs as well as the enhanced anticorrosion capability of the carbon matrix brought by its improved graphitization degree, the resultant Co‐SAs/SNPs@NC catalyst exhibits outstanding ORR activity and remarkable stability in alkaline media, outperforming Co‐SAs‐based catalyst (Co‐SAs@NC), and benchmark Pt/C catalyst. Density functional theory calculations reveal that the strong interaction between Co‐SNPs and Co‐N4 sites can increase the valence state of the active Co atoms in Co‐SAs/SNPs@NC and moderate the adsorption free energy of ORR intermediates, thus facilitating the reduction of O2. Moreover, the practical zinc‐air battery assembled with Co‐SAs/SNPs@NC catalyst demonstrates a maximum power density of 223.5 mW cm–2, a high specific capacity of 742 W h kg–1 at 50 mA cm–2 and a superior cycling stability. [ABSTRACT FROM AUTHOR]

Aims: Immunoglobulin A nephropathy (IgAN) is the most common primary glomerular disease to cause end‐stage kidney disease. This study investigated the difference in urinary exosomal circular RNA (circRNA) expression profiles between patients with IgAN and healthy controls (HCs), for better understanding of gene regulation in exosomes of IgAN patients. Methods: A pairwise comparison of urinary circRNA expression profiles between IgAN patients and HCs was performed using methods, including high‐throughput sequencing and quantitative polymerase chain reaction. Moreover, the potential functions of differentially expressed circRNAs (DECs) in IgAN were investigated by gene ontology (GO) enrichment analysis; Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis; and the circRNA‐miRNA‐mRNA network. Results: We identified 450 upregulated and 26 downregulated circRNAs in the IgAN patients. GO analysis showed that these enriched circRNAs might regulate primary miRNA processing, the ability of angiotensin receptor binding, and stress fibre function. KEGG analysis suggested these DECs may be closely associated with the phosphoinositide‐3‐kinase‐protein kinase B/Akt (PI3K‐Akt) signalling pathways. Network analysis revealed the relationship between circRNAs and their target genes. Conclusion: The identified DECs may be useful for both researches on molecular aetiology of IgAN and development of potentially novel non‐invasive biomarkers of IgAN. SUMMARY AT A GLANCE: An RNA‐sequence analysis of RNAs in urinary exosomes identified a number of differentially expressed circular RNAs in immunoglobulin A nephropathy (IgAN) patients as compared to healthy controls. These circRNAs are associated with the regulation of pathways relevant to IgAN and may provide useful non‐invasive biomarkers for this condition. [ABSTRACT FROM AUTHOR]

Human placenta-derived mesenchymal stem cells (pMSCs) are considered a good source for cell therapy. The purpose of this study was to observe whether the transplantation of human pMSCs would affect the treatment of lupus nephritis (LN)-prone MRL/lpr mice. Multiple injections (at the 16th, 18th, and 20th week of age) of 1 × 106 pMSCs were administered. Urine was collected to evaluate proteinuria and urine creatinine levels. Blood was collected for the measurement of serum antinuclear antibody (ANA) and anti-double-stranded DNA (dsDNA) antibody levels. Renal tissues were collected for histological staining and examination by light and electron microscopy quantitative reverse transcription polymerase chain reaction (RT-qPCR) and Western Blot. The results confirmed that pMSC treatment reduced the severity of 24-h proteinuria, decreased the production of anti-dsDNA antibodies, and ameliorated renal pathological changes in MRL/lpr mice. Furthermore, pMSCs reduced renal inflammation by inhibiting the expression of nuclear factor kappa B (NF-κB) and then downregulating the expression of tumor necrosis factor-α (TNF-α), intercellular cell adhesion molecule-1 (ICAM-1), and plasminogen activator inhibitor-1 (PAI-1). Therefore, our present study demonstrated a protective effect of pMSCs against renal injury and inflammation in MRL/lpr mice. [ABSTRACT FROM AUTHOR]

Chemically cross-linked Si xO y cage clusters embedded in N-doped carbon were prepared by thermal treatment of octaammonium polyhedral oligomeric silsesquioxane (POSS; (SiO1.5C3H6NH3Cl)8) in an inert environment. Transmission electron microscopic studies show that by annealing at 900 °C, Si-rich clusters with a size of approximately 5 nm were formed and uniformly distributed in a lighter matrix. XPS analysis indicates that the sample obtained from annealing at 900 °C (P900) has a chemical composition of Si6.5O12.0C9.3N0.5 and it also contains substantial amounts of Si−C and C−O bonds, sp2 C, and a small number of C=N bonds, in addition to Si−O bonds. Together with thermogravimetric analysis, this suggests that the clusters are likely to be formed by chemical cross-linking several POSS cages through Si−C or C−O bonds, whereas the matrix may be N-doped carbon that results from carbonization of some detached side-chains. When used as a lithium-ion battery anode, P900 exhibits stable and high cycling and rate capacity. The capacity can be maintained for at least 1000 cycles. This is much better than results for anodes made from silicon oxides, which could be ascribed to 1) the less compact but fairly stable Si−O active sites brought by the cage structure and the cross-linking; 2) the small size of the clusters that ensures smooth and complete lithium insertion/extraction; and 3) the 'island-sea' morphology for the clusters-in-carbon hybrid that enhances interfacial interactions and facilitates charge conduction. [ABSTRACT FROM AUTHOR]

A series of dithienothiophene-based electrochromic polymers are synthesized by a Stille coupling reaction of 2,6-bis(trimethylstannyl)dithieno[3,2- b:2′,3′- d]thiophene, 2,5-dibromo-3,4-bis(dodecyloxy)thiophene, and tris(4-bromophenylamine). The resulting polymers have high molecular weights in the range of 59 200 to 81 300 g mol−1, and good solubility in common organic solvents. The polymer films are purple/red in neutral states and gradually become gray when oxidized to an intermediate state and blue when fully oxidized. Incorporation of triphenylamine into the polymer chains has resulted in a significant increase in the redox stability, which renders this a potential method to create high-performance electrochromic polymers. [ABSTRACT FROM AUTHOR]

An electrofluorochromic (EFC) conjugated copolymer ( PEFC) containing carbazole and benzothiadiazole (BTD) moieties is synthesized through Suzuki coupling followed by electrochemical polymerization, resulting in a nanoporous EFC polymer electrode. The electrode exhibits high sensitivity and selectivity in the EFC detection of cyanide anions (CN−) in largely aqueous electrolyte (67 vol % water) because electrochemical oxidation of PEFC leads to significant fluorescence quenching, and the presence of different concentrations (1 to 100 μ M) of CN− in the electrolyte can weaken the oxidative quenching to substantially different extents. Although PEFC is hydrophobic in the neutral state, it is converted to radical cation/dication states upon oxidation, rendering the PEFC some hydrophilicity. Moreover, its nanoporous morphology provides a large surface area and short diffusion distance, facilitating the movement of CN− in the electrolyte into the PEFC film to interact with receptors. Density functional theory calculations show that the noncovalent interaction between electron-deficient BTD and nucleophilic CN− is energy favorable in the oxidized states in both aqueous and organic media, suggesting that the specific π−-π+ interaction plays the main role in the CN− detection. [ABSTRACT FROM AUTHOR]

Inspired by the high transition-metal-ion content in mussel glues, and the cross-linking and mechanical reinforcement effects of some transition-metal ions in mussel threads, high concentrations of nickel(II), cobalt(II), and manganese(II) ions have been purposely introduced into the reaction system for dopamine polymerization. Kinetics studies were conducted for the Ni2+-dopamine system to investigate the polymerization mechanism. The results show that the Ni2+ ions could accelerate the assembly of dopamine oligomers in the polymerization process. Spectroscopic and electron microscopic studies reveal that the Ni2+ ions are chelated with polydopamine (PDA) units, forming homogeneous Ni2+-PDA complexes. This facile one-pot approach is utilized to construct transition-metal-ion-PDA complex thin coatings on graphene oxide, which can be carbonized to produce robust hybrid nanosheets with well-dispersed metallic nickel/metallic cobalt/manganese(II) oxide nanoparticles embedded in PDA-derived thin graphitic carbon layers. The nickel-graphene hybrid prepared by using this approach shows good catalytic properties and recyclability for the reduction of p -nitrophenol. [ABSTRACT FROM AUTHOR]

Titanium surface was modified by anodization in phosphoric acid solution at the voltages of 100 and 250 V, respectively. Surface characteristics and corrosion behaviors of anodized titanium were investigated before and after hydrothermal exposure in 3.5 wt.% NaCl solution at 160 °C for 24 h. It was found that anodization at 100 and 250 V resulted in the formation of a dense and a porous TiO2 layer, respectively. The existence of anatase in the oxide layers of the 250-V samples was confirmed by X-ray diffraction analysis but not in the oxide layers of the 100-V samples. After the hydrothermal exposure, the surface morphology of the 100-V sample changed significantly, and discrete nanorods were formed on the surface. In contrast, the 250-V sample basically preserved their original surface structures after the exposure except that numerous closely packed nanoparticles emerged on the surface. X-ray diffraction analysis indicated that the exposure transformed the amorphous oxides into crystalline anatase. The corrosion behavior investigation of anodized titanium showed that the hydrothermal exposure had slight influence on the corrosion resistance of the 100-V samples but decreased the corrosion resistance of the 250-V samples significantly. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Rocket-like vesicles formed are composed of poly(acrylic aicd) (PMAA )/poly(ethylene glycol) (PEG) complex coated hollow silica spheres, and the structure and composition of the vesicles are characterized using TGA, 1H NMR, FTIR, and TEM. Although only one-third of EG units of PEG brushes grafted to hollow silica spheres form the complex with PMAA via hydrogen bonding, the first 'booster' layer composed of PMAA/PEG complex can provide secure encapsulation of model compound calcein blue under an acidic condition. The second 'booster' layer composed of PEG brushes can be formed by changing acidic pH to 7.4 through the disassociation of the PMAA/PEG complex. A higher molecular weight PMAA exhibits a faster disassembly due to the formation of a looser PMAA/PEG complex on the surfaces of hollow silica spheres. [ABSTRACT FROM AUTHOR]

This paper presents a new approach for the preparation of poly(ethylene terephthalate) ( PET)/clay nanocomposites using surfactant-free clay (sodium montmorillonite, Na- MMT) with trisilanolphenyl polyhedral oligomeric silsesquioxane (Tsp- POSS) as dispersant. The dispersion of clay in the PET/Na- MMT/Tsp- POSS nanocomposites is enhanced over that in PET/Na- MMT by using a very small amount of Tsp- POSS, which acts as functional spacer to keep clay platelets apart and pull monomers in, and, at the same time, acts as a PET chain extender. As a result, thermomechanical properties and thermo-oxidative stability of PET/Na- MMT/Tsp- POSS are improved simultaneously compared with those of PET/organoclay nanocomposites. © 2013 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Azulene-containing conjugated polymers with near-infrared absorption up to 1.5 μm and beyond are achieved by treating with trifluoroacetic acid (TFA). Density functional theory calculations reveal that the near-infrared absorption arises from a strong intramolecular charge transfer transition on the polymer backbone, and the near-infrared absorption can be tuned by the degree of protonation. Furthermore, TFA treated polymers show a ten-fold enhancement in electrochromic contrast and significantly improved switching stability, suggesting that these polymers are promising candidates for fabrication of the first generation organic near-infrared devices. [ABSTRACT FROM AUTHOR]

Novel temperature and pH dual-responsive dendritic polyoligomeric silsesquioxane (POSS)-poly( N-isopropylacrylamide) (PNIPAm)-poly(2-hydroxyethyl methacrylate) (PHEMA) copolymers are prepared via atom transfer radical polymerization and click reactions. The cloud points ( Tc) decrease with decreasing pH from 10.0 to 5.0 due to the weakened inter-molecular interactions and enhanced intra-molecular hydrogen bonding, whereas the Tc exhibits a small increase from pH 5.0 to 4.0 because of the better solvation of PHEMA at highly acidic conditions. The above findings are corroborated by the different sizes of aggregates observed by dynamic light scattering. The encapsulation of a fluorescent dye and stimulated release by temperature and pH changes are also demonstrated. [ABSTRACT FROM AUTHOR]

We report, the preparation of nanocomposites having polyimide (PI) as matrix and graphene oxide (GO) as filler, analyses of matrix-filler interactions, and enhancements in thermomechanical properties of PI/GO as compared with pristine PI. The matrix-filler interactions were analyzed by 1H NMR, X-ray photoelectron spectroscopy, and density functional theory calculations. The data suggested stronger matrix-filler interactions in PI/GO as compared with PI/G composites. The stronger matrix-filler interactions and homogeneous dispersion of fillers lead to a significant enhancement in mechanical properties in PI/GO nanocomposites. Thus, with just 1 wt% GO content, the modulus of PI/GO composite increased by ∼106% as compared with pristine PI. Finally, thermal expansion coefficients of the nanocomposites are also investigated. A plausible hypothesis has been proposed in the text to explain the observed matrix-filler interactions and the subsequent property enhancements in nanocomposites. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Background: Our previous study has shown that porcine antigen-primed and CD4+ T cell-activated macrophages are capable of recognition and rejection of porcine xenografts after adoptive transfer. However, whether this is an absolute xenograft specific rejection remains to be confirmed. Methods:  Mouse islet allografts and neonatal porcine islet cell cluster (NICC) xenografts were admixed and transplanted under the left kidney capsule, and NICC xenografts alone were transplanted under the right kidney capsule of strepotozotocin-induced diabetic NOD-SCID mice. After achievement of normoglycemia, the NOD-SCID recipients were transferred with macrophages purified from NICC transplant NOD-SCID mice reconstituted with CD4+ T cells. Five weeks after macrophage transfer the left kidney with the admixed grafts were removed. Graft survival and function following macrophage transfer was assessed by blood glucose measurement and immunohistochemistry. Results and conclusions:  Adoptive transfer with activated macrophages did not affect the normalized blood glucose levels in NOD-SCID recipients of admixed grafts until left nephrectomy 5 weeks post-macrophage transfer. Insulin-positive and porcine C-peptide-negative mouse islets were detected in the admixed grafts. The surviving mouse islets in the admixed grafts were surrounded but not infiltrated by macrophages. The nephrectomized recipients demonstrated sustained hyperglycemia and completely destroyed NICC xenografts in their remaining right kidneys 8 weeks after macrophage transfer. Taken together, these data provide direct evidence of porcine islet xenograft specific rejection by activated macrophages. [ABSTRACT FROM AUTHOR]

Strength and toughness are the two most important prerequisites for structural applications. Unfortunately, these two properties are often in conflict in materials. Here, an effective and yet practical strategy is proposed to simultaneously strengthen and toughen poly(l‐lactide) (PLLA) using a simple rigid‐rubber "reinforcing element." This element consists of a rigid graphene oxide (GO) sheet covalently coupled with poly(caprolactone‐co‐lactide) (PCLLA) rubbery layers, which can be easily synthesized and incorporated into PLLA matrix to develop composites with well‐tailored GO/PLLA interfaces. It is demonstrated that by adding the "reinforcing element," i.e., GO‐graft‐rubber‐graft‐polyd‐lactide), PLLA exhibits higher strength and higher toughness, which could be attributed to the synergy of rigid GO and rubbery PCLLA working in tandem during deformation. It is further demonstrated that this strategy can also be applied to other filler systems, such as clay and particulate polyhedral oligomeric silsesquioxane, and other polymer systems, such as poly(methyl methacrylate). The strategy could be considered as a general design principle for reinforcing materials where both strength and toughness are the key concerns. A facile way of overcoming the conflict of strength and toughness in polymer is demonstrated by using a rigid‐rubber structure unit, i.e., a rigid structure coupled with rubbery layers. The rigid‐rubber structure unit can be easily synthesized and incorporated into polymer matrices to enhance both strength and toughness. The approach can be used as a general design principle for reinforcing polymers. [ABSTRACT FROM AUTHOR]