The fascinating pulley effect from moveable α‐cyclodextrin (α‐CD) based polyrotaxane favors toughening of hydrogels, but the strategy is rarely applied in bulk polymers because of the severe ...aggregation trend of α‐CDs. Herein, the authors propose a simple approach to moderately modify the α‐CDs of polyrotaxane by introducing large steric side groups and reactive CC so as to minimize the unwanted hydrogen bonds‐induced aggregation of α‐CDs and hydrophilicity of polyrotaxane. Accordingly, the proof‐of‐concept material, poly(methyl acrylate) crosslinked by the modified polyrotaxane, turns out to be rather homogeneous with optical transparency. The polyrotaxane crosslinks are movable under external force as disclosed by in situ small‐angle X‐ray scattering and other techniques, which is correlated to the relative amount of α‐CDs. A few polyrotaxane crosslinkers prove to be sufficient to simultaneously improve strength and toughness of poly(methyl acrylate) owing to the stress equalization. The present work provides an expandable toolbox for enhancing polymers.
A transparent topologically crosslinked poly(methyl acrylate) is prepared with modified polyrotaxane carrying large steric side groups and reactive CC double bonds as crosslinker. The resultant bulk polymer possesses homogeneous microstructure and favorable performance of pulley effect. A few polyrotaxane crosslinkers prove to be sufficient to simultaneously arouse strengthening and toughening effects owing to the superior stress equalization.
Osteosarcoma (OS) is the most common primary bone malignancy, mainly affecting children and adolescents. Currently, surgical resection combined with adjuvant chemotherapy has been standardized for OS ...treatment. Despite great advances in chemotherapy for OS, its clinical prognosis remains far from satisfactory; this is due to chemoresistance, which has become a major obstacle to improving OS treatment. Autophagy, a catabolic process through which cells eliminate and recycle their own damaged proteins and organelles to provide energy, can be activated by chemotherapeutic drugs. Accumulating evidence has indicated that autophagy plays the dual role in the regulation of OS chemoresistance by either promoting drug resistance or increasing drug sensitivity. The aim of the present review was to demonstrate thatautophagy has both a cytoprotective and an autophagic cell death function in OS chemoresistance. In addition, methods to detect autophagy, autophagy inducers and inhibitors, as well as autophagy‑mediated metastasis, immunotherapy and clinical prognosis are also discussed.
Characteristics of lung function impairment in bronchiectasis is not fully understood.
To determine the factors associated with lung function impairment and to compare changes in spirometry during ...bronchiectasis exacerbation and convalescence (1 week following 14-day antibiotic therapy).
We recruited 142 patients with steady-state bronchiectasis, of whom 44 with acute exacerbations in the follow-up were included in subgroup analyses. Baseline measurements consisted of chest high-resolution computed tomography (HRCT), sputum volume, purulence and bacteriology, spirometry and diffusing capacity. Spirometry, but not diffusing capacity, was examined during acute exacerbations and convalescence.
In the final multivariate models, having bronchiectasis symptoms for 10 years or greater (OR = 4.75, 95%CI: 1.46-15.43, P = 0.01), sputum culture positive for Pseudomonas aeruginosa (OR = 4.93, 95%CI: 1.52-15.94, P<0.01) and HRCT total score being 12 or greater (OR = 7.77, 95%CI: 3.21-18.79, P<0.01) were the major variables associated with FEV1 being 50%pred or less; and the only variable associated with reduced DLCO was 4 or more bronchiectatic lobes (OR = 5.91, 95%CI: 2.20-17.23, P<0.01). Overall differences in FVC and FEV1 during exacerbations and convalescence were significant (P<0.05), whereas changes in other spirometric parameters were less notable. This applied even when stratified by the magnitude of FEV1 and DLCO reduction at baseline.
Significant lung function impairment should raise alert of chest HRCT abnormality and sputum culture positive for Pseudomonas aeruginosa, in patients with predominantly mild to moderate steady-state bronchiectasis. Acute exacerbations elicited reductions in FVC and FEV1. Changes of other spirometric parameters were less significant during exacerbations.
ClinicalTrials.gov NCT01761214.
In this work, water triggered dynamic catechol-Fe
coordinate bonds are revealed and studied at atomic, molecular and macroscopic levels using Mössbauer spectroscopy, rheological analysis,
DOPA-iron ...complexation is found to be dynamic in the presence of water, and this dynamic manner is immobilized after removing water. Accordingly, a water saturated lipophilic polymer containing catechol-Fe
crosslinks, rather than the dry version, exhibits dynamic coordination-dissociation behavior. In addition, a migration of iron proves to be enabled in the catechol-Fe
crosslinked polymer immersed in seawater. Rearrangement of the dynamic catechol-Fe
coordinate bonds among different molecules is thus favored. Based on these results, we develop a bulk lipophilic polymer solid capable of repeated autonomic recovery of strength in seawater without manual intervention. When the polymer is damaged in seawater, reshuffling of the mobile hyperbranched polymer networks across the crack interface, owing to the dynamic catechol-Fe
crosslinkages activated by the alkaline circumstances, rebinds the damaged site. By taking advantage of the same mechanism, the polymer can be remolded with the help of seawater and this recycled polymer is still self-healable in seawater. Unlike in the case of conventional polymers where water would shield macromolecules from interacting, here, seawater is a necessary environmental assistant for the material interaction to take effect. The outcomes are beneficial for deepening the understanding of coordinate bonds, and the development of robust underwater self-healing lipophilic polymers.
A fluorescent method is described for trypsin determination through the strong electrostatic interactions between cationic polyelectrolytes and single-stranded DNA (ssDNA) templated Au nanoclusters ...(AuNCs). The ssDNA-AuNCs display improved fluorescence emission with excitation/emission maxima at 280/475 nm after being incorporated with poly(diallyldimethylammonium chloride) (PDDA). Fluorescent enhancement is mainly attributed to the electrostatic interactions occurring between PDDA and ssDNA templates. This can make the conformation of the ssDNA templates to change. Thus, it offers a better microenvironment for stabilizing and protecting ssDNA-AuNCs, and results in fluorescence emission enhancement. By using protamine as a model, the method is employed for the determination of trypsin. The assay enables trypsin to be determined with good sensitivity and a linear response ranging from 5 ng⋅mL
−1
to 60 ng⋅mL
−1
with a 1.5 ng⋅mL
−1
limit of detection. It is also extended to determine the trypsin contents in human’s serum samples with recoveries between 98.7% and 103.5% with relative standard deviations (RSDs) between 3.5% and 4.8%.
Graphical abstract
A novel fluorescent strategy has been developed for of trypsin determination by using protamine mediated fluorescent enhancement of DNA templated Au nanoclusters.
A self-healing system based on conventional epoxy resin was successfully developed in this work. Epoxy and its hardener mercaptan were microencapsulated as two-component healing agent, and then the ...microcapsules were embedded in epoxy matrix. Attractive healing effect can be acquired at low capsule content (e.g., 43.5% healing efficiency with 1 wt % capsules and 104.5% healing efficiency with 5 wt % capsules at 20 °C for 24 h). Since only a few healant proves to be sufficient for crack repairing, a better balance between strength and toughness restoration can thus be achieved. As a result of high flowability, fast consolidation, and molecular miscibility of the released healing agent consisting of epoxy and mercaptan, self-healing was allowed to proceed rapidly offering satisfactory repair effectiveness.
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The combination of polymers can produce a multicomponent polymeric system, with advanced performance that cannot be achieved by the individual components. An ideal case lies in the ...creation of all interface materials to maximize the synergistic hybrid effects. Thus far, however, even for the elaborate interpenetrating polymer networks, microheterogeneity is inevitably observed. Herein, we show a conceptual innovative approach to prepare molecular-level interlocking polymer networks by topological reorganization of two immiscible single polymer networks with orthogonal reversible covalent crosslinkages. The conventional phase separation is suppressed as gelation proceeds, and the interlocked networks are further unlocked to a homogenous structure, recovering the original single polymer networks. The resultant interlocking polymer networks show nonlinear improvement in mechanical performance in addition to smart adaptivity like self-healability. An extensible platform technology for bringing in new materials may thus be developed, which is breakthrough in the scope of classic polymer engineering dominated by irreversible covalent chemistry. Furthermore, the long-range interlocked networks themselves are a promising model system for studying soft condensed matter physics.
A systematic review and meta-analysis was conducted to evaluate the efficacy and safety of macrolide therapy in adults and children with bronchiectasis.
We searched the PUBMED, EMBASE, CENTRAL ...databases to identify relevant studies. Two reviewers evaluated the studies and extracted data independently. The primary outcome was the number of bronchiectasis exacerbations. Secondary outcomes included exacerbation-related admissions, quality of life (QoL), spirometry, 6-minute walk test (6MWT) and adverse events.
Nine eligible trials with 559 participants were included. Six were conducted on adults, and the remaining on children. Macrolide therapy significantly reduced the number of patients experiencing one or more exacerbation in adults risk ratio (RR) = 0.59; 95% CI, 0.40 to 0.86; P = 0.006; I2 = 65% and children RR = 0.86; 95% CI, 0.75-0.99; P = 0.04; I2 = 0%, but not the number of patients with admissions for exacerbation. Macrolide therapy was also associated with reduced frequency of exacerbations in adults (RR = 0.42; 95% CI, 0.29 to 0.61; P<0.001; I2 = 64%) and children (RR = 0.50; 95% CI, 0.35 to 0.71; P<0.001). Pooled analyses suggested that spirometry, including FEV1 and FVC, were significantly improved in adults but not in children. Macrolide therapy improved the QoL (WMD, -6.56; 95% CI, -11.99 to -1.12; P = 0.02; I2 = 86%) but no significant difference in 6MWT (WMD, 4.15; 95% CI, -11.83 to 20.13; P = 0.61; I2 = 31%) and the overall adverse events (RR, 0.96; 95% CI, 0.82 to 1.13; P = 0.66; I2 = 0%) in adults. However, reports of diarrhea and abdominal discomforts were higher with macrolide therapy.
Macrolide maintenance therapy, both in adults and children, was effective and safe in reducing bronchiectasis exacerbations, but not the admissions for exacerbations. In addition, macrolide administration in adults was associated with improvement in QoL and spirometry, but not 6WMT. Future studies are warranted to verify the optimal populations and clarify its potential effects on antimicrobial resistance.
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