Polyphenol-Assisted Chemical Crosslinking: A New Strategy to Achieve Highly Crosslinked, Antioxidative, and Antibacterial Ultrahigh-Molecular-Weight Polyethylene for Total Joint Replacement

Highly crosslinked ultrahigh-molecular-weight polyethylene (UHMWPE) bearings are wear-resistant to reduce aseptic loosening but are susceptible to oxidize in vivo/in vitro, as reported in clinical studies. Despite widespread acceptance of antioxidants in preventing oxidation, the crosslinking efficiency of UHMWPE is severely impacted by antioxidants, the use of which was trapped in a trace amount. Herein, we proposed a new strategy of polyphenol-assisted chemical crosslinking to facilitate the formation of a crosslinking network in high-loaded tea polyphenol/UHMWPE blends. Epigallocatechin gallate (EGCG), a representative of tea polyphenol, was mixed with UHMWPE and peroxide. Multiple reactive phenolic hydroxyl groups of tea polyphenol coupled with the nearby free radicals to form extra crosslinking sites. The crosslinking efficiency was remarkably enhanced with increasing tea polyphenol content, even at a concentration of 8 wt %. Given by the hydrogen donation principle, the high-loaded tea polyphenol also enhanced the oxidation stability of the crosslinked UHMWPE. The antioxidative performance was preserved even after tea polyphenol elution. Moreover, superior antibacterial performance was achieved by the in situ tea polyphenol release from the interconnected pathways in the present design. The strategy of polyphenol-assisted chemical crosslinking is applicable for producing highly crosslinked, antioxidative, and antibacterial UHMWPE, which has promising prospects in clinical applications.

Antibacterial and anti-inflammatory ultrahigh molecular weight polyethylene/tea polyphenol blends for artificial joint applications

Periprosthetic joint infection (PJI) is one of the main causes for the failure of joint arthroplasty. In view of the limited clinical effect of oral/injectable antibiotics and the drug resistance problem, there is a pressing need to develop antibacterial implants with therapeutic antimicrobial properties. In this work, we prepared a highly antibacterial ultrahigh molecular weight polyethylene (UHMWPE) implant by incorporating tea polyphenols. The presence of tea polyphenols not only improved the oxidation stability of irradiated UHMWPE, but also gave it the desirable antibacterial property. The potent antibacterial activity was attributed to the tea polyphenols that produced excess intracellular reactive oxygen species and destroyed the bacterial membrane structure. The tea polyphenol-blended UHMWPE had no biological toxicity to human adipose-derived stem cells and effectively reduced bacteria-induced inflammation in vivo. These results indicate that tea polyphenol-blended UHMWPE is promising for joint replacement prostheses with multifunctionality to meet patient satisfaction.

Stretchable Liquid Metal-Based Conductive Textile for Electromagnetic Interference Shielding

Conductive textiles (CTs) are promising electromagnetic interference (EMI) shielding materials. Nevertheless, limited stretchability and poor reliability restrict their potential applications in stretchable electronic devices because of the rigid conductive networks. Herein, a highly stretchable and reliable CT is developed for effective EMI shielding by designing a deformable liquid-metal (LM) coating and polydimethylsiloxane (PDMS) protective layer. The resultant PDMS-LM/Textile exhibits an outstanding EMI shielding efficiency (EMI SE) of 72.6 dB at a thickness of only 0.35 mm while maintaining EMI SEs of 66.0 and 52.4 dB under strains of 30 and 50%, respectively. The corresponding EMI SEs hold 91.7 and 80.3% retention after 5000 stretching-releasing cycles, respectively. The superior and durable EMI SE should be ascribed to the perfect connectivity and good deformability of conductive LM networks. Moreover, the LM coating has a robust fastness to the textile substrate, without any obvious decrease in EMI SE after 10 min of ultrasonic treatment and 100 peeling cycles because of the protective effect of the PDMS layer. This work provides a novel route to developing highly stretchable CTs for advanced EMI shielding applications, especially in the field of highly stretchable electronic devices.

Remifentanil protects neurological function of rats with cerebral ischemia-reperfusion injury via NR2B/CaMKIIα signaling pathway

The effects of remifentanil were studied on cerebral ischemia-reperfusion injury (IRI) in rats, and its regulatory effect was explored on the N-methyl D-aspartate receptor subtype 2B (NR2B)/calcium/calmodulin-dependent protein kinase type II subunit alpha (CaMKII) signaling pathway in cerebral tissues. A total of 40 Sprague-Dawley rats were randomly assigned into sham group, model group, low-dose group (remifentanil injected into the caudal veins at 2 μg/kg) and high-dose group (remifentanil injected into the caudal veins at 10 μg/kg). Then, in the model, low-dose and high-dose groups, the rat model of cerebral IRI was established through middle cerebral artery occlusion (namely, ischemia for 1 h and reperfusion for 2 h), while no thread was inserted into the rats in the sham group. Neurological function of rats in each group was evaluated, and the cerebral infarct size was measured using 2,3,5-triphenyltetrazolium chloride (TTC) staining. Moreover, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining was performed to determine the neuronal apoptosis level, and mitochondrial membrane potential was measured via JC-1 assay. Moreover, the reactive oxygen species (ROS) level in neurons and the malondialdehyde (MDA) content in cerebral tissues were determined using 2',7'-dichlorofluorescin diacetate (DCFH-DA) assay and enzyme-linked immunosorbent assay (ELISA), respectively. Finally, the expression levels of apoptosis-associated proteins and the NR2B/CaMKIIα signaling pathway-associated proteins in cerebral tissues were measured by Western blotting. Remifentanil preconditioning substantially decreased the neurological score of rats (p<0.01), cerebral infarct size (p<0.01), neuronal apoptosis level (p<0.01), ROS level in neurons (p<0.01), MDA content (p<0.01) and expression levels of cysteinyl aspartate specific proteinase-3 (Caspase-3), NR2B, phosphorylated CaMKIIα (p-CaMKIIα) and p-cAMP responsive element binding protein (p-CREB) (p<0.01), but it increased the mitochondrial membrane potential (p<0.01) and B-cell lymphoma 2 (Bcl-2)/Bcl-2-associated X protein (Bax) ratio (p<0.01). Remifentanil can repress the NR2B/ CaMKIIα signaling pathway in the neurons of rats with cerebral IRI to decrease the p-CREB expression, ROS level and MDA content in neurons, neuronal apoptosis level and cerebral infarct size, and increase the mitochondrial membrane potential, thereby protecting the neurological function.

Combined approaches to reveal genes associated with litter size in Yunshang black goats

Intensive artificial selection has been imposed in Yunshang black goats, the first black specialist mutton goat breed in China, with a breeding object of improving reproductive performance, which has contributed to reshaping of the genome including the characterization of SNP, ROH and haplotype. However, variation in reproductive ability exists in the present population. A WGS was implemented in two subpopulations (polytocous group, PG, and monotocous group, MG) with evident differences of litter size. Following the mapping to reference genome, and SNP calling and pruning, three approaches - GWAS, ROH analysis and detection of signatures of selection - were employed to unveil candidate genes responsible for litter size. Consequently, 12 candidate genes containing OSBPL8 with the minimum P-value were uncovered by GWAS. Differences were observed in the pattern of ROH between two subpopulations that shared similar low inbreeding coefficients. Two ROH hotspots and 12 corresponding genes emerged from ROH pool association analysis. Based on the nS_L statistic, 15 and 61 promising genes were disclosed under selection for MG and PG respectively. Of them, some promising genes participate in ovarian function (PPP2R5C, CDC25A, ESR1, RPS26 and SERPINBs), seasonal reproduction (DIO3, BTG1 and CRYM) and metabolism (OSBPL8, SLC39A5 and SERPINBs). Our study pinpointed some novel promising genes influencing litter size, provided a comprehensive insight into genetic makeup of litter size and might facilitate selective breeding in goats.

Highly improved aqueous lubrication of polymer surface by noncovalently bonding hyaluronic acid-based hydration layer for endotracheal intubation

Hydration lubrication is the key responsible for the exceptionally low boundary friction between biosurfaces. However, it is a challenge to settle a hydration layer on a polymer surface via a noncovalent manner. Herein, we develop a highly lubricated coating absorbed onto the polymer surface via intermolecular association of hyaluronic acid (HA)-based micelles. A poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) triblock copolymer (Pluronic, F127) is recruited to complex with HA and further self-assembled to form a thick micelle layer. High water-retaining capacity of the HA/F127 coating enables the decorated surface with excellent hydrophilicity and boundary lubrication, where the coefficient of friction in aqueous media is reduced by 60% compared with the bare polymer surface. The HA/F127 coating suppresses nonspecific protein adsorption and exhibits good biocompatibility. More remarkably, an in vivo cynomolgus monkey model, demonstrates the utility of the HA/F127 coating in alleviating or preventing complications of endotracheal intubation, such as foreign irritation, airway mucosal damage, and inflammatory response. This cost-effective and scalable approach is suitable to manufacture interventional devices especially disposable medical devices with highly lubricated surface.

[Progress of researches on the role of neutrophil extracellular traps in the immune responses against parasites]

Neutrophil extracellular trap (NET) is a type of bead-like, fibrous and reticular substances that is actively released by activated inflammatory neutrophils during the stage of infections or inflammatory responses. NET, which is composed of chromatin DNA and multiple intracellular protein components, may wrap pathogens to limit their diffusions. Meanwhile, NET may kill pathogens via a wide range of antibacterial proteins, which is considered as the third antibacterial mechanism of neutrophils, in addition to phagocytosis and degranulation. Recent studies have shown the involvement of NET in the immune response against parasitic infections. This review summarizes the advances of NETs in the immune responses against parasitic infections, so as to provide insights into the elucidation of the pathogenesis and development of therapeutics of parasitic diseases.

Specific Interaction With Human Serum Albumin Reduces Ginsenoside Cytotoxicity in Human Umbilical Vein Endothelial Cells

Human serum albumin (HSA) is an important component of plasma, which has the functions of maintaining colloid osmotic pressure and capillary membrane stability, promoting blood circulation, and anti-oxidation. Three-dimensional structure of HSA determines its ability to bind and transport hormones and other substances. In this study we examined the interactions between HSA and ginsenoside Rg3, Rg5, Rk1, Rh2, and Rh4, which are the main cytotoxic ginsenosides extracted from red ginseng. Heat transfer generated by the specific interaction between HSA and each ginsenoside was measured using isothermal titration calorimetry (ITC) assay, which demonstrated that all these 5 ginsenosides bound to HSA with binding constants of 3.25, 1.89, 6.04, 2.07, and 5.17 × 10⁵ M⁻¹, respectively. Molecular docking also displayed that these ginsenosides interact with HSA at different sites of the HSA surface. Importantly, cell viability assay showed that the cytotoxicity of these ginsenosides reduced significantly at the presence of HSA in human vascular endothelial cells (HUVEC). Taken together, this study reveals the mechanism by which these ginsenosides are transported in vivo by not causing damage in vascular endothelium, and also suggests HSA might be an ideal carrier help to transport and execute these ginsenoside functions in human body.

Structuring Hierarchically Porous Architecture in Biomass-Derived Carbon Aerogels for Simultaneously Achieving High Electromagnetic Interference Shielding Effectiveness and High Absorption Coefficient

Developing high-performance electromagnetic interference (EMI) shielding materials with high absorption coefficient is highly desired for eliminating the secondary pollution of reflected electromagnetic wave (EMW). Nevertheless, it has long been a daunting challenge to achieve high shielding effectiveness (SE) and ultralow or no reflection SE simultaneously. Herein, highly porous and conductive carbon nanotube (CNT)-based carbon aerogel with a meticulously designed hierarchically porous structure from micro and sub-micro to nano levels is developed by specific two-stage pyrolysis and potassium hydroxide activation processes. The resultant activated cellulose-derived carbon aerogels (a-CCAs) exhibit an ultrahigh EMI SE of 96.4 dB in the frequency range of 8.2-12.4 GHz in conjunction with an exceptionally high absorption coefficient of 0.79 at a low density of 30.5 mg cm^-3. The successful construction of hierarchically porous structure is responsible for the excellent "structurally absorbing" ability of a-CCAs, and the introduction of CNT-based heterogeneous conductive network can effectively dissipate the incident EMWs by interfacial polarization and microcurrent losses. Moreover, the as-prepared a-CCAs have a water contact angle of as high as 158.3°and a sliding angle of as low as 5.3°, revealing their superhydrophobic feature. The ingenious structure design proposed here provides a possible pathway to overcome the conflict between high EMI shielding performance and ultralow or no secondary reflection, and the as-prepared a-CCAs are exceedingly promising in the application of telecommunication, microelectronics, and spacecraft.

Lightweight and Robust Carbon Nanotube/Polyimide Foam for Efficient and Heat-Resistant Electromagnetic Interference Shielding and Microwave Absorption

Excellent electromagnetic interference (EMI) shielding ability, light weight, and good heat resistance are highly required for practical applications of EMI shielding materials, such as in areas of aerospace, aircraft, and automobiles. Herein, a lightweight and robust carbon nanotube (CNT)/polyimide (PI) foam was developed for efficient and heat-resistant EMI shielding. Thanks to poly(vinyl pyrrolidone) (PVP) as a surfactant that not only promotes the uniform dispersion of CNTs to form perfect CNT conductive networks but also can be removed in situ during the polymerization process, the density of resultant CNT/PI foam is only 32.1 mg·cm^-3, and the EMI shielding effectiveness (EMI SE) is up to 41.1 dB, which represents one of the highest EMI SE values compared to previously reported polymer-based foams. The CNT/PI foam also achieves the absorption coefficient (A) of up to 82.3%, which is very impressive in CNT/polymer foams at comparable EMI SE levels. The PI matrix endows the foam with excellent heat resistance. The as-prepared CNT/PI foam presents a higher EMI SE than 35 dB even after being subjected to the flame of an alcohol burner. Moreover, the compressive strength and compressive modulus are up to 240.9 and 323.9 kPa. These results indicate its certain application potential in the harsh requirement of aeronautics and aerospace industries as a highly efficient and lightweight EMI shielding material.

Genomic origin and EGFR-TKI treatments of pulmonary adenosquamous carcinoma

BACKGROUND

Adenosquamous carcinoma (ASC) of the lung is a heterogeneous disease that is composed of both adenocarcinoma components (ACC) and squamous cell carcinoma components (SCCC). Their genomic profile, genetic origin, and clinical management remain controversial.

PATIENTS AND METHODS

Resected ASC and metastatic tumor in regional lymph nodes (LNs) were collected. The ACC and SCCC were separated by microdissection of primary tumor. The 1021 cancer-related genes were evaluated by next-generation sequencing independently in ACC and SCCC and LNs. Shared and private alterations in the two components were investigated. In addition, genomic profiles of independent cohorts of adenocarcinomas and squamous cell carcinomas were examined for comparison. We have also carried out a retrospective study of ASCs with known EGFR mutation status from 11 hospitals in China for their clinical outcomes.

RESULTS

The most frequent alterations in 28 surgically resected ASCs include EGFR (79%), TP53 (68%), MAP3K1 (14%) mutations, EGFR amplifications (32%), and MDM2 amplifications (18%). Twenty-seven patients (96%) had shared variations between ACC and SCCC, and pure SCCC metastases were not found in metastatic LNs among these patients. Only one patient with geographically separated ACC and SCCC had no shared mutations. Inter-component heterogeneity was a common genetic event of ACC and SCCC. The genomic profile of ASC was similar to that of 170 adenocarcinomas, but different from that of 62 squamous cell carcinomas. The incidence of EGFR mutations in the retrospective analysis of 517 ASCs was 51.8%. Among the 129 EGFR-positive patients who received EGFR-TKIs, the objective response rate was 56.6% and the median progression-free survival was 10.1 months (95% confidence interval: 9.0-11.2).

CONCLUSIONS

The ACC and SCCC share a monoclonal origin, a majority with genetically inter-component heterogeneity. ASC may represent a subtype of adenocarcinoma with EGFR mutation being the most common genomic anomaly and sharing similar efficacy to EGFR TKI.

The optimal peripheral oxygen saturation may be 95-97% for post-cardiac arrest patients: A retrospective observational study

BACKGROUND

Current post-resuscitation guidelines recommend oxygen titration in adults with the return of spontaneous circulation after cardiac arrest. However, the optimal peripheral oxygen saturation (SpO₂) is still unclear for post-cardiac arrest care.

METHODS

We conducted a retrospective observational study of prospectively collected data of all cardiac arrest patients admitted to the intensive care units between 2014 and 2015. The main exposure was SpO₂, which were interfaced from bedside vital signs monitors as 1-min averages, and archived as 5-min median values. The proportion of time spent in different SpO₂ categories was included in separate multivariable regression models along with covariates. The primary outcome measure was hospital mortality and the proportion of discharged home as the secondary outcome was reported.

RESULTS

2836 post-cardiac arrest patients in ICUs of 156 hospitals were included. 1235 (44%) patients died during hospitalization and 818 (29%) patients discharged home. With multivariate regression analysis, the proportion of time spent in SpO₂ of ≤89%, 90%, 91%, and 92% were associated with higher hospital mortality. The proportion of time spent in SpO₂ of 95%, 96%, and 97% were associated with a higher proportion of discharged home outcome, but not associated with hospital mortality.

CONCLUSIONS

In this retrospective observational study, the optimal SpO₂ for patients admitted to the intensive care unit after cardiac arrest may be 95-97%. Further investigation is warranted to determine if targeting SpO₂ of 95-97% would improve patient-centered outcomes after cardiac arrest.

[Investigation on the content of persistent organic pollutants in fish from Dongting Lake in China]

Objective: To investigate the content of persistent organic pollutants (POPs) in fish from Dongting Lake. Methods: Ten sample collection points were set in lakeside city Yueyang and Yuanjiang. In July (wet season) and November (dry season) of 2012, 13 common fish species were captured by convenience sampling in Dongting Lake. Two to three fish with similar weight were selected in each season for the same species of fish. After sample preparation and pretreatment, the contents of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (dl-PCBs), indicator polychlorinated biphenyls and polybrominated diphenyls ether (PBDEs) in the samples were determined by high resolution gas chromatographer-high resolution mass spectrometry. Toxicity Equivalents (TEQ) of PCDD/Fs and dl-PCBs were calculated according to the revised toxicity equivalent factor (TEF) of WHO in 2005. The contents of POPs were expressed by median and quavtile. The differences of POPs in fish in different periods were compared by Wilcoxon rank sum test. Results: The content of PCDD/Fs of fish in Dongting Lake in wet season was 12.397 (8.865, 24.964) pg/g, higher than that in the dry season 0.771 (0.490, 1.442) pg/g (P<0.001), and the toxicity equivalent quantity (TEQ) were 0.150 (0.066,0.528) and 0.143 (0.066, 0.235) pg-TEQ/g without statistically significant difference (P>0.05). For the fish in wet and dry season from Dongting Lake,Σdl-PCBs of fish were 66.475 (28.065, 77.794) and 24.205 (18.237, 90.777) pg/g, respectively, and the TEQ were 0.061 (0.046, 0.268) and 0.075 (0.054, 0.182) pg-TEQ/g; Σ indicative PCBs were 237.764 (153.896, 335.483) and 119.711 (52.171, 408.696) pg/g, respectively; Σ PBDEs were 106.513 (64.834, 164.860) and 86.837 (61.872, 177.108) pg/g, respectively. The highest content of PCDD/Fs was found in grass carp (198.360 pg/g) in wet season. The higher content of PCBs was found in long-necked fish (2 332.509 pg/g) and PBDEs was found in pelteobagrus fulvidraco (343.857 pg/g), respectively. Conclusion: A lower burden was found in fishes from Dongting Lake, and the content of POPs varied in different seasons and fishes.