3-carene supresses inflammatory cytokine interleukin-4, interleukin-5 and interleukin-13 in a murine model of asthma

Asthma is a common airway disease associated with allergic inflammation. Environmental factors, such as pollens, pollution, insect-borne antigens, or commercial chemicals, cause this disease. The common symptoms of this airway allergic reaction are increasing mucus, narrowing of the airway wall, coughing, and chest tightness. Medications, such as steroids, alleviate the disease but with severe side effects. Several studies have reported the anti-inflammatory effects of tree-based essential oil components, particularly 3-carene. Therefore, this study used 3-carene to determine if it alleviates asthmatic symptoms in the murine model. First, BALB/c mice were sensitized to an ovalbumin and aluminium hydroxide mixture on day 7th and 14th. From days 21st to 23rd, the mice were challenged with 3-carene and budesonide. The lung trachea, plasma, and bronchiolar lavage fluid (BAL fluid) were collected on day 24. The 3-carene treatment suppressed the cytokine gene expression, such as interleukin-4 (IL-4), IL-5, and IL-13, reducing the lung epithelial cell thickness in the asthmatic model. These results suggest that essential oil 3-carene has an anti-asthmatic effect.

High-Temporal-Resolution In Situ Sensor for Oceanic CO2 Isotope Measurement Enabling Multidimensional Isotope Tracing Analysis (R13C, R18O, and R17O) via Laser Absorption Spectroscopy

Combined in situ analysis of oceanic CO2 concentrations and diverse C and O isotope characteristics can offer a unique perspective with multiple isotopic tracing dimensions for identifying marine biogeochemical processes. Applying this strategy in marine environments is urgently required, yet it faces inherent challenges in terms of existing analytical methods and instruments, e.g., a lack of in situ sensors, limited detectable isotope variety, and low-temporal-resolution data. Here, we report an underwater in situ dissolved CO2 isotope sensor based on mid-infrared tunable diode laser absorption spectroscopy (MIR-TDLAS) and membrane extraction technology. Through the proposed targeted strategies, the sensor is capable of providing high-temporal-resolution in situ measurement of all monosubstituted isotopes of dissolved CO2 (16O13C16O, 18O12C16O, and 17O12C16O) at marine background concentrations. The sensor is demonstrated to provide comparable precision to that of isotope ratio mass spectrometry. At 400 ppmv, the precision for R13C, R18O, and R17O could achieve 0.084, 0.042, and 0.013‰, respectively, for a 1 s integration time. By enabling a high-frequency in situ analysis in fixed-point time-series field deployment, a 17O anomaly with strong regularity is observed, which is not obvious in 18O and 13C, and therefore, the superiority of the proposed multidimensional in situ isotope tracing strategy is demonstrated. The developed sensor has great potential to open up new prospects for advancing marine carbon research.

Research on the impact of internet use on fertilizer and pesticide inputs: Empirical evidence from China

Fertilizers and pesticides are important agricultural production materials. Excessive use of fertilizers and pesticides can cause negative impacts such as decline in the quality of farm products and damage to the ecological environment. Increasing the efficiency of fertilizers and pesticides is an important step to accelerate the green transformation of agriculture. Using data from the 2015 China Household Finance Survey, this paper analyzes the impacts of Internet use on fertilizers and pesticides by farmers, and the mechanism behind the action with the help of the propensity score matching method and the instrumental variable method. The findings are: (1) Farmers who use the Internet have greater inputs of fertilizers and pesticides compared to farmers who do not use the Internet. (2) Farmers who do not use the Internet would have their inputs of fertilizers and pesticides increased by 21.9% and 47.7%, respectively, if they had used the Internet under the counterfactual hypothesis. (3) In the heterogeneity analysis, Internet use plays a positive and significant role in the inputs of fertilizer and pesticide in the eastern part of China, and Internet use has greater impact on pesticide inputs than on fertilizer in central and western regions. (4) Internet use has a positive and significant effect on fertilizer and pesticide inputs in both lower scale and higher scale operations, and a positive but not significant effect in moderate-scale operations.

PAEs Derivatives' Design for Insulation: Integrated In-Silico Methods, Functional Assessment and Environmentally Friendly Molecular Modification

As a common substance in production and life, phthalic acid esters (PAEs), the main component of plastics, have brought more and more serious problems to the environment. This study normalized the insulation, toxicity, and bioconcentration data of 13 PAEs to eliminate the dimensional coefficients of each index, and then used the comprehensive index method to calculate the comprehensive effect value of PAEs with three properties. The comprehensive effect value was used as the data source to construct the 3D-QSAR model of PAE molecular comprehensive effect. The DAP was selected as the target molecule, the distribution of each force field in the three-dimensional equipotential map was analyzed, and 30 molecular modification schemes were created. The constructed single-effect models of insulation, toxicity, and bioconcentration of PAEs and the scoring function module of DS software were used to evaluate the stability and environmental friendliness of PAE derivative molecules. Four PAE derivatives were screened for increased comprehensive effects, enhanced insulation, and reduced toxicity and bioconcentration. By calculating the binding energy of the target molecule and the derivative molecule with the degrading enzyme under different applied electric fields, it was found that the binding energy of DAP-1-NO2-2-CH2C6H5 decreases more than DAP does when there is an applied electric field, indicating that the degradation ability of degrading enzymes on PAE derivative molecules is reduced, which indirectly proves that the insulation is enhanced. The innovation of this paper lies in the insulation, toxicity, and bioenrichment data of PAEs being processed by mathematical method for the first time, and PAEs with high insulation, low toxicity, and low bioconcentration were designed by building a comprehensive model.

Risk Factors in Patients with Diabetes Hospitalized for COVID-19: Findings from a Multicenter Retrospective Study

METHODS

In this multicenter retrospective study, patients with COVID-19 in China were included and classified into two groups according to whether they were complicated with diabetes or not. Demographic symptoms and laboratory data were extracted from medical records. Univariable and multivariable logistic regression methods were used to explore the risk factors.

RESULTS

538 COVID-19 patients were finally included in this study, of whom 492 were nondiabetes and 46 were diabetes. The median age was 47 years (IQR 35.0-56.0). And the elderly patients with diabetes were more likely to have dry cough, and the alanine aminotransferase, lactate dehydrogenase, Ca, and mean hemoglobin recovery rate were higher than the other groups. Furthermore, we also found the liver and kidney function of male patients was worse than that of female patients, while female cases should be paid more attention to the occurrence of bleeding and electrolyte disorders. Moreover, advance age, blood glucose, gender, prothrombin time, and total cholesterol could be considered as risk factors for COVID-19 patients with diabetes through the multivariable logistic regression model in our study.

CONCLUSION

The potential risk factors found in our study showed a major piece of the complex puzzle linking diabetes and COVID-19 infection. Meanwhile, focusing on gender and age factors in COVID-19 patients with or without diabetes, specific clinical characteristics, and risk factors should be paid more attention by clinicians to figure out a targeted intervention to improve clinical efficacy worldwide.

Clinical characteristics and treatment outcome of COVID-19 patients with stroke in China: A multicenter retrospective study

OBJECTIVE

Previous studies mainly reported the clinical characteristics of novel coronavirus 2019 (COVID-19) infections, but the research on clinical characteristics and treatment outcomes of COVID-19 patients with stroke is still rare.

METHODS

A multi-center retrospective study was conducted at 11 hospitals in 4 provinces of China, and COVID-19 patients with stroke were enrolled from February 24 to May 4, 2020. We analyzed epidemiological, demographic, and clinical characteristics of cases as well as the laboratory test results, treatment regimens and outcomes, and the clinical characteristics and therapeutic outcomes were compared between severe and nonsevere patients, and by age group, respectively.

RESULTS

A total of 27 patients [mean age: 66.41 (SD 12.1) years] were enrolled. Among them, 9 (33.3%) were severe patients and 18 (66.7%) were nonsevere patients; 17 (63.0%) were female; 19 (70.4%) were aged 60 years and above. The most common symptoms were fever [19 (70.4%)], fatigue [12 (44.4%)] and cough [11 (40.7%)], respectively. Abnormal laboratory findings of COVID-19 patients with stroke included high levels of C-reactive protein [19 (73.1%)], D-dimer [14 (58.3%)], blood glucose [14 (53.8%)], fibrinogen [13 (50.0%)], and decreased lymphocytes [12 (44.4%)]. Comparing to nonsevere cases with stroke, severe patients with stroke were likely to be older, susceptible to receiving oxygen inhalation, and had more complications (p < 0.05). In addition, there were significant differences in lymphocytes, neutrophils, lactate dehydrogenase, C-reactive protein, creatine kinase between the severe cases and nonsevere cases (p < 0.05). The older patients had a decreased platelet count and elevated fibrinogen, compared with the younger (p < 0.05). All patients (100%) received antiviral treatment, 12 (44.4%) received antibiotics treatment, 26 (96.3%) received Traditional Chinese Medicine (Lung cleansing & detoxifying decoction), and oxygen inhalation was in 18 (66.7%). The median duration of hospitalization was 16 days. By May 4, 2020, a total of 26 (96.3%) patients were cured and discharged, and 1 (3.7%) patients died.

CONCLUSION

COVID-19 patients with stroke had poor indicators of coagulation system, and severe and older patients might have a higher risk of complications and unfavorable coagulation system. However, the overall treatment outcome is favorable.

Association of Overlapped and Un-overlapped Comorbidities with COVID-19 Severity and Treatment Outcomes: A Retrospective Cohort Study from Nine Provinces in China

OBJECTIVE

Several COVID-19 patients have overlapping comorbidities. The independent role of each component contributing to the risk of COVID-19 is unknown, and how some non-cardiometabolic comorbidities affect the risk of COVID-19 remains unclear.

METHODS

A retrospective follow-up design was adopted. A total of 1,160 laboratory-confirmed patients were enrolled from nine provinces in China. Data on comorbidities were obtained from the patients' medical records. Multivariable logistic regression models were used to estimate the odds ratio ( OR) and 95% confidence interval (95% CI) of the associations between comorbidities (cardiometabolic or non-cardiometabolic diseases), clinical severity, and treatment outcomes of COVID-19.

RESULTS

Overall, 158 (13.6%) patients were diagnosed with severe illness and 32 (2.7%) had unfavorable outcomes. Hypertension (2.87, 1.30-6.32), type 2 diabetes (T2DM) (3.57, 2.32-5.49), cardiovascular disease (CVD) (3.78, 1.81-7.89), fatty liver disease (7.53, 1.96-28.96), hyperlipidemia (2.15, 1.26-3.67), other lung diseases (6.00, 3.01-11.96), and electrolyte imbalance (10.40, 3.00-26.10) were independently linked to increased odds of being severely ill. T2DM (6.07, 2.89-12.75), CVD (8.47, 6.03-11.89), and electrolyte imbalance (19.44, 11.47-32.96) were also strong predictors of unfavorable outcomes. Women with comorbidities were more likely to have severe disease on admission (5.46, 3.25-9.19), while men with comorbidities were more likely to have unfavorable treatment outcomes (6.58, 1.46-29.64) within two weeks.

CONCLUSION

Besides hypertension, diabetes, and CVD, fatty liver disease, hyperlipidemia, other lung diseases, and electrolyte imbalance were independent risk factors for COVID-19 severity and poor treatment outcome. Women with comorbidities were more likely to have severe disease, while men with comorbidities were more likely to have unfavorable treatment outcomes.

Clinical features and risk factors for severe inpatients with COVID-19: A retrospective study in China

Background

A worldwide outbreak of coronavirus disease (COVID-19), since 2019, has brought a disaster to people all over the world. Many researchers carried out clinical epidemiological studies on patients with COVID-19 previously, but risk factors for patients with different levels of severity are still unclear.

Methods

562 patients with laboratory-confirmed COVID-19 from 12 hospitals in China were included in this retrospective study. Related clinical information, therapies, and imaging data were extracted from electronic medical records and compared between patients with severe and non-severe status. We explored the risk factors associated with different severity of COVID-19 patients by logistic regression methods.

Results

Based on the guideline we cited, 509 patients were classified as non-severe and 53 were severe. The age range of whom was 5–87 years, with a median age of 47 (IQR 35.0–57.0). And the elderly patients (older than 60 years old) in non-severe group were more likely to suffer from fever and asthma, accompanied by higher level of D-dimer, red blood cell distribution width and low-density lipoprotein. Furthermore, we found that the liver and kidney function of male patients was worse than that of female patients in both severe and non-severe groups with different age levels, while the severe females had faster ESR and lower inflammatory markers. Of major laboratory markers in non-severe cases, baseline albumin and the lymphocyte percentage were higher, while the white blood cell and the neutrophil count were lower. In addition, severe patients were more likely to be accompanied by an increase in cystatin C, mean hemoglobin level and a decrease in oxygen saturation. Besides that, advanced age and indicators such as count of white blood cell, glucose were proved to be the most common risk factors preventing COVID-19 patients from aggravating.

Conclusion

The potential risk factors found in our study have shown great significance to prevent COVID-19 patients from aggravating and turning to critical cases during treatment. Meanwhile, focusing on gender and age factors in groups with different severity of COVID-19, and paying more attention to specific clinical symptoms and characteristics, could improve efficacy of personalized intervention to treat COVID-19 effectively.

Association between early treatment with Qingfei Paidu decoction and favorable clinical outcomes in patients with COVID-19: A retrospective multicenter cohort study

The coronavirus disease 2019 (COVID-19) epidemic has been almost controlled in China under a series of policies, including "early diagnosis and early treatment". This study aimed to explore the association between early treatment with Qingfei Paidu decoction (QFPDD) and favorable clinical outcomes. In this retrospective multicenter study, we included 782 patients (males, 56 %; median age 46) with confirmed COVID-19 from 54 hospitals in nine provinces of China, who were divided into four groups according to the treatment initiation time from the first date of onset of symptoms to the date of starting treatment with QFPDD. The primary outcome was time to recovery; days of viral shedding, duration of hospital stay, and course of the disease were also analyzed. Compared with treatment initiated after 3 weeks, early treatment with QFPDD after less than 1 week, 1-2 weeks, or 2-3 weeks had a higher likelihood of recovery, with adjusted hazard ratio (HR) (95 % confidence interval [CI]) of 3.81 (2.65-5.48), 2.63 (1.86-3.73), and 1.92 (1.34-2.75), respectively. The median course of the disease decreased from 34 days to 24 days, 21 days, and 18 days when treatment was administered early by a week (P < 0.0001). Treatment within a week was related to a decrease by 1-4 days in the median duration of hospital stay compared with late treatment (P<0.0001). In conclusion, early treatment with QFPDD may serve as an effective strategy in controlling the epidemic, as early treatment with QFPDD was associated with favorable outcomes, including faster recovery, shorter time to viral shedding, and a shorter duration of hospital stay. However, further multicenter, prospective studies with a larger sample size should be conducted to confirm the benefits of early treatment with QFPDD.

Theoretical Design of Biodegradable Phthalic Acid Ester Derivatives in Marine and Freshwater Environments

The biodegradability of phtalic acid esters in marine and freshwater environments was characterized by their binding free energy with corresponding degrading enzymes. According to comprehensive biodegradation effects weights, the binding free energy values were converted into dimensionless efficacy coefficient using ratio normalization method. Then, considering comprehensive dual biodegradation effects value and the structural parameters of PAEs in both marine and freshwater environments, a 3D‐QSAR pharmacophore model was constructed, five PAE derivatives (DBP−COOH, DBP−CHO, DBP−OH, DINP−NH₂, and DINP−NO₂) were screened out based on their environmental friendliness, functionality and stability. The prediction of biodegradation effects on five PAE derivatives by biodegradation models in marine and freshwater environment increased by 15.90 %, 15.84 %, 27.21 %, 12.33 %, and 8.32 %, and 21.57 %, 15.21 %, 20.99 %, 15.10 %, and 9.74 %, respectively. By simulating the photodegradation path of the PAE derivative molecular, it was found that DBP−OH can generate ^.OH and provides free radicals for the photodegradation of microplastics in the environment.

Enhanced Biodegradation of Phthalic Acid Esters' Derivatives by Plasticizer-Degrading Bacteria (Burkholderia cepacia, Archaeoglobus fulgidus, Pseudomonas aeruginosa) Using a Correction 3D-QSAR Model

A phthalic acid ester’s (PAEs) comprehensive biodegradability three-dimensional structure-activity relationship (3D-QSAR) model was established, to design environmentally friendly PAE derivatives, which could be simultaneously degraded by plasticizer-degrading bacteria, such as Burkholderia cepacia, Archaeoglobus fulgidus, and Pseudomonas aeruginosa. Only three derivatives of diethyl phthalate (DEP (DEP-27, DEP-28 and DEP-29)) were suited for their functionality and environmental friendliness, which had an improved stability in the environment and improved the characteristics (bio-toxicity, bioaccumulation, persistence, and long-range migration) of the persistent organic pollutants (POPs). The simulation inference of the microbial degradation path before and after DEP modification and the calculation of the reaction energy barrier exhibited the energy barrier for degradation being reduced after DEP modification and was consistent with the increased ratio of comprehensive biodegradability. This confirmed the effectiveness of the comparative molecular similarity index analysis (CoMSIA) model of the PAE’s comprehensive biodegradability. In addition, a molecular dynamics simulation revealed that the binding of the DEP-29 derivative with the three plasticizer-degradation enzymes increased significantly. DEP-29 could be used as a methyl phthalate derivative that synergistically degrades with microplastics, providing directional selection and theoretical designing for plasticizer replacement.

Highly selective cis-1,4 copolymerization of dienes with polar 2-(3-methylidenepent-4-en-1-yl) pyridine: an approach for recyclable elastomers

We report the coordination copolymerization of a new polar diene-based monomer (MPEP), with isoprene or butadiene. After being quaternized, the resultant materials exhibit remarkable thermal reshaping and recycling properties.

Investigations of the humidity sensing properties of side-chain-type sulfonated poly (arylene ether ketone)s

Side-chain-type sulfonated poly (arylene ether ketone)s containing naphthalene moieties with a degree of sulfonation (Ds) from 0.2 to 1.9 were synthesized. Humidity sensors were fabricated by cast coating on silver–palladium interdigital microelectrodes. The properties of this series of materials in terms of water absorption, glass transition temperature, and humidity sensing were characterized in detail. The investigations on the humidity sensing performance showed that with the increase in the Ds, the hysteresis of our materials exhibits an increasing trend first, followed by a decrease. This special phenomenon has not been reported before and caught our attention. From the results of humidity sensing properties, among the materials, the one with 0.2 Ds is promising for applications in humidity sensing due to its small hysteresis and fast response to varied relative humidity (RH). For a better understanding of the humidity sensing behavior of the sensor, complex impedance spectra were also measured. In the long-term stability measurement, the deviation of the measured impedance of the sensor at 97% RH is not obvious, proving good stability in a humid environment.

Preparation of a Cross-Linked Sulfonated Poly(arylene ether ketone) Proton Exchange Membrane with Enhanced Proton Conductivity and Methanol Resistance by Introducing an Ionic Liquid-Impregnated Metal Organic Framework

A novel ionic liquid-impregnated metal-organic-framework (IL@NH₂-MIL-101) was prepared and introduced into sulfonated poly(arylene ether ketone) with pendent carboxyl groups (SPAEK) as the nanofiller for achieving hybrid proton exchange membranes. The nanofiller was anchored in the polymeric matrix by the formation of amido linkage between the pendent carboxyl group attached to the molecule chain of SPAEK and amino group belonging to the inorganic framework, thus leading to the enhancement in mechanical properties and dimensional stability. Besides, the hybrid membrane (IL@MOF-1) exhibits an enhanced proton conductivity up to 0.184 S·cm^-1 because of the incorporation of ionic liquid in the nanocages of NH₂-MIL-101. Moreover, the special structure of NH₂-MIL-101 contributes to a low leakage of ionic liquid so as to retain the stable proton conductivity of hybrid membranes under fully hydrated conditions. Furthermore, as a result of a cross-linked structure formed by inorganic nanofiller, the IL@MOF-1 hybrid membrane shows a lower methanol permeability (7.53 × 10^-7 cm² s^-1) and superior selectivity (2.44 × 10⁵ S s cm^-3) than the pristine SPAEK membrane. Especially, IL@MOF-1 performs high single-cell efficiency with a peak power density of 37.5 mW cm^-2, almost 2.3-fold to SPAEK. Electrochemical impedance spectroscopy and scanning electron microscopy indicated that the nanofiller not only contributed to faster proton transfer but also resulted in a tighter bond between the membrane and catalyst. Therefore, the incorporation of IL@NH₂-MIL-101 to prepare the hybrid membrane is proven to be suitable for application in direct methanol fuel cells.

A comparative study of side-chain-type poly(ether ether ketone) anion exchange membrane functionalized with different hetero-cycloaliphatic quaternary ammonium groups

Anion exchange membranes based on side-chain-type quarternized poly(ether ether ketone)s (QPEEKs), containing different hetero-cycloaliphatic quaternary ammonium groups, were prepared via a multi-step procedure, including polycondensation with a monomer containing pendant methylphenyl groups, bromomethylation, and followed by quaternization with 1-methylpyrrolidine (MPY), 1-methylpiperidine (MPRD), 1-methylimidazole (MIDZ) and N-methyl morpholine (MMPH), respectively. The properties of these membranes were then compared with the properties of conventional quarternized poly(ether ether ketone)s containing benzyltrimethylammonium (QPEEK-TMA). Model compounds, QMPY, QMPRD, QMIDZ and QMMPH, were synthesized and used to quantitatively compare the alkaline stability of hetero-cycloaliphatic quaternary ammonium groups using ¹H NMR. The results of this study indicated that the alkaline stability of all these model compounds is in the order of QMPY > QMPRD > QTMA > QMIDZ > QMMPH. These QPEEKs membranes display superior thermal, dimensional and mechanical stability. QPEEK-TMA, QPEEK-MPY and QPEEK-MPRD exhibit higher hydroxide conductivities and lower activation energies than QPEEK-MIDZ and QPEEK-MMPH. Furthermore, after exposure to 1 M NaOH at 60 °C for 24 days, QPEEK-MPY and QPEEK-MPRD demonstrated a loss in hydroxide conductivity of 28.5% and 33.4%, respectively. Both values were lower than that of QPEEK-TMA (37.7%). Therefore, among these side-chain-type QPEEKs membranes, QPEEK-MPY and QPEEK-MPRD, containing benzylmethylpyrrolidinium and benzylmethylpiperidinium as cation head-groups, are promising AEM materials for fuel cell construction.

Anion exchange membranes based on side-chain-type quarternized poly(ether ether ketone)s QPEEKs containing different hetero-cycloaliphatic quaternary ammonium groups were prepared via polycondensation, bromomethylation and quaternization.

Enhanced Proton Conductivity of Sulfonated Hybrid Poly(arylene ether ketone) Membranes by Incorporating an Amino-Sulfo Bifunctionalized Metal-Organic Framework for Direct Methanol Fuel Cells

Novel side-chain-type sulfonated poly(arylene ether ketone) (SNF-PAEK) containing naphthalene and fluorine moieties on the main chain was prepared in this work, and a new amino-sulfo-bifunctionalized metal-organic framework (MNS, short for MIL-101-NH₂-SO₃H) was synthesized via a hydrothermal technology and postmodification. Then, MNS was incorporated into a SNF-PAEK matrix as an inorganic nanofiller to prepare a series of organic-inorganic hybrid membranes (MNS@SNF-PAEK-XX). The mechanical property, methanol resistance, electrochemistry, and other properties of MNS@SNF-PAEK-XX hybrid membranes were characterized in detail. We found that the mechanical strength and methanol resistances of these hybrid membranes were improved by the formation of an ionic cross-linking structure between -NH₂ of MNS and -SO₃H on the side chain of SNF-PAEK. Particularly, the proton conductivity of these hybrid membranes increased obviously after the addition of MNS. MNS@SNF-PAEK-3% exhibited the proton conductivity of 0.192 S·cm^-1, which was much higher than those of the pristine membrane (0.145 S·cm^-1) and recast Nafion (0.134 S·cm^-1) at 80 °C. This result indicated that bifunctionalized MNS rearranged the microstructure of hybrid membranes, which could accelerate the transfer of protons. The hybrid membrane (MNS@SNF-PAEK-3%) showed a better direct methanol fuel cell performance with a higher peak power density of 125.7 mW/cm² at 80 °C and a higher open-circuit voltage (0.839 V) than the pristine membrane.

Preparation and characterization of silane-modified SiO2 particles reinforced resin composites with fluorinated acrylate polymer

A series of fluorinated dental resin composites were prepared with two kinds of SiO₂ particles. Bis-GMA (bisphenol A-glycerolate dimethacrylate)/4-TF-PQEA (fluorinated acrylate monomer)/TEGDMA (triethylene glycol dimethacrylate) (40/30/30, wt/wt/wt) was introduced as resin matrix. SiO₂ nanopartices (30nm) and SiO₂ microparticles (0.3µm) were silanized with 3-methacryloxypropyl trimethoxysilane (γ-MPS) and used as fillers. After mixing the resin matrix with 0%, 10%, 20%, 30% SiO₂ nanopartices and 0%, 10%, 20%, 30%, 40%, 50% SiO₂ microparticles, respectively, the fluorinated resin composites were obtained. Properties including double bond conversion (DC), polymerization shrinkage (PS), water sorption (W_p), water solubility (W_y), mechanical properties and cytotoxicity were investigated in comparison with those of neat resin system. The results showed that, filler particles could improve the overall performance of resin composites, particularly in improving mechanical properties and reducing PS of composites along with the addition of filler loading. Compared to resin composites containing SiO₂ microparticles, SiO₂ nanoparticles resin composites had higher DC, higher mechanical properties, lower PS and lower W_p under the same filler content. Especially, 50% SiO₂ microparticles reinforced resins exhibited the best flexural strength (104.04 ± 7.40MPa), flexural modulus (5.62 ± 0.16GPa), vickers microhardness (37.34 ± 1.13 HV), compressive strength (301.54 ± 5.66MPa) and the lowest polymerization (3.42 ± 0.22%).

Property Enhancement Effects of Side-Chain-Type Naphthalene-Based Sulfonated Poly(arylene ether ketone) on Nafion Composite Membranes for Direct Methanol Fuel Cells

Nafion/SNPAEK-x composite membranes were prepared by blending raw Nafion and synthesized side-chain-type naphthalene-based sulfonated poly(arylene ether ketone) with a sulfonation degree of 1.35 (SNPAEK-1.35). The incorporation of SNPAEK-1.35 polymer with ion exchange capacity (IEC) of 2.01 mequiv·g^-1 into a Nafion matrix has the property enhancement effects, such as increasing IECs, improving proton conductivity, enhancing mechanical properties, reducing methanol crossover, and improving single cell performance of Nafion. Morphology studies show that Nafion/SNPAEK-x composite membranes exhibit a well-defined microphase separation structure depending on the contents of SNPAEK-1.35 polymer. Among them, Nafion/SNPAEK-7.5% with a bicontinuous morphology exhibits the best comprehensive properties. For example, it shows the highest proton conductivities of 0.092 S cm^-1 at 25 °C and 0.163 S cm^-1 at 80 °C, which are higher than those of recast Nafion with 0.073 S cm^-1 at 25 °C and 0.133 S cm^-1 at 80 °C, respectively. Nafion/SNPAEK-5.0% and Nafion/SNPAEK-7.5% membranes display an open circuit voltage of 0.77 V and a maximum power density of 47 mW cm^-2 at 80 °C, which are much higher than those of recast Nafion of 0.63 V and 24 mW cm^-2 under the same conditions. Nafion/SNPAEK-5.0% membrane also has comparable tensile strength (12.7 MPa) to recast Nafion (13.7 MPa), and higher Young's modulus (330 MPa) than that of recast Nafion (240 MPa). By combining their high proton conductivities, comparable mechanical properties, and good single cell performance, Nafion/SNPAEK-x composite membranes have the potential to be polymer electrolyte materials for direct methanol fuel cell applications.

Synthesis and characterization of a novel resin monomer with low viscosity

OBJECTIVE

In this study, we designed and synthesized a novel macromolecule (tetramethyl bisphenol F acrylate, TMBPF-Ac) with low viscosity, excellent mechanical properties, and good biocompatibility. It could be used as a monomer for dental resin composites, which could reduce the risk of human exposure to bisphenol A derivatives in the oral environment. In addition, the monomer could be used without diluent, thereby avoiding the negative effect of a diluent METHODS: TMBPF-Ac was synthesized by a multistep condensation reaction. Its structure was confirmed by ¹H NMR spectra. Different resin mixtures were prepared, and then a number of performance and cytotoxicity tests were performed on these specimens.

RESULTS

¹H NMR spectra showed that the structure of TMBPF-Ac was in accordance with the design. The viscosity of TMBPF-Ac was obviously lower than that of bisphenol-A diglycidyl methacrylate. The three kinds of resins used in this study were in line with ISO 4049:2009 and ISO 10993-5:2009. TMBPF-Ac-based resin had better physical and biological properties.

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine: Brussels, Belgium. 15-18 March 2016

[This corrects the article DOI: 10.1186/s13054-016-1208-6.].

One-Step Microfluidic Fabrication of Polyelectrolyte Microcapsules in Aqueous Conditions for Protein Release

We report a microfluidic approach for one-step fabrication of polyelectrolyte microcapsules in aqueous conditions. Using two immiscible aqueous polymer solutions, we generate transient water-in-water-in-water double emulsion droplets and use them as templates to fabricate polyelectrolyte microcapsules. The capsule shell is formed by the complexation of oppositely charged polyelectrolytes at the immiscible interface. We find that attractive electrostatic interactions can significantly prolong the release of charged molecules. Moreover, we demonstrate the application of these microcapsules in encapsulation and release of proteins without impairing their biological activities. Our platform should benefit a wide range of applications that require encapsulation and sustained release of molecules in aqueous environments.

Considerations of the Effects of Naphthalene Moieties on the Design of Proton-Conductive Poly(arylene ether ketone) Membranes for Direct Methanol Fuel Cells

Novel sulfonated poly(arylene ether ketones) (SDN-PAEK-x), consisting of dual naphthalene and flexible sulfoalkyl groups, were prepared via polycondensation, demethylation, and sulfobutylation grafting reaction. Among them, SDN-PAEK-1.94 membrane with the highest ion exchange capacity (IEC = 2.46 mequiv·g(-1)) exhibited the highest proton conductivity, which was 0.147 S· cm(-1) at 25 °C and 0.271 S·cm(-1) at 80 °C, respectively. The introduction of dual naphthalene moieties is expected to achieve much enhanced properties compared to those of sulfonated poly(arylene ether ketones) (SNPAEK-x), consisting of single naphthalene and flexible sulfoalkyl groups. Compared with SNPAEK-1.60 with a similar IEC, SDN-PAEK-1.74 membrane showed higher proton conductivity, higher IEC normalized conductivity, and higher effective proton mobility, although it had lower analytical acid concentration. The SDN-PAEK-x membranes with IECs higher than 1.96 mequiv·g(-1) also exhibited higher proton conductivity than that of recast Nafion membrane. Furthermore, SDN-PAEK-1.94 displayed a better single cell performance with a maximum power density of 60 mW·cm(-2) at 80 °C. Considering its high proton conductivity, excellent single cell performance, good mechanical stabilities, low membrane swelling, and methanol permeability, SDN-PAEK-x membranes are promising candidates as alternative polymer electrolyte membranes to Nafion for direct methanol fuel cell applications.

Side-chain-type quaternized naphthalene-based poly(arylene ether ketone)s for anhydrous high temperature proton exchange membranes

The PA/Q-SCT-NPAEK-xx membranes with good proton conductivity, mechanical and thermal stabilities were prepared successfully.

Intermolecular ionic cross-linked sulfonated poly(ether ether ketone) membranes with excellent mechanical properties and selectivity for direct methanol fuel cells

The composite membranes based on APEEK and SPEEK with good proton conductivity, excellent mechanical and thermal stabilities were prepared successfully.

MOFs synthesized by the ionothermal method addressing the leaching problem of IL-polymer composite membranes

The liquid nature of ionic liquids (ILs) limits their use in potential electrolytes due to the problem of leakage. Herein, we design a new strategy to immobilize an ionic liquid by incorporating it within ZIF-8 (ZIF = zeolitic imidazolate framework) by the ionothermal method.

Preparation of Au Nanoparticles Immobilized Cross-Linked Poly(4-vinylpyridine) Nanofibers and Their Catalytic Application for the Reduction of 4-Nitrophenol

Catalytic nanofibers are prepared by the immobilization of Au nanoparticles (AuNPs) onto the surface of cross-linked electrospun poly(4-vinylpyridine) (P4VP) nanofibers. The crosslinking of the P4VP nanofibers by 1,4-diiodobutane via quaternization reaction greatly enhances the stability of the nanofibers against the solvent dissolution, which can then be used as promising platform for the immobilization of catalytic metal nanoparticles. The AuNPs immobilized cross-linked P4VP nanofibers have shown a good catalytic activity for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP).

UV irradiation-induced cross-linked bicarbonate anion exchange membranes based on vinylimidazolium-functionalized poly(arylene ether ketone)

A novel photo-cross-linking strategy for vinylimidazolium-functionalized poly(arylene ether ketone) bicarbonate anion exchange membranes is presented.

One-pot approach to prepare high-performance graphene-reinforced poly(vinyl chloride) using lithium alkyl as covalent bonding agent

PVC/graphene nanocomposites with high performance are fabricated by this one-pot method using n-BuLi as the initiator.

Novel side-chain-type sulfonated diphenyl-based poly(arylene ether sulfone)s with a hydrogen-bonded network as proton exchange membranes

Diphenyl-based poly(arylene ether sulfone) membranes with a side-chain-type architecture and a hydrogen-bonded network were prepared.

Flammability properties and electromagnetic interference shielding of PVC/graphene composites containing Fe3O4 nanoparticles

The presence of combined graphene with Fe₃O₄ nanoparticles in PVC matrix can endow the resulting nanocomposites with improved flame retardancy and electromagnetic interference shielding properties besides reinforced mechanical properties.

Fully aromatic naphthalene-based sulfonated poly(arylene ether ketone)s with flexible sulfoalkyl groups as polymer electrolyte membranes

Naphthalene-based poly(arylene ether ketone)s with pendant sulfoalkyl groups were prepared by a demethylation and sulfobutylation method. They exhibited high proton conductivity, low methanol permeability and high thermal stability.

Towards basic ionic liquid-based hybrid membranes as hydroxide-conducting electrolytes under low humidity conditions

We have developed basic ionic liquid-based hybrid membranes with ionic liquid modified zeolitic imidazolate frameworks (ZIFs) as fillers, aiming to enhance the electrochemical and physical properties of the membrane.

Novel in situ-foaming materials derived from a naphthalene-based poly(arylene ether ketone) containing thermally labile groups

A novel in situ-foaming material was prepared from a naphthalene-based poly(arylene ether ketone) by grafting with thermally-labile tert-butyloxycarbonyl which can decompose and in situ generate gases.