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Background: Botulinum neurotoxin injections are the most frequently performed cosmetic procedures, but conventional blind injection for glabellar wrinkles remains to have some limitations. Aims: We intend to directly inject botulinum neurotoxin into the glabella complex guided by real time ultrasound. We aim to propose a more efficient and safer botulinum neurotoxin injection strategy for glabellar wrinkles. Methods: A total of 40 subjects with moderate to severe glabellar lines were enrolled in this study to receive botulinum neurotoxin injection, either through ultrasound‐guided real time injection or conventional blind injection. Facial Wrinkle Scale (ranging from 0 = none to 3 = severe) and inter‐brow distance (from 3D scanned face images) were used to evaluate the glabellar wrinkles improvement. Paired t test and two‐sample t test were performed to analyze the within‐group and between‐group differences. Results: The wrinkle score reduction was significant (p < 0.0001) immediately after the injection in ultrasound‐guided injection group, but not in blind injection group (p = 0.163). Ultrasound‐guided injection also showed a higher performance of wrinkle score reduction and more effective inter‐brow distance increase over blind injection at Day 0 (p < 0.0001), Day 1 (p < 0.0001), Day 21 (p < 0.01) and Day 35 (p < 0.01) after initial treatment. Conclusions: The results of the study confirmed that botulinum neurotoxin injection for glabellar wrinkles under ultrasound guidance achieves quicker onset of action and better final outcomes compared to conventional blind injection. [ABSTRACT FROM AUTHOR]

Emerging evidence has implicated nicotinamide adenine dinucleotide (NAD+) metabolism in various inflammatory diseases. In the study, the role of NAD+ metabolism in Complete Freund's Adjuvant (CFA)‐evoked inflammatory pain and the underlying mechanisms are investigated. The study demonstrated that CFA induced upregulation of nicotinamide phosphoribosyltransferase (NAMPT) in dorsal root ganglia (DRG) without significant changes in the spinal cord. Inhibition of NAMPT expression by intrathecal injection of NAMPT siRNA alleviated CFA‐induced pain‐like behavior, decreased NAD+ contents in DRG, and lowered poly‐(ADP‐ribose) polymerase 1 (PARP1) activity levels. These effects are all reversed by the supplement of nicotinamide mononucleotide (NMN). Inhibition of PARP1 expression by intrathecal injection of PARP1 siRNA alleviated CFA‐induced pain‐like behavior, while elevated NAD+ levels of DRG. The analgesic effect of inhibiting NAMPT/NAD+/PARP1 axis can be attributed to the downregulation of the NF‐κB/IL‐1β inflammatory pathway. Double immunofluorescence staining showed that the expression of NAMPT/NAD+/PARP1 axis is restricted to DRG neurons. In conclusion, PARP1 activation in response to CFA stimulation, fueled by NAMPT‐derived NAD+, mediates CFA‐induced inflammatory pain through NF‐κB/IL‐1β inflammatory pathway. [ABSTRACT FROM AUTHOR]

Methanol steam reforming (MSR) provides an alternative way for efficient production and safe transportation of hydrogen but requires harsh conditions and complicated purification processes. In this work, an efficient electrochemical‐assisted MSR reaction for pure H2 production at lower temperature (~140 °C) is developed by coupling the electrocatalysis reaction into the MSR in a polymer electrolyte membrane electrolysis reactor. By electrochemically assisted, the two critical steps including the methanol dehydrogenation and water‐gas shift reaction are accelerated, which is attributed to decreasing the methanol dehydrogenation energy and promoting the dissociation of H2O to OH* by the applied potential. Furthermore, the reduced H2 partial pressure by the hydrogen oxidation and reduction process further promotes MSR. The combination of these advantages not only efficiently decreases the MSR temperature but also achieves the high rate of hydrogen production of 505 mmol H2 g Pt−1 h−1 with exceptionally high H2 selectivity (99 %) at 180 °C and a low voltage (0.4 V), and the productivity is about 30‐fold than that of traditional MSR. This study opens up a new avenue to design novel electrolysis cells for hydrogen production. [ABSTRACT FROM AUTHOR]

In this work, the silane coupling agents with 4‐carboxyphenyl (PhCOOH), amino, phenyl, 4‐aminophenyl and 4‐phenylmethylketone were employed to modify the interfaces of the polyimide/SiO2 (PIS) nanocomposites, and the effects of the interfacial structures on the dielectric and the mechanical properties for the PI‐based composites were predicted by molecular dynamics simulation. The results showed that the interface structure with PhCOOH simultaneously elevated the static dielectric permittivity (εs) and Young modulus of the PI‐based composites. Due to enhanced intrinsic polarization of the SiO2 particles and the interface polarization in the composites, the εs of PIS‐PhCOOH composites (6.66) was 28% higher than that of PIS (5.21). Young modulus of PIS‐PhCOOH (5.09 GPa) was higher than that of PIS (3.25 GPa), which was attributed to the increase of the number of hydrogen bonds and non‐bond interaction. In addition, the length of PhCOOH was found to be larger than the thickness of excluded volume region, showing that part of PhCOOH could be embedded into the gaps among PI chains and the interfacial load transfer efficiency was reinforced. These results provided an understanding of the atomic‐scale interfacial structures, which was beneficial for the design and preparation of the nanocomposites with superior dielectric and mechanical performances. [ABSTRACT FROM AUTHOR]

A simple and low‐cost approach was proposed to fabricate poly(vinylidene fluoride) (PVDF) and polyimide‐poly(amidic acid) (PI‐PAA) all‐organic hybrid films with excellent dielectric performance by solution casting and thermal imidization process. The results showed that the introduction of PVDF and PAA molecular chains into PI matrix significantly enhanced the dielectric permittivity and energy density of PI‐based composites. The permittivity and energy density of 15 wt% PI‐PAA/PVDF composites were 4.83 at 103 Hz and 5.55 J cm−3, which were 52% and 107% higher than that of PI (3.18 at 103 Hz, 2.68 J cm−3). In addition, the dielectric loss of 15 wt% PI‐PAA/PVDF composites was still maintained at a low level (0.009 at 103 Hz). The molecular dynamics results showed that the polarization strength of composites mainly originated from the intrinsic polarization strength. The intrinsic polarization strength of PI‐PAA/PVDF in the composites was 1010 times higher than interfacial polarization strength, and interfacial polarization was negligible. There was no significant difference between the self‐diffusion coefficients of 15 wt% PI‐PAA/PVDF and PI‐PAA, indicating that the relaxation polarization of polymer molecular chains was suppressed. This work provides an effective way for the preparation of dielectric for all organic high voltage direct current system. [ABSTRACT FROM AUTHOR]

High‐temperature proton exchange membrane fuel cells (HT‐PEMFCs) are crucial in future energy systems. However, the activity and stability of the electrocatalysts are severely restricted by high temperature and phosphoric acid poisoning. Herein, PtCe alloy as oxygen reduction reaction (ORR) electrocatalyst for HT‐PEMFCs exhibits fantastic performance. Ce can increase the electronic density of Pt, weakening phosphoric acid poisoning and improving ORR activity. The optimized electronic structure can also reduce the dipole effect between Pt and O, which suppresses the irreversible oxidation of Pt. Additionally, the dramatically negative heat of formation in PtCe catalyst brings high kinetic barrier of metal diffusion and dissolution. With this electrocatalyst, the HT‐PEMFCs show a preeminent peak power of 605 mW cm−2 with 0.3 mgPt cm−2. After 30000 cycles of accelerated stability test, the peak power density only decreases by 31.6%, achieving the goal of Department of Energy in 2020 (<40% loss). [ABSTRACT FROM AUTHOR]

In this work, the tensile strength of polyimide/silica composites with the covalently bonded interface (bonded PI/SiO2) is investigated by molecular dynamic simulation. It is found that the nanofiller with smaller size can bring out a larger number of hydrogen bonds and interfacial non‐bond energy in the composites, resulting in higher tensile strength. As the immobilization of the PI chains in the vicinity of SiO2, the covalently bonded interface is found to offer a greater reinforcing effect than the unbonded interface that is confirmed by the self‐diffusion coefficient. The tensile strength of 9 wt.% bonded PI/SiO2 composites is 11.34% higher than that of the unbounded composites. The tensile strength of PI/SiO2 composites is enhanced with the increase of SiO2 concentration up to critical mass percent (Xc), beyond which it will be decreased. To quantitatively predict Xc of PI/SiO2 composites, an empirical equation based on the non‐bond energy of the composites is proposed. The empirical equation showed that the Xc of PI/SiO2 composites ranged from 8.03 to 10.36 wt.%, which is consistent with experimental values. These results provided the understanding of size‐dependent covalently bonded interface structure, which would be beneficial to the design of nanocomposites with excellent mechanical performances. [ABSTRACT FROM AUTHOR]

The durability degradation during stack‐operating conditions seriously deteriorates the lifetime and performance of the fuel cell. To alleviate the rapid potential rise and performance degradation, an anode design is proposed to match the working temperature of high‐temperature proton exchange membrane fuel cells (HT‐PEMFCs) with the release temperature of hydrogen from palladium. The result is significantly enhanced hydrogen oxidation reaction (HOR) activity of Pd and superior performance of the Pd anode. Furthermore, Pd as hydrogen buffer and oxygen absorbent layer in the anode can provide additional in situ hydrogen and absorb infiltrated oxygen during local fuel starvation to maintain HOR and suppress reverse‐current degradation. Compared with the traditional Pt/C anode, the Pd/C also greatly improved HT‐PEMFCs durability during start‐up/shut‐down and current mutation. The storage/release of hydrogen provides innovative guidance for improving the durability of PEMFCs. [ABSTRACT FROM AUTHOR]

The functional groups on the surface of nanofillers could significantly improve the organic-inorganic interfacial compatibility and the interfacial load transfer efficiency. Wenlong Yang and Yu Wang designed the cover image that showed the interface structure of the polyimide/silica composites. [Extracted from the article]

Wenlong Yang and Yu Wang designed the cover image that shows flexible all-organic polyimide-poly(amidic acid)/poly(vinylidene fluoride) hybrid films. The incorporation of polyvinylidene fluoride and poly(amidic acid) with high intrinsic polarization strength into polyimide could significantly enhance the energy density and suppress the dielectric loss of PI-based composites. [Extracted from the article]

ABSTRACT The morphotropic phase boundary composition 47(Ba0.7Ca0.3)TiO3-0.53Ba(Zr0.2Ti0.8)O3 (calcium barium zirconate titanate, BCZT) were doped in poly(vinylidene fluoride) matrix by solution casting method. The effect of BCZT particles on polarization characteristics of composite films were investigated through dielectric spectra, hysteresis, and thermally stimulated discharge current measurements. It reveals that relative dielectric constant, remnant polarization, and energy storage density gradually increase and reach the maximum value with 39 at 100 Hz, 1.17 μC/cm2, and 3.69 J/cm3 at the concentration of 20 vol % BCZT. The Gaussian method was employed to decompose thermally stimulated discharge current composite peaks and an approximate model was used to analyze the activation energy levels of these films. The results indicated that the introduction of BCZT is effective for the charge carrier traps and activation energy distribution in the relaxation process of composite films. The decreased molecular movements, and increased interfaces formed between the BCZT grains and the poly(vinylidene fluoride) matrix may be responsible for these performances. And a new relaxation peak appeared at about 370 K in composites when BCZT concentration exceeded 20 vol %, which was considered to be caused by the ferroelectric-paraelectric phase transition of BCZT. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45362. [ABSTRACT FROM AUTHOR]

Using coupling agent isocyanatopropyltriethoxysilane (ICTOS) to modified nano-TiO2, the polyimide (PI) with different titanium dioxide (TiO2) contents (0, 1, 2, 3, 4, and 5 wt %) doped nano-composites were prepared by sol–gel method (PI/TiO2 ICTOS composites). The effect of ICTOS modification on polarization and time-to-breakdown properties of composites were investigated by thermally stimulated depolarization current (TSDC) method, dielectric, and Corona aging measurements. The TSDC spectra show that ICTOS modification enhanced α-peak intensity and make β-peak disappear in composites. Relevant trap parameters were calculated by an approximate model, and the results indicate that introduction of ICTOS is effective for the charge carrier traps, activation energy distribution in composites. Corona aging measurement show corona resistance was also sufficient improved in PI/TiO2 ICTOS composites. The changes of activation energy and intensity of traps in composites may be responsible for the corona resistance. [ABSTRACT FROM AUTHOR]

ABSTRACT Hybrid polyimide (PI)/titanium dioxide (TiO2) films were prepared by in situ polymerization and sol-gel and in-sol methods (where in-sol method indicates that in situ polymerization and the sol-gel method were used in the same samples). The mechanical and electrical properties were found to be sensitive to the processing methods and the dispersion of nano titanium dioxide (nano-TiO2) in the PI matrix. For the PI/TiO2 films prepared by the in situ polymerization method, their tensile strength increased with increasing TiO2- in situ ('TiO2- in situ' is 'the TiO2 nano-particles prepared by in situ polymerization method') concentration. However, the optimal corona lifetime of the PI/TiO2 films was 15 min at 20 kHz and 2 kV because of poor dispersion. For the PI/TiO2 films prepared by the sol-gel method, the corona lifetime reached 113 min because of superior dispersion and a tensile strength of about 19.63 MPa. A balance of mechanical and electrical performances was achieved with the in-sol method. The corona-resistant life of the PI/TiO2 films was 43 min, which was about six times longer than that of the neat PI. Their tensile strength was 83.5 MPa; these films showed no decrease in this value compared with the pure PI films. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44666. [ABSTRACT FROM AUTHOR]

This work reports the advanced potassium sodium niobate (K0.5Na0.5NbO3, KNN)/polyimide (KNN/PI) functional hybrid films with 5 vol%, 10 vol%, 20 vol%, 30 vol%, and 40 vol% KNN loaded. The structure, morphology, and dielectric properties of hybrid films have been measured. The results show that the KNN fillers are well dispersed in the PI matrix. An internal boundary layer capacitance structure is formed in the composite films. The dielectric permittivity of the film is as high as 22 when the concentration of KNN filler reaches 40 vol% at 102 Hz, which is five times larger than that of a pure PI matrix. Meanwhile, the loss tangent is lower than 0.05. In addition, the conductivity is lower than 10−8 (S m−1) at 102 Hz, which indicates the excellent insulation and is important for the practical use of this kind of KNN/PI hybrid films. It is believed that the KNN/PI hybrid films could be applied in future electronic fields. POLYM. COMPOS., 35:969-974, 2014. © 2013 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

ABSTRACT Polyimide (PI) films filled with K0.5Na0.5NbO3 (KNN50) particles at different weight 0, 5, 10, and 15 wt % had been prepared by in-situ dispersion polymerization process. The thermally stimulated current (TSDC) method was used to investigate the charge carrier trap levels and their distribution of the composite films. The TSDC spectra show that pure film has [ABSTRACT FROM AUTHOR]

B Front Cover b : Molecular dynamics simulation is used to investigate the effect of bonded interface on the mechanical performances of the PI/SiO SB 2 sb composites. The interfacial non-bond energy, the number of the hydrogen bonds, tensile strength, Young's modulus and shear modulus are investigated. As the SiO SB 2 sb concentration increased, the non-bond interaction energy between each PI chain and SiO SB 2 sb particle increased and the non-bond interaction energy in the bonded composites are higher than that of the unbonded. [Extracted from the article]

A type of polyimide/silica (PI/SiO2) copolymer model was established through the dehydration of tetraethyl orthosilicate molecules (TEOS) and bonding to a silane coupling agent. The content of SiO2 was controlled by adjusting the number of molecules which bound to the TEOS. Finally, the silica was formed into a hybrid model (hybrid PI/SiO2) with a small molecule embedded in the PI. The model was optimized by geometric and molecular dynamics and the changes in the model structure, Young's modulus, shear modulus, and glass‐transition temperature (Tg) were analyzed. The results showed that the density and cohesive energy density of the composites could be improved by doping SiO2 in PI. Young's modulus and shear modulus of PI/SiO2 hybrid materials were higher than undoped PI. The tensile strength reached 568.15 MPa when the doping content was 9%. Therefore, the structure design and content control of SiO2 was an effective way to improve the performance of a PI/SiO2 composite. The variation of Tg and tensile strength of PI/SiO2 hybrid composites is consistent with that of PI/SiO2 composite synthesized in real experiment, which will be a convenient method for new material design and performance prediction. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47335. Periodic unit cell of hybrid PI/SiO2 model. [ABSTRACT FROM AUTHOR]