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Cholinergic system conducts signal transmission in brain and muscle. Besides nervous system, the nonneuronal functions of cholinergic system have been proposed in various tissues. The expression of cholinergic proteins and release of acetylcholine in human skin have been reported, but its mechanism and influence on dermatological functions is not elucidated. Here, the expression profile of cholinergic markers was further investigated in skin and keratinocyte. The expression levels of choline acetyltransferase (ChAT), acetylcholinesterase (AChE), vesicular acetylcholine transporter (VAChT), and synaptophysin, were upregulated during differentiation of keratinocytes. In cultured keratinocytes, a transient exposure of solar light induced the release of acetylcholine, which was mediated by intracellular Ca2+ mobilization. The light-induced acetylcholine release was mediated by the present of opsin. The light-induced melanogenesis was inhibited by acetylcholine or AChE inhibitor in melanocyte in vitro and mouse skin ex vivo. These results indicated that the potential role of cholinergic system could be a negative regulator in skin pigmentation.

N,N,N′,N′,N“,N”-hexaalkylnitrilotriacetoamide (HRNTA) derivatives were found to be promising for the separation of trivalent actinides from lanthanides, which is a burning topic in the back end of the nuclear fuel cycle. In the present work, separation of Am3+ from Eu3+ was studied using the N,N,N’,N’,N’’,N’’-hexa-2-ethylhexylnitrilotriacetamide (H2EHNTA) derivative and the role of the diluent medium to control the extractable complex was demonstrated. The effect of alkyl chain length and branching in the alkyl chain of different HRNTA (R=methyl, n-butyl, n-hexyl, n-dodecyl and 2-ethylhexyl) derivatives on their complexation with Eu3+ were investigated using steady-state and time-resolved luminescence studies. Different species formed at different ligand to metal ratios were identified from the luminescence titration experiments and their lifetime values measured. The experimental results were corroborated with the help of density functional theoretical (DFT) calculations on Am3+ and Eu3+ complexes of HRNTA derivatives with varying alkyl chain length and branching.

Objective Neurodevelopmental diseases are common disorders caused by the disruption of essential neurodevelopmental processes. Recent human exome sequencing and genome‐wide association studies have shown that mutations in the subunits of the SWI/SNF (BAF) complex are risk factors for neurodevelopmental diseases. Clinical studies have found that ARID1A (BAF250a) is the most frequently mutated SWI/SNF gene and its mutations lead to mental retardation and microcephaly. However, the function of ARID1A in brain development and its underlying mechanisms still remain elusive. Methods The present study used Cre/loxP system to generate an Arid1a conditional knockout mouse line. Cell proliferation, cell apoptosis and cell differentiation of NSPCs were studied by immunofluorescence staining. In addition, RNA‐seq and RT‐PCR were performed to dissect the molecular mechanisms of Arid1a underlying cortical neurogenesis. Finally, rescue experiments were conducted to evaluate the effects of Neurod1 or Fezf2 overexpression on the differentiation of NSPCs in vitro. Results Conditional knockout of Arid1a reduces cortical thickness in the developing cortex. Arid1a loss of function inhibits the proliferation of radial glial cells, and increases cell death during late cortical development, and leads to dysregulated expression of genes associated with proliferation and differentiation. Overexpression of Neurod1 or Fezf2 in Arid1a cKO NSPCs rescues their neural differentiation defect in vitro. Conclusions This study demonstrates for the first time that Arid1a plays an important role in regulating the proliferation and differentiation of NSPCs during cortical development, and proposes several gene candidates that are worth to understand the pathological mechanisms and to develop novel interventions of neurodevelopment disorders caused by Arid1a mutations., Although Arid1a mutations are closely related to mental retardation and microcephaly, the function of Arid1a in brain development and its underlying mechanisms still remain elusive. The present study demonstrates for the first time that Arid1a plays an important role in regulating the proliferation and differentiation of neural stem/progenitor cells during cortical development, and proposes several gene candidates that are worth to understand the pathological mechanisms and to develop novel interventions of neurodevelopment disorders caused by Arid1a mutations.

Smart tactile sensing materials have excellent development prospects, including wearable health-monitoring equipment and energy collection. Hydrogels have received extensive attention in tactile sensing owing to their transparency and high elasticity. In this study, highly crosslinked hydrogels are fabricated by chemically crosslinking polyacrylamide with lithium magnesium silicate and decorated with carbon quantum dots. Magnesium lithium silicate provides abundant covalent bonds and improves the mechanical properties of the hydrogels. The luminescent properties endowed by the carbon dots further broaden the application of hydrogels for realizing flexible electronics. The hydrogel-based strain sensor exhibits excellent sensitivity (gauge factor 2.6), a broad strain response range (0-2000%), good cyclicity, and durability (1250). Strain sensors can be used to detect human motions. More importantly, the hydrogel can also be used as a flexible self-supporting triboelectric electrode for effectively detecting pressure in the range of 1-25 N and delivering a short-circuit current (I

Wearable strain sensors based on flexible conductive polymer composites (FCPCs) have attracted great attention due to their applications in the fields of human–machine interaction, disease diagnostics, human motion detection, and soft robotic skin. In recent decades, FCPC‐based strain sensors with high stretchability and sensitivity, short response time, and excellent stability have been developed, which are expected to be more versatile and intelligent. Smart strain sensors are required to provide wearable comfort, such as breathability, self‐cooling ability, and so forth. To adapt to the harsh environment, wearable strain sensors should also be highly adaptive to protect the skin and the sensor itself. In addition, portable power supply system, multisite sensing capability, and multifunctionality are crucial for the next generation of FCPC‐based strain sensor.

The enormous demand for waste heat utilization and burgeoning eco-friendly wearable materials has triggered huge interest in the development of thermoelectric materials that can harvest low-cost energy resources by converting waste heat to electricity efficiently. In particular, due to their high flexibility, nontoxicity, cost-effectivity, and promising applicability in various fields, organic thermoelectric materials are drawing more attention compared with their toxic, expensive, heavy, and brittle inorganic counterparts. Organic thermoelectric materials are approaching the figure of merit of the inorganic ones via the construction and optimization of unique transport pathways and device geometries. This review presents the recent development of the interdependence and decoupling principles of the thermoelectric efficiency parameters as well as the new achievements of high performance organic thermoelectric materials. Moreover, this review also discusses the advances in the thermoelectric devices with emphasis on their energy-related applications. It is believed that organic thermoelectric materials are emerging as green energy alternatives rivaling their conventional inorganic counterparts in the efficient and pure electricity harvesting from waste heat and solar thermal energy.

Smart skin is highly desired to be ultrasensitive and self-powered as the medium of artificial intelligence. Here, an ultrasensitive self-powered mechanoluminescence smart skin (SPMSS) inspired by the luminescence mechanism of cephalopod skin and the ultrasensitive response of spider-slit-organ is developed. Benefitting from the unique strain-dependent microcrack structure design based on Ti3 C2 Tx (MXene)/carbon nanotube synergistic interaction, SPMSS possesses excellent strain sensing performances including ultralow detection limit (0.001% strain), ultrahigh sensitivity (gauge factor, GF = 3.92 × 107 ), ultrafast response time (5 ms), and superior durability and stability (>45 000 cycles). Synchronously, SPMSS exhibits tunable and highly sensitive mechanoluminescence (ML) features under stretching. A relationship between ML features, strain sensing performances, and the deformation has been established successfully. Importantly, the SPMSS demonstrates excellent properties as triboelectric nanogenerator (4 × 4 cm2 ), including ultrahigh triboelectric output (open-circuit voltage VOC = 540 V, short-circuit current ISC = 42 µA, short-circuit charge QSC = 317 nC) and power density (7.42 W m-2 ), endowing the smart skin with reliable power source supply and self-powered sensing ability. This bioinspired smart skin exhibits multifunctional applications in health monitoring, visual sensing, and self-powered sensing, showing great potential in artificial intelligence.

The mechanical properties and microstructure of injection molded isotactic polypropylene parts with high orientation before and after annealing are analyzed. The mechanical properties of the annealed samples are improved effectively. Through thorough analysis of various structural characterizations, a microstructural model based on the fact that the total length of long period kept constant to analyze the variation of mechanical properties is proposed. It is suggested that the increase of overall crystallinity, the recombination of crystalline phase, and the increase of amorphous phase, respectively, are beneficial for the improvements of the strength, stiffness, and toughness of annealed samples.

Electrospun polyamide PA 66 nanofiber bundles were mechanically strengthened via compositing with polyvinyl alcohol (PVA). The highest tensile strength (126.4 MPa) was achieved for the bundles immersed in the solution with 5.0 wt% PVA, indicating sufficient PVA filling between nanofibers after drying the impregnated nanofiber bundles. The disappearance of voids for the bundles immersed in the PVA solution indicated a superb interface adhesion, which was responsible for the excellent mechanical properties of the composite bundles. Furthermore, the step-cycle and stress relaxation tests were carried out to shed light on the deformation evolution and the viscous stress of the bundles. The results further demonstrated the excellent mechanical properties of the composite bundles.

In this work, isotactic–polypropylene (iPP) specimens were prepared by a modified injection molding machine, in which high temperature preshear (HTPS) can be imposed on the molten polymer during the plasticizing stage. The effect of HTPS on the microstructure and mechanical property of iPP was investigated. It was found that spherulite size in core region of iPP part decreased steadily with the increasing HTPS duration, indicating that HTPS could substantially enhance iPP nucleation. Moreover, β-iPP formation correlated strongly with HTPS duration. That is, in the absence of HTPS, β-iPP existed only in intermediate region; with moderate HTPS duration, β-iPP could be unexpectedly formed in core region; however, long HTPS duration inhibited β-iPP formation in both intermediate region and core region. Based on the relationship between β-iPP formation and HTPS duration, metastable nuclei, instead of α-row nuclei, were proposed to be responsible for the development of β-iPP. Notched Izod impact test showed that moderate HTPS duration enhance the impact strength of injection molded iPP by decreasing the thickness of shear region and elevating β-iPP crystallinity in core region. Dynamic mechanical test indicated that with the increase of HTPS duration, the storage modulus of injection-molded iPP improves drastically. POLYM. ENG. SCI., 55:2714–2721, 2015. © 2015 Society of Plastics Engineers

Liquid-sensing behaviors of carbon black (CB)/polypropylene (PP) and carbon nanotubes (CNTs)/PP-conductive polymer composites (CPCs) were studied in detail. It was found that the CB/PP showed a higher liquid-sensing intensity but a poorer reproducibility toward the “good solvent” xylene. The main origin is that the conductive works formed by CB, the zero-dimensional filler, are vulnerable to the swelling effect of PP during the immersion-drying runs (IDRs), whereas CNTs in the CNTs/PP with a large aspect ratio have better capacity in maintaining the conductive networks. To investigate the influence of the remaining solvent on the evolution of conductive networks, liquid-sensing tests of the two composites after long-term immersion in xylene were investigated. Results showed that the liquid-sensing behaviors of CNTs/PP changed less weakly compared with that of the CB/PP. Liquid-sensing behaviors of the two composites, cyclohexane and tetrachloromethane, to the “poor solvents” were also studied. The results of this article indicate that liquid-sensing behaviors of the CPCs were affected by the microstructure of the conductive filler, the solubility parameter, and the molar volume of the solvent significantly. POLYM. COMPOS., 36:205–213, 2015. © 2014 Society of Plastics Engineers

The acid-corroded glass fiber (GF)/isotactic polypropylene (iPP) composite was injection molded by mixing–injection molding (MIM). Through this method, preshear can be imposed on melt during mix–plasticization process. The crystalline structure across the thickness direction of the injection-molded bars was investigated by wide-angle X-ray diffraction and differential scanning calorimetry (DSC). It was unexpectedly found that, in core region, the acid-corroded GF/iPP sample has the highest content of β-form crystals, followed by uncorroded GF/iPP and neat iPP. Additionally, the crystalline morphology was investigated by polarized optical microscopy (POM) and scanning electron microscopy, and the results showed that β-transcrystallization is preferably present in the acid-corroded GF/iPP system. Confirmed by POM and DSC, the acid-corroded GF shows strong β-nucleation ability to iPP under static condition. Combined with the main features of MIM, three β-nucleation origins in the acid-corroded GF/iPP system under injection molding condition are proposed: (1) precursors induced by preshear in the barrel, (2) row-nuclei induced by local shear, and (3) the acid-corroded GF nuclei. POLYM. COMPOS. 34:1250–1260, 2013. © 2013 Society of Plastics Engineers

Optimized conditions including the phosphine ligand (PPC) allow the efficient synthesis of trifluoromethylstyrenes from fluorinated vinyl chlorides and arylboronic acids.

Up to now, research on the dynamic process of conductive network formation has tended to focus on composite particles with one-dimensional geometry, such as carbon black and carbon nanotubes. However, studies on this subject based on fillers with two-dimensional structure, such as graphite, are rare in the literature. In this work, the dynamic percolation and rheological properties of poly(methyl methacrylate) (PMMA)–graphite composites under an electric field were investigated. The activation energies of conductive network formation and polymer matrix mobility were calculated from the temperature dependence of the percolation time and the zero-shear viscosity. It was found that the activation energy calculated from the zero-shear viscosity was not influenced by the electric field in the concentration range investigated, but the electric field had an effect on the activation energy calculated from the percolation time. This finding emphasizes that the electrical and rheological properties have different physical origins. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43810.

Polymer processing methods generally play a crucial role in determining the development of microstructure in the fabricated product. In this study, isotactic polypropylene (iPP) melt containing 0.05 wt % β-nucleating agent (β-NA) was extruded via a melt flow rate indicator. The molten extrudate was stretched into a fiber upon various take-up velocities (TVs). The microstructures of the fiber were investigated by differential scanning calorimeter, two-dimensional wide-angle X-ray diffraction, and small-angle X-ray scattering. Also, its tensile properties (including tensile strength, modulus, elongation at break, and toughness) were measured by tensile test. Interestingly, the tensile strength (135.0 MPa) of a melt-spun β-nucleated iPP fiber fabricated at 400 cm/min was enhanced by 115.2%, compared with that (62.7 MPa) prepared at 100 cm/min, with a considerable increment in toughness (from 661 to 853 MJ/m3). The enhancement mechanism for tensile properties was discussed based on the microstructures. This work offers a simple approach to prepare β-nucleated iPP fibers with excellent strength and toughness. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43454.

The nucleated isotactic polypropylene (iPP) was molded by water-assisted injection molding. The crystalline morphology and orientation distribution were studied. The results show that shear brought by melt filling and pressurized water penetration can separately induce the formation of oriented structures in skin region (i.e., the region near mold cavity wall) and the water channel region. For virgin iPP, slightly oriented lamellae appear exclusively in the above aforementioned regions. However, shish-kebab structure occurs not only in skin and water channel region of the iPP containing moderate content of nucleator (0.2 wt%) but also in the whole region of the iPP containing a higher content of nucleator (1 wt%). It is well known that nucleator cannot directly induce the development of shish-kebab in the absence of shear, thus the results indicate: shear flow actually distributes over a much broader range than expected; in shear field, nucleator is significantly helpful for the shear which is not sufficient to solely induce oriented structure to promote the formation of the oriented structure. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers

High density polyethylene (HDPE) was molded by a new polymer processing method, that is, water-assisted injection molding (WAIM), and its hierarchical structure was studied by two-dimensional small angle X-ray scattering (SAXS). For comparison, the hierarchical structure of HDPE molded by conventional injection molding (CIM) was also characterized. The result shows that the WAIM part exhibits a distinct skin-core-water channel structure which is different from the skin-core structure for the CIM part. In the skin layer of both WAIM and CIM parts, the shish-kebab structure was formed due to the shear stress brought by melt filling, but the lamellar orientation parameter of CIM part is smaller than that of WAIM part. The spherulites with random lamellar orientation are dominant at the core of both parts owing to the low cooling rate and feeble shear stress therein. Interestingly, the shish structure and the lamellae with low level of orientation can be found at the water channel layer of WAIM part. They are attributed to the shear stress brought by water penetration. Moreover, the lamellar orientation parameter in water channel layer is smaller than that of skin layer. In addition, the long period of WAIM part first increases and then decreases with the elevating distance from the skin surface, while that of CIM part tends to increase monotonously. In a word, one can conclude that the rapid cooling rate and shear brought by the injected water have significant influence on the structural evolution for the WAIM part. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

At an extremely small extrusion rate, an isotactic polypropylene melt was extruded through a slit die of an extruder. Simultaneously, the extruded melt was stretched at various stretching rates (SRs) at the die exit. The oriented structure and its subsequent recrystallization via self-seeding were investigated using polarized optical microscopy, two-dimensional wide-angle X-ray scattering and small-angle X-ray scattering. As expected, much slenderer and denser oriented structures were formed at larger SR, which indicates that orientation is preferably promoted with increasing SR. In the case of the crystalline morphology developed during recrystallization, a shish kebab-like structure was retrieved via the surviving oriented structure after annealing. Unexpectedly, for the sheet stretched at higher SR, a mainly sparse and short shish kebab structure was observed. For the sheet stretched at lower SR, a dense and long shish kebab structure was observed. This suggests that the oriented structure in the sheet stretched at lower SR has a better thermal stability than that in the sheet stretched at higher SR. This is discussed based on the relaxation of entangled junctions in the stretched networks with respect to varying chain length. Copyright © 2011 Society of Chemical Industry

On the premise that shear in the slit die of an extruder was minimized as far as possible, β-nucleated isotactic polypropylene (iPP) was extruded. Simultaneously, once the extrudate (in the melt state) left the die exit, it was stretched at various stretching rates (SRs). For iPP with a low content of β-nucleating agent (β-NA), the crystallinity of β-phase (Xβ) initially increases with increasing SR, and then decreases slightly with further increase in SR. However, for iPP containing a higher content of β-NA, with increasing SR, Xβ decreases monotonically, indicating a negative effect of SR on β-phase formation. Small-angle X-ray scattering and polarized optical microscopy experiments reveal that, when SR is less than 30 cm min−1, the increasing amount of row nuclei induced by increasing SR is mainly responsible for the increase of Xβ. In contrast, when SR exceeds 30 cm min−1, the overgrowth of shish structures unexpectedly restrains the development of β-phase, and spatial confinement is considered as a better explanation for the suppression of β-phase. Copyright © 2011 Society of Chemical Industry

The carbon nanotubes (CNTs)/rigid polyurethane (PU) foam composites with a low percolation threshold of ∼ 1.2 wt % were prepared by constructing effective conductive paths with homogeneous dispersion of the CNTs in both the cell walls and struts of the PU foam. The conductive foam presented excellent electrical stability under various temperature fields, highlighting the potential applications for a long-term use over a wide temperature range from 20 to 180°C. Compression measurements and dynamical mechanical analysis indicated 31% improvement in compression properties and 50% increase in storage modulus at room temperature in the presence of CNTs (2.0 wt %). Additionally, the incorporation of only 0.5 wt % CNTs induced remarkable thermal stabilization of the matrix, with the degradation temperature increasing from 450 to 499°C at the 50% weight loss. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

The carbon nanotubes/ultrahigh molecular weight polyethlene (CNTs/UHMWPE) conductive composite with a low percolation threshold had been successfully fabricated, and CNTs were only dispersed in the interface of matrix particles. Some factors, including CNTs concentration, processing temperature, and the time of isothermal treatment, which could exert influence on the positive temperature coefficient effect of the composite, were investigated. Similar with negative temperature coefficient effect, the resistivity decreased during isothermal treatment above the melting point of UHMWPE, which could be thought to be a relaxation process originated from movement of molecular chains. This relaxation, also a process of CNTs aggregating to reorganize the conductive network, was testified as a function of time, temperature, filler concentration, and heating rate. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

As a part of continuous efforts to systematically understand the morphological development in water-assisted injection molding, high density polyethylene with different molecular weights was molded in this study. Unexpectedly, it was found that shish kebab with high lamellar and molecular orientations was formed in the sample with a lower molecular weight (LMW) rather than in the higher one, especially in the water channel layer. Present finding is obviously inconsistent with the general consensus, that is, higher molecular weight (HMW) polymer is much easier to form preferential orientation in flow field than LMW one. Such anomalous phenomenon is explained by the fact that even though melts experienced the same processing, lower shear rate is practically achieved in HMW sample due to its high viscosity. The result indicates that the flow history in industrial processing method is far from that in laboratory one. Copyright © 2012 John Wiley & Sons, Ltd.

Electrically conductive carbon black (CB)/polypropylene (PP) nanocomposites with a segregated structure are fabricated by localizing CB particles at the interfaces among the PP granules. Interesting double-peak positive temperature coefficient (PTC) effect when exposed to temperature field is observed and ascribed to the breakage of unique segregated conductive network due to the volume expansion stemming from the crystal melting of interfacial PP and the bulk PP matrix. With extending thermal treatment time, the PTC intensity first increases and then decreases obviously. Long treatment time is required for the composites with high CB loadings to reach the PTC intensity maximum value. This phenomenon is attributed to the evolution of segregated microstructure during the thermal treatment, which is traced visually in situ through an optical microscope (OM). The diffusion due to the concentration gradient and the subsequent aggregation of CB particles lead to this behavior. A model based on the OM observation is proposed to reveal the origin of this novel resistivity-temperature behavior.

This article reports the positive temperature coefficient (PTC) and negative temperature coefficient (NTC) effects of a carbon black (CB)-filled electrically conductive microfibrillar poly(ethylene terephthalate) (PET)/polyethylene (PE) composite (FCMC). The composite contains in situ polymer microfibrils in the matrix of another polymer with CB particles selectively localized at microfibrils' surfaces. Anomalous attenuations of PTC and NTC intensities (IPTC and INTC) of FCMC were observed during heating–cooling runs (HCRs) and long-term isothermal treatments. Particularly, when the isothermal treatment time was 32 h, the IPTC decreased from 5.5 in the original sample to only 0.5, showing a tremendous attenuation ratio of up to 91%, and the NTC effect was completely eliminated. On the contrary, attenuations of PTC and NTC effects in a common conductive polymer composite (CCPC) were so weak as to be negligible through the same thermal treatments. Microstructural changes of the conductive network by Brownian motion and large size of the conductive component-CB coated PET microfibrils are both responsible for the great reductions in IPTC and INTC. The present results strongly suggest that thermal field induced microstructural transformation by Brownian motion helps to reveal the origin of PTC and NTC effects. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

This article reports the organic liquid stimuli-response behaviors of carbon black (CB)-filled electrically conductive microfibrillar poly(ethylene terephthalate) (PET)/polyethylene (PE) composite (FCMC) with CB particles selectively localized at PET microfibrils' surfaces. It was found that FCMC's thickness and CB concentration affected its responsivity significantly, a thinner FCMC film with a high CB content exhibited higher responsivity and better signals. In immersion-drying tests, FCMC displayed high and stable responsivities after six immersion-drying runs, indicating that the solvent absorption/desorption equilibrium state was achieved. After long-term immersion, FCMC showed obviously different organic liquid stimuli-response behaviors with faster response rate in immersion and higher terminal resistivity platform in drying, compared with samples without immersion treatment. Conductive network's microstructural changes induced by the long-term immersion and evident capillary effect, which resulted in slow evaporation of remaining solvent in FCMC's interfaces, are the reasons for the phenomenon. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011