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Academic identity formation is strongly influenced by higher education contexts. In the past decades, the Chinese higher education sector has attempted to integrate academic internationalization at the local level. In this context, international returnees and locally trained scholars may encounter different issues in the process of constructing academic identities at various stages of their careers. However, relatively few studies have critically analyzed how international returnees and locally trained scholars understand their academic identity formation during their student years, as they transition to becoming academics, and as they begin to become more established in academic roles under increasingly complex global-national-local conditions. Drawing upon the concept of social hybridization and the notion of global-national-local imbrications, this narrative study investigates six scholars' trajectories of academic identity formation across different stages of the early phase of their careers, including during their doctoral studies and their initial period as early career academics. The findings show that academics' identity development entails a process of struggle and confusion during earlier stages through to the construction of a more hybrid academic identity. By exploring the challenges and issues experienced by different cohorts of academics, scholars may better understand the internationalization of Chinese higher education and interweaving relationships with the global context. [ABSTRACT FROM AUTHOR]

There is an increasing focus on relationship-rich education and relational pedagogies in higher education. Engaging students as partners (SaP) to nurture values-based pedagogical relationships is one such approach, yet it is contested with limited research outside of Anglophone countries. To advance a collective understanding of SaP as a global practice, we interviewed 35 postgraduate students at a research-intensive university in Hong Kong with a hybridised educational setting combining Chinese and westernised strategies and heritages. Reflecting on their learner-teacher relationships as both undergraduate and postgraduate students, they discussed differing senses of student identity that shaped how they perceived their pedagogical relationships: entanglement of positioning themselves as followers, customers, and co-teachers. The influence of neoliberalism, capitalism, and marketisation of higher education in the Hong Kong context was evident throughout the interviews. We discuss the implications for learner-teacher relationships as a pedagogical partnership in the broader hybridised higher education context of Hong Kong. In doing so, we argue that students are navigating an in-betweenness that shapes how they see themselves and the pedagogical relationships they form with teaching staff. [ABSTRACT FROM AUTHOR]

Although there has been rapid advancement in piezoelectric sensors, challenges still remain in developing wearable piezoelectric sensors by a one-step, continuous and environmentally friendly method. In this work, a 1D flexible coaxial piezoelectric fiber was directly fabricated by melt extrusion molding, whose core and sheath layer are respectively slender steel wire (i.e., electrode) and PVDF (i.e., piezoelectric layer). Moreover, such 1D flexible coaxial piezoelectric fiber possesses short response time and high sensitivity, which can be used as a self-powered sensor for bending and vibration sensing. More interestingly, such 1D flexible coaxial piezoelectric fiber (1D-PFs) can be further endowed with 3D helical structure. Moreover, a wearable and washable motion monitoring system can be constructed via braiding such 3D helical piezoelectric fiber (3D-PF) into commercial textiles. This work paves a new way for developing 1D and 3D piezoelectric fibers through a one-step, continuous and environmentally friendly method, showing potential applications in the field of sensing and wearable electronics. [ABSTRACT FROM AUTHOR]

The advent of new technology is breaking the boundaries of traditional teaching and learning patterns with virtual worlds (VW) creating new frontiers in education. Previous research has explored the use of VW within educational settings. However, limited studies have investigated the transition processes that educators experience by adopting VW based online tools during the COVID-19 pandemic. This qualitative exploratory study investigated 18 Chilean lecturers' teaching experiences using a three-dimensional computer-mediated environment: Second Life. Findings suggest that changing from traditional to virtual teaching context is a complex process, which (re)shaped the lecturers' various senses of identity and agency towards different instructional approaches resulting in the sense of in-betweenness with multiple digital competencies. These changes indicated that they taught in an 'in-between' mode mapped by different teaching mediations. The participants' teaching experiences of shaping a sense of in-betweenness could provide a unique theoretical lens to explore instructors' teaching experiences from traditional to a technology-mediated online setting. [ABSTRACT FROM AUTHOR]

The content of Ce plays an important role in balancing the strength and plasticity of Al-Ce alloys, because it seriously affects the morphology and distribution of Ce-rich phase. Electromagnetic stirring (EMS) is an effective process for controlling Ce-rich phase. The effects of EMS on Ce-rich phase in hypoeutectic, eutectic and hypereutectic Al-Ce alloys were mainly studied. The results show that eutectic Al11Ce3 phase transits from lamellar-like to fibrous-like in Al-8Ce alloy and Al-12Ce alloy after EMS. The refinement of the lamellar spacings and eutectic Al11Ce3 fibres is insignificant, and the effect of load transfer strengthening and grain refining strengthening is unsatisfactory. Coarser primary Al11Ce3 phase is broken and eutectic Al11Ce3 phase is refined and spheroidized in Al-14Ce alloy after EMS. The lamellar spacing and eutectic Al11Ce3 fibre size greatly decrease in Al-14Ce alloy, from 2.14 μm to 1.28 μm and 0.94 μm to 0.43 μm, respectively. The load transfer strengthening and fine grain strengthening are enhanced. The tensile strength increases from 116.8 MPa to 184.6 MPa, the yield strength increases from 74.5 MPa to 107.6 MPa, and the elongation increases from 1.4% to 7.1%. This reflects that EMS play a more beneficial role in Al-14Ce alloy. [ABSTRACT FROM AUTHOR]

The 2019 MS6.0 Changning earthquake occurred in the tectonically stable Sichuan Basin, where the epicenter and its adjacent areas are important shale gas and salt mine production fields, resulting in hot debates on whether the seismogenic mechanism of the 2019 Changning earthquake is related to human activities. As source characteristics and fluid pressure can provide important constraints on whether an earthquake is induced, we investigate the seismogenic mechanisms of the mainshock and 9 MW⩾4.0 aftershocks. In overall, the mainshock and the majority of the aftershocks are characterized by relatively shallow focal depths (1–4 km) and significant non-double-couple (non-DC) components. However, the mainshock and the aftershocks differ in two aspects: (1) the compensated-linear-vector-dipole components dominate the non-DC components of the mainshock, whereas the isotropic components dominate the most aftershocks; (2) the fluid overpressure of the mainshock is over 30 MPa, whereas the fluid overpressure of the most aftershocks is less than 10 MPa. Thus, we propose that the mainshock is triggered by weakened fault strength with long-term fluid injection, and that its large non-DC components are associated with complex rupture processes. Comparatively, the aftershocks may be triggered by postseismic stress transfer by combining the Coulomb failure stress changes in the poroelastic medium. Our results highlight the possible role of fluid in the occurrence of the Changning earthquake sequence. [ABSTRACT FROM AUTHOR]

As a new class of porous material, polymer-metal-organic framework (polyMOF) has attracted tremendous interests owing to their combined advantages of polymer and crystalline MOF. However, the poor film-forming ability of polyMOF limits its widespread application, especially in membrane separation area. Herein, for the first time, we demonstrate the fabrication of freestanding polyMOF membrane. The polyMOF nanosheets are synthesized by a polymer-assisted self-inhibition crystal growth strategy. Followed by self-assembly through vacuum filtration, a 20 µm-thick free-standing polyMOF membrane is constructed. Benefiting from the inclusion of polymer with hydrophobic backbone and the continuously distributed non-coordinated hydrophilic groups along polymer chain, the polyMOF membrane attains excellent structure stability against water, as well as superior proton transfer property. Proton conductivity as high as 112 and 25.6 mS·cm−1 is obtained by this polyMOF membrane at 100% and 20% relative humidity (RH), respectively, which are two orders of magnitude higher than those of pristine MOF. The conductivity under low humidity (20% RH) is even over 8 times higher than that of commercial Nafion membrane (3 mS·cm−1). This study may provide some guidance on the development of polyMOF membranes. [ABSTRACT FROM AUTHOR]

Mixed culture fermentation (MCF) is challenged by the unqualified activity of enriched bacteria and unwanted methane dissolution under low temperatures. In this work, caproate production from xylose was investigated by MCF at a low temperature (20 °C). The results showed that a 9 d long hydraulic retention time (HRT) in a continuously stirred tank reactor was necessary for caproate production (∼0.3 g/L, equal to 0.6 g COD/L) from xylose (10 g/L). The caproate concentration in the batch mode was further increased to 1.6 g/L. However, changing the substrate to ethanol did not promote caproate production, resulting in ∼1.0 g/L after 45 d of operation. Four genera, Bifidobacterium, Caproiciproducens, Actinomyces, and Clostridium_sensu_stricto_12, were identified as the enriched caproate-producing bacteria. The enzymes in the fatty acid biosynthesis (FAB) pathway for caproate production were identified via metagenomic analysis. The enzymes for the conversion of (Cn+2)-2,3-Dehydroxyacyl-CoA to (Cn+2)-Acyl-CoA (i.e., EC 1.3.1.8 and EC 1.3.1.38) in the reverse β-oxidation (RBO) pathway were not identified. These results could extend the understanding of low-temperature caproate production. [ABSTRACT FROM AUTHOR]

The electricity production via psychrophilic microbial fuel cell (PMFC) for wastewater treatment in cold regions offers an alternative to avoid the unwanted methane dissolution of traditional anaerobic fermentation. But, it is seldom reported by mixed-culture, especially closed to 0 °C. Thus, a two-chamber mixed-culture PMFC at 4 °C was successfully operated in this study using acetate as an electron donor. The main results demonstrated a good performance of PMFC, including the maximum voltage of 513 mV at 1000 Ω, coulombic efficiency of 53%, and power density of 689 mW/m2. The cyclic voltammetry curves of enriched biofilm showed a direct electron transfer pathway. These good performances of mixed-culture PMFC were due to the high psychrophilic activity of enriched biofilm, including exoelectrogens genera of Geobacter (6.1%), Enterococcus (17.5%), and Clostridium_sensu_stricto_12 (3.8%). Consequently, a mixed-culture PMFC provides a reasonable strategy to enrich exoelectrogens with high activity. For low-temperature regions, the mixed-culture PMFC involved biotechnologies shall benefit energy generation and valuable chemical production in the future. Key points: • PMFC showed a maximum voltage of around 513 mV under a resistance of 1000 Ω. • The coulombic efficiency was 53% and the max power density was 689 mW/m2. • Geobacter, Enterococcus, and Clostridium_sensu_stricto_12 were key exoelectrogens. [ABSTRACT FROM AUTHOR]

Engaging students as partners (SaP) is an approach promoting meaningful pedagogical relationships in higher education. Scholars have called for more culturally situated research on SaP that compares Anglophone countries with other contexts. In response, we conducted an exploratory qualitative study by interviewing 36 undergraduate students from Australia, Mainland China, and Hong Kong. Adopting the relational lens of SaP, the interviews focused on conceptualisations of pedagogical partnership, specifically learner–teacher identities and power dynamics. Through comparative and reflexive thematic analysis, we found that understandings of partnership in different contexts were influenced by broader cultural differences. The findings showed that the perception of SaP in Australia was consistent with the prevailing Western discourse, but the notion of SaP was adapted and re-shaped in Mainland China, and in Hong Kong, there were diverse interpretations of it. This study contributes to new understandings of the influence of specific sociocultural and policy variations in SaP practises through culturally situated and comparative research using theorisations of perpetual translation. We argue for future research to contribute collective insights and nuanced, diverse understandings that expand SaP as an approach to global scholarship. [ABSTRACT FROM AUTHOR]

With the growing trend of globalization, an increasing number of Chinese students choose to study overseas. While researchers have conducted many studies to explore factors motivating these students to undertake higher education overseas, few studies have investigated Chinese students' motivations to pursue secondary education abroad. To fill this research gap, we interviewed 20 Chinese secondary students and four Chinese parents to explore Chinese students' motivations to pursue secondary education abroad by taking Canada as a study destination example. By adopting the push–pull model as the theoretical framework, we identify two macro-level push factors and three micro-level push factors that propel Chinese secondary students to study outside China. It also reveals five pull factors at the macro-level and two pull factors at the micro-level that attract these students to select Canada as a study abroad destination. On the basis of identifying these push–pull factors, we further discuss the similarities and differences of Chinese students' motivations to pursue secondary education abroad and to undertake higher education overseas. [ABSTRACT FROM AUTHOR]

Exosomes are small membrane-enclosed vesicles secreted by various types of cells. Exosomes not only participate in different physiological processes in cells, but also involve in the cellular responses to viral infection. Grass carp reovirus (GCRV) is a non-enveloped virus with segmented, double-stranded RNA genome. Nowadays, the exact role of exosomes in regulating the life cycle of GCRV infection is still unclear. In this study, the exosomes secreted from Ctenopharyngodon idellus kidney (CIK) cells infected or uninfected with GCRV were isolated, and the differential protein expression profiles were analyzed by proteomic technologies. A total of 1297 proteins were identified in the isolated exosomes. The differentially abundant proteins were further analyzed with functional categories, and numerous important pathways were regulated by exosomes in GCRV-infected CIK cells. These exosomal proteins were estimated to interact with the genes (proteins) of the top 10 most enriched signaling pathways. Furthermore, GW4869 exosome inhibitor suppressed the expression level of VP7 in GCRV-infected cells, suggesting that exosomes play a crucial role in the life cycle of GCRV infection. These findings could shed new lights on understanding the functional roles of exosomes in the cellular responses to GCRV infection. [ABSTRACT FROM AUTHOR]

Flexible strain sensor has promising features in successful application of health monitoring, electronic skins and smart robotics, etc. Here, we report an ultrasensitive strain sensor with a novel crack-wrinkle structure (CWS) based on graphite nanoplates (GNPs)/thermoplastic urethane (TPU)/polydimethylsiloxane (PDMS) nanocomposite. The CWS is constructed by pressing and dragging GNP layer on TPU substrate, followed by encapsulating with PDMS as a protective layer. On the basis of the area statistics, the ratio of the crack and wrinkle structures accounts for 31.8% and 9.5%, respectively. When the sensor is stretched, the cracks fracture, the wrinkles could reduce the unrecoverable destruction of cracks, resulting in an excellent recoverability and stability. Based on introduction of the designed CWS in the sensor, the hysteresis effect is limited effectively. The CWS sensor possesses a satisfactory sensitivity (GF = 750 under 24% strain), an ultralow detectable limit (strain = 0.1%) and a short respond time of 90 ms. For the sensing service behaviors, the CWS sensor exhibits an ultrahigh durability (high stability > 2×104 stretching-releasing cycles). The excellent practicality of CWS sensor is demonstrated through various human motion tests, including vigorous exercises of various joint bending, and subtle motions of phonation, facial movements and wrist pulse. The present CWS sensor shows great developing potential in the field of cost-effective, portable and high-performance electronic skins. [ABSTRACT FROM AUTHOR]

Highlights: The cationic waterborne polyurethanes microspheres with Diels-Alder bonds were synthesized for the first time. The electrostatic attraction not only endows the composite with segregated structure to gain high electromagnetic-interference shielding effectiveness, but also greatly enhances mechanical properties. Efficient healing property was realized under heating environment. It is still challenging for conductive polymer composite-based electromagnetic interference (EMI) shielding materials to achieve long-term stability while maintaining high EMI shielding effectiveness (EMI SE), especially undergoing external mechanical stimuli, such as scratches or large deformations. Herein, an electrostatic assembly strategy is adopted to design a healable and segregated carbon nanotube (CNT)/graphene oxide (GO)/polyurethane (PU) composite with excellent and reliable EMI SE, even bearing complex mechanical condition. The negatively charged CNT/GO hybrid is facilely adsorbed on the surface of positively charged PU microsphere to motivate formation of segregated conductive networks in CNT/GO/PU composite, establishing a high EMI SE of 52.7 dB at only 10 wt% CNT/GO loading. The Diels–Alder bonds in PU microsphere endow the CNT/GO/PU composite suffering three cutting/healing cycles with EMI SE retention up to 90%. Additionally, the electrostatic attraction between CNT/GO hybrid and PU microsphere helps to strong interfacial bonding in the composite, resulting in high tensile strength of 43.1 MPa and elongation at break of 626%. The healing efficiency of elongation at break achieves 95% when the composite endured three cutting/healing cycles. This work demonstrates a novel strategy for developing segregated EMI shielding composite with healable features and excellent mechanical performance and shows great potential in the durable and high precision electrical instruments. [ABSTRACT FROM AUTHOR]

A new type of dianionic Ir(III) CCC pincer complexes (SNHC-Ir, 1a-1c) is successfully designed and synthesized by developing a one-step methodology, which involves an initial coordination of Ir(I) with the NHC and subsequent metallation of double sp2C- H bonds. This method is considerably useful over those reported by using strong coordination ligand or carbonic anion exchange, and would provide an alternative efficient template of organometallics synthesis. Experimental and density functional theory (DFT) calculation results indicate that the spirocyclic framework is a favourable factor for the facile formation and stabilization of these complexes. Primary investigation shows that chloride 1b can well catalyze homo and hetero addition of styrene derivatives and remote olefin isomerization, which represents the first catalytic application of the dianionic CCC pincer complexes. [ABSTRACT FROM AUTHOR]

A series of methylamine-modified hyper-cross-linked resins were fabricated from chloromethylated polystrene-co-divinylbenzene by two continuous reactions (Friedel-Crafts alkylation and amination). The BET surface area and pore volume of the as-prepared resins took a positive correlation to the reaction time and temperature during alkylation reaction while lessened during amination process. When running batch adsorption experiments for adsorption of citric acid, the methylamine-modified resin named HM-65-2 showed higher adsorption capacity of 136.3 mg/g and selectivity of 6.98 (citric/glucose) than the precursor resins. The pseudo-second-order rate model fitted better than the pseudo-first-order model, implying the adsorption sites distributed on the resins surface tended to be heterogeneous. Subsequently, the interactions between citric acid and the resin were investigated by means of molecular simulation. Simulation result showed the addition of nitrogen-containing groups significantly enhanced the adsorption performance of citric acid. Lastly, the dynamic column experiments were performed to obtain the suitable operating conditions for the citric acid adsorption. [ABSTRACT FROM AUTHOR]

Tea tree oil (TTO) and its two characteristic components (terpinen-4-ol and 1,8-cineole) have been shown to inhibit Botrytis cinerea growth. In this study, we conducted a transcriptome analysis to determine the effects of TTO and its characteristic components, alone and in combination, against B. cinerea. Most differentially expressed genes (DEGs) from B. cinerea cells treated with terpinen-4-ol participated in the biosynthesis of secondary metabolites, and the metabolism of amino acids, carbohydrates, and lipids. All treatments containing terpinen-4-ol potentially induced mitochondrial dysfunction and oxidative stress. These were further confirmed by the decreased activities of several enzymes (e.g., succinate dehydrogenase (SDH), malate dehydrogenase (MDH), α-ketoglutarate dehydrogenase (α-KGDH), isocitrate dehydrogenase (ICDH)), the increased activities of certain enzymes (e.g., catalase (CAT), peroxidase (POD), superoxide dismutase (SOD)), and increased content of hydrogen peroxide (H2O2). 1,8-Cineole mainly affected DEGs involved in genetic information processing, resulting in cell death. This study provides insight into the molecular mechanism of B. cinerea inhibition by TTO, and explains the synergistic effect of terpinen-4-ol and 1,8-cineole on B. cinerea. [ABSTRACT FROM AUTHOR]

The mixed culture fermentation is an important environmental biotechnology that converts biodegradable organic wastes to valuable chemicals such as hydrogen, methane, acetate, ethanol, propionate, and so on. For the multistep process of hydrolysis, acidogenesis, acetogenesis/homoacetogensis, and methanogenesis, the typical metabolic reactions are firstly summarized. And then, since the final metabolites are always a mixture, the separation and purification processes are necessary to couple with anaerobic fermentation. Therefore, several typical coupling technologies including biogas upgrading, two-stage fermentation, gas stripping, membrane technology of pervaporation, membrane distillation, electrodialysis, bipolar membrane electrodialysis, and microbial fuel cells are summarized to separate the metabolites and recover energy. At last, the novel technologies such as the controlled metabolite production, medium chain carboxylic acid production, and high temperature ethanol recovery in thermophilic mixed culture fermentation are also reviewed. However, the novel concepts are still needed to meet the demands of better overall performances and lower total costs. [ABSTRACT FROM AUTHOR]

Liquid-sensing behaviors of carbon black (CB)/polyamide 6 (PA6)/high-density polyethylene (HDPE) composite containing conductive electrospun fibrous network were investigated by detecting electrical resistance variations toward different solvents. The material exhibited a good sensing selectivity, which could be predicted by Flory-Huggins interaction parameter χ . In immersion-drying runs (IDRs), the composite showed a large liquid-sensing responsivity but poor reproducibility toward 'good solvent' xylene. After long-term immersion treatment in xylene, the metastable conductive pathways became stabilized, and a better reproducibility was finally achieved. Absorption/desorption equilibrium state of the composite in 'moderate' or 'poor' solvents was reached more easily than that in good solvent. Additionally, more rapid response, higher sensing responsivity, and better reproducibility of the composite in 'moderate solvent' cyclohexane were observed at a higher environment temperature. These results indicated that liquid-sensing behaviors of conductive polymer composites could be tailored by tuning the microstructure or utilizing the pretreatment. [ABSTRACT FROM AUTHOR]

The microbial community compositions of a chemostat enriched in a thermophilic (55 °C) mixed culture fermentation (MCF) for hydrogen production under different operational conditions were revealed in this work by integrating denaturing gradient gel electrophoresis (DGGE), Illumina Miseq high-throughput sequencing, and 16S rRNA clone library sequencing. The results showed that the community structure of the enriched cultures was relatively simple. Clones close to the genera of Thermoanaerobacter and/or Bacillus mainly dominated the bacteria. And homoacetogens and archaea were washed out and not detected even by Illumina Miseq high-throughput sequencing which supported the benefit for hydrogen production. On the other hand, the results revealed that the metabolic shift was clearly associated with the change of dominated bacterial groups. The effects of hydrogen partial pressure (P) and pH from 4.0 to 5.5 on the microbial compositions were not notable and Thermoanaerobacter was dominant, thus, the metabolites were also not changed. While Bacillus, Thermoanaerobacter and Propionispora hippei dominated the bacteria communities at neutral pH, or Bacillus and Thermoanaerobacter dominated at high influent glucose concentrations, consequently the main metabolites shifted to acetate, ethanol, propionate, or lactate. Thereby, the effect of microbial composition on the metabolite distribution and shift shall be considered when modeling thermophilic MCF in the future. [ABSTRACT FROM AUTHOR]

Polymer processing generally plays a crucial role in determining the development of microstructure in the fabricated product. In this paper, isotactic polypropylene (iPP) containing 0.1 wt% β-nucleating agent was extruded via a slit die and immediately melt-stretched upon various stretching rates (SR) at the die exit. The microstructure of β-nucleated iPP samples was investigated using two-dimensional wide-angle X-ray diffraction and small-angle X-ray scatterings (2D-WAXD/SAXS) measurements. It is observed that, no matter what SR is, lamellar branching of β-form crystal is formed in melt-stretched samples, which is scarcely reported in open literatures. A method is proposed to calculate the crystallinity of daughter lamellae in β-crystal ( X). It is found that X decreases with increasing SR, indicating that lamellar branching of β-form crystal is restrained by higher SR. Such case should be attributed to the denser-oriented structures (e.g., shish) induced by higher SR, leaving a confined space between adjacent-oriented structures for the growth of daughter lamellae. [ABSTRACT FROM AUTHOR]

The effects of pH, hydrogen partial pressure (P), and influent glucose concentration on the metabolic distribution in chemostat were investigated in this work in extreme-thermophilic mixed culture fermentation (MCF) process. The results showed that acetate, ethanol, and hydrogen were the main metabolites. A shift of ethanol to acetate and hydrogen was observed as pH increasing from 4.0 to 7.0 or P decreasing from 0.64 to 0.05 atm. The maximum hydrogen yield was 3.16 ± 0.16 mol/mol glucose at P 0.05 atm. Lactate was only accumulated at low pH or high influent glucose concentration, while others such as butyrate and formate were rather low. Thermodynamic analysis illustrated that a mixture of acetate, ethanol, and/or lactate was essential for hydrogen production in extreme-thermophilic MCF. The hydrogen-producing rate was also calculated, and the maximum value was 2.2 ± 0.1 L/(L-reactor/day) at P 0.05 atm. Except hydrogen, other metabolites, such as liquid fatty acids and biofuels, could also be the producing targets in extreme-thermophilic MCF. [ABSTRACT FROM AUTHOR]

A carbon black (CB)/polypropylene (PP)/ultrahigh-molecular-weight polyethylene (UHMWPE) composite with a segregated structure was fabricated by using binary polymer granules as matrices. In preparation, an ethanol-assisted dispersion method was employed to disperse CB particles on the surface of the two polymer granules. The segregated conductive network was then constructed by hot compaction based on the volume exclusion effect of the polymer matrices. The conductive composite shows an ultralow percolation threshold of 0.34 vol.%. In temperature-resistivity test, a double positive temperature coefficient (PTC) effect was observed. In addition, the negative temperature coefficient (NTC) effect was eliminated significantly. These interesting temperature-resistivity behaviors were ascribed to the introduction of the binary polymer matrices and the mobility limitation of CB particles located at the PP/UHMWPE interface. These characteristics were probed by in situ morphology observation in heating process. The present paper provides a novel route for preparing conductive composites with an ultralow percolation threshold, a wider PTC region, and a zero NTC effect. [ABSTRACT FROM AUTHOR]

A new rhodamine derivative (RhB-NSal) bearing an electron-withdrawing group -NO at the 5-position of 2-hydroxyphenyl moiety was synthesized and its sensing behaviors for Cu in acetonitrile and aqueous acetate-buffer/acetonitrile (2/3, v/ v, pH 4.8) media were investigated. In each medium, significant absorption and fluorescence enhancements accompanied by an instant color change from colorless to pink were observed for RhB-NSal upon addition of Cu. RhB-NSal binds with Cu forming a 1:1 stoichiometric complex with an association constant of 6.72 (±0.03) × 10 M and 4.23 (±0.03) × 10 M, respectively. RhB-NSal displayed high selectivity for Cu over possibly competitive metal ions except that Fe and Bi ion can respectively bring about a little interference in absorption and fluorescence with its sensing for Cu. In dry acetonitrile, pronounced enhancements in the absorbance and emission of RhB-NSal were induced by Cu, with a detection limit of 0.49 μM, exhibiting higher sensitivity than that of a known analogue bearing no substituent on its phenol ring, RhB-Sal. In aqueous solution, RhB-NSal displayed likewise a high selectivity but a lower sensitivity for Cu than that in acetonitrile, with a detection limit of 14.98 μM, still more sensitive than RhB-Sal in absorption. By virtue of these properties, RhB-NSal could be used as an 'Off-On' fluorescent and colorimetric chemosensor for Cu in acetonitrile medium, and be developed to be a promising candidate of 'Off-On' eye-naked chemosensor for Cu in a weakly acidic aqueous medium. [ABSTRACT FROM AUTHOR]

The strain-sensing behaviors of carbon black (CB)/polypropylene (PP) and carbon nanotubes (CNTs)/PP conductive composites prepared by the vacuum-assisted hot compression were studied and compared. When ten extension-retraction cycles were applied, it was found for CB/PP, the value of the maximum responsivity (Δ R/ R, Δ R-the instantaneous variation of the resistance during the test, R-the original resistance) decreased gradually with increasing the cycle number, but it began to rise from the seventh cycle. The value of the min Δ R/ R increased during the whole test. While for CNTs/PP, both the values of the max and min Δ R/ R decreased rapidly. It is suggested that the different behaviors mainly depend on the distinction in the dimension of the conductive fillers and the preparation technique. [ABSTRACT FROM AUTHOR]

In this paper, injection-molded isotactic polypropylene (iPP) microparts and macroparts were respectively fabricated by the molds with different thickness under the same processing conditions. Comparative study on microstructure and mechanical property was carried out by means of scanning electron microscopy (SEM), two-dimensional wide-angle X-ray diffraction (2D-WAXD), two-dimensional small-angle X-ray scattering (2D-SAXS), differential scanning calorimetry (DSC) and tensile test. SEM images reveal that the two parts show distinctly different hierarchical structure. An obvious ‘skin–core’ structure is present for the macroparts, while a wide distribution of shish-kebab structure develops in both shear and core layer for microparts, exhibiting a specific ‘core-free’ morphology. 2D-WAXD, 2D-SAXS and DSC results show that microparts have higher orientation degree and crystallinity as compared to macroparts, which are responsible for the remarkably high tensile strength and modulus. Our work provides a good example for better understanding processing structure–property relationship of iPP through tuning their internal microstructure. [ABSTRACT FROM AUTHOR]

Carbon black (CB)/poly (lactic acid) (PLA) conductive biopolymer composite were fabricated by casting. A low percolation value (1.25 vol%) is achieved due to the formation of a two-dimensional conductive network in the composite. Vapor sensing behaviors of the CB/PLA conductive composite were studied. A high chemical selectivity with respect to different organic vapors and a good reproducibility to two typical solvents, ethyl acetate and ethanol, during exposure-drying runs have been demonstrated. The variations of the sensing behaviors during exposure-drying processes were associated with the evolvement of CB conductive networks. The results indicate that the Flory-Huggins interactions parameter x12, related to the solubility parameter (thermodynamic factor), molar volume (kinetic factor) and the measurement temperature, affects the vapor sensing behaviors of CB/PLA composite significantly. These results suggest CB/PLA conductive biopolymer composite can be applied as a nice vapor sensor candidate. [ABSTRACT FROM AUTHOR]

Syngas fermentation is a promising route for resource recovery. Acetate is an important industrial chemical product and also an attractive precursor for liquid biofuels production. This study demonstrated high fraction acetate production from syngas (H 2 and CO 2) in a hollow-fiber membrane biofilm reactor, in which the hydrogen utilizing efficiency reached 100 % during the operational period. The maximum concentration of acetate in batch mode was 12.5 g/L, while the acetate concentration in continuous mode with a hydraulic retention time of 9 days was 3.6 ± 0.1 g/L. Since butyrate concentration was rather low and below 0.1 g/L, the acetate fraction was higher than 99 % in both batch and continuous modes. Microbial community analysis showed that the biofilm was dominated by Clostridium spp., such as Clostridium ljungdahlii and Clostridium drakei, the percentage of which was 70.5 %. This study demonstrates a potential technology for the in situ utilization of syngas and valuable chemical production. [ABSTRACT FROM AUTHOR]

In order to further investigate shear-induced interfacial crystallization of polymer-based composites, an improved fiber-pulling device was designed and built. Its peculiar characteristic is that a force transducer is assembled to in situ monitor the variation of interfacial shear stress between the polymer matrix and pulling fiber. Thus, the relationship between interfacial shear stress and the subsequent crystalline morphology can be quantitatively established. In the preliminary study via this device, isotactic polypropylene (iPP)/glass fiber composite was adopted as a model system. The results indicate that interfacial crystallization kinetics is promoted by the presence of interfacial shear stress. Furthermore, there are two thresholds of interfacial shear stress for interfacial crystalline morphology. To be specific, one (0.017 MPa) is for the induction of iPP nucleation, above which α-form iPP crystals are obviously encouraged during the subsequent isothermal crystallization; the other is for the generation of β-form iPP crystals (0.042 MPa), above which β-form crystals are favored to be triggered in the transcrystalline region. [ABSTRACT FROM AUTHOR]

The crystallization in isotactic polypropylene (iPP) melt inclusions, encapsulated by transcrystallinity and spherulites, was investigated by polarized light microscope. Generally, owing to the proceeding of crystallization in melt inclusions, a negative pressure will be built up. Up to a critical value, the negative pressure is released by the formation of cavitation in melt. Unexpectedly, β-crystals with different morphologies emerge at different locations in the melt inclusions. For low molecular weight iPP, only smaller β-crystals around bubbles are discernable. Turn to higher molecular weight iPP, apart from the smaller β-crystals, fan-shaped ones can be developed under suitable conditions (e.g., lower than 131 °C) at the growth front of spherulites and transcrystallinity. Considering the characteristics of molecular weight and morphology, it is proposed that β-crystals are induced by different mechanisms. That is, smaller β-crystals are resulted from the stress caused by the appearance of bubbles while the fan-shaped ones are derived due to the temperature gradient during the release of negative pressure. [ABSTRACT FROM AUTHOR]

Current-voltage electrical behavior of in situ microfibrillar carbon black (CB)/poly(ethylene terephthalate) (PET)/polyethylene (PE) (m-CB/PET/PE) composites with various CB concentrations at ambient temperatures was studied under a direct-current electric field. The current-voltage ( I-V) curves exhibited nonlinearity beyond a critical value of voltage. The dynamic random resistor network (DRRN) model was adopted to semi-qualitatively explain the nonlinear conduction behavior of m-CB/PET/PE composites. Macroscopic nonlinearity originated from the interfacial interactions between CB/PET micro fibrils and additional conduction channels. Combined with the special conductive networks, an illustration was proposed to interpret the nonlinear I-V characteristics by a field emission or tunneling mechanism between CB particles in the CB/PET microfibers intersections. [ABSTRACT FROM AUTHOR]

Polyamide 66 (PA 66) nanofiber bundles were first electrospun and then introduced into isotactic polypropylene (iPP) melts to prepare nanofiber bundle/iPP composites. To reveal the influences of matrix molecular weight ( M) on the transcrystalline layer, three kinds of iPP with different M were adopted. Polarized optical microscope was employed to investigate the transcrystallinity. In the presence of PA 66 nanofiber bundle, the heterogeneous nucleation distinctly happened in iPP melts. Moreover, the higher the iPP M, the denser the nuclei. Both a decrease in matrix M and an increase in isothermal crystallization temperature led to an increase in the induction time. The maximum temperature at which the transcrystalline layer can be optically observed increased with the increase of M. The growth rate of transcrystallinity decreased with the increasing M and crystallization temperature. Moreover, selective melting of the transcrystalline layers confirmed that it was merely composed of α form crystal for all composites. [ABSTRACT FROM AUTHOR]

The conductive polymer composite (CPC) based on carbon black (CB), polyethylene (PE), and poly(ethylene terephthalate) (PET) was fabricated, in which the majority of CB particles were selectively localized in the surface of in situ deformed, highly oriented PET microfibrils. The on-line measurement of the electrical resistivity of the CPC materials indicated that the critical time for conductive network formation decreased with the increase of the annealing temperature and the filler loading. The activation energy for conductive network formation was about 96 kJ/mol, which was much higher than that for common CB/PE composite due to the large size of the conductive microfibrils. By a thermodynamic percolation model, the percolation threshold at equilibrium state was 1.735 vol.%, below which the effective conductive network was never formed. The reorganization velocity of the conductive microfibrils was a function of annealing temperature. This study extended insight into the dynamic process of the conductive network formation during annealing. [ABSTRACT FROM AUTHOR]

It is well known that water-assisted injection molding (WAIM) process can be fulfilled based on the melt filling stage of conventional injection molding (CIM) process. However, due to the different physical fields involved during WAIM and CIM processes, WAIM part should exhibit unique morphological features compared with the CIM one. In this study, isotactic polypropylene (iPP) parts were prepared by WAIM and CIM, respectively, and their comparative study on morphology were therefore carried out by means of polarized optical microscopy (POM) and two-dimensional (2D) wide-angle X-ray diffraction (WAXD). POM observations illustrated that the WAIM part exhibits a 'skin-core-water channel' structure, while the CIM part shows a typical 'skin-core' structure. 2D-WAXD results showed obvious arclike reflections in each position along thickness direction of the WAIM part, indicating a pronounced molecular orientation. Furthermore, a parent-daughter model (or branched shish-kebab structure) appears at 0 and 100 μm for both the parts, and the fraction of daughter lamellae for WAIM part is lower than that of CIM part. As for the 1D-WAXD curves, it is noticed that there is a very tiny (300) reflection of β-form in the CIM part, while it is invisible in all positions of the WAIM part. In addition, the crystallinity and crystalline size L of CIM part are found to be higher than that of WAIM part. Those results demonstrate that water penetration and rapid cooling rate have a significant effect on the morphological features of WAIM part. [ABSTRACT FROM AUTHOR]

PWWP domains are found in eukaryotic proteins from yeast to mammals and are involved in DNA methylation, DNA repair and regulation of transcription. Here we report the resonance assignments of TbTFIIS2-2 PWWP domain from Trypanosoma brucei for further understanding of the relationship between its structure and function. [ABSTRACT FROM AUTHOR]

In this study, porous bioglass/gelatin/alginate bone tissue engineering scaffolds were fabricated by three-dimensional printing. The compressive strength and in vitro biomineralization properties of the bioglass–gelatin–alginate scaffolds (BG/Gel/SA scaffolds) were significantly improved with the increase of bioglass content until 30% weight percentage followed by a rapid decline in strength. In addition, the cells attach and spread on the BG/Gel/SA scaffolds surfaces represents good adhesion and biocompatibility. Furthermore, the cells (rat bone marrow mesenchymal stem cells, mBMSCs) proliferation and osteogenic differentiation on the BG/Gel/SA scaffolds were also promoted with the increase of bioglass content. Overall, the adding of bioglass in Gel/SA scaffolds promotes mechanical strength and in vitro osteogenic properties and the 30 BG scaffold (30%wt BG) has potential applications in bone tissue engineering and bone regenerative repair because of good compressive strength, biocompatibility, and in vitro osteogenesis. [ABSTRACT FROM AUTHOR]

Actin-depolymerizing factor (ADF)/cofilin proteins are a family of actin-binding proteins expressed in almost all eukaryotic cells, and play a significant role in regulating actin-filament dynamics. Here we report the resonance assignments of a putative ADF/cofilin from Trypanosoma brucei for further understanding of the relationship between its structure and function. [ABSTRACT FROM AUTHOR]

Brain metastasis is a significant unmet clinical problem in breast cancer treatment. It is always associated with poor prognosis and high morbidity. Recently, Slit2/Robo1 pathway has been demonstrated to be involved in the progression of breast carcinoma. However, until present, there are no convincing reports that suggest whether the Slit2/Robo1 axis has any role in brain metastasis of breast cancer. In this study, we investigated the correlation between Slit2/Robo1 signaling and breast cancer brain metastasis for the first time. Our results demonstrated that (1) Invasive ductal carcinoma patients with low expression of Slit2 or Robo1 exhibited worse prognosis and brain-specific metastasis, but not liver, bone or lung. (2) Lower expression of Slit2 and Robo1 were observed in patients with brain metastasis, especially in their brain metastasis tumors, compared with patients without brain metastasis. (3) The interval from diagnosis of breast cancer to brain metastasis and brain metastasis to death were both much shorter in patients with low expression of Slit2 or Robo1 compared with the high expression group. Overall, our findings indicated that Slit2/Robo1 axis possibly be regarded as a significant clinical parameter for predicting brain metastasis in breast cancer patients. [ABSTRACT FROM AUTHOR]