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A controlled polymerization strategy is developed by confining the step-growth polycondensation to take place exclusively in the nanochannels of dendritic mesoporous silica nanoparticles. A variety of conjugated polymers with rich structural patterns were obtained in high yields. The molecular weights were precisely controlled with narrow molecular weight distributions. The obtained conjugated polymers were freely processed in solution and casted in film, showing bright fluorescence emission. All the features of this controlled polymerization method endow the conjugated polymers great potential for future applications.

Conjugated polymers are attractive components of modern plastic electronics and photovoltaic devices. They are synthesized mainly through a step-growth polymerization (SGP) mechanism. However, due ...

Fluorescent electronic tongues are designed for the quick discrimination of nitroaromatics in aqueous solution through fluorescence quenching of soluble conjugated polymeric nanoparticle (SCPN) arrays supported with water-borne polyurethane. The quenching efficiencies dominantly depend on the overlap of the absorbance spectra of the nitro-analytes and the emission spectra of the SCPNs, as well as the LUMO level of the nitro-analytes. The unique quenching responses towards eight nitroaromatics were recorded by reading the RGB values and then the differences were analyzed by linear discriminant analysis (LDA). The fluorescent electronic tongues showed high sensitivity towards the nitroaromatics in a relatively low concentration of 0.1 mM with rapid response time (within minutes of exposure time). In the prediction test of unknown nitro-analytes via the leave-one-out cross-validation method, the evaluation accuracy reached 100% within the test scope, suggesting that the fluorescent electronic tongues in this work are promising for quick sensing and identifying nitroaromatics in wastewater for field use.

A catalytic heterogenous Suzuki polymerization method was developed by confining the Pd(II)-catalyzed cross coupling reactions to take place exclusively in the nanochannels of dendritic mesoporous silica nanoparticles. Conjugated polymers with various monomer combinations, including donor-acceptor structures, were obtained in high yields. The molecular weights of the obtained polymers were well controlled with narrow molecular weight distributions (PDI value down to 1.13). All the polymeric products were highly soluble in common organic solvents, granting them with high processability. All the features of this confined Suzuki polymerization method endow the conjugated polymers great potential in optoelectronic applications.

To explore the space for further optimization of BaCeO3-based single-phase cathode, series of perovskite materials BaCe0.5Fe0.5-xBixO3-δ (x = 0, 0.1, 0.2, 0.3) as cobalt-free cathodes for proton conducting solid oxide fuel cells are evaluated in this assignment. The influence of the firing temperature on cathode microstructures and the electrochemical performance of fuel cells is evaluated, which states clearly that the best sintering temperature for BaCe0.5Fe0.3Bi0.2O3-δ cathode is 900 °C. Moreover, a special attention is paid to the effect of the Bi doping amount on the phase structure and electrochemical performance. With the cathode BaCe0.5Fe0.3Bi0.2O3-δ, the single cell achieves the polarization resistance of 0.061 Ω cm2 and the maximum power density of 943 mW cm−2 at 700 °C. These encouraging electrochemical results demonstrate that BaCe0.5Fe0.3Bi0.2O3-δ is a promising cobalt-free cathode for proton-conducting solid oxide fuel cells.

Conjugated polymer (CP) aggregates with linear/cross-linked structures are widely reported as photocatalysts for hydrogen evolution reaction. For full disclosure of the relationship between the photocatalytic performance and structural features of the CP photocatalysts, homogeneous dispersion of these CPs in aqueous medium is necessary, which however is difficult to be achieved. Herein, we report several coassembled polymeric dots (Pdots) consisting of PEG45-b-PMMA103 and CPs with various structural features. We found that the Pdots of hyperbranched soluble CP nanoparticles (SCPNs) exhibit a high H2 evolution rate up to 840 μmol h–1 g–1 with no platinum or rhodium as a cocatalyst, superior to their analogues with the linear or cross-linked structure. A possible charge-transfer mechanism suggests that the photoelectrons directly mobilize to the surface of these single-particulate Pdots over three-dimensional skeleton and successfully avoid the ineffective intermolecular charge transfer, leading to the shortened diffusion path of photoelectrons and enhanced photolysis efficacy. We believe that the high dispersion stability (2 months), solution processability, and structural tunability of these Pdots with hyperbranched SCPNs would inspire further research on designing multicomponent photocatalysts for highly efficient visible light-driven hydrogen evolution reaction.

Mg-doped La2Ce2O7-δ (LCO) is investigated to develop an easily sintered and chemically stable proton conductor for fabricating high-performance solid oxide fuel cells (SOFCs). All La2-xMgxCe2O7-δ ceramics possess a pure fluorite-type structure. The sintering activity of Mg-doped LCO increases obviously, and fully dense La1.85Mg0.15Ce2O7-δ (LMCO) electrolyte membrane is successfully prepared by co-firing at the temperature as low as 1300 °C for 5 h. Besides, LMCO exhibits the highest electrical conductivity of 7.41 × 10−3 S cm−1 in dry air and 1.55 × 10−2 S cm−1 in wet H2 (∼3% H2O) at 700 °C among the investigated oxides, and retains excellent chemical stability against CO2 and H2O. The LMCO-based fuel cell also displays very encouraging power performance, reaching as high as 897 mWcm−2 at 700 °C. The results demonstrate LMCO is a promising alternative as proton conductor for achieving both chemically stable and high-performance SOFCs with reduced sintering temperature.

Nanofiber-structured La2NiO4+δ (LNO) and LaNi0.6Fe0.4O3-δ (LNF) cathodes, which were fabricated by an electrospinning technique, were used for proton-conducting solid oxide fuel cells (H-SOFCs) for the first time, aiming to develop high-performance cobalt-free cathodes for H-SOFCs. High porosity and large specific surface area of LNO, LNF nanofiber-structured cathodes were beneficial for the cathode reactions, resulting in an encouraging peak power density of 508 mWcm−2 and 551 mWcm−2 for LNO and LNF cathode cell at 700 °C, respectively. The nanofiber-structured cathodes showed a higher fuel cell performance and lower polarization resistance compared with that of the cell using corresponding powder cathode, suggesting the construction of nanofiber-structured cathode provided an alternative and promising route to prepare high performance cathodes for H-SOFCs. Keywords: Proton conductor, Cobalt-free cathode, Nanofiber, Solid oxide fuel cells

In this work, two asymmetric NiO-BaZr0.1Ce0.7Y0.2O3-δ (NiO-BZCY) anode substrates were prepared via the phase-inversion tape casting method for Ce0.8Sm0.2O2-δ (SDC)-based solid oxide fuel cells. The results showed that the anode support structure significantly influenced the electrochemical properties of the cells. The cell supported on the anode substrate consisted of a finger-like layer and a sponge-like layer outputs highest electrochemical performance with a maximum power density of 823 mW cm−2 at 650 °C and shows great superiority over the cell fabricated by a typical dry-pressing method. The excellent performances demonstrate that the phase-inversion tape casting technique is a good strategy in fabricating anode supports for SOFCs, and the anode structure with the relatively dense sponge-like layer as top surface is optimal to construct the complete cell.

A fluorescence sensing array (or fluorescent electronic tongue) based on six sorts of soluble conjugated polymeric nanoparticles (SCPNs) decorated with PEG chains is designed for the rapid identification of heavy metal ions in water. The observed fluorescence attenuation originates from the photoinduced electron transfer (PET) between the sensors (donors) and the target analytes (acceptors). An 18-dimensional vector generated by the array is then subjected to linear discriminant analysis (LDA) and hierarchical clustering analysis (HCA) to build a chemical database pool for distinguishing nine analytes (Cr3+, Fe3+, Co2+, Zn2+, Cu2+, Pb2+, Sn4+, Ni2+, Cd2+) at 1 mM level. The prediction tests of “unknown samples” using the array are carried out, reaching 100% accuracy. With good disposability (filter paper as substrates) and high sensitivity (within minutes exposure time), this type of SCPN-based fluorescent electronic tongue enables multiple heavy metal ion detection and water quality analysis with high efficiency and low cost.

To systematically study the impact of root restriction (RR) on the aroma quality of grape berry, in this study, free and bound compounds were investigated in ‘Red Alexandria’ grape skin and pulp produced with and without RR during development and ripening. Compared with the control, RR advanced the initiation of free-terpene synthesis and increased their concentrations at 14–18 weeks post-flowering (wpf) by promoting the conversion of bound terpenes to free terpenes. In addition, RR significantly regulated the aromatic series at 14–18 wpf and advanced the date of aroma maturation. Network analyses indicated that the correlations among bound compounds were more conserved than those among free compounds, and the skin network displayed tight coordination compared with the pulp network. Terpenes were highly intercorrelated and played a core role in these networks. Finally, 10 bound compounds in pulp were screened out as indicators of the developmental timing of grape.

Fluorescent water-dispersible conjugated polymeric nanoparticles (WDCPNs) were synthesized for cellular imaging. Sonogashira polycondensations of various combinations of symmetric monomers (Ax + By, x > 2, y ≥ 2) were firstly conducted in confined nanoreactors to produce soluble conjugated polymeric nanoparticles (SCPNs) with narrow size distribution and tunable fluorescences emission. The subsequent click reaction between the terminal alkyne groups in the SCPNs and azide terminated PEG1000 endowing good dispersity of the WDCPNs in aqueous solutions and stable fluorescence emission. The WDCPNs exhibited bright fluorescence in cellular imaging and showed good biocompatibility as revealed by cell variability assay, demonstrating them as ideal fluorescent probes for biological imaging and detection.

A fluorescence sensing array (or fluorescent electronic nose) is designed on a disposable paper card using 36 sets of soluble conjugated polymeric nanoparticles (SCPNs) as sensors to easily identify wide ranges of volatile analytes, including explosives and toxic industrial chemicals (amines and pungent acids). A 108-dimensional vector obtained from the fluorescent color change in the sensing array is defined and directly treated as an index in a standard chemical library (30 kinds of volatile analytes and a control group). Hierarchical clustering analysis (HCA) and principal component analysis (PCA) indicated the diversity in electronic structures; saturated vapor pressure and miscibility of analytes are keys in differentiating the analytes, with electron-rich arenes and alkylamines enhancing fluorescence and electron-deficient analytes attenuating fluorescence. A support vector machine (SVM) works well to predict an unknown sample, reaching 99.5% accuracy. The excellent fluorescence stability (no fluorescence quenching after being exposed in air for one month) and high sensitivity (emission color changes within minutes when exposed to analytes) suggest that the fluorescent polymer-based electronic nose will play an important role in field detection and identification of a wide spreading of hazardous substances.

A perovskite-type BaCe0.5Fe0.3Bi0.2O3-δ (BCFB) was employed as a novel cathode material for proton-conducting solid oxide fuel cells (SOFCs). The single cells with the structure of NiO-BaZr0.1Ce0.7Y0.2O3-δ (BZCY7) anode substrate|NiO-BZCY7 anode functional layer|BZCY7 electrolyte membrane|BCFB cathode layer were fabricated by a dry-pressing method and investigated from 550 to 700 °C with humidified hydrogen (~3% H2O) as the fuel and the static air as the oxidant. The low interfacial polarization resistance of 0.098 Ω cm2 and the maximum power density of 736 mW cm−2 are achieved at 700 °C. The excellent electrochemical performance indicates that BCFB may be a promising cathode material for proton-conducting SOFCs.

A series of composites with nominal compositions of BaCe0.8Sm0.2O3-δ (BCS)-Ce0.8Sm0.2 O1.9 (SDC) (20:80, 35:65, 50:50, 65:35 wt.%) are synthesized by a modified citric acid-nitrate sol-gel combustion method and evaluated as the electrolytes for low-temperature solid oxide fuel cells (SOFCs). The TEM results show that doped BaCeO3 decorated SDC particles are formed after calcining at 1000 °C for 3 h. X-ray diffraction results reveal that the composites are only composed of BaCeO3-based and SDC phases without any other impurity phases. Besides, BaCeO3-based phase is uniformly distributed in the sintered electrolytes according to EDS element mapping. The open cell voltages (OCVs) of the single cells increase gradually with increasing the proportion of BaCeO3-based phase, and are higher than those for bare SDC-based cells. Besides, the power performances of the cells are superior to SDC-based cells when BaCeO3-based phase is lower than 35 wt.%. Electrochemical impedance spectroscopy analysis indicates that, in addition to blocking electronic current leakage, BaCeO3-based phase would induce higher ohmic and polarization resistance, which is detrimental to power performance. Further specific effort should be focused on synthesizing uniform SDC@BCS core-shell electrolyte powders and minimizing the proportion of BCS phase towards high-performance SOFCs with high OCVs.

Partial internal short circuit resulting from the Ce4+/Ce3+ redox reaction is currently one of the most critical issues that hinder the practical application of solid oxide fuel cells (SOFCs) with doped ceria electrolytes. In this work, a new strategy utilizing a Sr diffusion induced in situ solid-state reaction to generate a blocking layer to prevent Ce0.8Sm0.2O1.9 (SDC) from reduction is proposed for the first time. As a proof of concept, Ni-SrCe0.95Yb0.05O3−δ is deployed as a Sr source for the electron-blocking interlayer and was evaluated as an anode for SDC-based SOFCs. A thin interlayer composed of SrCe1−x(Sm,Yb)xO3−δ and SDC is formed in situ during the sintering process of the half cell due to the interdiffusion of metal cations, and the interlayer thickness is highly dependent on the sintering temperature. The high-resolution TEM results indicate that the SrCe1−x(Sm,Yb)xO3−δ perovskite phase is generated and coated on the SDC grains, forming an SDC@SrCe1−x(Sm,Yb)xO3−δ core–shell structure. The SrCe1−x(Sm,Yb)xO3−δ phase effectively suppresses the Ce4+/Ce3+ redox reaction and hence eliminates electronic conduction through the electrolyte membrane. Consequently, the OCVs of the fuel cell are significantly improved after incorporating the electron-blocking interlayer and increase with increasing the interlayer thickness. The OCVs of the cell sintered at 1250 °C reach 0.962, 0.989, 1.017, and 1.039 V at 650, 600, 550, and 500 °C, respectively. The present results demonstrate that Ni-SrCeO3-based composites are promising alternative anodes for CeO2-based SOFCs towards enhanced working efficiency at high operating voltages.

A combinatorial polymerization method has been exploited to prepare a library of soluble conjugated polymeric nanoparticles (SCPNs) through palladium catalyzed polycondensations in confined nanoreactors. The strategy of independent variation within two complementary families of simple and symmetrical monomers, Ax and By (x > 2, y ≥ 2), plus post-polymerization modification with variant terminal groups greatly increases the number of polymers and improves the efficiency of polymer preparation. Fluorescence properties (band gap) of the SCPNs are easily tuned by selecting the monomer units (A or B) and the terminal (T) substituents through this “TABulated synthesis” method, providing fluorescent polymers that cover the whole visible spectrum, from blue to red. This library of SCPNs is further utilized for multicolor fluorescence sensing of explosives, showing a high Stern–Volmer quenching constant (Ksv). Meanwhile, the Ksv values of the SCPNs were mapped with the variation of the T, A, and B building blocks to predict the possible SCPN member with the optimal Ksv value (Ksv up to 1.2 × 105 M−1), showing the academic significance of this method. We believe that such a combinatorial “TAB” strategy provides a straightforward method to quickly synthesize libraries of polymeric nanoparticles, which will promote widespread studies on the functional materials in interdisciplinary fields.

Pears are one of the most popular nutrient-rich fruits in the world. The pear core and mesocarp have significantly different metabolism, although they display similar profiles. Most strikingly, the core is more acidic in taste. Our results showed that there is more titrated acid but lower total soluble solids in the core compared to the mesocarp, and the content of citric acid was more than 17-fold higher in the core compared to the mesocarp at the ripening stage. Proteomics was used to investigate the difference between core and mesocarp tissues during "Cuiguan" pear ripening. Fifty-four different protein expression patterns were identified in the core and mesocarp. In general, common variably expressed proteins between the core and mesocarp were associated with important physiological processes, such as glycolysis, pyruvate metabolic processes, and oxidative stress. Further, protein level associated qRT-PCR verification revealed a higher abundance of fructose-bisphosphate aldolase and NADP-dependent malic enzymes, which may play a role in the low acid content in the mesocarp, whereas a higher abundance of disulfide isomerase-like 2-2 and calcium-dependent lipid-binding in the core may explain why it is less prone to accumulate sugar. The different levels of a few typical ROS scavenger enzymes suggested that oxidative stress is higher in the core than in the mesocarp. This study provides the first characterization of the pear core proteome and a description of its variation compared to the mesocarp during ripening.

This study investigated the evolution of both free and bound volatile compounds in ‘Shine Muscat’ grape from post-fruit set to post-maturity and limiting factors of the lipoxygenase (LOX) pathway. C6 compounds and terpenes were the main free and bound volatile compounds, respectively. At pre-softening, volatile compounds concentrations were mainly regulated by expansion dilution, and terpene concentrations decreased significantly, which resulted in the minimum terpene concentrations occurred at softening. The volatile compounds were mainly regulated by metabolic synthesis at post-softening, and the production of C6 compounds, terpenes and esters largely began at 10, 12 weeks post-flowering and maturity stages, respectively. In the LOX pathway, LOX, alcohol dehydrogenase and the substrate alcohols were the limiting factors. The aroma maturity stages occurred at 15.4 weeks post-flowering. Finally, the developmental patterns of the volatile compounds in grape were summarized considering previous results in neutral and non-Muscat aromatic varieties.

Developing highly efficient ceria-based solid oxide fuel cells with high power density is still a big concern for commercial applications. In this work, a novel structured Ce0.8Sm0.2O2-δ (SDC)-based fuel cell with a bilayered anode consisting of Ni-SDC and Ni-BaZr0.1Ce0.7Y0.2O3-δ (Ni-BZCY) was designed. In addition to the catalysis function, the Ni-BZCY anode "functional" layer also provides Ba source for generating an electron-blocking layer in situ at the anode/electrolyte interface during sintering. The Ni-BZCY thickness significantly influences the quality of the electron-blocking layer and electrochemical performances of the cell. The cell with a 50 μm thick Ni-BZCY layer exhibits the best performance in terms of open circuit voltage (OCV) and peak power density (1068 mW cm(-2) at 650 °C). The results demonstrate that this cell with an optimal structure has a distinct advantage of delivering high power performance with a high efficiency at reduced temperatures.

Two types of ceria–bismuth bilayer films Gd 0.1 Ce 0.9 O 2−δ |Er 0.4 Bi 1.6 O 3 (GDC|ESB) and Sm 0.075 Nd 0.075 Ce 0.85 O 2−δ |ESB (SNDC|ESB) assembled with ESB–La 0.74 Bi 0.1 Sr 0.16 MnO 3−δ (ESB–LBSM) cathode are evaluated based on anode supported single cells, in order to compare and investigate the influence of different ceria-based materials GDC and SNDC with different ionic conductivity on the performance of the ceria–bismuth bilayer electrolyte films for high performance low temperature solid oxide fuel cells (HPLT-SOFCs). The single cell with GDC|ESB bilayer film outputs the maximum power density (MPD) of 895 mW cm −2 with interfacial polarization resistance (R p ) of 0.079 Ω cm 2 at 650 °C. When SNDC is used, which has a much higher ionic conductivity with respect to GDC, the cell with SNDC|ESB bilayer film achieves the MPD of 930 mW cm −2 and the R p of 0.035 Ω cm 2 at the same conditions which shows better electrochemical performance. Furthermore, the SNDC|ESB bilayer film cell shows higher power output in the entire operation temperature range compared with GDC|ESB-based cell and has the MPD of 271 mW cm −2 at 500 °C which demonstrate the superiority of SNDC|ESB bilayer structure cell in LT-SOFC operations.

It remains true that through its signaling mechanisms, Ca2+ also has specific, direct effects on plant metabolic activities, which are poorly understood due to the currently trendy pursuit of Ca2+ signaling studies. This paucity triggered us to examine the virtues of calcium nutrition by investigating carbohydrate metabolism using combinations of physiological and microscopy techniques in Ca2+ sufficient and Ca2+ starved grapevines (Vitis vinifera L.). Net photosynthesis was severely down-regulated in Ca2+ deficient vines, which paralleled with altered chloroplast ultrastructure and reduced chlorophyll concentration. Interestingly, the activities of Rubisco, sucrose phosphate synthase (SPS), sucrose synthase (SS), and fructose-1, 6-bisphosphatase (FBPase) were elevated in Ca2+ deficient vines, while ADP-glucose pyrophosphorylase (AGPase) and phosphoribulose kinase (PRK) activities were reduced. Since plants evolved adaptive mechanisms to cope up with lack or excess of nutrients, these metabolic changes in Ca2+ deficient and sufficient grapevines could be interpreted as acclimation reactions to establish optimal homeostasis. However, given the controversial nature of calcium’s multifunctionality, we need concrete evidence for this radical new paradigm.

In this study, volatile compounds in the pulp and skin of 10 table grape cultivars of three aroma types (Strawberry, Fox and Muscat aroma) were analyzed. Overall, 27–39 compounds in the pulp and 28–52 compounds in the skin were identified for each cultivar. No significant difference was found in the number of volatiles and the contents of each type of volatile (e.g., C6 compounds, esters and alcohols) among the three aroma types of cultivars, except that the types and contents of terpenes in the skin of the Muscat aroma type were significantly higher than those of the other two aroma types. There were 8 (Strawberry and Fox), 19 (Strawberry and Muscat) and 29 (Fox and Muscat) compounds in the whole grape were selected as the significantly different variables between the two grape aroma types. The differences in volatiles profiles were the smallest between the Strawberry and Fox types and the greatest between the Fox and Muscat types. Compared with the volatiles of the other two types, the Strawberry, Fox and Muscat grape aromas had a total of 27, 37 and 32 significantly different compounds, respectively. Finally, the aroma types were partly generated by the interaction of these compounds.

ABA plays a crucial role in controlling several ripening-associated processes in grape berries. The soluble proteins named as PYR (pyrabactin resistant)/PYL (PYR-like)/RCAR (regulatory component of ABA receptor) family have been characterized as ABA receptors. Here, the function of a grape PYL1 encoding gene involved in the response to ABA was verified through heterologous expression. The expression level of VlPYL1 was highest in grape leaf and fruit tissues of the cultivar Kyoho, and the expression of VlPYL1 was increased during fruit development and showed a reduction in ripe berries. Over-expression of VlPYL1 enhances ABA sensitivity in Arabidopsis. Using the transient overexpression technique, the VlPYL1 gene was over-expressed in grape berries. Up-regulation of the VlPYL1 gene not only promoted anthocyanin accumulation but also induced a set of ABA-responsive gene transcripts, including ABF2 and BG3. Although tobacco rattle virus (TRV)-induced gene silencing (VIGS) was not successfully applied in the "Kyoho" grape, the application of the transient overexpression technique in grape fruit could be used as a novel tool for studying grape fruit development.

Aroma is an important part of quality in table grape, but the key aroma compounds and the aroma series of table grapes remains unknown. In this paper, we identified 67 aroma compounds in 20 table grape cultivars; 20 in pulp and 23 in skin were active compounds. C6 compounds were the basic background volatiles, but the aroma contents of pulp juice and skin depended mainly on the levels of esters and terpenes, respectively. Most obviously, ‘Kyoho’ grapevine series showed high contents of esters in pulp, while Muscat/floral cultivars showed abundant monoterpenes in skin. For the aroma series, table grapes were characterized mainly by herbaceous, floral, balsamic, sweet and fruity series. The simple and visualizable aroma profiles were established using aroma fingerprints based on the aromatic series. Hierarchical cluster analysis (HCA) and principal component analysis (PCA) showed that the aroma profiles of pulp juice, skin and whole berries could be classified into 5, 3, and 5 groups, respectively. Combined with sensory evaluation, we could conclude that fatty and balsamic series were the preferred aromatic series, and the contents of their contributors (β-ionone and octanal) may be useful as indicators for the improvement of breeding and cultivation measures for table grapes.