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We investigate the solution self-assembly of a mixture of positively charged homopolymers and AB diblock copolymers, in which the A blocks are negatively charged, and the B blocks are neutral. The electrostatic complexation between oppositely charged polymers drives the formation of many ordered phases. The microstructures and phase diagrams are calculated using self-consistent field theory (SCFT) based on an ion-pair model with an equilibrium constant K to characterize the strength of binding between positively and negatively charged monomers. The effects of the charge ratio, representing the ratio of charges from the homopolymer over all charges from polymers in the system, on the ordered structure are systematically studied, both for hydrophobic and hydrophilic A blocks. The charge ratio plays an important role in determining the phase boundaries in the phase diagram of salt concentration versus polymer concentration. We also provide information about the varying tendency of the domain spacing and core size of the spherical phase when the charge ratio is changed, and the results are in good agreement with experiments. These studies provide a deep understanding of the self-assembled microstructures of oppositely charged diblock copolymer-homopolymer systems. [ABSTRACT FROM AUTHOR]

A novel AIE active dual-channel chemosensor G1 based on coumarin derivatives was constructed, which shows high sensitivity and selectivity detection of Fe3+ (in water solution, LOD = 4.88 × 10−7 M) in DMSO/H 2 O (1:9, v/v, pH = 7.2) binary solutions and had strong anti-interference toward Hg2+, Ag+, Ca2+, Cu2+, Co2+, Ni2+, Cd2+, Pb2+, Zn2+, Cr3+and Mg2+. Notably, the actual usage of sensor G1 was further demonstrated by NAND logic gates and test kits. • AIE based sensor G1. • G1 shows colorimetric and "turn-on" fluorescence detection of Fe3+ with high sensitivity and selectivity. • G1 responds with Fe3+ in DMSO/H 2 O, 1:9, pH = 7.2. • Test strips and NAND logic gates based on G1 was prepared and constructed. A novel AIE active dual-channel coumarin derivatives, chemosensor G1 , was synthesised and used for detecting Fe3+ (in water solution) in DMSO/H 2 O (1:9, v/v, pH = 7.2) binary solutions, which induced the colour of solution of G1 from yellow to shallow orange and increased the fluorescence emission, indicating that G1 could act as a corking colorimetric and "turn-on" fluorescence probe for detecting Fe3+. What's more, sensor G1 has good anti-interference toward Ca2+, Hg2+, Cu2+, Ag+, Cd2+, Co2+, Ni2+, Mg2+, Pb2+, Zn2+ and Cr3+. Notably, the actual usage of sensor G1 was further demonstrated by logic gates and test kits. [ABSTRACT FROM AUTHOR]

A novel mercury specifically selective and highly sensitive chemosensor SD based on Rhodamine B hydrazone derivatives had been designed and synthesized. • Sensor SD demonstrates selective "naked-eye" recognition and fluorescence "turn-on" response for Hg2+ in aqueous solution. • Sensor SD has been detected successfully Hg2+ in tap water. • Test strips of SD were prepared and convenient and rapidly detected Hg2+. A novel chemical sensor SD based on Rhodamine B hydrazide derivative was designed and synthesized, which displayed both colorimetric and "turn-on" fluorescence responses for Hg2+ in DMSO/H 2 O (1 : 9, v/v) solution. In the presence of mercury ions, the sensor SD showed an obvious change in color from colorless to distinct rose red by naked eyes and rapidly provided bright orange fluorescence under UV lamp in the aqueous solution. The detection limit on fluorescence response of SD to Hg2+ was as low as 2.71 × 10−7M. Compared to other metal ions such as Fe3+, Co2+, Ni2+, Cd2+, Pb2+, Zn2+, Cr3+, Cu2+, Ag+, Ca2+and Mg2+, SD could only selectively recognizes Hg2+.The results of the Job's plot and infrared spectra analysis suggested that the combined stoichiometry between SD and Hg2+ was 1:1. Notably, SD could be used as molecular switch controlled by EDTA and Hg2+ cyclically. In addition, SD -based test strips were produced which could be used as a convenient and efficient Hg2+ test kits. SD also could qualitatively detect Hg2+ in tap water. [ABSTRACT FROM AUTHOR]

A novel highly selective chemosensor Z based on rhodamine B hydrazone derivatives was designed and synthesized, and it showed both colorimetric and “turn-on” fluorescence responses for CN− in an aqueous solution. The results showed that after adding CN− ions in aqueous solution, the chemosensor Z showed significant color change from colorless to pale-yellow, which was visible to the naked eye, and it rapidly produced strong green fluorescence. The probe could distinguish CN− by deprotonation and intramolecular charge transfer (ICT) mechanisms, as evidenced by 1H-NMR titration and DFT calculations. In addition, the detection limit of the fluorescence response of the sensor for CN− was 5.81 × 10−8 M, which was measured by titration. The chemosensor Z has been successfully used to detect CN− in sprouting potatoes. Z-containing test strips have also been prepared, and they can be used as a colorimetric tool for CN− detection in potential applications. [ABSTRACT FROM AUTHOR]

Abstract: MicroRNAs (miRNAs) play critical roles in post-transcriptional regulation and act as important endogenous regulators to various stresses. Cold, wounding and high-salinity are three common environmental stress stimuli influencing crops growth and development. In this study, we identified 31 known miRNAs and 3 novel miRNAs in wheat. Moreover, 19 stress-regulated miRNAs using RT-qPCR data in which the effects of three stresses were surveyed from the known miRNAs. Among them, 16, 12 and 8 miRNAs were regulated under cold, wounding and high-salinity treatments, respectively. Of which 4 miRNAs were highly responsive to cold stress in wheat by northern blot, and 6 wounding-regulated and 3 high-salinity-regulated miRNAs were detected. Meanwhile, miR159, miR393 and miR398 were responsive to multiple stress stimuli. Besides, 2 novel miRNAs were regulated by cold stress. While, the analyses of targets suggested miR159, miR398 and miR6001 could responses to stress conditions in regulation pathways. Taken together, the results of this study suggest that wheat miRNAs may play important roles in response to abiotic stress. [Copyright &y& Elsevier]

A new high-selectivity and high-sensitivity copper (II) sensor F2 based on benzimidazole derivatives was designed and synthesized. • The synthesis process of F2 is simple and environmentally friendly. • F2 shows "naked-eye" and fluorescence "turn-off" response for Cu2+. • The mechanism of action of F2 on Cu2+ may be ligand-metal charge transfer (LMCT). • A test strips of F2 was prepared to detect Cu2+ quickly and easily. • F2 has been used for ultra-sensitive IMPLICATION logic gates. Reversible dual channel sensor F2 for detection Cu2+ is designed and synthesized. F2 is substantially unaffected by other cationic ions during the recognition of Cu2+. It is worth noting that the low detection limit of sensor F2 is 9.09 × 10−9, and the detection limit is lower that to the reported sensor for identifying Cu2+. Through various experiments and characterization, it is proved that ligand-metal charge transfer (LMCT) is the interaction mechanism between F2 and Cu2+. It is further certified that the stoichiometry between F2 and Cu2+ is 1:1. In addition, the fluorescence changes of F2 upon the addition of Cu2+ and EDTA are applied as an ultrasensitive IMPLICATION logic gate at the molecular level. At the same time, molecular keyboard experiments have achieved information protection at the molecular level. More importantly, the test strips containing F2 can be easily and quickly tested to achieve on-site inspection. [ABSTRACT FROM AUTHOR]