Controlled Synthesis of Heterogeneous Metal–Titania Nanostructures and Their Applications

We describe a new synthetic approach to heterogeneous metal–TiO₂ nanomaterials based on conversion of Ti³⁺ to hydrous TiO₂ occurring uniquely on the nanostructured metallic surfaces such as Pt, Au, and Ni nanowires and nanoparticles. The TiO₂ growth mechanism was studied by designing an electrochemical cell. A variety of heterogeneous metal–TiO₂ nanostructures, such as segmented metal–TiO₂ nanowires, core–shell metal–TiO₂ nano/microparticles, and composite metal–TiO₂ nanotubes, can be fabricated by varying the morphology of the seeding metal nanostructure or controlling selective TiO₂ growth on different surfaces of the metallic nanomaterial. Altering the reaction time and Ti³⁺ concentration allows the TiO₂ segment lengths or TiO₂ shell thicknesses to be finely tuned. Coaxial Au–TiO₂ nanorod arrays were demonstrated to be fast lithium-ion storage materials, while the core–shell Ni–TiO₂ nanoparticles exhibited excellent photodegradation properties as magnetic recyclable photocatalysts

Mathematical model and exact algorithm for the home care worker scheduling and routing problem with lunch break requirements

<p>Home health care or home care (HHC/HC) refers to the delivery of social, medical and paramedical services to clients in their own homes. Each day, care workers start from the HHC/HC centre, visit some clients and return to the centre. During the service delivery process, there is usually a lunch break for each worker. In this paper, we address a real-life home care worker scheduling and routing problem with the consideration of lunch break requirements. A three-index mathematical model is constructed for the problem. The problem is decomposed into a master problem and several pricing sub-problems, and is optimally solved by a branch-and-price (B&P) algorithm. Specifically, a sophisticated label-correcting algorithm is designed to address lunch break constraints in pricing sub-problems; some cutting-edge acceleration strategies are applied during the column generation process. Experimental results show that the proposed B&P algorithm is able to produce satisfied solutions within an acceptable runtime and outperforms the mixed integer programming solver CPLEX.</p

Transition between Collective Behaviors of Micromotors in Response to Different Stimuli

We report a Ag₃PO₄ microparticle system showing collective behaviors in aqueous medium. Transition between two emergent patterns, namely “exclusion” and “schooling”, can be triggered by shift in chemical equilibrium upon the addition or removal of NH₃ or in response to UV light. The transitions are consistent with a self-diffusiophoresis mechanism resulting from ion gradients. The reported system is among the few examples of nanomotors that are based on a reversible nonredox reaction and demonstrates new design principles for micro/nanomotors. Potential applications of the reported system in logic gates, microscale pumping, and hierarchical assembly have been demonstrated

Schoenus indet.

We report a Ag₃PO₄ microparticle system showing collective behaviors in aqueous medium. Transition between two emergent patterns, namely “exclusion” and “schooling”, can be triggered by shift in chemical equilibrium upon the addition or removal of NH₃ or in response to UV light. The transitions are consistent with a self-diffusiophoresis mechanism resulting from ion gradients. The reported system is among the few examples of nanomotors that are based on a reversible nonredox reaction and demonstrates new design principles for micro/nanomotors. Potential applications of the reported system in logic gates, microscale pumping, and hierarchical assembly have been demonstrated

Transition between Collective Behaviors of Micromotors in Response to Different Stimuli

We report a Ag₃PO₄ microparticle system showing collective behaviors in aqueous medium. Transition between two emergent patterns, namely “exclusion” and “schooling”, can be triggered by shift in chemical equilibrium upon the addition or removal of NH₃ or in response to UV light. The transitions are consistent with a self-diffusiophoresis mechanism resulting from ion gradients. The reported system is among the few examples of nanomotors that are based on a reversible nonredox reaction and demonstrates new design principles for micro/nanomotors. Potential applications of the reported system in logic gates, microscale pumping, and hierarchical assembly have been demonstrated

Transcriptomic analysis reveals the roles of gibberellin-regulated genes and transcription factors in regulating bolting in lettuce (<i>Lactuca sativa</i> L.)

<div><p>A cool temperature is preferred for lettuce cultivation, as high temperatures cause premature bolting. Accordingly, exploring the mechanism of bolting and preventing premature bolting is important for agriculture. To explore this relationship in depth, morphological, physiological, and transcriptomic analyses of the bolting-sensitive line S39 at the five-leaf stage grown at 37°C were performed in the present study. Based on paraffin section results, we observed that S39 began bolting on the seventh day at 37°C. During bolting in the heat-treated plants, GA3 and GA4 levels in leaves and the indoleacetic acid (IAA) level in the stem reached a maximum on the sixth day, and these high contents were maintained. Additionally, bolting begins in the fifth day after GA3 treatment in S39 plants, GA3 and GA4 increased and then decreased, reaching a maximum on the fourth day in leaves. Similarly, IAA contents reached a maximum in the stem on the fifth day. No bolting was observed in the control group grown at 25°C, and significant changes were not observed in GA3 and GA4 levels in the controls during the observation period. RNA-sequencing data implicated transcription factors (TFs) in regulating bolting in lettuce, suggesting that the high GA contents in the leaves and IAA in the stem promote bolting. TFs possibly modulate the expression of related genes, such as those encoding hormones, potentially regulating bolting in lettuce. Compared to the control group, 258 TFs were identified in the stem of the treatment group, among which 98 and 156 were differentially up- and down-regulated, respectively; in leaves, 202 and 115 TFs were differentially up- and down-regulated, respectively. Significant changes in the treated group were observed for C2H2 zinc finger, AP2-EREBP, and WRKY families, indicating that these TFs may play important roles in regulating bolting.</p></div

Changes in hormone contents, morphology and stem length after treatment with exogenous hormones.

<p>Plants in the fifth-leaf stage were treated with the exogenous plant growth regulator GA3 or its biosynthetic inhibitor CCC in the same amount of water. There were four different treatment modes. Changes in stem length and endogenous hormone levels in leaves and stems were examined at the control temperature after the different treatments. (A and B) GA4 and GA3 contents in leaves. (C and D) IAA contents in leaves and stems. (E-H) The morphology of lettuce plants without any treatment or treated with water, GA or CCC, respectively. (I) Stem elongation in S39 plants after treatment with exogenous hormone for 18 days.</p

Verification of differentially expressed genes by RT-qPCR.

<p>Twenty genes were chosen for RT-qPCR validation. The white and black bars represent the relative expression levels of each gene in the control and high-temperature groups, as detected by RT-qPCR and RNA-Seq, respectively. To plot the RNA-Seq data, gene expression in the control group was set to be the same as that observed by RT-qPCR, and relative expression in the high-temperature group was calculated using the fold-change detected by RNA-Seq. The bars represent the standard deviation (n = 3); 1 represents the control temperature, and 2 represents the high temperature. Asterisks indicate that the gene transcriptions are significantly different between control and treatment group (unpaired t test, P< 0.05).</p

Self-Assembled DNA Monolayer Buffered Dynamic Ranges of Mercuric Electrochemical Sensor

Sensors with wide dynamic ranges (DRs) are typically constructed by utilizing a set of ligands with varied affinities for the same target. We report here a novel buffer self-assembled monolayer (BSAM) strategy, to fabricate sensors with extraordinarily broad DRs using a single recognition ligand. We demonstrated the concept of BSAM by constructing the electrochemical mercuric sensors with different surface probe densities (SPD) on a gold electrode. These sensors are based on the coordination of Hg²⁺ with a pair of thymine (T) formed between the two proximate poly­(T) oligonucleotides on the electrode surface and Hg²⁺ binding induced DNA strand displacement of ferrocene tagged poly­(A). There are three types of T–Hg²⁺–T coordination: those formed between (a) two poly­(T) strands where none are hybridized with poly­(A) strands, thus contributing zero effect on releasing the signaling probe, (b) poly­(A)/poly­(T) hybridized and nonhybridized poly­(T) strands, resulting in the release of a signaling probe from the surface; and (c) two poly­(A)/poly­(T) hybridized strands, causing the release of two signaling probes from the surface. The DRs from 10 pM to 0.1 mM at varied SPDs were observed, attributing to the tunable Hg²⁺ storage capability of the poly­(T) SAM formed on the surface due to the coordination mechanism of (a) and (b). The DR was able to be further extended to 1 mM by using the longer poly­(T) strands. The ready-to-use sensor exhibited great selectivity against the common interferential metal ions. As demonstrated, the BSAM strategy is a facile way to fabricate sensors with tunable and wide DRs

Family assignment of transcription factors that showed differential expression in the high-temperature group vs. the control group.

<p>The number of genes assigned to each family is shown behind a comma. (A and C) Genes with higher expression and lower expression in the stem tip, respectively. (B and D) Genes with higher expression and lower expression in leaves, respectively.</p