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Enhancing the generation of reactive oxygen species (ROS) is an effective anticancer strategy. However, it is a great challenge to control the production and to image ROS in vivo, both of which are vital for improving the efficacy and accuracy of cancer therapy. Herein, an activatable semiconducting theranostic nanoparticle (NP) platform is developed that can simultaneously enhance ROS generation while self-monitoring its levels through ratiometric photoacoustic (PA) imaging. The NP platform can further guide in vivo therapeutic effect in tumors. The theranostic NP platform is composed of: (i) cisplatin prodrug and ferric ion catalyst for ROS generation, a part of combination cancer therapy; and (ii) a ratiometric PA imaging nanoprobe consisting of inert semiconducting perylene-diimide (PDI) and ROS activatable near-infrared dye (IR790s), used in ratiometric PA imaging of ROS during cancer treatment. Ratiometric PA signals are measured at two near-infrared excitation wavelengths: 680 and 790 nm for PDI and IR790s, respectively. The measurements show highly accurate visualization of OH generation in vivo. This novel ROS responsive organic theranostic NP allows not only synergistic cancer chemotherapy but also real-time monitoring of the therapeutic effect through ratiometric PA imaging.

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Perovskite oxides hosting ferroelectricity are particularly important materials for modern technologies. The ferroelectric transition in the well-known oxides BaTiO and PbTiO is realized by softening of a vibration mode in the cubic perovskite structure. For most perovskite oxides, octahedral-site tilting systems are developed to accommodate the bonding mismatch due to a geometric tolerance factor t = (A-O)/[√2(B-O)] < 1. In the absence of cations having lone-pair electrons, e.g., Bi and Pb, all simple and complex A-site and B-site ordered perovskite oxides with a t < 1 show a variety of tilting systems, and none of them become ferroelectric. The ferroelectric CaMnTiO oxide is, up to now, the only one that breaks this rule. It exhibits a columnar A-site ordering with a pronounced octahedral-site tilting and yet becomes ferroelectric at T ≈ 650 K. Most importantly, the ferroelectricity at T < T is caused by an order-disorder transition instead of a displacive transition; this character may be useful to overcome the critical thickness problem experienced in all proper ferroelectrics. Application of this new ferroelectric material can greatly simplify the structure of microelectronic devices. However, CaMnTiO is a high-pressure phase obtained at 7 GPa and 1200 °C, which limits its application. Here we report a new method to synthesize a gram-level sample of ferroelectric CaMnTiO, having the same crystal structure as CaMnTiO and a similarly high Curie temperature. The new finding paves the way for the mass production of this important ferroelectric oxide. We have used neutron powder diffraction to identify the origin of the peculiar ferroelectric transition in this double perovskite and to reveal the interplay between magnetic ordering and the ferroelectric displacement at low temperatures.

Following structural dynamics in real time is a fundamental goal towards a better understanding of chemical reactions. Recording snapshots of individual molecules with ultrashort exposure times is a key ingredient towards this goal, as atoms move on femtosecond (10−15 s) timescales. For condensed-phase samples, ultrafast, atomically resolved structure determination has been demonstrated using X-ray and electron diffraction. Pioneering experiments have also started addressing gaseous samples. However, they face the problem of low target densities, low scattering cross sections and random spatial orientation of the molecules. Therefore, obtaining images of entire, isolated molecules capturing all constituents, including hydrogen atoms, remains challenging. Here we demonstrate that intense femtosecond pulses from an X-ray free-electron laser trigger rapid and complete Coulomb explosions of 2-iodopyridine and 2-iodopyrazine molecules. We obtain intriguingly clear momentum images depicting ten or eleven atoms, including all the hydrogens, and thus overcome a so-far impregnable barrier for complete Coulomb explosion imaging—its limitation on molecules consisting of three to five atoms. In combination with state-of-the-art multi-coincidence techniques and elaborate theoretical modelling, this allows tracing ultrafast hydrogen emission and obtaining information on the result of intramolecular electron rearrangement. Our work represents an important step towards imaging femtosecond chemistry via Coulomb explosion.

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Purpose Based on the strategy and new institutional economic literature, this study aims to explore how different levels of supplier concentration (SC) will be characterized by differences in switching cost and coordinated adaptation in an ecosystem, thereby shaping its research and development (R&D) intensity, innovation performance and innovation efficiency. Design/methodology/approach This study adopted a set of panel data of Chinese listed firms in the Growth Enterprise Board and their top five suppliers from 2012 to 2016. A Tobit model is used to test the hypotheses. Findings The study finds that SC has an inverted U-shape effect on R&D intensity. This finding implies that firms are more likely to invest in R&D when SC is intermediate level. While it has a U-shape relationship between SC and innovation output, both lower SC and higher SC are more efficient in innovation because of their advantage in low switching cost and better coordinative adaptability, respectively. Originality/value The study complements the innovation ecosystem literature by using SC to represent the structure of the interdependence between firms and suppliers in an ecosystem, then examining the correlation between SC and firms’ innovation investment and output, respectively. Second, combining strategy and new institutional economic literature, the non-linear effects of SC on firms’ innovation are found.

Supply uncertainty has been elevated to a strategic level concern in driving supply chain success. This paper considers that a firm faces a deterministic demand and procures from two unreliable suppliers: one is subject to a random disruption and might deliver all or nothing of the firm's order, while the other one exposes to a random yield risk for the firm's order. We explore the models of no recourse and ordering with recourse, and derive optimal solutions for each model. We provide the conditions under which single or dual sourcing strategy should be used. We also compare the decisions and profits among different models through computational experiments and find that it is more beneficial to order from the relatively expensive supplier as a backup source.