The Synthesis of Warfarin Using a Reconfigurable-Reactor Platform Integrated to a Multiple-Variable Optimization Tool

Optimization of the asymmetric synthesis of warfarin, an important anticoagulant, has been evaluated using a reconfigurable reaction platform capable of performing batch, continuous flow, and plug-flow synthesis. Further, this platform has been integrated with a novel, multidimensional, multiple variable analysis tool that can evaluate multiple critical quality attributes (CQA), percent conversion and enantiomeric excess in this case, from a single injection that is repeatedly recycled in a closed loop of chromatography columns, a detector and a heart-cut valve. Further, the new, integrated analysis system also facilitates validation of each QA, providing a high-level of confidence in analytical measurements, which are obtained without operator intervention.     

Rational behavior is a ‘double-edged sword’ when considering voluntary vaccination

Of particular importance for public health is how to understand strategic vaccination behavior in social networks. Social learning is a central aspect of human behavior, and it thus shapes vaccination individuals’ decision-making. Here, we study two simple models to address the impact of the more rational decision-making of individuals on voluntary vaccination. In the first model, individuals are endowed with memory capacity for their past experiences of dealing with vaccination. In addition to their current payoffs, they also take account of the historical payoffs that are discounted by a memory-decaying factor. They use such overall payoffs (weighing the current payoffs and historical payoffs) to reassess their vaccination strategies. Those who have higher overall payoffs are more likely imitated by their social neighbors. In the second model, individuals do not blindly learn the strategies of neighbors; they also combine the fraction of infection in the past epidemic season. If the fraction of infection surpasses the perceived risk threshold, individuals will increase the probability of taking vaccination. Otherwise, they will decrease the probability of taking vaccination. Then we use evolutionary game theory to study the vaccination behavior of people during an epidemiological process. To do this, we propose a two-stage model: individuals make vaccination decisions during a yearly vaccination campaign, followed by an epidemic season. This forms a feedback loop between the vaccination decisions of individuals and their health outcomes, and thus payoffs. We find that the two more rational decision-making models have nontrivial impacts on the vaccination behavior of individuals, and, as a result, on the final fraction of infection. Our results highlight that, from an individual’s viewpoint, the decisions are optimal and more rational. However, from the social viewpoint, the strategies of individuals can give rise to distinct outcomes. Namely, the rational behavior of individuals plays a ‘double-edged-sword’ role on the social effects.     

A sonochemical route for the encapsulation of drug in magnetic microspheres

This study focused on the preparation and characterization of magnetic targeted antibiotic microspheres (MTAMs). MTAMs were prepared by a sonochemical method in the presence of hydrophobic Fe₃O₄ nanoparticles and tetracycline. The properties of MTAMs were characterized by transmission electron microscopy, Fourier-transform infrared spectrum, thermogravimetric analysis, vibration sample magnetometry, and bacteriostatic experiment. The results indicated that the superparamagnetic microspheres have ultrafine size (below 230 nm), high saturation magnetization (80.90 emu/g), high biocompatibility, biodegradability, controlled-release, and antibiotic effect. It has been proved that MTAMs can carry out the function of magnetic targeted drugs delivery system by putting together magnetic materials and antibiotics. The possible formation mechanism of MTAMs was also discussed. In summary, MTAMs had potential in medical imaging, drug targeting, and catalysis.     

Specific “Unlocking” of a Nanozyme‐Based Butterfly Effect To Break the Evolutionary Fitness of Chaotic Tumors

Chaos and the natural evolution of tumor systems can lead to the failure of tumor therapies. Herein, we demonstrate that iridium oxide nanoparticles (IrO_x) possess acid‐activated oxidase and peroxidase‐like functions and wide pH‐dependent catalase‐like properties. The integration of glucose oxidase (GOD) unlocked the oxidase and peroxidase activities of IrO_x by the production of gluconic acid from glucose by GOD catalysis in cancer cells, and the produced H₂O₂ was converted into O₂ to compensate its consumption in GOD catalysis owing to the catalase‐like function of the nanozyme, thus resulting in the continual consumption of glucose and the self‐supply of substrates to generate superoxide anion and hydroxyl radical. Moreover, IrO_x can constantly consume glutathione (GSH) by self‐cyclic valence alternation of Ir^IV and Ir^III. These cascade reactions lead to a “butterfly effect” of initial starvation therapy and the subsequent pressure of multiple reactive oxygen species (ROS) to completely break the self‐adaption of cancer cells.     

Specific “Unlocking” of a Nanozyme-Based Butterfly Effect To Break the Evolutionary Fitness of Chaotic Tumors

Chaos and the natural evolution of tumor systems can lead to the failure of tumor therapies. Herein, we demonstrate that iridium oxide nanoparticles (IrO_x) possess acid-activated oxidase and peroxidase-like functions and wide pH-dependent catalase-like properties. The integration of glucose oxidase (GOD) unlocked the oxidase and peroxidase activities of IrO_x by the production of gluconic acid from glucose by GOD catalysis in cancer cells, and the produced H₂O₂ was converted into O₂ to compensate its consumption in GOD catalysis owing to the catalase-like function of the nanozyme, thus resulting in the continual consumption of glucose and the self-supply of substrates to generate superoxide anion and hydroxyl radical. Moreover, IrO_x can constantly consume glutathione (GSH) by self-cyclic valence alternation of Ir^IV and Ir^III. These cascade reactions lead to a “butterfly effect” of initial starvation therapy and the subsequent pressure of multiple reactive oxygen species (ROS) to completely break the self-adaption of cancer cells.     

Improvement of the large aperture Ti：sapphire amplifiers in the petawatt femtosecond laser system at SIOM

We report the recent improvement on the petawatt (PW) femtosecond Ti:sapphire chirped pulse amplification (CPA) laser system at Shanghai Institute of Optics and Fine Mechanics (SIOM), Chinese Academy of Sciences. By enlarging the sizes of the pump and signal beams in the large aperture Ti:sapphire amplifiers and optimizing the whole laser system, the output laser energy before the pulse compressor is upgraded to 42.6 J. Accordingly, the peak power of the laser system exceeds 1 PW. The shot-to-shot instability of the output laser energy at about 40 J is less than ±5%.     

Geomagnetic responses in high latitudes during the storm of july 15—16, 2000

The ionospheric equivalent currents in the high latitudes and the auroral electrojet system during the geomagnetic storm on July 15–16, 2000 are analyzed by using geomagnetic data from IMAGE chain. The large-scale vortices of equivalent currents are observed in the storm. The vortices on the dusk side of ionosphere correspond to four-celled pattern of plasma convection associated with NBZ, region I and region II field-aligned currents. Only one vortex can be found on the dawn side of ionosphere after interplanetary magnetic field (IMF) turns southward. In the initial phase of the storm, the center of eastward electrojets tends to shift equatorward. It arrives at 58.62° latitude of corrected geomagnetic coordinates (CGM). The westward electrojets are strong in the main phase. The center of westward electrojets in this period moves equatorward and may be beyond the southernmost station (56.45°) of the chain.

     

Tectonic motion characteristics of the Earth planet: from 80 MaBP up to now

Copyright by Science in China Press 2004 1 Introduction The theory of plate tectonics dictates that the Earths surface is made up of a rela-tively small number of rigid spherical shells or plates of the lithosphere that move with respect to each other. At present, the absolute motions of plates are described relative to hotspots mainly[1]. However, there are some deficiencies as follows[2,3]: ①the hotspot data are strictly inaccurate; ②the hotspots possibly move with respect to each other…     

A theorem on Butterworth matching for piezoelectric ceramic emission transducer

A theorem on Butterworth matching for piezoelectric ceramic emission transducer is presented and proved.The complicated problem of broad-band matching is changed to a simple arithmetical one due to explicit formulas of the theorem.It is shown in an example that after matching,bandwidth of the transducer increases remarkably while the power gain is close to 1.     

Amplified spontaneous emission contrast of CPA laser

The influence on the level of amplified spontaneous emission （ASE） contrast resulting from the different seed pulse energies has been experimentally studied in a 10-TW-level femtosecond Ti：sapphire chirped pulse amplification laser. It is found that, with the seed pulse energy increasing, the ASE pedestal is suppressed more efficiently, and the ASE contrast is improved with a saturable tendency. The measurement of -2×10^-8 ASE contrast in the range of more than 50 ps before the main pulse is achieved in the laser.