a b s t r a c tWe propose an explanatory and computational theory of transformative discoveries in science. The theory is derived from a recurring theme found in a diverse range of scientific change, scientific discovery, and knowledge diffusion theories in philosophy of science, sociology of science, social network analysis, and information science. The theory extends the concept of structural holes from social networks to a broader range of associative networks found in science studies, especially including networks that reflect underlying intellectual structures such as co-citation networks and collaboration networks. The central premise is that connecting otherwise disparate patches of knowledge is a valuable mechanism of creative thinking in general and transformative scientific discovery in particular. In addition, the premise consistently explains the value of connecting people from different disciplinary specialties. The theory not only explains the nature of transformative discoveries in terms of the brokerage mechanism but also characterizes the subsequent diffusion process as optimal information foraging in a problem space. Complementary to epidemiological models of diffusion, foraging-based conceptualizations offer a unified framework for arriving at insightful discoveries and optimizing subsequent pathways of search in a problem space. Structural and temporal properties of potentially high-impact scientific discoveries are derived from the theory to characterize the emergence and evolution of intellectual networks of a field. Two Nobel Prize winning discoveries, the discovery of Helicobacter pylori and gene targeting techniques, and a discovery in string theory demonstrated such properties. Connections to and differences from existing approaches are discussed. The primary value of the theory is that it provides not only a computational model of intellectual growth, but also concrete and constructive explanations of where one may find insightful inspirations for transformative scientific discoveries.

Myeloid-derived suppressor cells (MDSCs) are a heterogenic population of immature myeloid cells with immunosuppressive effects, which undergo massive expansion during tumor progression. These cells not only support immune escape directly but also promote tumor invasion via various non-immunological activities. Besides, this group of cells are proved to impair the efficiency of current antitumor strategies such as chemotherapy, radiotherapy, and immunotherapy. Therefore, MDSCs are considered as potential therapeutic targets for cancer therapy. Treatment strategies targeting MDSCs have shown promising outcomes in both preclinical studies and clinical trials when administrated alone, or in combination with other anticancer therapies. In this review, we shed new light on recent advances in the biological characteristics and immunosuppressive functions of MDSCs. We also hope to propose an overview of current MDSCs-targeting therapies so as to provide new ideas for cancer treatment.

Inexpensive energy from the wind and the sun comes with unwanted volatility, such as ramps with the setting sun or a gust of wind. Controllable generators manage supply-demand balance of power today, but this is becoming increasingly costly with increasing penetration of renewable energy. It has been argued since the 1980s that consumers should be put in the loop: "demand response" will help to create needed supply-demand balance. However, consumers use power for a reason, and expect that the quality of service (QoS) they receive will lie within reasonable bounds. Moreover, the behavior of some consumers is unpredictable, while the grid operator requires predictable controllable resources to maintain reliability. The goal of this chapter is to describe an emerging science for demand dispatch that will create virtual energy storage from flexible loads. By design, the grid-level services from flexible loads will be as controllable and predictable as a generator or fleet of batteries. Strict bounds on QoS will be maintained in all cases. The potential economic impact of these new resources is enormous. California plans to spend billions of dollars on batteries that will provide only a small fraction of the balancing services that can be obtained using demand dispatch. The potential impact on society is enormous: a sustainable energy future is possible with the right mix of infrastructure and control systems.

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Numerous studies have explored the possibility of uncovering information from web search queries but few have examined the factors that affect web query data sources. We conducted a study that investigated this issue by comparing Google Trends and Baidu Index. Data from these two services are based on queries entered by users into Google and Baidu, two of the largest search engines in the world. We first compared the features and functions of the two services based on documents and extensive testing. We then carried out an empirical study that collected query volume data from the two sources. We found that data from both sources could be used to predict the quality of Chinese universities and companies. Despite the differences between the two services in terms of technology, such as differing methods of language processing, the search volume data from the two were highly correlated and combining the two data sources did not improve the predictive power of the data. However, there was a major difference between the two in terms of data availability. Baidu Index was able to provide more search volume data than Google Trends did. Our analysis showed that the disadvantage of Google Trends in this regard was due to Google's smaller user base in China. The implication of this finding goes beyond China. Google's user bases in many countries are smaller than that in China, so the search volume data related to those countries could result in the same issue as that related to China.

3D connected porous LGPU scaffolds with adjustable degradation and a strong anti-inflammatory effect were prepared for neural tissue repair.

Zn-doped titanium oxide (TiO 2 ) nanotubes electrode was prepared on a titanium plate by direct anodic oxidation and immersing method in sequence. Field emission scanning electron microscopy (FESEM)showed that the Zn-doped TiO 2 nanotubes were well aligned and organized into high density uniform arrays with diameter ranging from 50 to 90 nm. The length and the thickness were about 200 and 15 nm respectively. TiO 2 anatase phase was identified by X-ray diffraction (XRD). X-ray photoelectronspectroscopy (XPS) indicated that Zn ions were mainly located on the surface of TiO 2 nanotubes in form of ZnO clusters. Compared with TiO 2 nanotubes electrode, about 20 nm red shift in the spectrum of UV-vis absorption was observed. The degradation of pentachlorophenol (PCP) in aqueous solution under the same condition (initial concentration of PCP: 20 mg/L; concentration of Na 2 SO 4 : 0.01 mol/L and pH: 7.03) was carried out using Zn-doped TiO 2 nanotubes electrode and TiO 2 nanotubes electrode. The degradation rates of PCP using Zn-doped TiO 2 nanotubes electrode were found to be twice and 5.8 times as high as that using TiO 2 nanotubes electrode by UV radiation (400 μw/cm 2 ) and visible light radiation (4500 μw/cm 2 ), respectively. 73.5% of PCP was removed using Zn-doped TiO 2 nanotubes electrode against 48.5% removed using TiO 2 nanotubes electrode in 120 min under UV radiation. While under visible light radiation, the degradation efficiency of PCP was 18.4% using Zn-doped TiO 2 nanotubes electrode against 3.2% using TiO 2 nanotubes electrode in 120 min. The optimum concentration of Zn doping was found to be 0.909%. The PCP degradation efficiencies of the 10 repeated experiments by Zn-doped TiO 2 nanotubes electrode were rather stable with the deviation within 3.0%.TiO 2 nanotubes electrode, Zn-doped, photoelectrocatalytic degradation, PCP Photocatalysis belongs to one of the important advanced oxidation processes and has the advantages of efficient degradation, complete degradation of compounds and mild experimental condition [1,2] . It has been found that many organic pollutants can be degraded efficiently in the photocatalysis process using TiO 2 as photocatalyst. Because of the difficulty of separating the suspended TiO 2 powders from water and the low utilization of the photocatalysts, the fixed TiO 2 photocatalyst has become more popular [3,4] . However, the high recombination rate of the photoinduced electron/hole pairs and the low light utilization efficiency to solar irradiation in photocatalysis process make it hard to be put into practical application.Previous studies have proved that photoelectrocatalysis could well separate the photoinduced electron/hole pairs [5] , however, the utilization efficiency of visible light is still low. Recently, it has been reported that the metals doping can remarkably increase the photocata-