Development of Bacteriophage Based Detection Technique for Food Safety and Environment Monitoring

Foodborne or waterborne pathogens which are responsible for numerous worldwide outbreaks of disease have caused serious health problems and enormous economic cost. Development of new bacterial detection technologies with high sensitivity and specificity is of great importance for food safety and public health. This has highlighted the significance of developing rapid and effective techniques for pathogen screening. Thus we aim to explore a bacteriophage mediated detection system for foodborne or waterborne bacteria monitoring. Bacteriophage as a novel recognition probe has been applied in various biosensor by immobilizing phage particles on solid sensor surface. They possess high specificity for targeted microorganism and a rapid infection between phage and its host cell. Their characteristics including low cost, robustness, fast and easy production plus high tolerance under extreme conditions make phages superior for bacteria detection at resource-limited settings. We utilize biotin-streptavidin interaction system for an engineered phage immobilization on biosensor surface. The fusion of biotin acceptor peptide (BAP) gene and biotin ligase (BirA) gene to phage capsid protein gene enabled the display of BAP ligand and the expression of protein BirA during the replication cycle of phage infection. Then produced phage progenies could be biotinylated in vivo and immobilized on the streptavidin coated magnetic beads. Compared with wild type phage, the recombinant phage showed a significantly higher immobilization efficiency of 82.8% on the magnetic bead and the resulting bio-probe showed a capture efficiency of 86.2% of E.coli within 20 min. This phage based biomagnetic separation coupled PCR detection provided a detection limit of 102 CFU/mL bacteria without additional pre-enrichment. For the detection of pathogenic Escherichia coli O157:H7, we compared phage-based biosorbent and antibody-based one and found that the capture efficiency of our phage assay was about 20% higher than that of antibody based magnetic separation assay under extreme conditions. Then we developed a membrane filter based colorimetric detection assay to offer a convenient and rapid way for the identification of general E.coli from field water on-site. This phage mediated detection provided a convenient and quantitative detection of bacteria number as the colored signal present at the site corresponding to the located bacterial colony

Core Firm Based View on the Mechanism of Constructing an Enterprise Innovation Ecosystem: A Case Study of Haier Group

The fierce competitive status of the business world has urged innovation activities to transform from mechanistic to ecological and organic. An innovation ecosystem consists of multilateral organizations and emerges as a favorable mechanism for value co-creation and sustainable growth. Yet the theorizing of an innovation ecosystem is still at an early stage and in-depth studies from emerging economy leaders are insufficient. This study aims to investigate how an innovation ecosystem is constructed and coordinated from a core-firm based view. An exploratory single case study on the Haier Group is adopted. Through analyzing the multi-bedded units (i.e., six innovation projects/technological breakthroughs), we extract and depict Haier’s innovation ecosystem and the ecological niches within it. We highlight an innovation ecosystem that promotes sustainable development and is based on complementarities in technologies and resources, while at the same time integrates non-technological issues such as strategy, culture, institution, and the market. Regarding ecosystem coordination, value appropriability should be ensured to sustain the innovation ecosystem. Moreover, we argue that the ultimate purpose of innovation ecosystem is not to facilitate the realization of one specific project, but rather to improve the overall success rate of innovations within it. This research complements and extends literature on enterprise innovation ecosystems, and provides implications as to the construction, coordination, and sustainability of innovation ecosystems for emerging economy firms

The political logic of status competition: cases from China, 1962-1979

Why do state leaders adopt competitive strategies in pursuit of great-power status? Competitive status-seeking acts incur tremendous risks for a state’s geopolitical security as it entails challenging a higher-ranked power. To explain why leaders opt for such risky policies, this study underscores the instrumental importance of great-power status for states and that of personal prestige for the leaders. My central assertion is that leaders undertake competitive status-seeking measures in hopes of furthering their interests in both geopolitical and domestic political arenas. Competitive status-seeking strategy is a preferable policy for leaders who rely upon personal prestige as a dominant vehicle for political survival at home while regarding great-power status as a route to geopolitical security. Through an in-depth study of three cases from the 1962-1979 period of China’s foreign and security policy, this thesis illustrates how this political logic informed the leadership decision on competitive assertions of status. During this period, China’s policy illustrates three varieties of competitive status-seeking strategy—namely, offensive alliance, delegitimation strategy, and display of military power. These strategies respectively display diplomatic, ideological, and military aspects of state power, which serve as central vehicles for leaders to assert great-power status. Invariably they were motivated by leaders’ pragmatic concerns for great-power status in geopolitics and personal prestige in domestic elite politics. As demonstrated by the case studies, competitive stats-seeking measures provide a critical vehicle for leaders to cope with imperatives of geopolitical competition and domestic political survival simultaneously. This study seeks to make three original contributions to the literature on status ambitions and international conflict. First, it treats status aspirations as a variable rather than an invariant driver of state policy as often assumed. Second, it claims that leaders may assert great-power status on their nation’s behalf with a view to enhancing geopolitical security. In this regard, status and security are treated as complementary rather than antithetical. The final aspect of originality in my argument lies in its integration of rationalist and psychological microfoundations. While my argument highlights the instrumental rationality of state leaders in trying to advance geopolitical security and legitimize their authority in domestic elite politics, it also addresses how leaders inspire emotional reactions from domestic audiences to support their risky policy

IDEA: Interactive DoublE Attentions from Label Embedding for Text Classification

Current text classification methods typically encode the text merely into embedding before a naive or complicated classifier, which ignores the suggestive information contained in the label text. As a matter of fact, humans classify documents primarily based on the semantic meaning of the subcategories. We propose a novel model structure via siamese BERT and interactive double attentions named IDEA ( Interactive DoublE Attentions) to capture the information exchange of text and label names. Interactive double attentions enable the model to exploit the inter-class and intra-class information from coarse to fine, which involves distinguishing among all labels and matching the semantical subclasses of ground truth labels. Our proposed method outperforms the state-of-the-art methods using label texts significantly with more stable results.Comment: Accepted by ICTAI202

Single-Agent and Mean-Field Time-Inconsistent Stopping Problems in Discrete Time

In this thesis, we first consider single-agent time-inconsistent stopping problems under non-exponential discounting in discrete time with infinite horizon. We extend the iterative approach introduced by Huang and Zhou (2017) to time-inhomogeneous setting and establish the existence of nonstationary subgame perfect Nash equilibria. Under certain continuity assumptions, we further show the existence of a unique optimal equilibrium which dominates any other equilibria pointwisely. Explicit examples of time-homogeneous model with time-inhomogeneous equilibria are also constructed. We then apply the single-agent results to mean field stopping games where each agent plays against other agents as well as against future selves. We construct a single-agent optimal equilibrium for each fixed mean field interaction represented by the proportion of players that have stopped at each time and use this to show the existence of two-layer equilibria in two examples of mean field time-inconsistent stopping games