Globalization and technological changes are inexorable and impact both urban and rural communities. Innovation and entrepreneurship play an increasingly important role in shaping economic development ...policy in the U.S. However, innovation and business activities are unevenly distributed across the States. Most economic and public resources supporting innovation and entrepreneurship activities are concentrated in large urban and metropolitan areas, while small and hinterland communities are left behind and still facing barriers to sustain economic growth. Therefore, the purpose of my research is to understand the regional determinants of innovation and entrepreneurship activities, and explore how the development patterns differ across various geographical regimes (i.e. urban and rural, large and small communities, metropolitan and non-metropolitan regions). The empirical models of my studies mainly draw from the theories of urbanization/localization economies, endogenous growth and geographical knowledge spillover of entrepreneurship, all of which emphasize the critical role of human capital, innovation, industries and entrepreneurship in economic development. This dissertation research is organized into three chapters consisting of three stand-alone articles. The first article studies the spatial patterns of general and high-tech startup rates and explores regional factors associated with entrepreneurship in smaller micropolitan areas in the United States. The results show that general entrepreneurship in small cities is mainly predicted by population growth, the middle-age population group, the presence of small businesses, and natural amenities. High-tech startup activities in small cities are positively associated with human capital, creative knowledge, high-tech clustering, and proximity to a large metropolitan area. This research sheds light on local entrepreneurship policy in the small-city context, which is often neglected in regional entrepreneurship studies. The second article assesses the efficacy of the Small Business Innovation Research (SBIR) Program on innovation, employment, and business formation in small and nonmetropolitan counties. The primary goal is to further understand rural innovation and growth process by a way of government intervention on small business development. Using panel data and employing fixed-effect models, the results suggest that, compared to large metropolitan counties, the SBIR may not be an effective program to generate employment and entrepreneurship opportunities in small and nonmetropolitan regions, but it could be a viable source to improve rural innovation outcome. This study contributes to the innovation policy agenda in small and nonmetropolitan regions, which is an important and emerging topic in the field. The third essay aims to understand whether and how entrepreneurship is associated with income inequality in U.S. Metropolitan Statistical Areas (MSAs). In this study, entrepreneurship activities are measured by new firm formation and self-employment rates. The empirical analyses indicate that these two commonly used entrepreneurship measures represent different streams of entrepreneurial activities and can impact income inequality differently across U.S. cities. This study highlights the need for differentiating entrepreneurship in understanding its role in income inequality and, more broadly, in regional development. Policymakers at the regional and local levels will gain insights into whether promoting entrepreneurship as an economic development strategy has any unforeseen impact on the income gap.
In this paper, we propose and experimentally demonstrate a novel scheme that helps to solve an any-number-armed bandit problem by utilizing two parallel simultaneously-generated chaotic signals and ...the epsilon (
ɛ
)-greedy strategy. In the proposed scheme, two chaotic signals are experimentally generated, and then processed by an 8-bit analog-to-digital conversion (ADC) with 4 least significant bits (LSBs), to generate two amplitude-distribution-uniform sequences for decision-making. The correspondence between these two random sequences and different arms is established by a mapping rule designed in virtue of the ɛ-greedy-strategy. Based on this, decision-making for an exemplary 5-armed bandit problem is successfully performed, and moreover, the influences of the mapping rule and unknown reward probabilities on the correction decision rate (CDR) performance for the 4-armed to 7-armed bandit problems are investigated. This work provides a novel way for solving the arbitrary-number-armed bandit problem.
Resistance to androgen deprivation therapy, or castration-resistant prostate cancer (CRPC), is often accompanied by metastasis and is currently the ultimate cause of prostate cancer-associated deaths ...in men. Recently, secondary hormonal therapies have led to an increase of neuroendocrine prostate cancer (NEPC), a highly aggressive variant of CRPC. Here, we identify that high levels of cell surface receptor Trop2 are predictive of recurrence of localized prostate cancer. Moreover, Trop2 is significantly elevated in CRPC and NEPC, drives prostate cancer growth, and induces neuroendocrine phenotype. Overexpression of Trop2 induces tumor growth and metastasis while loss of Trop2 suppresses these abilities in vivo. Trop2-driven NEPC displays a significant up-regulation of PARP1, and PARP inhibitors significantly delay tumor growth and metastatic colonization and reverse neuroendocrine features in Trop2-driven NEPC. Our findings establish Trop2 as a driver and therapeutic target for metastatic prostate cancer with neuroendocrine phenotype and suggest that high Trop2 levels could identify cancers that are sensitive to Trop2-targeting therapies and PARP1 inhibition.
Biohybrid microrobotics are exploited as a delivery approach to actively transport therapeutic payload to tumors. However, the therapeutic utility of this approach can be diminished by tumor hypoxia. ...Moreover, current biohybrid microrobotics design is mainly focused on the living organisms’ motility and biocompatibility, yet the unique biological function of the natural organism is often overlooked. Here, an all‐in‐one self‐propelled volvox‐based multifunctional robot, that is, Volbot, with built‐in capabilities of fluid mixing, multimode imaging, and photosynthesis‐mediated in situ oxygen generation that can potentially relieve hypoxia is developed. Volbots can follow a pre‐specified route and directionality under the control of a magnetic field. Red‐light irradiation (λ = 650 nm) can enhance the Volbot's locomotive behavior, enhance the mixing of biofluids, and modulate the oxygen production to improve the efficacy of photodynamic therapy. Moreover, Volbots can absorb near‐infrared irradiation and produce localized hyperthermia to treat tumors. Subcutaneous tumor suppression can be achieved by this high‐yield oxygen‐producing biohybrid “microfactory” in a photodynamic/photothermal‐synergistic therapy strategy. Furthermore, Volbots also offer imaging capabilities and exhibit considerable promise as a multifunctional microrobotics‐based theranostic approach for a precision tumor therapy strategy.
An all‐in‐one self‐propelled volvox‐based multifunctional robot, with built‐in capabilities of fluid mixing, multimode imaging, and photosynthesis‐mediated in situ oxygen generation that can potentially relieve hypoxia is developed.
Purpose: Parenting for Lifelong Health for Young Children (PLH-YC) is a program to prevent child maltreatment. This study aimed to examine the feasibility, acceptability and preliminary effects of ...the adapted program for Chinese parents. Methods: A pre–post single-arm pilot trial was conducted with 21 Chinese parents. A mixed-method design was utilized to collect questionnaire-based quantitative data and qualitative data of interviews and focus group discussions. Results: Program implementation was feasible, with overall high recruitment, enrollment, attendance, acceptability and fidelity. Quantitative results demonstrated reductions in general child maltreatment, physical and emotional abuse, child behavioral problems, and improvements in positive parenting. Thematic analyses identified reduced violent discipline, psychological aggression, and child behavioral problems, strengthened parent–child bonds, increased parenting confidence, and decreased family conflict. Conclusion: The adapted PLH-YC program for Chinese parents has shown good feasibility and acceptability, and exhibited a significant association with reduced child maltreatment. Further randomized controlled trials are required.
Due to the biodegradable, biocompatible, sustainable, and renewable properties of lignocellulosic materials, there is growing interest in developing functional materials based on lignocellulosic ...components using green strategies. For example, the surface of lignocellulosic materials can be modified using polyphenols with inherent characteristics such as metal chelation and reducibility to prepare functional materials with flame retardant, antibacterial, and self-cleaning properties. Understanding the fundamental interaction mechanisms between lignocellulosic materials and polyphenols is crucial for these applications and the design of lignocellulosic-based functional materials. In this study, we used wood fibers (WFs) and tannic acid (TA) as typical representatives of lignocellulosic materials and polyphenols, respectively. We combined adsorption isotherm models and density functional theory simulations to reveal the interaction mechanisms between the main components of WFs (cellulose, hemicellulose, and lignin) and TA. Cellulose and hemicellulose primarily interacted with TA through hydrogen bonding, electrostatic interaction, and hydrophobic interaction, while lignin–TA interactions are hydrogen bonding and electrostatic interaction. For WFs, their pore structure and exposed surface components determined their binding with TA. The adsorption of TA on WFs followed the Langmuir model for monolayer adsorption, with the main driving forces being hydrogen bonding, electrostatic interactions, and van der Waals forces between surface cellulose components and TA. Our findings provide new insights into the interaction mechanisms between lignocellulosic materials and polyphenols, offering valuable guidance for the development of lignocellulosic/polyphenol composite functional materials with environmental, biomedical, and engineering applications.
•Asymmetrically coupled semiconductor lasers networks can generate multiple chaos signals.•Delta-like autocorrelation functions are obtained for each channel chaotic signals.•Average cross ...correlations are below 0.1 between multiple chaos signals.•Effective bandwidth over 20 GHz; good rubustness.
We propose and numerically demonstrate a novel multiple delta-like autocorrelation chaos generation scheme in virtue of asymmetrically-coupled semiconductor lasers (ACSLs) networks. The properties of auto-correlation function (ACF), cross correlation, and effective bandwidth of the generated multiple chaos signals are systematically investigated in ACSLs networks with different topology and network sizes. The results show that not only delta-like ACF traces are obtained but also low cross correlations are observed in the chaotic signals outputted by ACSLs networks. Besides, the average effective bandwidth of generated multi-channel chaos can be greater than 20 GHz over a wide dynamic operation range. Moreover, the delta-like ACF, low correlation and wideband properties of multiple chaotic signals are robust to parameter mismatches between SLs. This work realizes wideband multi-channel chaos generation that simultaneously achieves delta-like ACF and low correlation, and is valuable for the applications in high-speed random bit generator, accurate multi-target, multi-angle radar detection, and ultrafast photonic decision making.
Pedestrian accessibility is an important factor in urban transport and land use policy and critical for creating healthy, sustainable cities. Developing and evaluating indicators measuring ...inequalities in pedestrian accessibility can help planners and policymakers benchmark and monitor the progress of city planning interventions. However, measuring and assessing indicators of urban design and transport features at high resolution worldwide to enable city comparisons is challenging due to limited availability of official, high‐quality, and comparable spatial data, as well as spatial analysis tools offering customizable frameworks for indicator construction and analysis. To address these challenges, this study develops an open source software framework to construct pedestrian accessibility indicators for cities using open and consistent data. It presents a generalized method to consistently measure pedestrian accessibility at high resolution and spatially aggregated scale, to allow for both within‐ and between‐city analyses. The open source and open data methods developed in this study can be extended to other cities worldwide to support local planning and policymaking. The software is made publicly available for reuse in an open repository.
In this paper, we propose and experimentally demonstrate a novel hybrid chaos-based three-dimensional (3-D) constellation scrambling scheme to simultaneously improve the physical layer security and ...transmission performance of the coherent optical orthogonal frequency division multiplexing (CO-OFDM) system. A 3-D regular hexahedron signal constellation is constructed by the constellation figure of merit principle, which not only expands the encryption dimension but improves the error performance. The dynamic parameters for constellation scrambling are generated by the 5-D hybrid chaotic scheme based on the combination of a 3-D hyperchaotic Hénon mapping and two independent 1-D Logistic mappings, as such a key space of ∼10 133 is introduced to enhance the security level of OFDM data encryption during transmission. Furthermore, a transmission experiment for encryption of 144 Gbps 16-quadrature-amplitude-modulation OFDM data over a 100 km standard single-mode fiber in a CO-OFDM system is demonstrated. Compared with the case of using the 3-D rectangular constellation, a 2 dB bit error rate performance improvement is achieved. The results show that the proposed scheme could effectively enhance the system security and transmission performance, which suggests a scalable strategy for future physically secured CO-OFDM systems.
Solid‐state optics has been the pillar of modern digital age. Integrating soft hydrogel materials with micro/nanooptics could expand the horizons of photonics for bioengineering. Here, wet‐spun ...multilayer hydrogel fibers are engineered through ionic‐crosslinked natural polysaccharides that serve as multifunctional platforms. The resulting flexible hydrogel structure and reversible crosslinking provide tunable design properties such as adjustable refractive index and fusion splicing. Modulation of the optical readout via physical stimuli, including shape, compression, and multiple optical inputs/outputs is demonstrated. The unique permeability of the hydrogels is also combined with plasmonic nanoparticles for molecular detection of SARS‐CoV‐2 in fiber‐coupled biomedical swabs. A tricoaxial 3D printing nozzle is then employed for the continuous fabrication of living optical fibers. Light interaction with living cells enables the quantification and digitalization of complex biological phenomena such as 3D cancer progression and drug susceptibility. These fibers pave the way for advances in biomaterial‐based photonics and biosensing platforms.
Polysaccharide‐based, multilayered hydrogel fibers in the photonics arena are explored. Natural ionic‐crosslinking hydrogels are leveraged for developing a hydrogel fiber fusion splicing method and combined with nanoplasmonic‐based photonics for detecting biotargets such as SARS‐CoV‐2. The integration of living entities in the cytocompatible light‐guiding core enables the digitalization and quantification of complex 3D biological events, such as cancer invasive proliferation.
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