Divergent developmental trajectories and strategic coupling in the Pearl River Delta: Where is a sustainable way of regional economic growth?

This paper interprets regional economic sustainability in the context of the globalization of late-coming regions. Drawing upon the concept of strategic coupling from economic geography, this paper proposes two types of strategic coupling, captive and proactive coupling, for better understanding regional sustainability and resilience through the experiences of the Pearl River Delta in China. It finds that sub-regional economies under captive coupling become highly dependent on exogenous growth and are vulnerable to external shocks. This trajectory looks less sustainable according to the general understanding, but it interestingly shows better resilience during and after the 2008 global financial crisis. In contrast, the ones under proactive coupling are less volatile, but growing much slower and are less resilient. By reporting these regional economic dynamics, this paper argues that sustainability in late-coming regions cannot be explained by either intra-regional forces or the means of global integration alone. In contrast, it has to be explained by the combination of both; the alleged strategic coupling in which economic growth and learning happens. This paper thus calls for greater attention to strategic coupling, the trade-off of globalization and resilience for understanding regional sustainability, rather than purely focusing on resource utilization and ecological balance

Research progress of knitted sensors in the field of sports and fitness apparel

Knitted sensor has the advantages of lightness, conformity, good strain tensile recovery and formability, which provides a possibility for flexible and non-inductive motion signal monitoring and smart wearable sports health clothing preparation. This paper reviews the preparation methods of knitted sensors, analyzes the influence of yarn types, fabric microstructure and tensile sensing direction on its sensing performance, and compares the advantages and disadvantages of knitted sensors in the fields of life and health, human movement and other fields. It is pointed out that the type, structure and weaving method of the conductive yarn are important factors affecting the performance and wearing comfort of knitted sensors, and the electrical characteristics of the two-dimensional extension and three-dimensional deformation in the strain stretching process of knitted sensors determine the effective strain sensing range. This paper outlines the development opportunities and challenges faced by knitted sensors in the field of sports and health clothing

Nanoengineered Drug Delivery Systems for the Treatment of Sensorineural Hearing Loss

© 2020 Yutian MaInner ear disease is the leading cause of hearing impairment in developed countries. An estimated 466 million people suffer from hearing loss worldwide and this number is on the rise. Sensorineural hearing loss (SNHL) is the most common form of hearing impairment and is characterised by the degeneration of key structures of the sensory pathway in the cochlea of the inner ear (the cochlea) such as the sensory hair cells, the primary auditory neurons and their synaptic connection to the hair cells. Current research focuses on developing techniques to administer growth proteins such as neurotrophins to repair or regenerate damaged auditory neurons, as well as preventing loss of primary auditory neurons. Drug delivery systems are being developed to treat SNHL, such as cell-based drug delivery systems and gene vectors, however nanoengineered systems show promise to address the specific needs of neurotrophin-based therapies such as safety, high dosing and long-term delivery to the cochlea. Research carried out in this thesis has developed this technology further by the scale-up production of nanoengineered silica-based supraparticles (SPs) (~550 micrometers) with high porosity) and the development of several strategies towards their application as viable drug delivery platforms for achieving sustained drug release in the inner ear, as detailed in Chapters 3-6. In Chapter 3, a gel-mediated electrospray technique was developed to synthesise silica supraparticles (Si-SPs) in high yields. The Si-SPs were assembled from different primary silica particles i.e., particles with no pores, small pores (2-3 nm) and bimodal large pores (2-3 nm and 15-64 nm). A high loading of fluorescently labelled model protein (fluorescein isothiocyanate (FITC)-lysozyme) and neurotrophic factor (a drug for the treatment of inner ear disease) in the Si-SPs was possible and the resulting particle system could achieve sustained drug release for over 150 days. The findings demonstrate that gel-mediated electrospray is a robust and automatable technology to produce Si-SPs, which is a promising platform for clinical translation and commercialisation. In Chapter 4, the pharmacokinetics of the neurotrophin brain-derived neurotrophic factor (BDNF) from Si-SPs was examined as engineering drug delivery systems with well-defined pharmacokinetics is important for clinical translation. BDNF-loaded Si-SPs were surgically implanted either directly into the cochlea, or onto a semi-permeable membrane (the round window membrane; RWM) that is a boundary between the middle and inner ear. Treatment duration was for either 3 or 7 days whereby the fluids from the cochleae were sampled and tested for BDNF levels. The results showed that the BDNF released from the Si-SPs was detected in the cochlear fluids indicating that the approach has potential as a clinically relevant neurotrophin delivery strategy to treat people with hearing impairment. In Chapter 5, a bioengineering coating strategy was developed for retarding the initial burst release of neurotrophins from the Si-SPs. Applying a fibrin coating on the surface of the Si-SPs and embedding the fibrin-coated Si-SPs within an alginate CaCO3 hydrogel both slowed the initial burst release to improve the drug release kinetics. The results demonstrate the suitability of alginate CaCO3 hydrogel systems for surgical handing of the Si-SP system. In Chapter 6, a chitosan and an alginate layer-by-layer coating on the Si-SPs was developed as an alternative strategy for delaying the initial burst release of uncoated Si-SPs. Chitosan and alginate are two biocompatible polysaccharides that interact electrostatically via the carboxyl groups from alginate (negatively charged) and the amine groups on chitosan (positively charged). By varying the layer number and hence, the thickness of the coating, different release profiles were attained. In vitro neurotrophins release profiles showed that chitosan-alginate-coated silica supraparticles ((Chi/Alg)Si-SPs) experienced a delayed initial burst release. Spiral ganglion neurons culture and neurite length analysis indicated that the neurotrophins released from (Chi/Alg)Si-SPs had maintained biological activity. Functional hearing was tested using auditory brainstem responses (ABRs) to determine the safety profile of surgical delivery of coated SPs to the inner ear. Hearing thresholds were maintained within the normal range following RWM, however an increase in thresholds for high frequency sounds were observed following implantation of (Chi/Alg)Si-SPs into the cochlea. Scanning electron microscopy images of (Chi/Alg)Si-SPs collected following in vivo implantation along with a commercial viable fibrin sealant indicated the biodegradability of (Chi/Alg)Si-SPs post-implantation. These results indicate that (Chi/Alg)Si-SPs can potentially be used as a clinically applicable platform for sustained inner ear neurotrophin delivery. In summary, this thesis expands knowledge in the development and engineering of Si-SPs in addressing key neurotrophin delivery issues for the treatment of hearing loss, including high yield, sustained drug release, well-defined pharmacokinetics and biodegradability

Potential Regulatory Roles of MicroRNAs and Long Noncoding RNAs in Anticancer Therapies

MicroRNAs and long noncoding RNAs have long been investigated due to their roles as diagnostic and prognostic biomarkers of cancers and regulators of tumorigenesis, and the potential regulatory roles of these molecules in anticancer therapies are attracting increasing interest as more in-depth studies are performed. The major clinical therapies for cancer include chemotherapy, immunotherapy, and targeted molecular therapy. MicroRNAs and long noncoding RNAs function through various mechanisms in these approaches, and the mechanisms involve direct targeting of immune checkpoints, cooperation with exosomes in the tumor microenvironment, and alteration of drug resistance through regulation of different signaling pathways. Herein we review the regulatory functions and significance of microRNAs and long noncoding RNAs in three anticancer therapies, especially in targeted molecular therapy, and their mechanisms. Keywords: microRNAs, long noncoding RNAs, targeted therapy, chemoresistance, immune checkpoin

Research on wearable devices for safety of underground mine personnel

In view of problems of low positioning accuracy of underground personnel positioning system and incomplete functions of underground personnel vital signs monitoring system, a wearable device with functions of personnel positioning, falling or lying posture monitoring and heart rate monitoring was studied. The device adopts combination of RSSI ranging and step calculation to improve positioning accuracy of underground personnel. Three-axis acceleration sensor is used to detect abnormal movement of person, and heart rate sensor is used to obtain heart rate data. The test results show that the device can achieve accurate positioning of underground personnel, can accurately determine falling or lying posture of underground personnel, and alarm abnormal state

Dynamic Equivalent Resistance Model of Knitted Strain Sensor under In-Plane and Three-Dimensional Surfaces Elongation

The dynamic equivalent resistance is a major index that determines the sensing performance of knitted strain sensors, and has the characteristics of in-plane and three-dimensional curved strain sensing. Therefore, in addition to establishing the in-plane equivalent resistance, it is necessary to establish a three-dimensional equivalent resistance model to fully explain the surface sensing performance. This project establishes two equivalent resistance models of knitted strain sensors under in-plane deformation and one equivalent resistance model of three-dimensional curved surface strain. Based on the length of resistance and the geometric topological structure, an in-plane strain macro–micro equivalent resistance model and a topological equivalent resistance model are established, respectively. In addition, a three-dimensional curved surface equivalent resistance model is created based on the volume resistance. By comparing the theoretical model with the experimental data, the results prove that the proposed in-plane and three-dimensional models can be utilized to calculate the resistance change of knitted strain sensors. Length resistance, coil transfer, and curved surface deformation depth are the main factors that affect the equivalent resistance of knitted strain sensors

Surface Tension of R290/Lubricant Oil Mixtures from 243 to 333 K

Propane (R290) is a promising natural refrigerant with zero ODP and very low GWP. The surface tension of a refrigerant/oil mixture is of importance for its capillary flow rate, wettability, and heat transfer performance. In this study, the surface tension of R290 with three commercial lubricants 3GS, RL68H, and AB4 was measured in the temperature range from 243 to 333 K by the differential capillary rise method. The expanded uncertainty of the surface tension data was less than 0.32 mN m–1 (k = 2). The obtained surface tensions were correlated as a function of temperature and composition, and the average absolute deviations between the experimental and calculated results were 0.03 mN m–1 for R290/3GS, 0.06 mN m–1 for R290/RL68H, and 0.09 mN m–1 for R290/AB4 mixtures

Accurate identification of cross-sectional bending stiffness in large-scale wind turbine blades through static loading test

To ensure the safe and stable operation of wind turbines, it is essential that the blades have sufficient bending stiffness to prevent excessive deflection and tower impact. A method combining static loading test and numerical analysis is proposed to solve the problem of identifying the cross-sectional bending stiffness of actual blades. Two working conditions, namely multi-point static test and single-point static calibration, are considered. A mathematical model of a cantilever beam with an initial small curvature and variable cross section is established. By fitting the deflection measurement data obtained from the static loading test, the deflection differential equation is solved by the finite difference method to obtain expressions for the cross-sectional bending stiffness under large and small deflection. The analysis results of several blade models show that the bending stiffness identification error for most blade sections is less than 10%, confirming the effectiveness of this method. This provides a practical and theoretical basis for the design, analysis, and refinement of test parameters for large-scale blades