Development of microcantilever biosensing platforms

Microcantilever sensor system as a promising field attracted much attention recently. This system has the potential to be applied for a biosensing technology which is parallel reference, label free, sensitive and real time. In this thesis, polyimide has been selected as a material to fabricate cantilever due to its excellent physical, electrical and mechanical properties, on top of its cost advantage. Importantly, we showed it is feasible to microfabricate large array of microcantilever sensors with high-power UV laser directly. It is low cost and rapid, the parameters for laser direct writing fabrication has been studied. The thesis also shows that it is possible to functionalise the polyimide film first and subsequently cut it to functionalised cantilever sensor array. The unique fabrication and functionalisation process can solve the problem of high-cost microfabrication using silicon and low-efficient functionalisation using capillary tubing all together. In addition, the fabrication process has been further developed to avoid the problem of the cross contamination from receptors on both sides. With this improvement, we developed an internally referenced microcantilever biosensors system for DNA hybridization detection. Different receptors can be coated on each side of the polymer film before fabricating to cantilever biosensors This newly developed capability enables us to coat receptors with similar but slightly different biological properties on each side of the cantilever sensor, a process which is extremely difficult by using conventional capillary tubing methods due to the possibility of thiol exchange on surfaces and hence cross-contamination. A polyimide microcantilever sensor with embedded microfluidic channel has been developed in this thesis. Photoresist material is used to form the precise microfluidic channel within the microcantilever device. The multilayer polymer film device is still soft enough to operate in static mode. The main advantage of the system presented here is that since the device is made entirely of polymer materials, the fabrication process is simple and low-cost. The magnetic beads have been used to amplify the signal of the biosensing processing; the application of polyimide microfluidic microcantilevers to the detection of Cryptosporidium and thrombin is reported in this thesis. Paper based autonomous micocantilever system has also been investigated in this thesis. We build a cantilever system without external pump or force with paper and magnetic field. The limitation of the system is that it takes too much time to pump magnetic beads through the cantilever with capillary. However, we found that it has the potential to develop a long time range timer based on the slowest property. Different methods have been investigated to slow down the speed, when liquid pass through the paper microfluidic. Finally, we demonstrate some timer devices whose ranges are from minutes to month. The devices have the potential to be used as time-based diagnostic assays, food label, etc

Exchange of health service innovations between East and West

In the 21st century, countries worldwide face complex challenges that strain their health systems. The World Health Organization advocates for a global exchange of health innovations to promote learning among countries about solutions to common health system challenges (e.g., increasing health expenditure, aging population). Spreading innovations is like the ripple effect after throwing a pebble into a pond. It is a dynamic, non-linear process influenced by various contextual factors. Diffusion therefore cannot be “off-the-shelf” deals and contextual differences can either facilitate or hinder the process.Current scientific evidence, however, primarily documented diffusion within Western health systems. Innovation diffusion between contexts with significant differences is under-researched. How innovations diffuse between East and West remains unclear and the same applies to the transnational diffusion process. We therefore need to advance the understanding of the factors and processes of transnational diffusion of health service innovations between health systems in the East and West. With this aim, we conducted a systematic review, semi-structured interviews, and case studies in China (regarding Dutch innovations in elderly care) and The Netherlands (regarding Chinese traditional acupuncture). This PhD thesis provides novel insights into factors that facilitate and/or hinder the transnational diffusion of health service innovations between health systems in the East and West; and how these factors affect the diffusion process. We found that various factors often interact to affect the transnational diffusion of health service innovations between East and West. The structural and especially cultural fit between the innovation and the system influences transnational diffusion (innovation-system fit). Especially when strongly held norms and values in the context are not compatible with those embedded in the original innovation. When such incompatibility exists, mutual adaptations are often needed. The global journey of innovations can be facilitated by change agents whose knowledge work, culture work, and structural work serve to overcome the innovation-system fit barrier. Trust work may be additionally necessary depending on the perceived trustworthiness of change agents and on whether the innovation is ‘invited’ to the adoption context or not. Trust work may also be needed to establish a long-lasting international social network linking the country from which innovations originated, and the country into which innovations are introduced. Such international social networks are instrumental as a channel to exchange innovations, knowledge, and culture between the East and the West and provide a platform for the diverse tasks of change agents. The transnational diffusion process remains complex, non-linear, and recursive, which requires incremental steps and long-term commitment.<br/

Promoting Education and Literacy through the Preservation of Yongning River Boatman Work Songs

Yongning River Boatman Work Songs are traditional folk music from the Yongning River region, performed by boatmen for practical purposes during laborious tasks. The study’s objective is to investigate the promotion of education and literacy through the preservation of the Yongning River Boatman Work Song. Three key informants, including an inheritor of intangible cultural heritage, an academic expert, and a cultural heritage preservationist, provide comprehensive insights into this multifaceted topic. Data was analyzed thematically using a mixed-methods approach, including in-depth interviews, document analysis, and observations. The findings highlight the transformative power of these songs as educational tools, bridging the past and present, fostering cultural identity, and enabling multifaceted learning. Additionally, community collaboration among local individuals, cultural centers, educational institutions, and government authorities plays a pivotal role in preserving and promoting these songs. Successful initiatives for engaging the younger generation ensure the intergenerational transmission of this cultural heritage. This research suggests that cultural preservation, education, and community involvement are intertwined elements that can enrich education and enhance literacy while safeguarding intangible cultural heritage

An Empirical Study on the Change of Consumption Level of Chinese Residents

With the rapid development of Chinese economy since the reform and opening up, people's living standards have been improved, and people's consumption level has been gradually improved. Consumption plays an important role in stimulating economic growth. At present, China needs to adjust its economic structure and optimize its industrial structure. Therefore, it is very important to analyze the factors that affect the consumption level of Chinese residents and study the main factors for promoting the healthy and sustainable development of Chinese economy. Therefore, based on the statistical data from 1995 to 2018, this paper collects the variable data that affects the consumption level of residents, such as the freight volume of infrastructure railway and highway, the per capita disposable income of national residents, ordinary college students, the consumer&nbsp; price index of residents, the average real wage index and the gross domestic product. And through the establishment of multiple linear regression model and the stepwise regression, the paper also finds out the main factors influencing the consumption level of residents. Using R language and analyzing the results of the research, we can draw the conclusion that the national per capita disposable income, ordinary college students and consumer price index and GDP are the main factors that affect the consumption level of Chine

An Empirical Study on Patient Queuing after Medical Staff Supporting Disaster Areas in Northwest China

Recently, the new coronavirus has brought great disaster to human beings, so we have to take strong measures to suppress the large-scale outbreak of the disease. In this paper, by looking up the data of medical staff supporting Wuhan area in Northwest China, we build a queuing model of &nbsp;to analyze the waiting time and staying time of patients. Secondly, due to the increase of patients, the burden of outpatient service is gradually increasing, which leads to the speed of epidemic spread greatly accelerated. Therefore, &nbsp;model is constructed to analyze the relationship between patients and healers. The experimental results show that: (1) at the beginning of the data of more than 1000 medical staff, the patients were served for too long, which led to low efficiency. When they were supported, the efficiency was increasing with the increase of support, and the time was shortened, which was very helpful to relieve the medical pressure of outpatient. (2) With the increase of patients, at the same time, the number of healers is increasing, of course, there are also healthy people in it. At this time, we should focus on finding a suitable node, reducing the number of patients and increasing the number of healers, so as to effectively control the epidemic

Comparative Research on Air Conditioner with Gas-injected Rotary Compressor through Injection Port on Blade

Rotary compressors are widely utilized in air conditionders and heat pumps. However, when rotary compressors were applied in room air conditioners, VRFs and domestic water heaters, the systems will experience heavily degradation of the heating capacity and COP as the ambient temperature goes low. Aimed at these problems, considerable research has been carried out to raise a series of solutions, such as economizer technology, cascade-type vapor compression heat pump system and two stage coupling heat pump system. At present, economizer technology has become a critical method to improve the performance of air source heat pumps with rotary compressors in low ambient temperature. A novel vapor injection structure on a blade for a rotary compressor has been proposed in previous paper to overcome the drawback of the traditional cylinder injection structure. Based on a verified numerical model, the performance of air source heat pumps with rotary compressors with different economizer technology including a two-stage rotary compressor, a single-stage rotary compressor with traditional injection structure and a single rotary compressor with the novel injection structure has been investigated. The results indicate that: compared to rotary compressors with traditional injection structure, air source heat pump with a rotary compressor with proposed injection structure can enhance the heating capacity and COP by 13%~15% and 4.8%~9.6%, respectively; and compared to the twin-cylinder rotary compressor, the performance of air source heat pump with a rotary compressor with proposed injection structure is almost the same, so the rotary compressor with the novel injection structure could be considered to replace the two-stage rotary compressor

A Novel Vapor Injection Structure on the Blade for Rotary Compressor

Rotary compressors have been extensively used in room air conditioners and household refrigerators for their advantages, including high efficiency, strong adaptability, and low cost. However, when air source heat pumps with rotary compressors are applied in cold regions, a series of problems appear. The gas injection has been proved an effective technology to enhance both the heating capacity and COP of scroll, screw, and rotary compressors. In the one-cylinder rotary compressor with gas injection, the compressor injection port is often opened on the cylinder wall. In order to extend the injection time for injecting more refrigerant, the injection port is settled as close as possible to the discharge port. However, the limited area of the injection port and the unavoidable back-flowing of the injection refrigerant into the suction tube diminish the merits of gas injection on the one-cylinder rotary compressor. A novel vapor injection structure on the blade for the rotary compressor has been proposed in this paper to overcome the back-flowing drawback of the traditional cylinder injection structure and increase the injection area. Based on a verified numerical model, the performance of a rotary compressor with the blade injection structure has been investigated. The results indicate that: the proposed vapor injection structure can eliminate the back-flowing of the injected refrigerant; compared to the traditional injection structure, the new structure can enhance the volumetric efficiency and mass flow-rate by 1.8~2.7% and 26.6~57.2%, respectively; and compared to the traditional injection structure, the new structure can increase the heating capacity and COP by 23.1~48.9% and 3.2~8.0%, respectively

High photo-excited carrier multiplication by charged InAs dots in AlAs/GaAs/AlAs resonant tunneling diode

We present an approach for the highly sensitive photon detection based on the quantum dots (QDs) operating at temperature of 77K. The detection structure is based on an AlAs/GaAs/AlAs double barrier resonant tunneling diode combined with a layer of self-assembled InAs QDs (QD-RTD). A photon rate of 115 photons per second had induced 10nA photocurrent in this structure, corresponding to the photo-excited carrier multiplication factor of 10^7. This high multiplication factor is achieved by the quantum dot induced memory effect and the resonant tunneling tuning effect of QD-RTD structure.Comment: 10 pages,5 figures. Submitted to Applied Physics Letter