61 research outputs found
The Process of Reestablishing Home: Returned Indonesian Chinese in Songping Farm
No full text本文以生活在松坪农场的印尼归侨群体为个案 ,追溯其在特殊情境下跨国迁徙、安家农场的历史过程 ,从记忆、现实与向往三个层面 ,探讨该群体对于“家”之归属感的建构及特点Taking returned Indonesian Chinese as a case, this paper traces the processes of their resettlement in Songping Farm after a transnational migration. Through three perspectives, i.e., memory, reality and expectation, the author argues that the returned migrants memory of the life in Indonesia before their return has actively influenced their efforts in building their new home in China and their expectation for a better future has guided their daily life as well
Selection of downstream steps by analysis of protein surface property: A case study for recombinant human lactoferrin purification from milk of transgenic cow
No full text
Protein purification has long been regarded as an art rather than a science. Trial and error is the widely used practice for a protein to be purified from the crude extract. In this study, we carried out a rational approach by analysis of the protein surface properties before setting out to do experiments. The target protein was recombinant human lactoferrin (rHLF), to be purified from milk of transgenic cow. We need to overcome two major problems. One is its possible co-precipitation with casein during initial separation; the other is the difficulty in separating its homologous counterpart, bovine lactoferrin (BLF). By calculation of the surface hydrophobicity, an initial separation step was decided by calcium precipitation, which removed casein but left rHLF in the supernatant. Then the average surface hydrophobicity and electric potential of rHLF were compared with those of BLF. There was a more significant difference in the electric potentials than the average surface hydrophobicity (ASH) between the homologous pairs. Therefore, the purification step should be favored by ion exchange chromatography (IEC) instead of hydrophobic interaction chromatography (HIC). Experiments were performed to verify the prediction. After removing casein, one step cationic ion exchange chromatography realized complete separation of rHLF from BLF with rHLF recovery up to 83%, while the resolution of HIC process was very limited due to the small difference in ASH between them. The laboratory process was then successfully scaled up to pilot-plant scale of 5001 milk of transgenic cow per batch. Average rHLF recovery of 79%and purity of 98.9% were attained for five batches. The purified rHLF displayed bioactivities as good as the natural human-resource lactoferrin standard. (C) 2015 Elsevier Ltd. All rights reserved.</p
Social Memory and Construction of Identity: A case study on the returned Overseas Chinese in Songping Farm
No full text本文选择华侨农场和生活在农场里的归侨作为研究对象 ,运用社会记忆的相关理论 ,通过参与观察及口述访谈 ,剖析社会记忆如何作用于归侨的认同建构。本文提出 ,在对国家或地方的认同建构上 ,“归侨意识”始终贯串着归侨的集体记忆 ,认同建构是情景性的 ,流动的 ,是一个交织着多重利益的复杂的心理过程。本文希望通过实证研究 ,达到反思移民安置与地方融入这一社会现象的目的。对移民的安置不但是提供物质性安排 ,更重要的是营建一个和谐宽容的社会心理环境 ,使移民与安置地尽快融为一体 ,共谋发展On the basis of oral documents, this article studies the construction of the collective identity cherished by the returned Overseas Chinese in Songping Farm. The author tries to analyze how the returned Overseas Chinese identity has become the cohesion of the group, and the deep meaning of collective social memory and structural amnesia are explored along with the change of time, place and situation. It is argued that in order to improve the integration of the returned migrants into the local society, it is much more important to create social environments full with harmony and equality than simply provide necessary materials
Investigating Genetically Engineered Virus-Like Particles Using Molecular Dynamics Simulations for Enhanced Vaccine Development
No full textVirus-like particles (VLPs) mimic the structure of viruses without containing viral genetic material, making them safe and highly immunogenic platforms for vaccine development. Genetic modifications can expand the use of VLPs, such as the insertion of antigens to target various diseases. However, designing stable VLP-based vaccines through genetic engineering is challenging and unpredictable due to the complex nature of protein interactions involved in VLP assembly and the unknown effects of genetic modifications on VLP scaffolds. These challenges have limited the development of VLP-based vaccines. This project aims to overcome these limitations by leveraging computational tools to investigate and predict the overall stability of genetically modified VLP-based vaccines. This project began by constructing and establishing purification pathways for chimeric VLPs incorporating hydrophobic insertions using Hepatitis B core (HBc) and Human heavy chains ferritin (HFn). Initial investigations revealed that models predicted by AlphaFold2 were stable as initial structures, providing a basis for accurate simulation studies. Subsequently, the self-assembly properties of eight HBc derivatives were investigated through experimental validation and molecular dynamics (MD) simulations from a thermodynamic perspective. It was found that HBc derivative assembly failures could result in different morphologies as dissociative dimers or large multi-subunit polymers. Instability in dimer formations or improper (reduced) intradimer distances were identified as possible explanations of assembly-incompetent dimers. Polar solvation energies were found to play a critical role in causing assembly-incompetent dimers. MD simulations on dimers can offer preliminary predictions regarding the assembly properties of HBc derivatives, enhancing vaccine design efficiency by reducing the risk of self-assembly failures in engineered proteins. To simulate the surface physical properties of VLP assemblies more accurately, large partial VLP models, each consisting of 17 chains, were constructed for the HBc chimeric model vaccines using the wild-type (wt) HBc assembly template. This approach allowed for a comparison of the effects of inserted epitopes and insertion strategies on HBc modifications. Simulation results showed that the insertion site significantly affects the conformational stability of the VLP and secondary structures of inserted epitopes. Separate insertions at different sites on HBc, i.e. at the N-terminus and major immunodominant region (MIR), caused instability, while serial insertions at the MIR hindered VLP assembly. However, inserting a different epitope of the same length at the MIR led to successful assembly, indicating that the amino acid sequence is more critical than length. These insertions also modulate surface hydrophobicity and overall stability, which could be accurately predicted by MD simulations. The methodology was further applied to the Murine polyomavirus (MPV) capsid protein VP1. Study results showed that binding energies calculated from MD simulations correlate well with the thermal stability of genetically engineered VP1 capsomeres. Larger foreign insertions lead to less compact backbones and increased flexible regions, resulting in reduced thermal stability in VP1 capsomeres. Van der Waals interactions were identified as key stabilizing factors of the capsomere structures. These findings suggest that the influence of inserted antigens on the viral structural protein is complicated (depending on both size and sequence), and therefore using small protein tags and minimizing structural disruption is a more effective strategy for antigen replacement on VLP platforms. The integration of computational modeling and simulation with research validation in this thesis represents a significant advancement in the field of VLP vaccine development. The findings not only improve our understanding of genetically modified VLP derivatives but also provide a methodological framework for reducing development costs and accelerating the response to emerging infectious diseases. Future research should continue to explore the integration of computational methods with traditional vaccine development processes to establish a new paradigm that enhances the efficiency and precision of vaccine design.Thesis (Ph.D.) -- University of Adelaide, School of Chemical Engineering, 202
Modeling and optimization of a utility system containing multiple extractions steam turbines
No full textMathematical Optimization of the Liquid Separation Condenser Used in the Organic Rankine Cycle
No full textAbstractThe liquid separation condenser (LSC) is superior in terms of performance because of its relatively low pressure drop without reducing heat transfer coefficients. It is compact, material saving, and suitable for use in the organic Rankine cycle. However, the total performance of LSC is dependent on tube and fin configurations. A suitable combination of these structural parameters can improve LSC performance significantly. In this study, a mixed-integer nonlinear programming (MINLP) model is formulated to optimize the tube pass, tube number per pass, tube length, tube diameter, and fin number simultaneously. The objective function is the annual total cost of investment and operation. A solution is proposed to solve the formulated MINLP model. A case study is presented to verify the model and solution algorithm
Improving PGF Retrieval Effectiveness with Active Learning
No full textMultimedia education is playing a significant and increasing role for education purposes, thus leading to a large number of electronic documents. Plane geometry figures (PGFs), as important components of these documents, are regarded as very helpful information to most retrieval systems in the field of mathematics education. However, the burdensome work of annotation has become one of the chief obstacles to improve the efficiency of retrieval systems. In this paper, we introduce an active learning-based frame to select candidate instances for training the classifiers in retrieval systems, which are an emerging non-text-based information systems. In addition, an enhanced uncertainty measure and the selection of specific features of PGFs are proposed for our active learning algorithm. Comparative experiment results indicate that the proposed method effectively improves the performance of the PGF retrieval system and reduces the burdensome annotation workload.National Natural Science Foundation of China [61300061, 61472014, 61573028]CPCI-S(ISTP)1125-113
Synthesis and Design of a Trigeneration System of Large Public Buildings
No full textAbstractBuilding energy systems, especially large public building energy systems (LPBES), are major energy consumers and pollutant emissions contributors. In this paper, a superstructure of LPBES incorporating the candidate equipments and their possible combinations are constructed. The thermodynamic performance model, investment cost model, CO2 emission model of the equipments are formulated. The variations of the energy demand and power importation price are addressed by multiple scenarios problem. A multi-objective mixed integer linear programming (MILP) model is formulated. The economic objective is the minimization of the total annual cost of the LPBES and the environmental objective is the minimization of the annual global CO2 emission. The augmented ɛ–constraint method is applied to achieve the Pareto Frontier of the design configuration to reflect the set of solutions representing optimal trade-offs between the economic and environmental objectives. The synthesis and design of the energy system of an airport in north China is studied to test the proposed synthesis and design strategy and the formulated model. Economic optimal scheme and environmental optimal scheme are presented. The Pareto solutions consist of optimal configurations that adapt their operational strategy during a specific range in the Pareto Frontier are presented to show the trade-offs scheme between economic and environmental objectives
Reduction of supercooling of water by TiO<sub>2</sub> nanoparticles as observed using differential scanning calorimeter
No full textOperational planning optimization of multiple interconnected steam power plants considering environmental costs
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