Find Research Output

Research Output
  • All
  • Scholar Profiles
  • Research Units
  • Research Output
Department Publication Year Content Type Data Sources

1.Advances in freshwater risk assessment: improved accuracy of dissolved organic matter-metal speciation prediction and rapid biological validation

Author:Zhang, XK;Li, BL;Deng, JM;Qin, BQ;Wells, M;Tefsen, B


Abstract:Speciation modeling of bioavailability has increasingly been used for environmental risk assessment (ERA). Heavy metal pollution is the most prevalent environmental pollution issue globally, and metal bioavailability is strongly affected by its chemical speciation. Dissolved organic matter (DOM) in freshwater will bind heavy metals thereby reducing bioavailability. While speciation modeling has been shown to be quite effective and is validated for use in ERA, there is an increasing body of literature reporting problems with the accuracy of metalDOM binding in speciation models. In this study, we address this issue for a regional-scale field area (Lake Tai, with 2,400 km(2) surface area and a watershed of 36,000 km(2)) where speciation models in common use are not highly accurate, and we tested alternative approaches to predict metal-DOM speciation/bioavailability for lead (Pb) in this first trial work. We tested five site-specific approaches to quantify Pb-DOM binding that involve varying assumptions about conditional stability constants, binding capacities, and different components in DOM, and we compare these to what we call a one-size-fits-all approach that is commonly in use. We compare model results to results for bioavailable Pb measured using a whole-cell bioreporter, which has been validated against speciation models and is extremely rapid compared to many biological methods. The results show that all of the site-specific approaches we use provide more accurate estimates of bioavailability than the default model tested, however, the variation of the conditional stability constant on a site-specific basis is the most important consideration. By quantitative metrics, up to an order of magnitude improvement in model accuracy results from modeling active DOM as a single organic ligand type with site-specific variations in Pb-DOM conditional stability constants. Because the biological method is rapid and parameters for site-specific tailoring of the model may be obtained via high-throughput analysis, the approach that we report here in this first regional-scale freshwater demonstration shows excellent potential for practical use in streamlined ERA.

2.Biophysical characterizations of human mitochondrial transcription factor A and its binding to tumor suppressor p53

Author:Wong, TS;Rajagopalan, S;Freund, SM;Rutherford, TJ;Andreeva, A;Townsley, FM;Petrovich, M;Fersht, AR


Abstract:Human mitochondrial transcription factor A (TFAM) is a multi-functional protein, involved in different aspects of maintaining mitochondrial genome integrity. In this report, we characterized TFAM and its interaction with tumor suppressor p53 using various biophysical methods. DNA-free TFAM is a thermally unstable protein that is in equilibrium between monomers and dimers. Self-association of TFAM is modulated by its basic C-terminal tail. The DNA-binding ability of TFAM is mainly contributed by its first HMG-box, while the second HMG-box has low-DNA-binding capability. We also obtained backbone resonance assignments from the NMR spectra of both HMG-boxes of TFAM. TFAM binds primarily to the N-terminal transactivation domain of p53, with a K-d of 1.95 +/- 0.19 mu M. The C-terminal regulatory domain of p53 provides a secondary binding site for TFAM. The TFAM-p53-binding interface involves both TAD1 and TAD2 sub-domains of p53. Helices alpha 1 and alpha 2 of the HMG-box constitute the main p53-binding region. Since both TFAM and p53 binds preferentially to distorted DNA, the TFAM-p53 interaction is implicated in DNA damage and repair. In addition, the DNA-binding mechanism of TFAM and biological relevance of the TFAM-p53 interaction are discussed.

3.Low-Complexity Noncoherent Signal Detection for Nanoscale Molecular Communications

Author:Li, B;Sun, MW;Wang, SY;Guo, WS;Zhao, CL


Abstract:Nanoscale molecular communication is a viable way of exchanging information between nanomachines. In this investigation, a low-complexity and noncoherent signal detection technique is proposed to mitigate the inter-symbol-interference (ISI) and additive noise. In contrast to existing coherent detection methods of high complexity, the proposed noncoherent signal detector is more practical when the channel conditions are hard to acquire accurately or hidden from the receiver. The proposed scheme employs the molecular concentration difference to detect the ISI corrupted signals and we demonstrate that it can suppress the ISI effectively. The difference in molecular concentration is a stable characteristic, irrespective of the diffusion channel conditions. In terms of complexity, by excluding matrix operations or likelihood calculations, the new detection scheme is particularly suitable for nanoscale molecular communication systems with a small energy budget or limited computation resource.

4.Outbreak analysis with a logistic growth model shows COVID-19 suppression dynamics in China

Author:Zou, Y;Pan, S;Zhao, P;Han, L;Wang, XX;Hemerik, L;Knops, J;van der Werf, W

Source:PLOS ONE,2020,Vol.15

Abstract:China reported a major outbreak of a novel coronavirus, SARS-CoV2, from mid-January till mid-March 2020. We review the epidemic virus growth and decline curves in China using a phenomenological logistic growth model to summarize the outbreak dynamics using three parameters that characterize the epidemic's timing, rate and peak. During the initial phase, the number of virus cases doubled every 2.7 days (range 2.2-4.4 across provinces). The rate of increase in the number of reported cases peaked approximately 10 days after suppression measures were started on 23-25 January 2020. The peak in the number of reported sick cases occurred on average 18 days after the start of suppression measures. From the time of starting measures till the peak, the number of cases increased by a factor 39 in the province Hubei, and by a factor 9.5 for all of China (range: 6.2-20.4 in the other provinces). Complete suppression took up to 2 months (range: 23-57d.), during which period severe restrictions, social distancing measures, testing and isolation of cases were in place. The suppression of the disease in China has been successful, demonstrating that suppression is a viable strategy to contain SARS-CoV2.

5.The behavioural causes of bullwhip effect in supply chains: A systematic literature review

Author:Yang, Y;Lin, J;Liu, G;Zhou, L


Abstract:The bullwhip effect, also known as demand information amplification, is one of the principal obstacles in supply chains. In recent decades, extensive studies have explored its operational causes and have proposed corresponding solutions in the context of production inventory and supply chain systems. However, the underlying assumption of these studies is that human decision-making is always rational. Yet, this is not always the case, and an increasing number of recent studies have argued that behavioural and psychological factors play a key role in generating the bullwhip effect in real-world supply chains. Given the prevalence of such research, the main objective of this study is to provide a systematic literature review on the bullwhip effect from the behavioural operations perspective. Using databases, including Scopus, Wiley Online Library, Google Scholar and Science Direct, we selected, summarised and analysed 53 academic studies. We find that most studies build their models and simulations based on the 'beer distribution game' and analyse the results at the individual level. We also demonstrate the importance of studying human factors in the bullwhip effect through adapting Sterman's double-loop learning model. Based on this model, we categorise and analyse the behavioural factors that have been studied and identify the explored behavioural factors for future research. Based on our findings, we suggest that future studies could consider social and cultural influences on decision-making in studying the bullwhip effect. In addition, further aspects of human mental models that cause this effect can be explored.

6.A Handshake Protocol With Unbalanced Cost for Wireless Updating

Author:Cai, JR;Huang, X;Zhang, J;Zhao, JW;Lei, YX;Liu, DW;Ma, XF

Source:IEEE ACCESS,2018,Vol.6

Abstract:Wireless updating is an essential method to update system files or fix bugs in Internet of Things (IoT) devices. A significant and challenging problem in wireless updating is security. First, without security guarantees, attackers can utilize the updating procedure to install harmful programs into the victim devices. Second, it is challenging to provide security for wireless updating, since in many IoT scenarios, the devices to be updated are computationally limited devices and located far from the center that issues update files. Currently, there are two types of solution to protect the wireless updating. The first one is the transport layer security (TLS) protocol or secure sockets layer (SSL) protocol that are used by wireless updating schemes for mobile terminals with the following operation systems: Windows, Debian, Android, and iOS. Another solution is the elliptic curve Diffie-Hellman (ECDH)-based handshake in the software-defined function (SDF) wireless updating scheme for the IoT devices. However, both the two solutions require equal computation tasks on the update file issuing center and the device to be updated. Normally, the former is much powerful than the latter. Therefore, to further address the security problem in wireless updating, we propose a novel solution with unbalanced computation costs on the two parties. In particular, we design an improved ECDH-based handshake protocol for the SDF wireless updating scheme, namely, the unbalanced OpenFunction handshake protocol. The protocol transfers significant computation task from the limited IoT device to the powerful center. The security of the protocol is analyzed. A prototype is realized to test the performance of the protocol. The experiment results show that in the same experimental platform, our protocol is much lightweight than the TLS handshake protocol and SSL handshake protocol.

7.Re-using 'uncomfortable heritage': the case of the 1933 building, Shanghai

Author:Pendlebury, J;Wang, YW;Law, A


Abstract:This paper opens up a discussion over the processes of forgetting and remembering that occur in the adaptive reuse of quite commonplace buildings that, nevertheless, have been classified as 'heritage'. For most buildings survival depends upon finding a new economic use once original use has ceased. At this point decisions are also made about what stories are carried forward from the building's past. The principal case study discussed in this paper is the former Shanghai Municipal Abattoir, a modernist concrete sculpture now branded 1933 Shanghai. The paper delineates how a process of 'strategic forgetting and selective remembrance' has been undertaken, negotiating the bloody nature of the building's past, in its reuse as an upscale commercial venue. Reuse is further considered within the wider frames of a 1920-1930s Shanghai urban branding 'imaginary' and as a 'building of control and reform' - a category of buildings developed from the eighteenth-century European Enlightenment-thinking. In reflecting upon this negotiation in the heritage making process with potentially difficult past events, we propose the category of 'uncomfortable heritage', as part of a wider spectrum of 'dark heritage', and conclude with a final reflection upon 1933 Shanghai as a heterotopic space.

8.On the theoretical distribution of the wind farm power when there is a correlation between wind speed and wind turbine availability

Author:Kan, C;Devrim, Y;Eryilmaz, S


Abstract:It is important to elicit information about the potential power output of a wind turbine and a wind farm consisting of specified number of wind turbines before installation of the turbines. Such information can be used to estimate the potential power output of the wind farm which will be built in a specific region. The output power of a wind turbine is affected by two factors: wind speed and turbine availability. As shown in the literature, the correlation between wind speed and wind turbine availability has an impact on the output of a wind farm. Thus, the probability distribution of the power produced by the farm depending on the wind speed distribution and turbine availability can be effectively used for planning and risk management. In this paper, the theoretical distribution of the wind farm power is derived by considering the dependence between turbine availability and the wind speed. The theoretical results are illustrated for real wind turbine reliability and wind speed data.

9.The isolation of a DNA aptamer to develop a fluorescent aptasensor for the thiamethoxam pesticide

Author:Luo, Y;Jin, ZY;Wang, JN;Ding, P;Pei, RJ


Abstract:Aptamers, which are called chemical antibodies for their high affinity and specificity to targets, have great potential as analytical tools to detect pesticides. In this work, a DNA aptamer for thiamethoxam was isolated by an improved SELEX (systematic evolution of ligands by exponential enrichment) strategy, in which the ssDNA library was fixed on streptavidin-agarose beads through a short biotin labeled complementary strand. After 13 rounds of selection, the random ssDNA pool was successfully enriched. Three sequences were chosen as aptamer candidates through sequencing and analysis and were transformed into fluorescent probes to evaluate their interactions with thiamethoxam. A fluorescent turn-on aptasensor for thiamethoxam based on the best aptamer (FAM-Thi13) and a short quenching strand were further designed and showed a quantitative linear range from 10 to 1000 nM with a detection limit of 1.23 nM for thiamethoxam. Molecular docking and molecular dynamics were used to investigate the binding site of the main probe of the aptasensor (FAM-Thi13) and thiamethoxam. Satisfactory results were also obtained in quantifying thiamethoxam in environmental water samples by the developed fluorescent aptasensor.

10.Brain Storm Optimization Algorithm for Multi-objective Optimization Problems

Author:Xue, JQ;Wu, YL;Shi, YH;Cheng, S


Abstract:In this paper, a novel multi-objective optimization algorithm based on the brainstorming process is proposed(MOBSO). In addition to the operations used in the traditional multi-objective optimization algorithm, a clustering strategy is adopted in the objective space. Two typical mutation operators, Gaussian mutation and Cauchy mutation, are utilized in the generation process independently and their performances are compared. A group of multi-objective problems with different characteristics were tested to validate the effectiveness of the proposed algorithm. Experimental results show that MOBSO is a very promising algorithm for solving multi-objective optimization problems.

11.SLP-76 Sterile alpha Motif (SAM) and Individual H5 alpha Helix Mediate Oligomer Formation for Microclusters and T-cell Activation

Author:Liu, HB;Thaker, YR;Stagg, L;Schneider, H;Ladbury, JE;Rudd, CE


Abstract:Despite the importance of the immune adaptor SLP-76 in T-cell immunity, it has been unclear whether SLP-76 directly self-associates to form higher order oligomers for T-cell activation. In this study, we show that SLP-76 self-associates in response to T-cell receptor ligation as mediated by the N-terminal sterile alpha motif (SAM) domain. SLP-76 co-precipitated alternately tagged SLP-76 in response to anti-CD3 ligation. Dynamic light scattering and fluorescent microscale thermophoresis of the isolated SAM domain (residues 1-78) revealed evidence of dimers and tetramers. Consistently, deletion of the SAM region eliminated SLP-76 co-precipitation of itself, concurrent with a loss of microcluster formation, nuclear factor of activated T-cells (NFAT) transcription, and interleukin-2 production in Jurkat or primary T-cells. Furthermore, the H5 alpha helix within the SAM domain contributed to self-association. Retention of H5 in the absence of H1-4 sufficed to support SLP-76 self-association with smaller microclusters that nevertheless enhancedanti-CD3-drivenAP1/NFAT transcription and IL-2 production. By contrast, deletion of the H5 alpha helix impaired self-association and anti-CD3 induced AP1/NFAT transcription. Our data identified for the first time a role for the SAM domain in mediating SLP-76 self-association for T-cell function.

12.Infrared motion detection and electromyographic gesture recognition for navigating 3D environments

Author:Chen, KY;Liang, HN;Yue, Y;Craig, P


Abstract:This research explores the suitability and effectiveness of two relatively new types of input device for navigating 3D virtual environments. These are infrared motion detection, like the Leap Motion tracker, and electromyographic gesture recognition, like the Myo Armband. Despite the introduction of a variety of new input devices intended to provide a more natural interaction experience, navigation within 3D virtual environments is still normally done on more traditional control devices such as game controllers or the keyboard-mouse combination. This study investigates the potential of new devices to support navigation in 3D environments through an experiment conducted with 27 participants using three different types of input devices to play a ball-balancing maze-like game. The input devices tested are a standard game controller, a Leap Motion tracker for infrared motion detection, and the Myo Armband for electromyographic gesture recognition. Results demonstrated the real potential of both types of device to support navigation interaction within 3D environments.

13.Push or Pull? The impact of ordering policy choice on the dynamics of a hybrid closed-loop supply chain

Author:Lin,Junyi;Zhou,Li;Spiegler,Virginia L.M.;Naim,Mohamed M.;Syntetos,Aris

Source:European Journal of Operational Research,2022,Vol.300

Abstract:We study the dynamic behaviour of a hybrid system where manufacturing and remanufacturing operations occur simultaneously to produce the same serviceable inventory for order fulfilment. Such a hybrid system, commonly found in the photocopier and personal computer industries, has received considerable attention in the literature. However, its dynamic performance and resulting bullwhip effect, under push and pull remanufacturing policies, remain unexplored. Relevant analysis would allow considering the adoption of appropriate control strategies, as some of the governing rules in a push-based environment may break down in pull-driven systems, and vice versa. Using nonlinear control theory and discrete-time simulation, we develop and linearise a nonlinear stylised model, and analytically assess bullwhip performance of push- and pull-controlled hybrid systems. We find the product return rate to be the key influencing factor of the order variance performance of pull-controlled hybrid systems, and thus, to play an important role towards push or pull policy selection. Product demand frequency is another important factor, since order variance has a U-shaped relation to it. Moreover, the product return delay shows a supplementary impact on the system's dynamics. In particular, the traditional push-controlled hybrid system may be significantly influenced by this factor if the return rate is high. The results highlight the importance of jointly considering ordering structure and product demand characteristics for bullwhip avoidance.

14.Effects of China's urban basic health insurance on preventive care service utilization and health behaviors: Evidence from the China Health and Nutrition Survey

Author:Dong, WY;Gao, JM;Zhou, ZL;Bai, RH;Wu, Y;Su, M;Shen, C;Lan, X;Wang, X

Source:PLOS ONE,2018,Vol.13

Abstract:Background Lifestyle choices are important determinants of individual health. Few studies have investigated changes in health behaviors and preventive activities brought about by the 2007 implementation of Urban Resident Basic Health Insurance (URBMI) in China. This study, therefore, aimed to explore whether URBMI has reduced individuals' incentives to adopt healthy behaviors and utilize preventive care services. Methods Data were drawn from two waves of the China Health and Nutrition Survey. Respondents were categorized according to their insurance situation before and after the URBMI reform in 2006 and 2011. Propensity score matching and difference-in-differences methods were used to measure levels of preventive care and behavior changes over time. Estimations were also made based on gender, self-reported health, and income. Results We found that URBMI implementation did not change residents' utilization of preventive care services or their smoking habits, drinking habits, or other risky behaviors overall. However, the likelihood of sedentariness did increase by five percentage points. Females tended to be more sedentary while males were less likely to drink soft drinks. Residents with poor self-reported health exercised less while those who reported good health were more likely to be sedentary. Low-and middle-income residents were likely to be sedentary while middle-income people tended to smoke after becoming insured. Conclusion Since URBMI implementation, some unhealthy behaviors like sedentariness have increased among those who were newly insured, and different subgroups have reacted differently. This suggests that the insurance design needs to be optimized and effective measures need to be adopted to help improve people's lifestyle choices.

15.Forecasting Based Power Ramp-Rate Control For PV Systems Without Energy Storage

Author:Chen, XY;Du, Y;Wen, HQ


Abstract:The intermittency of solar photovoltaic (PV) power generation causes problems to the grid, especially for the islands or weak grids. The utilities have imposed ramp limitations in some countries or regions, such as Germany, Puerto Rico, Ireland, Hawaii, etc. There are three ways to achieve power ramp-rate control (PRRC), one is by using energy storage system (ESS), the second is active power curtailment, and the third is by using ESS-MPPT hybrid system. The use of ESS is still too expensive for utilities-level real power compensation. It requires maintenance and has limited lifetime. The conventional active power curtailment cannot deal with power drops. In this project, we proposed a PRRC method which does not require any ESS. The PV generation is curtailed before the actual shading occurs by using a forecasting system. The curtailed PV generation has been evaluated by using a case study. The proposed PRRC can limit the ramp-rate effectively. The curtailed generation can be very small in certain cases which could make it has the advantage over ESS.

16.Linear-scale models for discharge estimation: Asymmetric compound open channel flows

Author:Singh Prateek Kumar;Tang Xiaonan;Rahimi H.

Source:Proceedings of the Institution of Civil Engineers - Water Management,2021,Vol.

Abstract:This study evaluates recent three methods namely Interacting Divided Channel Method (IDCM), Modified Divided Channel Method (MDCM) and Momentum Transfer Divided Channel Method (MTDCM), which include momentum exchange on the interface for prediction of discharge. These methods are compared intensivel...



Source:PR Magazine,2021,Vol.




Source:scientific and technological innovationInformation,2021,Vol.




Source:Architectural Journal,2011,Vol.


20.Learning for Adaptation An edusemiotic perspective on intercultural communication competence

Author:Shen, JM;Sheng, Y;Zhou, Y


Abstract:The conceptualization of intercultural communication competence (ICC) has been updated tentatively since it was formulated in the 1970s. A common recognition is that development of ICC can only be realized through an individual's adaptation, which results from the integration of the multiple forces within the individuals themselves. However, most of the existing research on ICC has focused on the conscious aspects of competence like abilities or skills that are distinguishable, that is, what to adapt, rather than the less conscious aspect, or its correlation with the unconscious part, that is, the how to adapt, or what the process of adaptation is. The absence of investigation into the adaptation process may have been a consequence of the educational context of studies on ICC, which depends much on, or is heavily affected by, the Cartesian dualistic viewpoints that emphasize the dichotomy of mind-body while ignoring the "middle" in between. Based on our previous semiotic analysis that explained the process of intercultural communication as a form of semiosis, this paper adopts more perspectives from edusemiotics to conceptualize learning following a triadic framework with emphasis on the process as the "middle," which renders it possible to reflect on the process of individuals' adaptation in contexts of intercultural communication.
Total 5,474 results found
Copyright 2006-2020 © Xi'an Jiaotong-Liverpool University 苏ICP备07016150号-1 京公网安备 11010102002019号