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  • 1157951.
    Wu, W.
    et al.
    Katholieke Universiteit Leuven.
    Verpoest, I.
    Katholieke Universiteit Leuven.
    Varna, Janis
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    A novel axisymmetric variational analysis of stress transfer into fibreS through a partially debonded interface1998In: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 58, no 12, p. 1863-1877Article in journal (Refereed)
    Abstract [en]

    Most existing models for the problem of fibre/matrix stress-transfer through a partially debonded interface roughly solve the stress distribution in the debonded zone, neglecting the presence of the perfectly bonded zone. However the stress interactions between two zones is what makes the problem essentially different from the stress-transfer problem for a perfectly bonded interface. This paper suggests a variational approach based on the principle of minimum complementary energy not only in a perfectly bonded zone but also in a zone with a discontinuous interface. The debonded interface is treated as an external boundary on which a presumed interfacial shear stress is specified. A new analytical model, including stress non-uniformity in the radial direction and crack interaction, is derived to describe the stress state around fibre breaks and debonding tips in a single fibre embedded in an infinite matrix. For the presumed shear stress at the debonded interface the minimisation procedure renders the most accurate closed-form solution (under used assumptions) for both interactive zones. Finally, the ‘best' shear stress distribution at the debonded interface is found by using Coulomb's friction law and simple numerical iterations. The stress profiles along both axial and radial directions are presented and compared with results from a numerical model[1] available in the literature and also from finite-element analysis. Good agreements are achieved. Extensive applications of this approach and the derived model are also discussed

  • 1157952.
    Wu, W.
    et al.
    Katholieke Universiteit Leuven.
    Verpoest, I.
    Katholieke Universiteit Leuven.
    Varna, Janis
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    An improved analysis of the stresses in a single-fibre fragmentation test-II. 3-phase model1998In: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 58, no 1, p. 41-50Article in journal (Refereed)
    Abstract [en]

    A new model has been developed for the analyses of the stress state in a single-fibre specimen containing a coated fibre. This model is a generalization of the 2-phase model developed in Part I[1] for the case of 3 phases: fibre/coating/matrix. The stress distributions in radial and axial directions are obtained by using the principle of minimum complementary energy. Assumptions made to simplify the stress analysis are: (a) the axial stress distribution is uniform across the fibre cross-section; (b) the axial stress distribution is uniform across the coating thickness; (c) the non-uniform axial stress distribution in the matrix is given by a decreasing function which is obtained by a minimization procedure. The model developed has been used in a parametric analysis to determine the effect of the coating properties and geometry on the rate of stress transfer and shear stress concentration at the fibre end.

  • 1157953. Wu, W.
    et al.
    Verpoest, I.
    Varna, Janis
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Determination of interfacial fracture toughness from the fragmentation test data by variational models1999In: ICCM-12 Europe: 12th International Conference on Composite Materials ; Palais des Congrès, Paris / [ed] Thierry Massard; Alain Vautrin, Tours: ICCM , 1999Conference paper (Refereed)
  • 1157954.
    Wu, W.
    et al.
    Katholieke Universiteit Leuven.
    Verpoest, I.
    Katholieke Universiteit Leuven.
    Varna, Janis
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Prediction of energy release rate due to the growth of an interface crack by variational analysis2000In: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 60, no 3, p. 351-360Article in journal (Refereed)
    Abstract [en]

    In our previous studies (Wu W, Verpoest I, Varna J. A novel axisymmetric variational analysis of the stress transfer into fibre through a partially debonded interface. Composites Science and Technology 1998;58:1863-77 and Wu W, Jacobs E, Verpoest I, Varna J. Variational approach to the stress transfer problem through partially debonded interfaces in a three phase composite. Composites Science and Technology 1999;59:519-35) on the stress transfer problem for a single fragment of a fibre or a fibre with an additional interphase, embedded in an infinite matrix with a partially debonded interface, we presented two axisymmetric models, based on the principle of minimum complementary energy. In this paper, some parts of models, useful in the application of fracture mechanics, are first summarised. An expression is then given for the strain energy release rate due to a crack extension in an arbitrary composite system subjected to mixed traction-displacement boundary conditions and with thermal residual stresses included. This expression is suitable for a stress-based variational model. An important advantage is that it can include the friction work at the crack surfaces, in a rather simple but exact way, without using both the displacement and stress distributions at the crack surfaces as inputs. As an application of the expression, we illustrate how to calculate the energy release rate due to the growth of an interface crack in a single fibre fragment with a partially debonded interface under thermomechanical load, by using models in the above references. It is found that the energy release rate can be calculated by using only the rate of change of the strain energy related to the perturbation stress components. A second application is the energy change which is due to fibre breakage. The numerical results indicate that the energy release rate due to the growth of an interface debond or a similar problem can now be determined in a reliable way for both 2- and 3-phase composites.

  • 1157955. Wu, W.
    et al.
    Verpoest, I.
    Varna, Janis
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Stress analysis in a three phase material with fibre, coating and matrix1997In: Damage and failure of interfaces: proceedings of the First International Conference on Damage and Failure of Interfaces, Vienna, Austria, 22 - 24 September 1997 / [ed] Hans-Peter Rossmanith, Rotterdam: Balkema Publishers, A.A. / Taylor & Francis The Netherlands , 1997Conference paper (Refereed)
  • 1157956.
    Wu, Wei
    Umeå University, Faculty of Social Sciences, Umeå School of Business.
    Board composition and firm performance: a quantitative study on Chinese listed companies2009Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 1157957.
    Wu, Wei
    et al.
    So Med University, Guangdong , China .
    Huang, Qiaobing
    So Med University, Guangdong , China .
    He, Fei
    So Med University,Guangdong , China .
    Xiao, Mingjia
    So Med University,Guangdong , China .
    Pang, Shiyu
    So Med University,Guangdong , China .
    Guo, Xiaohua
    So Med University,Guangdong , China .
    Brunk, Ulf
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Zhao, Kesen
    So Med University,Guangdong , China .
    Zhao, Ming
    So Med University,Guangdong , China .
    Roles of Mitogen-Activated Protein Kinases in the Modulation of Endothelial Cell Function Following Thermal Injury2011In: Shock, ISSN 1073-2322, E-ISSN 1540-0514, Vol. 35, no 6, p. 618-625Article in journal (Refereed)
    Abstract [en]

    Several mitogen-activated protein kinases (MAPKs) are activated during thermal injury, and the p38 MAPK is specifically involved in endothelial cell (EC) actin and myosin rearrangement (stress-fiber formation) with ensuing cellular contraction and enhanced vessel permeability. Inhibition of p38 MAPK and extracellular signal-related kinase MAPK by their inhibitors SB203580 and PD98059, respectively, significantly reduces burn serum-induced EC stress-fiber formation, whereas SB203580 also inhibits burn serum-induced EC tight-junction damage and thereby general blood vessel hyperpermeability. The JNK MAPK inhibitor, SP600125, on the contrary, influences neither stress-fiber formation nor EC tight-junction damage. Extracellular signal-related kinase MAPK inhibition significantly decreases burn serum-induced Monocyte chemotactic protein-1 (MCP-1) release, whereas SB203580 and SP600125 have only limited such effects. Western blotting, real-time reverse transcriptase-polymerase chain reaction, and confocal laser scanning microscopy proved that SP600125 significantly inhibits burn serum-induced intercellular adhesion molecule 1 expression, whereas SB203580 depresses the expression of P selectin. In vivo studies, using the dominant negative adenoviral approach of MAPK kinase 3b and MAPK kinase 6b to block p38 MAPKs, and MKK4 and MKK7 to block JNK MAPKs, show that the latter MAPKs are involved in the regulation of P selectin and intercellular adhesion molecule 1 expression, respectively, following thermal injury. Taken together, the results suggest that several MAPKs play important, although different, roles in general EC alterations following burn injuries.

  • 1157958.
    Wu, Wei
    et al.
    Jinzhou Med Univ, Sch Humanities & Management, Jinzhou 121001, Liaoning, Peoples R China;Jinzhou Med Univ, Biol Anthropol Inst, 40,Sect 3,Songpo Rd, Jinzhou 121001, Liaoning, Peoples R China;LPKL CPCR, Jinzhou 121001, Liaoning, Peoples R China.
    Zhai, Guiying
    Jinzhou Med Univ, Biol Anthropol Inst, 40,Sect 3,Songpo Rd, Jinzhou 121001, Liaoning, Peoples R China;LPKL CPCR, Jinzhou 121001, Liaoning, Peoples R China.
    Xu, Zejun
    Jinzhou Med Univ, Biol Anthropol Inst, 40,Sect 3,Songpo Rd, Jinzhou 121001, Liaoning, Peoples R China;LPKL CPCR, Jinzhou 121001, Liaoning, Peoples R China.
    Hou, Bo
    Jinzhou Med Univ, Biol Anthropol Inst, 40,Sect 3,Songpo Rd, Jinzhou 121001, Liaoning, Peoples R China;LPKL CPCR, Jinzhou 121001, Liaoning, Peoples R China.
    Liu, Dahua
    Jinzhou Med Univ, Biol Anthropol Inst, 40,Sect 3,Songpo Rd, Jinzhou 121001, Liaoning, Peoples R China;LPKL CPCR, Jinzhou 121001, Liaoning, Peoples R China.
    Liu, Tianyi
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Plastic Surgery.
    Liu, Wei
    Jinzhou Med Univ, Biol Anthropol Inst, 40,Sect 3,Songpo Rd, Jinzhou 121001, Liaoning, Peoples R China;LPKL CPCR, Jinzhou 121001, Liaoning, Peoples R China.
    Ren, Fu
    Jinzhou Med Univ, Biol Anthropol Inst, 40,Sect 3,Songpo Rd, Jinzhou 121001, Liaoning, Peoples R China;LPKL CPCR, Jinzhou 121001, Liaoning, Peoples R China.
    Whole-exome sequencing identified four loci influencing craniofacial morphology in northern Han Chinese2019In: Human Genetics, ISSN 0340-6717, E-ISSN 1432-1203, Vol. 138, no 6, p. 601-611Article in journal (Refereed)
    Abstract [en]

    Facial shape differences are one of the most significant phenotypes in humans. It is affected largely by skull shape. However, research into the genetic basis of the craniofacial morphology has rarely been reported. The present study aimed to identify genetic variants influencing craniofacial morphology in northern Han Chinese through whole-exome sequencing (WES). Phenotypic data of the volunteers' faces and skulls were obtained through three-dimensional CT scan of the skull. A total of 48 phenotypes (35 facial and 13 cranial phenotypes) were used for the bioinformatics analysis. Four genetic loci were identified affecting the craniofacial shapes. The four candidate genes are RGPD3, IGSF3, SLC28A3, and USP40. Four single-nucleotide polymorphism (SNP) site mutations in RGPD3, IGSF3, and USP40 were significantly associated with the skull shape (p<1x10(-6)), and three SNP site mutations in RGPD3, IGSF3, and SLC28A3 were significantly associated with the facial shape (p<1x10(-6)). The rs62152530 site mutation in the RGPD3 gene may be closely associated with the nasal length, ear length, and alar width. The rs647711 site mutation in the IGSF3 gene may be closely associated with the nasal length, mandibular width, and width between the mental foramina. The rs10868138 site mutation in the SLC28A3 gene may be associated with the nasal length, alar width, width between tragus, and width between the mental foramina. The rs1048603 and rs838543 site mutations in the USP40 gene may be closely associated with the pyriform aperture width. Our findings provide useful genetic information for the determination of face morphology.

  • 1157959. Wu, Weihua
    et al.
    Tang, Shaobin
    Gu, Junjing
    Cao, Xinrui
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. Department of Physics, Institute of Theoretical Physics, Xiamen University, Xiamen, China.
    Realizing semiconductor to metal transition in graphitic ZnO and MoS2 nanocomposite with external electric field2015In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 5, no 120, p. 99153-99163Article in journal (Refereed)
    Abstract [en]

    First-principles calculations have been used to investigate the structural and electronic properties of graphitic ZnO and MoS2 (g-ZnO/MoS2) nanocomposites. It is found that the binding strength of g-ZnO/MoS2 exhibits strong dependence of atomic arrangement of g-ZnO relative to MoS2. The coupling interaction of g-ZnO/MoS2 obviously reduces the semiconducting band gaps, compared to both individual sheets, which are sensitive to its stacking orders. Interestingly, the vertical external electric field (E-field) can be applied to enhance the stability of g-ZnO/MoS2 and increase charge transfers between these two component. Furthermore, the E-field with the positive direction from MoS2 to g-ZnO can tune the band gap of g-ZnO/MoS2 nanocomposites, whereas this nanocomposites produce the semiconducting to metallic behavior transitions when the E-field changes from positive to negative direction, regardless of the stacking pattern. The tunable electronic properties of g-ZnO/MoS2 nanocomposites under the E-field are attributed to the changes in electrostatic potential difference between atom layer of MoS2 and interlayer region close to g-ZnO. Present results suggest that the g-ZnO/MoS2 heterojunction provides promising applications for MoS2-based optoelectronic and nanoelectronic devices, such as fabricating field effect transistor (FET).

  • 1157960.
    Wu, Weiling
    KTH, School of Technology and Health (STH).
    Carbon Footprint: A case study on the municipality of Haninge2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    AbstractCarbon Footprints, as an indicator of climate performance, help identify major GHG emission sources and potential areas of improvement. In the context of greatly expanding sub-national climate efforts, research on Carbon Footprint accounting at municipality level is timely and necessary to facilitate the establishment of local climate strategies. This study aims at exploring the methodologies for Carbon Footprint assessment at municipality level, based on the case study of Haninge municipality in Sweden. In the study, a Greenhouse Gas inventory of Haninge is developed and it is discussed how the municipality can reduce its Carbon Footprint. The Carbon Footprint of Haninge is estimated to be more than 338,225 tonnesCO2eq, and 4.5 tonnes CO2eq per capita. These numbers are twice as large as the production-based emissions, which are estimated to be 169,024 tonnes CO2eq in total, and approximately 2.3 tonnes CO2eq per capita. Among them the most important parts are emissions caused by energy use, and indirect emissions caused by local private consumption. It is worth noting that a large proportion of emissions occur outside Haninge as a result of local consumption. Intensive use of biomass for heat production and electricity from renewable sources and nuclear power have significantly reduced the climate impact of Haninge. The major barrier for Carbon Footprint accounting at municipality level is lack of local statistics. In the case of Sweden, several databases providing emission statistics are used in the research, including KRE, RUS, NIR and Environmental Account.

     

  • 1157961.
    Wu, Weiwei
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Law, Department of Law.
    The Application of National Treatment Clause in NAFTA: Focusing on the issue of "likeness"2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
  • 1157962.
    Wu, Weiwei
    et al.
    School of Computer Science, Southeast University, Nanjing, Jiangsu, China.
    Wang, Wanyuan
    School of Computer Science and Engeering, Southeast University, Nanjing, Jiangsu China.
    Fang, Xiaolin
    Computer Science and Engineering, Harbin Institute of Technology, Harbin, Heilongjiang China.
    Junzhou, Luo
    School of Computer Science and Engineering, Southeast University, Nanjing, Jiangsu China.
    Vasilakos, Athanasios
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Electricity Price-aware Consolidation Algorithms for Time-sensitive VM Services in Cloud Systems2019In: IEEE Transactions on Services Computing, ISSN 1939-1374, E-ISSN 1939-1374Article in journal (Refereed)
    Abstract [en]

    Despite the salient feature of cloud computing, the cloud provider still suffers from electricity bill, which mainly comes from 1) the power consumption of running physical machines and 2) the dynamically varying electricity price offered by smart grids. In the literature, there exist viable solutions adaptive to electricity price variation to reduce the electricity bill. However, they are not applicable to serving time-sensitive VM requests. In serving time-sensitive VM requests, it is potential for the cloud provider to apply proper consolidation strategies to further reduce the electricity bill. In this work, to address this challenge, we develop electricity-price-aware consolidation algorithms for both the offline and online scenarios. For the offline scenario, we first develop an consolidation algorithm with constant approximation, which always approaches the optimal solution within a constant factor of 5. For the online scenario, we propose an $O(\log(\frac{L_{max}}{L_{min}}))$ -competitive algorithm that is able to approach the optimal offline solution within a logarithmic factor, where $\frac{L_{max}}{L_{min}}$ is the ratio of the longest length of the processing time requirement of VMs to the shortest one. Our trace-driven simulation results further demonstrate that the average performance of the proposed algorithms produce near-optimal electricity bill.

  • 1157963.
    Wu, Weixian
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Social Sciences, Department of Informatics and Media, Media and Communication Studies.
    Popularity of Brand Posts on Sina Weibo: A Correlation Analysis of the Influential Factors on Tuborg’s Brand Community2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Social media continues to serve as vehicles for fostering relationships with customers. One specific way to implement this is to create and operate brand fan communities on social networking sites. Brands can place posts (including videos, messages, quizzes, information, and other material) in these brand communities. By customer’s reposting or commenting on the posts, it subsequently reflects the brand post popularity. In order to investigate the possible drivers for brand post popularity in the Chinese social media context, this thesis selects Tuborg’s Green Fest as the case, its official account on Weibo as the platform, and analyzes the correlation between six driven factors and brand post popularity pairwise. 

    Results show that interactivity is the most important factor for popularity; a higher level of interactivity would help boost popularity. Followed by entertaining content and vividness are also two factors that positively related to brand post popularity. Moreover, the post theme of Fans interaction is most popular with fans, while the theme of Green Fest information would have negative impact on post popularity. Nevertheless, informational content is not welcome by the fans either, which may have a negative influence on popularity. Managers of brands that operate brand fan communities can be guided by this research with regards to deciding which characteristics or content to place in their brand posts. 

  • 1157964.
    Wu, Wenbiao
    et al.
    KTH, Superseded Departments, Electronic Systems Design.
    Sander, Ingo
    KTH, Superseded Departments, Electronic Systems Design.
    Jantsch, Axel
    KTH, Superseded Departments, Electronic Systems Design.
    Transformational System Design based on a Formal Computational Model and Skeletons2000In: Proceedings of the Forum on Design Languages, 2000Conference paper (Refereed)
  • 1157965.
    Wu, Wenbiao
    et al.
    KTH, Superseded Departments, Electronic Systems Design.
    Sander, Ingo
    KTH, Superseded Departments, Electronic Systems Design.
    Jantsch, Axel
    KTH, Superseded Departments, Electronic Systems Design.
    Transformational System Design based on a Formal Computational Model and Skeletons2000In: Proceedings of the Forum on Design Languages, 2000Conference paper (Refereed)
  • 1157966.
    Wu, Wenbin
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology.
    Delay-tolerant data delivery in a distributed sensor network testbed2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Sensei-UU testbed is an inexpensive, expandable, relocatable testbed, which is designed by CoRe group in Uppsala University. It provides wireless sensor network (WSN) experiments with repeatable mobility. However, end nodes are always deployed in extreme environments where connectivity is not able to be guaranteed and Sensei-UU testbed lacks the ability to deal with this case. Reliable data delivery, therefore, is an important feature of delay tolerant network and it will extend the usage of Sensei-UU testbed. This thesis work investigates Sensei-UU testbed and improves it to support delay-tolerant data delivery.

    The thesis report  starts with an introduction of related background concepts regarding wireless sensor network, Sensei-UU testbed and delay tolerant network. Then a detailed technical solution of delivering delay-tolerant data in Sensei-UU testbed is presented in terms of system analysis, design and implementation.

  • 1157967.
    Wu, Wenda
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Machine Learning Based Fault Prediction for Real-time Scheduling on Shop Floor2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Nowadays, scheduling on a shop floor is only focused on the availabil-ity of resources, where the potential faults are not able to be predicted.

    A big data analytics based fault prediction was proposed to be ap-plied in scheduling, which require a real-time decision making. To select a proper machine learning algorithm for real-time scheduling, this paper first proposes a data generation method in terms of pattern complexity and scale. Three levels of depth, an index of data complex-ity, and three levels of data attributes, an index of data scale, are used to obtain the data sets. Based on those data sets, ten commonly used machine learning algorithms are trained, in which the parameters are adjusted to achieve a high accuracy. The testing results including three indexes including training time, testing time and prediction accuracy, are used to evaluate the algorithms.

    The results of the tests shows that when working with data of sim-ple structure and small scale, typical machine learning methods like Naive Bayes classifier and SVM is good enough with fast training an high accuracy. When dealing with complex data on large scale, deep learning methods like CNN and DBN outperform all other methods.

  • 1157968.
    Wu, Wendy Yi-Ying
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Tabar, Laszlo
    Tot, Tibor
    Fann, Ching-Yuan
    Yen, Amy Ming-Fang
    Chen, Sam Li-Sheng
    Chiu, Sherry Yueh-Hsia
    Ku, May Mei-Sheng
    Hsu, Chen-Yang
    Beckmann, Kerri R.
    Smith, Robert A.
    Duffy, Stephen W.
    Chen, Hsiu-Hsi
    Imaging Biomarkers as Predictors for Breast Cancer Death2019In: Journal of Oncology, ISSN 1687-8450, E-ISSN 1687-8469, article id 2087983Article in journal (Refereed)
    Abstract [en]

    Background. To differentiate the risk of breast cancer death in a longitudinal cohort using imaging biomarkers of tumor extent and biology, specifically, the mammographic appearance, basal phenotype, histologic tumor distribution, and conventional tumor attributes. Methods. Using a prospective cohort study design, 498 invasive breast cancer patients diagnosed between 1996 and 1998 were used as the test cohort to assess the independent effects of the imaging biomarkers and other predictors on the risk of breast cancer death. External validation was performed with a cohort of 848 patients diagnosed between 2006 and 2010. Results. Mammographic tumor appearance was an independent predictor of risk of breast cancer death (P=0.0003) when conventional tumor attributes and treatment modalities were controlled. The casting type calcifications and architectural distortion were associated with 3.13-fold and 3.19-fold risks of breast cancer death, respectively. The basal phenotype independently conferred a 2.68-fold risk compared with nonbasal phenotype. The observed deaths did not differ significantly from expected deaths in the validation cohort. The application of imaging biomarkers together with other predictors classified twelve categories of risk for breast cancer death. Conclusion. Combining imaging biomarkers such as the mammographic appearance of the tumor with the histopathologic distribution and basal phenotype, accurately predicted long-term risk of breast cancer death. The information may be relevant for determining the need for molecular testing, planning treatment, and determining the most appropriate clinical surveillance schedule for breast cancer patients.

  • 1157969.
    Wu, Wendy Yi-Ying
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Törnberg, Sven
    Elfström, Klara Miriam
    Liu, Xijia
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Nyström, Lennarth
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Jonsson, Håkan
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Overdiagnosis in the population-based organized breast cancer screening program estimated by a non-homogeneous multi-state model: a cohort study using individual data with long-term follow-up2018In: Breast Cancer Research, ISSN 1465-5411, E-ISSN 1465-542X, Vol. 20, article id 153Article in journal (Refereed)
    Abstract [en]

    Background: Overdiagnosis, defined as the detection of a cancer that would not become clinically apparent in a woman’s lifetime without screening, has become a growing concern. Similar underlying risk of breast cancer in the screened and control groups is a prerequisite for unbiased estimates of overdiagnosis, but a contemporary control group is usually not available in organized screening programs.

    Methods: We estimated the frequency of overdiagnosis of breast cancer due to screening in women 50–69 years old by using individual screening data from the population-based organized screening program in Stockholm County 1989–2014. A hidden Markov model with four latent states and three observed states was constructed to estimate the natural progression of breast cancer and the test sensitivity. Piecewise transition rates were used to consider the time-varying transition rates. The expected number of detected non-progressive breast cancer cases was calculated.

    Results: During the study period, 2,333,153 invitations were sent out; on average, the participation rate in the screening program was 72.7% and the average recall rate was 2.48%. In total, 14,648 invasive breast cancer cases were diagnosed; among the 8305 screen-detected cases, the expected number of non-progressive breast cancer cases was 35.9, which is equivalent to 0.43% (95% confidence interval (CI) 0.10%–2.2%) overdiagnosis. The corresponding estimates for the prevalent and subsequent rounds were 15.6 (0.87%, 95% CI 0.20%–4.3%) and 20.3 (0.31%, 95% CI 0.07%–1.6%), respectively. The likelihood ratio test showed that the non-homogeneous model fitted the data better than an age-homogeneous model (P<0.001).

    Conclusions: Our findings suggest that overdiagnosis in the organized biennial mammographic screening for women 50–69 in Stockholm County is a minor phenomenon. The frequency of overdiagnosis in the prevalent screening round was higher than that in subsequent rounds. The non-homogeneous model performed better than the simpler, traditional homogeneous model.

  • 1157970.
    Wu, Wendy Y-Y
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Nyström, Lennarth
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Jonsson, Håkan
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Estimation of overdiagnosis in breast cancer screening using a non-homogeneous multi-state model: a simulation study2018In: Journal of Medical Screening, ISSN 0969-1413, E-ISSN 1475-5793, Vol. 25, no 4, p. 183-190Article in journal (Refereed)
    Abstract [en]

    Objectives: Overdiagnosis is regarded as a harm of screening. We aimed to develop a non-homogeneous multi-state model to consider the age-specific transition rates for estimation of overdiagnosis, to validate the model by a simulation study where the true frequency of overdiagnosis can be calculated, and to compare our estimate with the cumulative incidence method. Methods: We constructed a four-state model to describe the natural history of breast cancer. The latent disease progression and the observed states for each individual were simulated in a trial with biennial screening of women aged 51-69 and a control group of the same size without screening. We performed 100 repetitions of the simulation with one million women to evaluate the performance of estimates. A sensitivity analysis with reduced number of controls was performed to imitate the data from the service screening programme. Results Based on the 100 repetitions, the mean value of the true frequency of overdiagnosis was 12.5% and the average estimates by the cumulative incidence method and the multi-state model were 12.9% (interquartile range: 2.46%) and 13.4% (interquartile range: 2.16%), respectively. The multi-state model had a greater bias of overdiagnosis than the cumulative incidence method, but the variation in the estimates was smaller. When the number of unscreened group was reduced, the variation of multi-state model estimates increased. Conclusions: The multi-state model produces a proper estimate of overdiagnosis and the results are comparable with the cumulative incidence method. The multi-state model can be used in the estimation of overdiagnosis, and might be useful for the ongoing service screening programmes.

  • 1157971.
    Wu, Wenhao
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences.
    MODEL-BASED EVALUATION OF DOSE REGIMENS IN PRETERM AND TERM NEONATES FOR DEXMEDETOMIDINE AND VANCOMYCIN2017Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Background: Dexmedetomidine (Dexdor) is a sedative and an analgesic compound approved for intravenous use in adults, but it is also used off-label in neonates. There are no pharmacokinetic (PK) data to support buccal administration of Dexdor in neonates. Vancomycin is an antibiotic commonly used to treat methicillin-resistant Staphylococcus aureus (MRSA), and the best predictor of successful outcome is the 24-h area under the concentration-time curve (AUC24) to MIC ratio of > 400. Specific dosing guidelines to ensure efficacy and safety in preterm neonates are currently lacking. Objective: To find an appropriate dose range for Dexdor for single buccal administration to neonates with a postmenstrual age (PMA) of 32 – 44 weeks. To find a vancomycin dose regimen predicting the best efficacy/toxicity ratio for newborns at 32 – 40 gestation weeks. Methods: Published PK-models where used to simulate expected PK profiles for different dosing regimens of Dexdor and vancomycin in preterm and term neonates using Berkeley Madonna, Insight-Rx and Excel. Results: The most appropriate dose of Dexdor for buccal administration is 1 ± 0.25 μg/kg, given 0.5 - 1 hour before a minor procedure. Currently used vancomycin regimen for neonates (15 mg/kg twice daily) is most likely insufficient in treating MRSA. PMA is a significant covariate, and it is suggested that dosing in preterm neonates should be adjusted according to PMA. Conclusions: Dosing 1 ± 0.25 μg/kg of Dexdor should be a safe and adequate starting dose for buccal administration to neonates, but clinical studies are required to confirm this. For vancomycin, a revised dose regimen is suggested for preterm neonates that take into account both weight and PMA.

  • 1157972.
    Wu, Wenlin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Physiology and Developmental Biology, Comparative Physiology.
    Lind, Maria I
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Physiology and Developmental Biology, Comparative Physiology.
    SERCA pump expression and iron uptake in a Drosophila cell line.2009Conference paper (Refereed)
  • 1157973.
    Wu, Wenqi
    KTH, School of Industrial Engineering and Management (ITM).
    Energy analysis of a hybrid forwarder2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 1157974. Wu, Wen-Ya
    et al.
    Tjiu, Weng Weei
    Wan, Wei
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Tan, Hui Ru
    Teo, Siew Lang
    Guo, Shifeng
    Ter Lim, Sze
    Lin, Ming
    Endotaxial growth of FexGe single-crystals on Ge(001) substrates2018In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 20, no 21, p. 2916-2922Article in journal (Refereed)
    Abstract [en]

    Revealing the structure-property relationship is nontrivial for the application of materials. The magnetic configurations of FeGe are strongly dependent on the internal structures and positions of Fe and Ge atoms, e.g., B20-type cubic phase configuring into magnetic skyrmions. Although endotaxial FexGe islands on (001) Ge substrate can be obtained with a dynamically controlled growth process, it is not possible to obtain the crystal structural information from conventional approaches, such as X-ray diffraction or 2D electron diffractions due to the embedded growth structures at the nanometer scale, which are too small to be probed. Through a 3D rotational electron diffraction method combined with high resolution transmission electron microscopy, we have successfully determined the specific phase of each FexGe island on the Ge substrate. Three major phases (two hexagonal and one monoclinic) were found existing in the FexGe islands with nearly equal probability and independent of the deposition temperatures and time. All the islands with different phases were inclined to {111} Ge planes, which was due to a comparatively higher energy barrier for Fe atom diffusion through {111} Ge than other Ge planes. The epitaxial growth relationship at the interface was as follows: FeGemono.4-2-1)//Ge.111), FeGemono.15-6]//Ge.1-10], Fe3Ge2.201)//Ge.111) and Fe3Ge2.-112]//Ge.1-10], Fe13Ge8.40-1)//Ge.111) and Fe13Ge8.124]//Ge.1-10]. Ferromagnetism for the as-deposited samples was observed via SQUID, which most probably is attributed to the hexagonal FeGe phases.

  • 1157975.
    WU, WENYAN
    Blekinge Institute of Technology, School of Engineering.
    Themal Mass Flowmeter---Realzie in two- wire installtaion2012Independent thesis Basic level (degree of Bachelor)Student thesis
    Abstract [en]

    For more than 20 years, the thermal mass flow meters have been widely used in several industries such as the petroleum refining industry, waste water processing and steeling making industry. I will call it “TMF” in the rest of the article. The TMF’ low-flow sensitivity and fast response have made them the first choice for many critical gas flow application. However, there are still some inadequacies in the TMF. Such as interruption among the wires, high cost of the installation and influenced by temperature. Some of the problem comes from its way of the connection--- four-wire connection. Two-wire connection can resolve some of these problems. In this thesis, the author presents a new type of two-wire installation and use of TMF which can be realized low production cost. The author found a new measurement method, which is detecting the functional relationship between working current of a traditional TMF and the flow. The author also designs a measurement converter needed for adequate signal processing so that flow value measurement values can be shown in computers.

  • 1157976.
    Wu, Wenzhuo
    KTH, School of Electrical Engineering (EES).
    Charging time estimation and study of charging behavior for automotive Li-ion battery cells using a Matlab/Simulink model2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    An accurate estimation of the charging time of an automotive traction battery is possible only with the knowledge of different parameters of the battery and the vehicle. If this information is not available to the driver, the full time needed for charging of the battery may have to be assessed only from experience. A long route planning and estimation of required service life of the vehicle are therefore only roughly possible. Furthermore, with a better knowledge of estimated charging time, better management of public charging stations and better utilization of charging equipment can be achieved. An algorithm based on Matlab/Simulink model is made in the present thesis to estimate the charging time of a Li-ion battery pack which consists of 32 cells with 40 Ah each, as well as to investigate the impact of different cell balancing methods and different charging strategies on charging process. The theoretical background of the battery and charging modelling is investigated and different battery models are compared to get the best trade-off between the model accuracy and computation complexity. In the end, an electrical equivalent circuit model from reference [1], consists of a series resistor and two ZARC elements, is chosen to represent the battery cell. The parameters of the equivalent circuit are updated according to the SOC, current and temperature changes during the charging process. The whole simulation model of the algorithm consists of a charging controller (implementing the charging strategy), cell balancing logic controller, and cell balancing hardware simulation circuit and battery cell models. Different balancing criteria: based on SOC (with PWM drive) and based on terminal voltage (with/without advance) are implemented in the cell balancing logic controller, as well as different balancing windows, to investigate their impact on charging time. As for charging strategy, traditional CCCV is investigated, further investigation is conducted into improved CCCV method. The impact of initial SOC, charging rate and aging factor on charging behavior are investigated as well. Experiment results are validated by the comparison of the results with the ones got from a Hardware-in-the-loop simulation system.

  • 1157977.
    Wu, Winnie
    Stockholm University, Faculty of Social Sciences, School of Business.
    Svensk import från Kina: En studie om importprocessen av konsumentprodukter ur ett kommunikations- och kulturskillnadsperspektiv2006Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Att importera från Kina har blivit populärt med den ökade konkurrensen från globaliseringen som driver små och medelstora företag att aktivt arbeta med sitt inköp. Detta kan ske genom att söka efter de rätta kinesiska leverantörer som kan producera till lägsta pris och har bra kvalité. Kina är känd för att kunna leverera till lägsta pris och en kvalité som kan variera. Det gäller att kunna kommunicera med kineserna för att göra bra inköp. Tillvägagångssättet att kommunicera på har förändrats med IT-tekniken och det har underlättat mycket av kommunikationen. Att göra affärer med kineserna kan vara annorlunda eftersom kulturskillnaderna är rätt stora, men hur mycket har denna globalisering ändrat på importprocessen är intressant att undersöka. Undersökningsfrågan för denna studie är; ”Hur kan importprocessen av konsumentprodukter till Sverige från Kina förbättras och förenklas för importörer?” Huvudsyftet med uppsatsen är att skapa en ökad förståelse för importprocess från Kina till Sverige i sin tur för att skapa gynnsammare förutsättningar för importen till Sverige. Delsyftena för uppsatsen är att: kartlägga de olika stegen i importprocessen från Kina, identifiera hur skillnader i affärskultur och kommunikationsproblem påverkar importprocessen, slutligen ge förslag till utveckling och förenkling av svensk import från Kina. Teoretiska referensramen baseras på en egen KiK-modell för att analysera de tre nyckel- faktorerna: importprocessen, kulturskillnader och kommunikation. Undersökningen baserades på teorier kring de tre områden och intervjuer med inköpare i svenska företag. Uppsatsens slutsatser var bland annat; *Företag väljer att använda agenter för att spara tid och energi för att komma in den kinesiska marknaden. *En del företag har valt att efter skapat ett nätverk på egen hand ta hand om importprocessen och lämnar agenterna. *För att få bra pris är det bra med att skapa goda relationer med kinesiska leverantören. Guanxi gäller även importaffärer och man får bättre service när man tillhör den inre gruppen. *Ibland undviker kineserna att svara när de gjort fel för att behålla sin heder, vilket förknippas med mianzi. *Direkt kommunikation dvs. ansikte mot ansikte kommunikation, i inköpsarbetet är inte alltid nödvändigt. Dessutom sker relativt lite interaktion mellan parterna under inköpsprocessen med hjälp av telefonkontakt. Mycket sker med hjälp av e-post och fax. Företag behöver sända och ta emot information till sina leverantörer i Kina och de befinner i olika tidszoner. *Affärsvärldens kommunikation sker på engelska och kineserna har blivit bättre på att kommunicera på engelska. Dock finns det svaga kunskaper i engelska hos vissa kinesiska leverantörer och det utgör ett hinder i interaktionen. *Förbättring från kinesernas sida i engelska kunskaper och marknadsföring skulle förenkla importen från Kina för västerlänningar.

  • 1157978. Wu, Woffles
    et al.
    Carlisle, Ian
    Huang, Peter
    Ribe, Natalia
    Russo, Rosalba
    Schaar, Claudia
    Verpaele, Alexis
    Strand, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Dermatology and Venereology.
    Novel Administration Technique for Large-Particle Stabilized Hyaluronic Acid-Based Gel of Nonanimal Origin in Facial Tissue Augmentation2010In: Aesthetic Plastic Surgery, ISSN 0364-216X, E-ISSN 1432-5241, Vol. 34, no 1, p. 88-95Article in journal (Refereed)
    Abstract [en]

    The use of large-particle stabilized hyaluronic acid-based gel of nonanimal origin (NASHA(TM)) for facial aesthetic procedures is widespread and increasing. A panel of experts with extensive clinical experience with NASHA-based gel recently attended an advisory board meeting to develop guidelines for its use in volumetric tissue augmentation. Discussions included details of the blunt-cannula injection technique currently recommended for administration of large-particle NASHA-based gel. With the aim of optimizing patient comfort and control over administration of NASHA-based gel, the panel members explored an alternative, sharp-needle technique. In this article we describe the new technique in detail, together with practical recommendations and precautions. The technique has several advantages over blunt-cannula injection: improved patient comfort, lack of need for a skin incision, increased precision regarding the implant position, and improved control of injection volume. However, the sharp-needle technique requires a high level of skill and a good knowledge of facial anatomy.

  • 1157979.
    Wu, Wu
    KTH, School of Information and Communication Technology (ICT).
    Adapting Information-Centric Networking to Small Sensor Nodes for Heterogeneous IoT Networks2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The Internet of Things (IoT) industry has experienced rapid development nowadays and connecting billions of things into the Internet is already possible. However, there are still some scalability bottlenecks such as costs and power consumption. Moreover, compared with traditional network, the novel IoT network is more information-centric than host-centric. Therefore, we decide to explore feasibility of applying Content Centric Network (CCN) which is an architecture of information-centric networking (ICN) to address these problems.

    During recent years, information-centric networking (ICN) is growing popular because it is an effort of network infrastructure evolution from host-centric to information-centric. It has some intrinsic nice features for Internet of Things (IoT). This report will demonstrate them and also present how to implement CCN for wireless sensor network (WSN). The challenges will be presented and the solutions to them will also be demonstrated. After the implementation, there will be some experiments on it and application evaluation of information-centric networking (ICN) to wireless sensor network (WSN) based on a thorough comparison with MQ Telemetry Transport Sensor Network (MQTT-SN).

    The result shows that Content Centric Network (CCN) has some advantages over MQ Telemetry Transport (MQTT) in the wireless sensor network (WSN) domain. However, compared with that industry mature solution: MQ Telemetry Transport Sensor Network (MQTT-SN), the Content Centric Network (CCN) is not a perfect alternative for now. More research and implementation work are needed to make it more competitively.

  • 1157980.
    Wu, X
    et al.
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Women's and Children's Health.
    Blanck, A
    Olovsson, M
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Women's and Children's Health.
    Moller, B
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Women's and Children's Health.
    Lindblom, B
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Women's and Children's Health.
    Expression of basic fibroblast growth factor (bFGF), FGF receptor 1 andFGF receptor 2 in uterine leiomyomas and myometrium during the menstrualcycle, after menopause and GnRHa treatment.2001In: Acta Obstet. Gynecol. Scand., Vol. 80, p. 497-504Article in journal (Refereed)
  • 1157981. Wu, X.
    et al.
    Bruschi, M.
    Waag, T.
    Schweeberg, T.
    Tian, Y.
    Meinhardt, T.
    Stigler, R.
    Larsson, K.
    Funk, M.
    Steinmueller-Nethl, D.
    Rasse, M.
    Krueger, A.
    Functionaliation of Bone Implants with Nanodiamd Particles and Angiopoitein-1 to Improve Vascularization and Bone Regeneration2017In: Journal of Materials Chemistry B, Vol. 5, no 32, p. 6629-Article in journal (Refereed)
  • 1157982. Wu, X.
    et al.
    Cai, K.
    Meng, Ziyang
    KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Scheduled anticipatory anti-windup design2015In: Proceedings of the World Congress on Intelligent Control and Automation (WCICA), IEEE conference proceedings, 2015, no March, p. 319-326Conference paper (Refereed)
    Abstract [en]

    This paper considers scheduled anti-windup design of linear systems in the presence of input saturation. We introduce the scheduled controller design method into the anticipatory anti-windup scheme. The proposed controllers are triggered depending on the response of the system, rather than only considering the worst noise case off-line, and then activating the anti-windup scheme before the physical actuator arrives saturation. The system stability and certain levels of performance are guaranteed under the proposed anti-windup scheme. The control feedback law is analyzed under the scheme of static feedback compensator, while the results are presented using the linear matrix inequality technique. The advantage of the proposed scheduled anticipatory scheme over immediate activation is illustrated through a numerical example.

  • 1157983.
    Wu, X
    et al.
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Pharmacy, Department of Medicinal Chemistry. ORGFARM.
    Ekegren, J K
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Pharmacy, Department of Medicinal Chemistry. ORGFARM.
    Larhed, Mats
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Pharmacy, Department of Medicinal Chemistry. ORGFARM.
    Microwave-promoted aminocarbonylation of aryl iodides, aryl bromides and aryl chlorides in water.2006In: Organometallics, no 25, p. 1434-1832Article in journal (Refereed)
  • 1157984. Wu, X.
    et al.
    Jörnvall, H.
    Berndt, Kurt D.
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institutet.
    Oppermann, U.
    Codon optimization reveals critical factors for high level expression of two rare codon genes in Escherichia coli: RNA stability and secondary structure but not tRNA abundance2004In: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, E-ISSN 1090-2104, Vol. 313, no 1, p. 89-96Article in journal (Refereed)
    Abstract [en]

    Expression patterns in Escherichia coli of two small archaeal proteins with a natural content of about 30% rare codons were analyzed. The proteins, a histone-like protein from Sulfolobus shibatae (Ssh10), and a glutaredoxin-like protein from Methanobacterium thermoautotrophicum (mtGrx), were produced with expression plasmids encoding wild-type genes, codon-optimized synthetic, and GST-fusion genes. These constructs were expressed in BL21 (DE3), its LysS derivative, and modified strains carrying copies for rare codon tRNAs or deletions in the RNAseE gene. Both Ssh10 and mtGrx expression levels were constitutively high in BL21(DE3) and its derivatives, with the exception of the LysS phenotype, which prevented high level expression of the Ssh10 wild-type gene. Surprisingly, a codon-optimized mtGrx gene construct displayed undetectable levels of protein production. The translational block observed with the synthetic mtGrx gene could be circumvented by using a synthetic mtGrx-glutathione S-transferase (GST) fusion construct or by in vitro translation. Taken together, the results underscore the importance of mRNA levels and RNA stability, but not necessarily tRNA abundance for efficient heterologous protein production in E. coli.

  • 1157985. Wu, X.
    et al.
    Li, F.
    Zhang, B.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. Dalian University of Technology (DUT), China.
    Molecular complexes in water oxidation: Pre-catalysts or real catalysts2015In: Journal of Photochemistry and Photobiology C: Photochemistry Reviews, ISSN 1389-5567, E-ISSN 1873-2739, Vol. 25, p. 71-89Article in journal (Refereed)
    Abstract [en]

    Artificial photosynthesis is considered a promising method to produce clean and renewable energy by sunlight. To accomplish this aim, development of efficient and robust catalysts for water oxidation and hydrogen production is extremely important. Owing to the advantages of easily modified structures and traceable catalytic processes, molecular water oxidation catalysts (WOCs) attract much attention during the past decade. However, the transformation of molecular WOCs to metal oxides/hydroxides or metal ions may occur under the harsh catalytic conditions, making the identification of true active species difficult. In this article, recent progress on molecular complexes acting as real catalysts or precursors toward water oxidation was briefly reviewed. We summarized the commonly used physical techniques and chemical methods that enable to distinguish homogeneous catalysts from heterogeneous catalysts. The factors that affect the nature of WOCs, such as reaction conditions, transition metal centers, and supporting ligands were discussed as well.

  • 1157986. Wu, X.
    et al.
    Meng, Ziyang
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Multiple anti-windup loops under multiple activations: Dynamic case to enlarge domain of attraction2013In: Chinese Control Conf., CCC, 2013, p. 943-949Conference paper (Refereed)
    Abstract [en]

    A multiple anti-windup loops under multiple dynamic activations strategy is proposed to enlarge the domain of attraction. This work is parallel to the multiple activation case with static compensators. The traditional anti-windup compensator is activated immediately as the saturation occurs. It was shown recently that, by delaying the activation of the anti-windup mechanism to a certain level, the performance can be improved for the closed-loop system. It was further shown that better performance can be obtained by activating an anti-windup mechanism in anticipation of actuator saturation, in comparison with the delayed activation design. This paper considers the anti-windup design problem of enlarging domain of attraction under a dynamic multiple activation scheme. In this multiple activation scheme, the anticipatory, delayed and immediate activation mechanism is incorporated in the same framework simultaneously. A furthermore significant performance improvements over both the immediate and delayed activation schemes can be observed. The proposed dynamic multiple activation scheme established a unified anti-windup framework and can be readily extended to the traditional immediate, delayed and anticipatory activation anti-windup mechanisms.

  • 1157987. Wu, X.
    et al.
    Meng, Ziyang
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Multiple anti-windup loops under multiple static activations: Enlargement of the domain of attraction2013In: Chinese Control Conf., CCC, 2013, p. 909-914Conference paper (Refereed)
    Abstract [en]

    Anti-windup design is an intuitive and efficient way to deal with input saturation nonlinearities. In the classic anti-windup design, the compensator is set to be activated immediately as the control signal saturates the actuator. An important innovation in the anti-windup activation mechanism is to delay the activation of the anti-windup mechanism until the saturation reaches to a certain severity which led to a performance improvement of the resulting closed-loop system. More recently, it was shown that by activating a static anti-windup mechanism in anticipation of actuator saturation, significant further performance improvements can be achieved in comparison with the delayed activation design. In addition, we have combined both the delayed and anticipatory activation mechanisms, to develop the multiple activation strategy, in terms of L2 gain performance. This paper furthermore considers the problem of enlarging domain of attraction and demonstrates that the multiple activation of a static multiple feedback anti-windup mechanism would also lead to significant performance improvements over both the immediate and delayed activation schemes.

  • 1157988. Wu, X
    et al.
    Oppermann, M
    Berndt, Kurt D
    Karolinska Institutet.
    Bergman, T
    Jörnvall, H
    Knapp, S
    Oppermann, U
    Thermal unfolding of the archaeal DNA and RNA binding protein Ssh102008In: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, E-ISSN 1090-2104, Vol. 373, no 4, p. 482-487Article in journal (Refereed)
    Abstract [en]

    The reversible thermal unfolding of the archaeal histone-like protein Ssh10b from the extremophile Sulfolobus shibatae was studied using differential scanning calorimetry and circular dichroism spectroscopy. Analytical ultracentrifugation and gel filtration showed that Ssh10b is a stable dimer in the pH range 2.5-7.0. Thermal denaturation data fit into a two-state unfolding model, suggesting that the Ssh10 dimer unfolds as a single cooperative unit with a maximal melting temperature of 99.9 degrees C and an enthalpy change of 134 kcal/mol at pH 7.0. The heat capacity change upon unfolding determined from linear fits of the temperature dependence of DeltaH(cal) is 2.55 kcal/(mol K). The low specific heat capacity change of 13 cal/(mol K residue) leads to a considerable flattening of the protein stability curve (DeltaG (T)) and results in a maximal DeltaG of only 9.5 kcal/mol at 320 K and a DeltaG of only 6.0 kcal/mol at the optimal growth temperature of Sulfolobus.

  • 1157989. Wu, X.
    et al.
    Pang, J.
    Yang, Tao
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Anti-windup design for Active Disturbance Rejection Control2014In: Proceedings of the 33rd Chinese Control Conference: July 28-30, 2014, Nanjing, China, IEEE Computer Society, 2014, p. 2389-2395Conference paper (Refereed)
    Abstract [en]

    An anti-windup compensate algorithm for active disturbance rejection mechanism is proposed in this paper. This paradigm extends the traditional anti-windup scheme to the Active Disturbance Rejection Control (ADRC) mechanism, to deal with the input saturation nonlinearity and meanwhile reject the disturbance automatically by using Extended State Observer (ESO). The output of anti-windup compensator is treated as a part of unknown disturbances and is introduced into the ESO, which can online observe both internal and external disturbances (parameter uncertainties and model mismatches). The controller input is yielded by using a nonlinear feedback combination, and it is used to compensate the integrator windup caused by the saturation nonlinearity element. On the other hand, in order to determine the parameters of the ESO and the anti-windup compensator feedback gain, the L2 gain is adopted. The effectiveness and the robustness against model and parameter uncertainties of the proposed method is verified by an example of the seeker platform.

  • 1157990.
    Wu, X. -S
    et al.
    Chinese Acad Sci, CAS Key Lab Lunar & Deep Space Explorat, Beijing, Peoples R China; Chinese Acad Sci, CAS Ctr Excellence Comparat Planetol, Hefei, Anhui, Peoples R China.
    Cui, J.
    Chinese Acad Sci, CAS Key Lab Lunar & Deep Space Explorat, Beijing, Peoples R China; Chinese Acad Sci, CAS Ctr Excellence Comparat Planetol, Hefei, Anhui, Peoples R China; Sun Yat Sen Univ, Sch Atmospher Sci, Zhuhai, Peoples R China.
    Xu, S. S.
    Univ Calif Berkeley, Space Sci Lab, Berkeley, CA, USA.
    Lillis, R. J.
    Univ Calif Berkeley, Space Sci Lab, Berkeley, CA, USA.
    Yelle, R. V.
    Univ Arizona, Lunar & Planetary Lab, Tucson, AZ, USA.
    Edberg, Niklas J. T.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Vigren, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Rong, Z. -J
    Chinese Acad Sci, Inst Geol & Geophys, Beijing, Peoples R China.
    Fan, K.
    Chinese Acad Sci, Inst Geol & Geophys, Beijing, Peoples R China.
    Guo, J. -P
    Sun Yat Sen Univ, Sch Atmospher Sci, Zhuhai, Peoples R China.
    Cao, Y. -T
    Chinese Acad Sci, CAS Key Lab Lunar & Deep Space Explorat, Beijing, Peoples R China.
    Jiang, F. -Y
    Chinese Acad Sci, CAS Key Lab Lunar & Deep Space Explorat, Beijing, Peoples R China; Univ Arizona, Lunar & Planetary Lab, Tucson, AZ USA.
    Wei, Y.
    Chinese Acad Sci, Inst Geol & Geophys, Beijing, Peoples R China.
    Mitchell, D. L.
    Univ Calif Berkeley, Space Sci Lab, Berkeley, CA, USA.
    The Morphology of the Topside Martian Ionosphere: Implications on Bulk Ion Flow2019In: Journal of Geophysical Research - Planets, ISSN 2169-9097, E-ISSN 2169-9100, Vol. 124, no 3, p. 734-751Article in journal (Refereed)
    Abstract [en]

    Abstract

    Prior to the Mars Atmosphere and Volatile Evolution mission, the only information on the composition of the Martian ionosphere came from the Viking Retarding Potential Analyzer data, revealing the presence of substantial ion outflow on the dayside of Mars. Extensive measurements made by the Mars Atmosphere and Volatile Evolution Neutral Gas and Ion Mass Spectrometer allow us to examine the morphology of the Martian ionosphere not only in unprecedented detail but also on both the dayside and the nightside of the planet. Above 300 km, various ionospheric species present a roughly constant density scale height around 100 km on the dayside and 180 km on the nightside. An evaluation of the ion force balance, appropriate for regions with near‐horizontal magnetic field lines, suggests the presence of supersonic ion outflow predominantly driven by the ambient magnetic pressure, with characteristic dayside and nightside flow velocities of 4 and 20 km/s, respectively, both referred to an altitude of 500 km. The corresponding total ion outflow rates are estimated to be 5 × 1025 s−1 on the dayside and 1 × 1025 s−1 on the nightside. The data also indicate a prominent variation with magnetic field orientation in that the ion distribution over regions with near‐vertical field lines tends to be more extended on the dayside but more concentrated on the nightside, as compared to regions with near‐horizontal field lines. These observations should have important implications on the pattern of ion dynamics in the vicinity of Mars.

  • 1157991. Wu, X.
    et al.
    Walter, R.
    Su, M.
    Ambrosi, G.
    Azzarello, P.
    Bottcher, M.
    Chang, J.
    Chernyakova, M.
    Fan, Y.
    Farnier, C.
    Gargano, F.
    Grenier, I.
    Hajdas, W.
    Mazziotta, M. N.
    Pearce, Mark
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Pohl, M.
    Zdziarski, A.
    PANGU: A Wide Field Gamma-Ray Imager and Polarimeter2016In: SPACE TELESCOPES AND INSTRUMENTATION 2016: ULTRAVIOLET TO GAMMA RAY, SPIE - International Society for Optical Engineering, 2016, article id UNSP 99056EConference paper (Refereed)
    Abstract [en]

    PANGU (the PAir-productioN Gamma-ray Unit) is a gamma-ray telescope with a wide field of view optimized for spectro-imaging, timing and polarization studies. It will map the gamma-ray sky from 10 MeV to a few GeV with unprecedented spatial resolution. This window on the Universe is unique to detect photons produced directly by relativistic particles, via the decay of neutral pions, or the annihilation or decay light from anti-matter and the putative light dark matter candidates. A wealth of questions can be probed among the most important themes of modern physics and astrophysics. The PANGU instrument is a pair-conversion gamma-ray telescope based on an innovative design of a silicon strip tracker. It is light, compact and accurate. It consists of 100 layers of silicon micro-strip detectors of 80 x 80 cm(2) in area, stacked to height of about 90 cm, and covered by an anticoincidence detectors. PANGU relies on multiple scattering effects for energy measurement, reaching an energy resolution between 30-50% for 10 MeV - 1GeV. The novel tracker will allow the first polarization measurement and provide the best angular resolution ever obtained in the soft gamma ray and GeV band.

  • 1157992. Wu, X.
    et al.
    Wanders, A.
    Wardega, P.
    Tinge, B.
    Gedda, L.
    Bergstrom, S.
    Sooman, L.
    Gullbo, J.
    Bergqvist, M.
    Hesselius, P.
    Lennartsson, J.
    Ekman, S.
    Hsp90 is expressed and represents a therapeutic target in human oesophageal cancer using the inhibitor 17-allylamino-17-demethoxygeldanamycin2009In: Br J Cancer, Vol. 100, no 2, p. 334-43Article in journal (Refereed)
    Abstract [en]

    Heat shock protein 90 (Hsp90) has been demonstrated to protect oncogenic variants of signalling molecules from degradation and may consequently serve as a therapeutic target for the treatment of oesophageal cancer for which adequate therapy is often lacking. We studied the expression of Hsp90 in tumour tissues of human oesophageal cancer and the impact of Hsp90 inhibition on oesophageal cancer cell lines using the drug 17-allylamino-17-demethoxygeldanamycin (17-AAG). Quantitative immunohistochemistry was performed on formalin-fixed paraffin-embedded tissues from patients with oesophageal cancer. In squamous cell carcinoma, a marked upregulation of Hsp90 could be noted in dysplastic epithelium and invasive cancer compared with normal epithelium. In adenocarcinoma, Hsp90 was expressed in neoplastic epithelium and also in normal non-neoplastic glands weakly. The inhibition of Hsp90 using 17-AAG led to a significant decrease in cell proliferation and viability in human oesophageal cancer cell lines. Using a clonogenic cell survival assay, Hsp90 inhibition significantly sensitised the cells for gamma-photon irradiation. Heat shock protein 90 was found to be critical for proper signalling induced by both epidermal growth factor and insulin-like growth factor-1, in which the inhibition of signalling by 17-AAG correlated with the observed reduction in cell proliferation and viability. These results showed that Hsp90 was selectively expressed in oesophageal cancer tissue compared with the corresponding normal tissue, and the inhibition of Hsp90 resulted in decreased proliferation and viability as well as radiosensitisation of oesophageal cancer cells. Heat shock protein 90 represents a potential therapeutic target in the treatment of patients with oesophageal cancer, alone or in combination with radiotherapy.

  • 1157993.
    Wu, Xi Vivien
    Jönköping University, School of Health and Welfare.
    Holistic clinical assessment for undergraduate nursing students2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    A major focus in nursing education is on the judgement of clinical performance, and it is a complex process due to the diverse nature of nursing practice. Difficulties in the development of valid and reliable assessment measures in nursing competency continue to pose a challenge in nursing education. A holistic approach in the assessment of competency comprises knowledge, skills and professional attitudes, wherein the notion of competency incorporates professional judgement and management skills in the clinical situation. Therefore, the thesis aims to develop a holistic clinical assessment tool with a reasonable level of validity and reliability to meet the needs of clinical education.

    The conceptual framework underlying this research is formed by establishing a theoretical connection between the practice of learning, and of pedagogy and assessment. This research consists of five studies. In Study I, a systematic review was conducted to explore the current assessment practices and tools for nursing undergraduates. In Studies II, III and IV, a qualitative approach with focus group discussions was adopted to explore the views of final-year undergraduate nursing students, preceptors, clinical nurse leaders and academics on the clinical assessment. Based on the multiple perspectives, it therefore addresses concerns in clinical assessment. In Study V, a holistic clinical assessment tool was developed, for which a psychometric testing was conducted.

    The systematic review indicated that limited studies adequately evaluate the psychometric properties of the assessment instrument. The qualitative studies have raised an awareness of professional and educational issues in relation to clinical assessment. Workload, time, availability of resources, adequate preparation of preceptors, and availability of valid and reliable clinical assessment tools were deemed to influence the quality of students’ clinical learning and assessment. In addition, the presence of support systems and formal educational programs for preceptors influenced their preparation and self-confidence. Nursing leaderships in hospitals and educational institutions have a joint responsibility in shaping the holistic clinical learning environment and making holistic clinical assessment for students. The involvement of all stakeholders in the development of a valid and reliable assessment tool for clinical competency is also essential to the process. The Holistic Clinical Assessment Tool (HCAT) was developed by the author based on the systematic review, qualitative findings and the core competencies of registered nurse from the professional nursing boards. The HCAT consists of 4 domains and 36 assessment items. Furthermore, testing of the psychometric properties indicated that the HCAT has satisfactory content validity, construct validity, internal consistency and test-retest reliability.

    In conclusion, the HCAT is meritorious in that it carries the potential to be used as a valid measure to evaluate clinical competency in nursing students, and provide specific and ongoing feedback to enhance the students’ holistic clinical learning experience. The HCAT not only functions as a tool for self-reflection for the students, but also guides the preceptors in clinical teaching and assessment. In addition, the HCAT can be used for peer-assessment and feedback. It is imperative that the clinical and academic institutions establish various levels of ongoing support for both students and preceptors in the process of clinical assessment.

  • 1157994.
    Wu, Xi Vivien
    et al.
    Jönköping University, School of Health and Welfare. Alice Lee Centre for Nursing Studies, Yong Loo Lin School of Medicine, National University of Singapore.
    Enskär, Karin
    Jönköping University, School of Health and Welfare, HHJ, Dep. of Nursing Science. Jönköping University, School of Health and Welfare, HHJ. CHILD.
    Heng, D. G. N.
    Nursing Education, National University Hospital, Singapore.
    Pua, L. H.
    Department of Education and Practice, Nursing Service, Tan Tock Seng Hospital, Singapore.
    Wang, W.
    Alice Lee Centre for Nursing Studies, Yong Loo Lin School of Medicine, National University of Singapore.
    The perspectives of preceptors regarding clinical assessment for undergraduate nursing students2016In: International Nursing Review, ISSN 0020-8132, E-ISSN 1466-7657, Vol. 63, no 3, p. 473-481Article in journal (Refereed)
    Abstract [en]

    AIM: To explore the perspectives of preceptors about clinical assessment for undergraduate nursing students in transition to practice.

    BACKGROUND: The assessment of clinical competence is a complex process due to the diverse nature of nursing practice. As such, nurse preceptors play a crucial role in clinical assessment for nursing students. Although preceptors may enjoy the process of clinical teaching and assessment, they face challenges that need to be addressed to facilitate students' clinical learning and assessment.

    METHODS: An exploratory qualitative approach was adopted. A purposive sample of 17 preceptors from two tertiary hospitals in Singapore was recruited to participate in three focus group discussions from March to July 2014.

    FINDINGS: Five themes emerged from the data analysis: the need for a valid and reliable clinical assessment tool; meaningful reflection and feedback; varied methods in clinical assessment; high level of commitment and struggles with dual roles and the need to enhance the support system for preceptors.

    CONCLUSIONS: There is no doubt that a valid and reliable clinical assessment tool can serve as a guide for preceptors to enhance their clarity in assessment and feedback. It is essential for all stakeholders to be involved in the development of the clinical assessment tool. Workload, time, support system and formal educational programmes for preceptors influenced their preparation and self-confidence.

    IMPLICATIONS FOR NURSING AND/OR HEALTH POLICY: The themes that emerged from the focus group discussions could assist in the development of a more reliable and valid clinical assessment tool to evaluate the clinical competence of nursing students in transition to practice. Clinical and educational institutions could collaborate closely to develop an educational programme and a preceptorship handbook, focusing on pedagogical contents for clinical education and assessment.

  • 1157995.
    Wu, Xi Vivien
    et al.
    Jönköping University, School of Health and Welfare. Alice Centre for Nursing Studies, Singapore.
    Enskär, Karin
    Jönköping University, School of Health and Welfare, HHJ, Dep. of Nursing Science. Jönköping University, School of Health and Welfare, HHJ. CHILD.
    Lee, Cindy Ching Siang
    Alice Centre for Nursing Studies, Singapore.
    Wang, Wenru
    Alice Centre for Nursing Studies, Singapore.
    A systematic review of clinical assessment for undergraduate nursing students2015In: Nurse Education Today, ISSN 0260-6917, E-ISSN 1532-2793, Vol. 35, no 2, p. 347-359Article, review/survey (Refereed)
    Abstract [en]

    BACKGROUND: Consolidated clinical practicum prepares pre-registration nursing students to function as beginning practitioners. The clinical competencies of final-year nursing students provide a key indication of professional standards of practice and patient safety. Thus, clinical assessment of nursing students is a crucial issue for educators and administrators.

    OBJECTIVE: The aim of this systematic review was to explore the clinical competency assessment for undergraduate nursing students.

    DATA SOURCES: PubMed, CINAHL, ScienceDirect, Web of Science, and EBSCO were systematically searched from January 2000 to December 2013.

    METHODS: The systematic review was in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Published quantitative and qualitative studies that examined clinical assessment practices and tools used in clinical nursing education were retrieved. Quality assessment, data extraction, and analysis were completed on all included studies.

    RESULTS: This review screened 2073 titles, abstracts and full-text records, resulting in 33 included studies. Two reviewers assessed the quality of the included studies. Fourteen quantitative and qualitative studies were identified for this evaluation. The evidence was ordered into emergent themes; the overarching themes were current practices in clinical assessment, issues of learning and assessment, development of assessment tools, and reliability and validity of assessment tools.

    CONCLUSION: There is a need to develop a holistic clinical assessment tool with reasonable level of validity and reliability. Clinical assessment is a robust activity and requires collaboration between clinical partners and academia to enhance the clinical experiences of students, the professional development of preceptors, and the clinical credibility of academics.

  • 1157996.
    Wu, Xi Vivien
    et al.
    Jönköping University, School of Health and Welfare. Alice Lee Centre for Nursing Studies, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
    Enskär, Karin
    Jönköping University, School of Health and Welfare, HHJ, Dep. of Nursing Science. Jönköping University, School of Health and Welfare, HHJ. CHILD.
    Pua, Lay Hoon
    Department of Education and Practice, Nursing Service, Tan Tock Seng Hospital, Singapore.
    Heng, Doreen Gek Noi
    Nursing Education, National University Hospital, Singapore.
    Wang, Wenru
    Alice Lee Centre for Nursing Studies, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
    Clinical nurse leaders’ and academics’ perspectives on clinical assessment of final-year nursing students: a qualitative study2017In: Nursing and Health Sciences, ISSN 1441-0745, E-ISSN 1442-2018, Vol. 19, no 3, p. 287-293Article in journal (Refereed)
    Abstract [en]

    The nature of nursing practice is diverse; therefore, clinical assessment is a complex process. This study explores the perceptions of clinical nurse leaders and academics on clinical assessment for undergraduate nursing education during transition to practice. An explorative qualitative approach was applied. Eight nurse managers, six clinical nurse educators, and eight academics from two tertiary hospitals and a university in Singapore participated in four focus group discussions. Thematic analysis was conducted. Four overriding themes were revealed: the need for a valid and reliable clinical assessment tool, preceptors' competency in clinical assessment, challenges encountered by the students in clinical assessment, and the need for close academic and clinical collaboration to support preceptors and students. Closer academic-clinical partnership is recommended to review the clinical education curriculum. Clinical and educational institutions need to work closely to design a learning program to enhance preceptors' competence in clinical pedagogy and assessment. Furthermore, a stress management program could build students' resiliency in coping with unfamiliar clinical environments. Ongoing support needs to be provided for both preceptors and students to enrich the preceptorship and learning experiences.

  • 1157997.
    Wu, Xi Vivien
    et al.
    Jönköping University, School of Health and Welfare. National University of Singapore.
    Enskär, Karin
    Jönköping University, School of Health and Welfare, HHJ, Dep. of Nursing Science. Jönköping University, School of Health and Welfare, HHJ. CHILD.
    Pua, Lay Hoon
    Tan Tock Seng Hospital, Singapore.
    Heng, Doreen Gek Noi
    National University Hospital, Singapore.
    Wang, Wenru
    National University of Singapore.
    Development and psychometric testing of Holistic Clinical Assessment Tool (HCAT) for undergraduate nursing students2016In: BMC Medical Education, ISSN 1472-6920, E-ISSN 1472-6920, Vol. 16, p. 1-9, article id 248Article in journal (Refereed)
    Abstract [en]

    Background:A major focus in nursing education is on the judgement of clinical performance, and it is a complexprocess due to the diverse nature of nursing practice. A holistic approach in assessment of competency is advocated.Difficulties in the development of valid and reliable assessment measures in nursing competency have resulted in thedevelopment of assessment instruments with an increase in face and content validity, but few studies have testedthese instruments psychometrically. It is essential to develop a holistic assessment tool to meet the needs of the clinicaleducation. The study aims to develop a Holistic Clinical Assessment Tool (HCAT) and test its psychometric properties.

    Methods:The HCAT was developed based on the systematic literature review and the findings of qualitative studies.An expert panel was invited to evaluate the content validity of the tool. A total of 130 final-year nursing undergraduatestudents were recruited to evaluate the psychometric properties (i.e. factor structure, internal consistency and test-retestreliability) of the tool.

    Results:The HCAT has good content validity with content validity index of .979. The exploratory factor analysis revealsa four-factor structure of the tool. The internal consistency and test-retest reliability of the HCAT are satisfactory withCronbach alpha ranging from .789 to .965 and Intraclass Correlation Coefficient ranging from .881 to .979 for the foursubscales and total scale.

    Conclusions:HCAT has the potential to be used as a valid measure to evaluate clinical competence in nursingstudents, and provide specific and ongoing feedback to enhance the holistic clinical learning experience. In addition,HCAT functions as a tool for self-reflection, peer-assessment and guides preceptors in clinical teaching and assessment.

  • 1157998.
    Wu, Xi Vivien
    et al.
    Jönköping University, School of Health and Welfare. Alice Lee Centre for Nursing Studies, Yong Loo Lin School of Medicine, National University of Singapore.
    Wang, Wenru
    Alice Lee Centre for Nursing Studies, Yong Loo Lin School of Medicine, National University of Singapore.
    Pua, Lay Hoon
    Department of Education and Practice, Nursing Service, Tan Tock Seng Hospital, Singapore.
    Heng, Doreen Gek Noi
    Nursing Education, National University Hospital, Singapore.
    Enskär, Karin
    Jönköping University, School of Health and Welfare, HHJ, Dep. of Nursing Science. Jönköping University, School of Health and Welfare, HHJ. CHILD.
    Undergraduate nursing students' perspectives on clinical assessment at transition to practice2015In: Contemporary Nurse: health care across the lifespan, ISSN 1037-6178, E-ISSN 1839-3535, Vol. 51, no 2-3, p. 272-285Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Assessment of clinical competence requires explicitly defined standards meeting the national standards of the nursing profession. This is a complex process because of the diverse nature of nursing practice.

    OBJECTIVES: To explore the perceptions of final-year undergraduate nursing students regarding clinical assessment at transition to practice.

    METHODS: An exploratory qualitative approach was adopted. Twenty-four students participated in three focus group discussions. Thematic analysis was conducted.

    FINDINGS: Five themes emerged: the need for a valid and reliable clinical assessment tool, the need for a flexible style of reflection and specific feedback, the dynamic clinical learning environment, students' efforts in learning and assessment, and the unclear support system for preceptors.

    CONCLUSIONS: Workload, time, resource availability, adequate preparation of preceptors, and the provision of valid and reliable clinical assessment tools were deemed to influence the quality of students' clinical learning and assessment. Nursing leadership in hospitals and educational institutions has a joint responsibility in shaping the clinical learning environment and providing clinical assessments for the students.

  • 1157999. Wu, Xiangbao
    et al.
    Tyrcha, Joanna
    Stockholm University, Faculty of Science, Department of Mathematics.
    Levy, William
    A neural network solution to the transverse patterning problem depends on repetition of the input code1998In: Biol. Cybern., no 79, p. 203-213Article in journal (Refereed)
  • 1158000. Wu, Xiangbao
    et al.
    Tyrcha, Joanna
    Stockholm University, Faculty of Science, Department of Mathematics.
    Levy, William
    A special role for input codes in solving the transverse patterning problem1997In: Computational Neuroscience: Trends in Research, p. 885-889Article in journal (Refereed)
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