Temporal-spatial analysis of severe acute respiratory syndrome among hospital inpatients

Background. We report the temporal-spatial spread of severe acute respiratory syndrome (SARS) among inpatients in a hospital ward during a major nosocomial outbreak and discuss possible mechanisms for the outbreak. Methods. All inpatients who had stayed in the same ward as the initial index case patient for any duration before isolation were recruited into a cohort and followed up to document the occurrence of SARS. The normalized concentration of virus-laden aerosols at different locations of the ward was estimated by use of computational fluid dynamics modeling. The attack rates in the various subgroups stratified by bed location were calculated. Multivariate Cox proportional hazards regression was used to document important risk factors. Results. The overall attack rate of SARS was 41% (30 of 74 subjects). It was 65%, 52%, and 18% in the same bay, adjacent bay, and distant bays, respectively (P = .001). Computation fluid dynamics modeling indicated that the normalized concentration of virus-laden aerosols was highest in the same bay and lowest in the distant bays. Cox regression indicated that staying in the ward on 6 or 10 March entailed higher risk, as well as staying in the same or adjacent bays. The epidemic curve showed 2 peaks, and stratified analyses by bed location suggested >1 generation of spread. Conclusions. The temporal-spatial spread of SARS in the ward was consistent with airborne transmission, as modeled by use of computational fluid dynamics. Infected health care workers likely acted as secondary sources in the latter phase of the outbreak. © 2005 by the Infectious Diseases Society of America. All rights reserved.published_or_final_versio

Autosomal Dominant Gain-of-function STAT1 Mutation is a Novel Genetic Etiology of Penicillium Marneffei Infection

Symposium / Free Paper 4: ImmunologyConference Theme: Inflammatory Basis of Perinatal and Childhood DiseasesBackground: Penicillium marneffei infection is indigenous to Southeast Asia. Majority of cases occur in patients with AIDS and secondary immunodeficiencies. We previously reported 4 HIV-negative children with chronic mucocutaneous candidiasis (CMC) and severe penicilliosis. Hyper-IgE syndrome was diagnosed in one of them, but extensive genetic studies on IL12-IFNγ axis, CARD9 and AIRE were unrevealing for the rest. Recently, STAT1 hyperphosphorylation causing defective Th1 and Th17 immunity is recognized as a cause of CMC. Objective: To investigate the genetic and functional defects of STAT1 signaling in children affected by penicilliosis. Methods: Targeted sequencing of STAT1 gene or total exome sequencing was performed in 3 patients with CMC and penicilliosis. PBMCs were isolated from patients and normal controls. Intracellular STAT1 phosphorylation (pSTAT1) towards interferon-α and interferon-γ stimulation was evaluated by flow cytometry. Cytokine production in PBMCs towards PMA and ionomycin stimulation was assessed. PBMCs were co-cultured with live Candida albicans and P. marneffei to evaluate interferon-γ response. Results: Heterozygous STAT1 missense mutations were identified in all 3 patients. Two mutations were located in the coiled-coil domain (P1 and P2) and one in the DNA-binding domain (P3). All 3 patients recovered from penicilliosis, but P1 eventually died of fulminant aspergillosis. The percentage of pSTAT1-positive PBMCs induced by interferon-α and interferon-γ was significantly higher in all 3 patients than normal controls, indicating that they had gain-of-function mutations. PBMCs from all patients displayed defective interferon-γ and interleukin-17 production towards PMA and PMA plus ionomycin, respectively. Interferon-γ production induced by C. albicans and P. marneffei in P2 was significantly lower than normal controls. Conclusions: For the first time, we demonstrated STAT1 gain-of-function mutation as an important and novel genetic etiology of invasive mycosis including penicilliosis and aspergillosis. Penicilliosis should be regarded as an indicator disease for primary immunodeficiencies in children without HIV infection unless proven otherwise.published_or_final_versio

Severe mycobacterial infections in two pairs of Chinese siblings with interleukin-12 receptor β1 deficiency

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Studying ICT supported pedagogical practices

During the past decade there has been an exponential growth in the use of information and communication technology (ICT) and this has made pervasive impacts both on the society and on our daily lives. It is thus not surprising to find increasing interest, attention and investment put into the use of ICT in education all around the world. In addition to efforts to make use of ICT to improve learning, the emergence of the knowledge economy has also brought about in recent years a much greater emphasis on education and a number of masterplans in ICT in education has been produced in many countries. Such masterplans detailed not only strategies for implementation but more importantly embedded the plans within a broader framework of education reform that aimed to develop students’ capacities for self-learning, problem-solving, information seeking and analysis, critical thinking and the ability to communicate, collaborate and learn via the internet, abilities that figured much less importantly in the school curricula before. In this context, a new term, “emerging pedagogical practice”, was used in SITES (the Second International Information Technology in Education Study, conducted under the auspices of the IEA) (Pelgrum, 1999) to highlight the changing pedagogical goals and practices that has resulted from the use of ICT in education, as opposed to those uses that just aimed at enhancing the effectiveness of “traditionally important pedagogical practices”. However, the concept of “emerging pedagogical practice” as depicted in the SITES Module 1 (M1) report is still rather vague. When schools have access to computers and the Internet to support teaching and learning, how would teachers and students make use of them? What impact has ICT made on classroom practices? What changes, if any, has ICT made on the roles of teachers and students and the interactions between them? Has the introduction of ICT in schools brought about the desired education reforms envisaged in the ICT in education masterplans or are these wishful optimisms? Are there more effective models of ICT implementation in schools, and if so what are their characteristics? In conjunction with the SITES M1 Hong Kong study, we have conducted a study of good practices in the use of ICT for teaching and learning using the case studies approach. The main goal of this extension study was to explore the above questions in the context of good practices as commonly recognized by members of the education community, and to develop ways of disseminating such good practices. This paper describes the conceptual framework and methodology used in this study and reports briefly on some key findings from the study. The research methodology used in this Study is based on a model of pedagogical practice that is couched within a broad curriculum framework where the pedagogical practice is the implemented curriculum. There are two parts to the research. The first part is to investigate and to build models of pedagogical practices involving use of ICT. Here the assumption (substantiated by observations) is that the way ICT is incorporated into classrooms is very much dictated by the teachers’ general beliefs and approaches to education. The second component of the methodology deals with the models (strategies) of educational change used in different schools in introducing ICT across the curriculum and to explore if particular models of pedagogical practice is linked with specific school implementation strategies.published_or_final_versio

Are L-myc genotypes prognostic markers in non-small cell lung carcinoma (NSCLC) in our Chinese patients?

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Super-Resolution Imaging of Subcortical White Matter using Stochastic Optical Reconstruction Microscopy (STORM) and Super-Resolution Optical Fluctuation Imaging (SOFI).

AIMS: The spatial resolution of light microscopy is limited by the wavelength of visible light (the "diffraction limit", approximately 250 nm). Resolution of sub-cellular structures, smaller than this limit, is possible with super resolution methods such as stochastic optical reconstruction microscopy (STORM) and super-resolution optical fluctuation imaging (SOFI). We aimed to resolve subcellular structures (axons, myelin sheaths and astrocytic processes) within intact white matter using STORM and SOFI. METHODS: Standard cryostat-cut sections of subcortical white matter from donated human brain tissue and from adult rat and mouse brain were labelled using standard immunohistochemical markers (neurofilament-H, myelin associated glycoprotein, GFAP). Image sequences were processed for STORM (effective pixel size 8-32 nm) and for SOFI (effective pixel size 80 nm). RESULTS: In human, rat and mouse subcortical white matter high quality images for axonal neurofilaments, myelin sheaths and filamentous astrocytic processes were obtained. In quantitative measurements, STORM consistently underestimated width of axons and astrocyte processes (compared with electron microscopy measurements). SOFI provided more accurate width measurements, though with somewhat lower spatial resolution than STORM. CONCLUSIONS: Super resolution imaging of intact cryo-cut human brain tissue is feasible. For quantitation, STORM can under-estimate diameters of thin fluorescent objects. SOFI is more robust. The greatest limitation for super-resolution imaging in brain sections is imposed by sample preparation. We anticipate that improved strategies to reduce autofluorescence and to enhance fluorophore performance will enable rapid expansion of this approach. [232 words] This article is protected by copyright. All rights reserved

Anode modification of polyfluorene-based polymer light-emitting devices

A glycerol-modified poly(3,4-ethylene dioxythiophene) (PEDOT): poly(styrene sulfonate) (PSS) layer was used as an anode buffer layer in polymer light-emitting devices using poly(9,9-dioctylfluorene) (F8) as the emitter. Devices with a configuration of indium tin oxide/PEDOT:PSS (with or without glycerol)/F8/CsF/Al were fabricated. It was found that the glycerol-modified device showed a much larger current density than the unmodified device. At an operating voltage of 6 V, the glycerol-modified device showed a luminance of 1300Cd/m 2 and a current efficiency of 1.7 Cd/A compared to the corresponding values of 500Cd/m 2 and 1.3 Cd/A in the unmodified device. Analysis by ultraviolet spectroscopy suggests that the two devices have the same energy level structure and the performance improvement should not be due to change in the PEDOT/polymer interface. It was further found that incorporating a suitable amount of glycerol into the PEDOT:PSS layer can increase its conductivity by six times. This leads to a better balance in the hole and electron currents and thus improved device efficiency. © 2002 American Institute of Physics.published_or_final_versio

Endoscopic submucosal dissection vs laparoscopic colorectal resection for early colorectal epithelial neoplasia

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P53 intron 2 polymorphisms and mutations in non-small cell lung carcinoma in Hong Kong

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《學習2.0》：一個支援新高中通識教育及專題研究的學習及評估平臺

Liberal Studies as a mandatory subject in the New Secondary School curriculum will be implemented starting from September 2009. This subject adopts an inquiry-based approach and the content is structured around a range of important contemporary issues. Teachers face new challenges in teaching and assessing this subject: how to guide students to read critically, find useful information from the internet, formulate inquiry questions and to undertake evidence-based inquiry; how to support student collaboration and at the same time be able to assess the efforts and achievements of individual students; and how to provide adequate feedback to students at various stages of inquiry such that assessment can be both formative and summative. In addition, facilitating students to work autonomously online generally brings heavy workload on teachers. This paper introduces the Learning 2.0 project which comprises the development of an open-source online learning and assessment platform using Web 2.0 technology to provide support for the learning and teaching in the NSS Liberal Studies Curriculum.published_or_final_versio