727 research outputs found

    Enterovirus 71 Infection Induces Apoptosis in Vero Cells

    Get PDF
    The effects of Enterovirus 71 (HEV71) infection on African green monkey kidney cells (Vero) were investigated. It was found that the infected cells showed progressive cellular morphological changes characteristic in apoptotic cells within 10 hours post-infection. The number of apoptotic cells correlated significantly with the number of HEV71 antigen positive cells when cells were labeled using terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL) and stained for HEV71 antigen. Approximately 11, 26, 45 and 50 of the infected cells were apoptotic at 12, 24, 48 and 72 hours post-infection, respectively. Internucleosomal DNA fragmentation, characteristic in the late stage of apoptosis was noted beginning on day 2 post-infection. The DNA fragmentation, however, was absent in cells treated with the heat- and ultraviolet light-inactivated virus inocula. These results demonstrate the capacity of HEV71 to induce apoptosis in the infected cells. The induction, however, requires high level of HEV71 infectivity and the presence of live virus particles, suggesting the need for the presence of specific viral proteins for apoptosis to occur

    Hydrophobic Modification of Layered Clays and Compatibility for Epoxy Nanocomposites

    Get PDF
    Recent studies on the intercalation and exfoliation of layered clays with polymeric intercalating agents involving poly(oxypropylene)-amines and the particular uses for epoxy nanocomposites are reviewed. For intercalation, counter-ionic exchange reactions of clays including cationic layered silicates and anionic Al-Mg layered double hydroxide (LDH) with polymeric organic ions afforded organoclays led to spatial interlayer expansion from 12 to 92 angstrom (X-ray diffraction) as well as hydrophobic property. The inorganic clays of layered structure could be modified by the poly(oxypropylene) amine-salts as the intercalating agents with molecular weights ranging from 230 to 5,000 g/mol. Furthermore, natural montmorillonite (MMT) clay could be exfoliated into thin layer silicate platelets (ca. 1 nm thickness) in one step by using polymeric types of exfoliating agents. Different lateral dimensions of MMT, synthetic fluorinated Mica and LDH clays had been cured into epoxy nanocomposites. The hydrophobic amine-salt modification resulting in high spacing of layered or exfoliation of individual clay platelets is the most important factor for gaining significant improvements of properties. In particular, these modified clays were reported to gain significant improvements such as reduced coefficient of thermal expansion (CTE), enhanced thermal stability, and hardness. The utilization of these layered clays for initiating the epoxy self-polymerization was also reported to have a unique compatibility between clay and organic resin matrix. However, the matrix domain lacks of covalently bonded crosslink and leads to the isolation of powder material. It is generally concluded that the hydrophobic expansion of the clay inter-gallery spacing is the crucial step for enhancing the compatibility and the ultimate preparation of the advanced epoxy materials

    The Impact of Interpretation Biases on Psychological Responses to the COVID-19 Pandemic:a Prospective Study

    Get PDF
    BACKGROUND: This study investigates the longitudinal role of interpretation biases in the development and maintenance of health anxiety during the pandemic. Individual differences in behavioural responses to the virus outbreak and decision-making were also examined. METHODS: Two hundred seventy-nine individuals from a pre-pandemic study of interpretation bias and health anxiety completed an online survey during the third wave of the COVID-19 pandemic in Hong Kong. Participants’ health anxiety, interpretation biases, and COVID-specific behaviours (i.e. practice of social distancing, adherence to preventive measures, information seeking), and health decision-making were assessed. RESULTS: Pre-pandemic tendencies to interpret ambiguous physical sensations as signals for illness did not predict health anxiety during the pandemic, b = −0.020, SE = 0.024, t = −0.843, p = .400, 99% CI [−0.082, 0.042], but were associated with a preference for risky treatment option for COVID-19, b = 0.026, SE = 0.010, Wald = 2.614, p = .009, OR = 1.026, 99% CI [1.001, 1.054]. Interpretation biases and health anxiety symptoms during the pandemic were associated with each other and were both found to be significant predictors of practice of social distancing, adherence to preventive measures, and information seeking behaviour. CONCLUSIONS: This study adds to the growing evidence of the role of interpretation biases in health anxiety and the way that people respond to the ongoing pandemic. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12529-022-10079-5

    Three-dimensional flow structure behind an Ahmed vehicle model

    Get PDF
    Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.The lasting high fuel cost has recently inspired resurgence in drag reduction research for vehicles, which calls for a thorough understanding of the vehicle wake. The simplified Ahmed vehicle model is characterized by controllable flow separation, thus especially suitable for this purpose. In spite of a considerable number of previous investigations, our knowledge of flow around this model remains incomplete. This work aims to revisit turbulent flow structure behind this model. Two rear slant angles, i.e., α = 25º and 35º, of the model were examined, representing two distinct flow regimes. The Reynolds number was 5.26×104 based on the model height (H) and incident flow velocity. Using particle image velocimetry (PIV), flow was measured with and without a gap (g/H = 0.174) between the vehicle underside and ground in three orthogonal planes, viz. the x-z, x-y and y-z planes, where x, y and z are the coordinates along longitudinal, transverse and spanwise directions, respectively. The flow at g/H = 0 serves as an important reference for the understanding of the highly complicated vehicle wake (g/H ≠ 0). While reconfirming the well documented major characteristics of the mean flow structure, both instantaneous and time-averaged PIV data unveil a number of important features of the flow structure, which have not been previously reported. As such, considerably modified flow structure models are proposed for both regimes. The time-averaged velocities, second moments of fluctuating velocities and vorticity components are presented and discussed, along with their dependence on g/H in the two distinct flow regimes.dc201

    NTMG (N-terminal Truncated Mutants Generator for cDNA): an automatic multiplex PCR assays design for generating various N-terminal truncated cDNA mutants

    Get PDF
    The sequential deletion method is generally used to locate the functional domain of a protein. With this method, in order to find the various N-terminal truncated mutants, researchers have to investigate the ATG-like codons, to design various multiplex polymerase chain reaction (PCR) forward primers and to do several PCR experiments. This web server (N-terminal Truncated Mutants Generator for cDNA) will automatically generate groups of forward PCR primers and the corresponding reverse PCR primers that can be used in a single batch of a multiplex PCR experiment to extract the various N-terminal truncated mutants. This saves much time and money for those who use the sequential deletion method in their research. This server is available at http://oblab.cs.nchu.edu.tw:8080/WebSDL/

    Cytokine and Chemokine Profiling in Patients with Hand, Foot and Mouth Disease in Singapore and Malaysia

    Get PDF
    Hand, foot and mouth disease (HFMD) is a prevalent contagious childhood disease typically associated with fever, oral lesions and limb exanthema. While HFMD is caused by a plethora of serotypes of viruses under the genus Enterovirus within the Picornaviridae family, Coxsackievirus A16 (CV-A16) and Enterovirus 71 (EV-A71) are considered the main etiological agents. In recent years however, other viruses have also been isolated in considerable numbers from infected individuals in many regions, joining the legion commonly associated with HFMD. The present study investigated the cytokine and chemokine profiles of HFMD patients from Singapore and Malaysia for the first time. Comparative cohort studies of EV-A71-associated HFMD cases revealed that the Malaysia cohort had a distinct profile from the Singapore cohort, and this could be partly attributed by different EV-A71 genotypes. As the isolation of CV-A6, instead of CV-A16, had become prevalent in the Singapore cohort, it was also of particular interest to study the differential cytokine and chemokine profiles. Our data revealed that overlapping as well as unique profiles exist between the two major causative clinical isolates in the Singapore cohort. Having a better understanding of the respective immunological profiles could be useful for more accurate HFMD diagnosis, which is imperative for disease transmission control until multi-valent vaccines and/or broad-spectrum anti-viral drugs become available

    Relativistic Mass Ejecta from Phase-transition-induced Collapse of Neutron Stars

    Full text link
    We study the dynamical evolution of a phase-transition-induced collapse neutron star to a hybrid star, which consists of a mixture of hadronic matter and strange quark matter. The collapse is triggered by a sudden change of equation of state, which result in a large amplitude stellar oscillation. The evolution of the system is simulated by using a 3D Newtonian hydrodynamic code with a high resolution shock capture scheme. We find that both the temperature and the density at the neutrinosphere are oscillating with acoustic frequency. However, they are nearly 180^{\circ} out of phase. Consequently, extremely intense, pulsating neutrino/antineutrino fluxes will be emitted periodically. Since the energy and density of neutrinos at the peaks of the pulsating fluxes are much higher than the non-oscillating case, the electron/positron pair creation rate can be enhanced dramatically. Some mass layers on the stellar surface can be ejected by absorbing energy of neutrinos and pairs. These mass ejecta can be further accelerated to relativistic speeds by absorbing electron/positron pairs, created by the neutrino and antineutrino annihilation outside the stellar surface. The possible connection between this process and the cosmological Gamma-ray Bursts is discussed.Comment: 40 pages, 11 figures, accepted for publication in JCA

    Gait Retraining for the Reduction of Injury Occurrence in Novice Distance Runners: 1-Year Follow-up of a Randomized Controlled Trial

    Get PDF
    Background: The increasing popularity of distance running has been accompanied by an increase in running-related injuries, such that up to 85% of novice runners incur an injury in a given year. Previous studies have used a gait retraining program to successfully lower impact loading, which has been associated with many running ailments. However, softer footfalls may not necessarily prevent running injury. Purpose: To examine vertical loading rates before and after a gait retraining program and assess the effectiveness of the program in reducing the occurrence of running-related injury across a 12-month observation period. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: A total of 320 novice runners from the local running club completed this study. All the participants underwent a baseline running biomechanics evaluation on an instrumented treadmill with their usual running shoes at 8 and 12 km/h. Participants were then randomly assigned to either the gait retraining group or the control group. In the gait retraining group (n = 166), participants received 2 weeks of gait retraining with real-time visual feedback. In the control group (n = 154), participants received treadmill running exercise but without visual feedback on their performance. The training time was identical between the 2 groups. Participants’ running mechanics were reassessed after the training, and their 12-month posttraining injury profiles were tracked by use of an online surveillance platform. Results: A significant reduction was found in the vertical loading rates at both testing speeds in the gait retraining group (P 0.99), whereas the loading rates were either similar or slightly increased in the control group after training (P = .001 to 0.461, Cohen’s d = 0.03 to −0.14). At 12-month follow-up, the occurrence of running-related musculoskeletal injury was 16% and 38% in the gait retraining and control groups, respectively. The hazard ratio between gait retraining and control groups was 0.38 (95% CI, 0.25-0.59), indicating a 62% lower injury risk in gait-retrained runners compared with controls. Conclusion: A 2-week gait retraining program is effective in lowering impact loading in novice runners. More important, the occurrence of injury is 62% lower after 2 weeks of running gait modification. Registration: HKUCTR-1996 (University of Hong Kong Clinical Trials Registry)

    A Gestão Estratégica dos Recursos Humanos nas Autarquias Locais: estudo de caso na Câmara Municipal de Cantanhede

    Get PDF
    Os Recursos Humanos são fundamentais para o prosseguimento da missão e dos objetivos de qualquer organização. A Gestão Estratégica dos Recursos Humanos, permite que uma organização alcance os seus objetivos, através do aumento da probabilidade de realização dos mesmos. Esta lógica de Gestão dos Recursos Humanos, revela-se como uma promessa explícita de eficácia organizacional, que pode ser alcançada pelo desenvolvimento do conjunto de práticas de RH internamente consistentes e adequadas aos contextos organizacionais. O concretizar de uma Gestão Estratégica dos Recursos Humanos nas organizações da Administração Pública, considerando a complexidade humana e o valor inerente, é uma via para o desenvolvimento a todos os níveis. Nas Câmaras Municipais, enquanto órgãos executivos de uma das formas de Autarquias Locais que é o Município, a Gestão Estratégica dos Recursos Humanos torna-se um investimento necessário para a melhoria contínua na prestação de serviços públicos. Isso, tendo em conta que a descentralização de competências da Administração Pública Central, para as Autarquias Locais, acarreta um aumento de responsabilidades e requer maior capacidade de resposta às demandas sociais. É no contexto da Administração Pública, em particular das Autarquias Locais, que se realiza o estudo de caso na Câmara Municipal de Cantanhede. O objetivo desta investigação é compreender a dinâmica do sector dos Recursos Humanos nas Autarquias Locais, sob a perspetiva da Gestão Estratégica dos Recursos Humanos, e perceber a importância que esta tem no desempenho global dessas organizações. O tipo de pesquisa que se materializa é qualitativo e exploratório, com a realização de observação direta, análise documental e entrevistas semiestruturadas. Verifica-se com este estudo, que é preocupação da Câmara Municipal de Cantanhede e do sector dos Recursos Humanos, desenvolver procedimentos estratégicos de Gestão dos Recursos Humanos. Apesar de ser um processo limitado pelos problemas relativos à atualização das carreiras, baixa remuneração, ausência de compensações e prémio de desempenho. Para que a Gestão Estratégica dos Recursos Humanos tenha efetivamente campo de ação, é preciso que a Gestão dos Recursos Humanos seja desmistificada enquanto conceito e experienciada de forma expressiva nas Autarquias Locais, em conjunto com o reforço da autonomia dessas organizações. / Human Resources are fundamental for the pursuit of the mission and goals of any organization. The Strategic Management of Human Resources allows an organization to achieve its objectives by increasing the probability of achieving them. This Human Resource Management logic is an explicit promise of organizational effectiveness that can be achieved by developing a set of HR practices that are internally consistent and appropriate to organizational contexts. The realization of a Strategic Management of Human Resources in Public Administration organizations, considering the human complexity and the inherent value, is a way for development at all levels. In the Municipal Councils, as an executive bodies of one of the forms of Local Authorities that is the Municipality, the Strategic Management of Human Resources becomes a necessary investment for the continuous improvement in the provision of public services. This, taking into account that the decentralization of competences of the Central Public Administration, for Local Authorities, entails an increase in responsibilities and requires greater capacity to respond to social demands. It is in the context of the Public Administration, in particular the Local Authorities, that the case study is carried out in Cantanhede Town Hall. The objective of this research is to understand the dynamics of the Human Resources sector in Local Authorities, from the perspective of the Strategic Management of Human Resources, and realize the importance it has in the overall performance of these organizations. The type of research that materializes is qualitative and exploratory, with direct observation, documental analysis and semi-structured interviews. It is verified with this study, that is concern of the Cantanhede Town Hall and of the Human Resources sector to develop strategic human resources management procedures. Although it is a process limited by the problems related to the updating of the careers, low remuneration, absence of compensations and performance bonus. In order for the Strategic Management of Human Resources to have an effective field of action, it is necessary that the Human Resources Management be demystified as a concept and experienced in an expressive way in Local Authorities, together with the reinforcement of the autonomy of these organizations
    corecore