HKUMed finds Omicron SARS-CoV-2 can infect faster and better than Delta in human bronchus but with less severe infection in lung

A study led by researchers from the LKS Faculty of Medicine at The University of Hong Kong (HKUMed) provides the first information on how the novel Variant of Concern (VOC) of SARS-CoV-2, the Omicron SARS-CoV-2 infect human respiratory tract. The researchers found that Omicron SARS-CoV-2 infects and multiplies 70 times faster than the Delta variant and original SARS-CoV-2 in human bronchus, which may explain why Omicron may transmit faster between humans than previous variants. Their study also showed that the Omicron infection in the lung is significantly lower than the original SARS-CoV-2, which may be an indicator of lower disease severity. This research is currently under peer review for publication.A study led by researchers from the LKS Faculty of Medicine at The University of Hong Kong (HKUMed) provides the first information on how the novel Variant of Concern (VOC) of SARS-CoV-2, the Omicron SARS-CoV-2 infect human respiratory tract. The researchers found that Omicron SARS-CoV-2 infects and multiplies 70 times faster than the Delta variant and original SARS-CoV-2 in human bronchus, which may explain why Omicron may transmit faster between humans than previous variants. Their study also showed that the Omicron infection in the lung is significantly lower than the original SARS-CoV-2, which may be an indicator of lower disease severity. This research is currently under peer review for publication

Large-eddy simulation of turbulent flows and pollutant transport inside and above idealized urban street canyons under different unstable thermal stratification

Large-eddy simulation (LES) is employed to study the behaviours of flows and pollutant transport inside and over idealized urban street canyons under different unstable thermal stratification. Three configurations of idealized street canyon, consisting of building-height-to-street-width (aspect) ratios, 0.5, 1 and 2, are considered. Under unstable stratification, the vertical profiles of streamwise velocity and temperature over the bottom rough surface are more uniform and the turbulent transport of momentum and heat are enhanced. Inside the street canyons, the ventilation performance, which are characterized by the air exchange rate (ACH), pollutant exchange rate (PCH), pollutant retention time and average pollutant concentration, is found improved in unstable stratification.postprin

Numerical modeling of flows and pollutant dispersion within and above urban street canyons under unstable thermal stratification by large-eddy simulation

Recently, with the ever increasing urban areas in developing countries, the problem of air pollution due to vehicular exhaust arouses the concern of different groups of people. Understanding how different factors, such as urban morphology, meteorological conditions and human activities, affect the characteristics of street canyon ventilation, pollutant dispersion above urban areas and pollutant re-entrainment from the shear layer can help us improve air pollution control strategies. Among the factors mentioned above, thermal stratification is a significant one determining the pollutant transport behaviors in certain situation, e.g. when the urban surface is heated by strong solar radiation, which, however, is still not widely explored. The objective of this study is to gain an in-depth understanding of the effects of unstable thermal stratification on the flows and pollutant dispersion within and above urban street canyons through numerical modeling using large-...published_or_final_versio

Pathogenesis of SARS coronavirus infection using human lung epithelial cells: an in vitro model.

published_or_final_versio

Is Melanoma a stem cell tumor? Identification of neurogenic proteins in trans-differentiated cells

BACKGROUND: Although several genes and proteins have been implicated in the development of melanomas, the molecular mechanisms involved in the development of these tumors are not well understood. To gain a better understanding of the relationship between the cell growth, tumorigenesis and differentiation, we have studied a highly malignant cat melanoma cell line that trans-differentiates into neuronal cells after exposure to a feline endogenous retrovirus RD114. METHODS: To define the repertoire of proteins responsible for the phenotypic differences between melanoma and its counterpart trans-differentiated neuronal cells we have applied proteomics technology and compared protein profiles of the two cell types and identified differentially expressed proteins by 2D-gel electrophoresis, image analyses and mass spectrometry. RESULTS: The melanoma and trans-differentiated neuronal cells could be distinguished by the presence of distinct sets of proteins in each. Although approximately 60–70% of the expressed proteins were shared between the two cell types, twelve proteins were induced de novo after infection of melanoma cells with RD114 virus in vitro. Expression of these proteins in trans-differentiated cells was significantly associated with concomitant down regulation of growth promoting proteins and up-regulation of neurogenic proteins (p = < 0.001). Based on their physiologic properties, >95% proteins expressed in trans-differentiated cells could be associated with the development, differentiation and regulation of nervous system cells. CONCLUSION: Our results indicate that the cat melanoma cells have the ability to differentiate into distinct neuronal cell types and they express proteins that are essential for self-renewal. Since melanocytes arise from the neural crest of the embryo, we conclude that this melanoma arose from embryonic precursor stem cells. This model system provides a unique opportunity to identify domains of interactions between the expressed proteins that halt the tumorigenic potential of melanoma cells and drive them toward neurogenerative pathways involved in early neurogenesis. A better understanding of these proteins in a well-coordinated signaling network would also help in developing novel approaches for suppression of highly malignant tumors that arise from stem-like embryonic cells

Affective state influences retrieval-induced forgetting for integrated knowledge

Selectively testing parts of learned materials can impair later memory for nontested materials. Research has shown that such retrieval-induced forgetting occurs for low-integrated materials but may be prevented for high-integrated materials. However, previous research has neglected one factor that is ubiquitous in real-life testing: affective stat

A comparative study of the quality of life of patients with advanced chronic obstructive pulmonary disease and terminal cancer

2005-2006 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Randomized trial of use of incentive to increase the response rate to a mailed survey

Author name used in this publication: Tong M. F. ChanAuthor name used in this publication: Sonny H. M. TseAuthor name used in this publication: Mary C. DayAuthor name used in this publication: Edmond T. F. TongAuthor name used in this publication: Lorna K. P. Suen2003-2004 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Laser spectroscopy of the C1Σ+-X1Σ+ transition of ScBr

The laser induced fluorescence spectrum of scandium monobromide (ScBr) between 795 and 845 nm has been recorded and analyzed. ScBr was produced by reacting laser vaporized Sc atoms with ethyl bromide (C 2H 5Br). Spectra of six vibrational bands of both Sc 79Br and Sc 81Br isotopomers of the C 1Σ +-X 1Σ + transition were observed. A least-squares fit of the measured line positions yielded accurate molecular constants for the v = 0-3 levels of the C 1Σ + state and the v = 0-2 levels of the X 1Σ + state. The equilibrium bond length of the C 1Σ + state has been determined to be 2.4776 . © 2012 Elsevier B.V. All rights reserved.postprin