Sustainable development and high density living

Thesis (B.Sc)--University of Hong Kong, 2006.published_or_final_versio

Valuing the acute subjective experience

Psychedelics, including psilocybin, and other consciousness-altering compounds such as 3,4-methylenedioxymethamphetamine (MDMA), currently are being scientifically investigated for their potential therapeutic uses, with a primary focus on measurable outcomes: for example, alleviation of symptoms or increases in self-reported well-being. Accordingly, much recent discussion about the possible value of these substances has turned on estimates of the magnitude and duration of persisting positive effects in comparison to harms. However, many have described the value of a psychedelic experience with little or no reference to such therapeutic benefits, instead seeming to find the experience valuable in its own right. How can we make sense of such testimony? Could a psychedelic experience be valuable even if there were no persisting beneficial effects? If so, how? Using the concept of psychological richness, combined with insights from the philosophy of aesthetics and the enhancement literature, this essay explores potential sources of value in the acute subjective experience, apart from the value derived from persisting beneficial effects

SarS, a SarA Homolog Repressible by agr, Is an Activator of Protein A Synthesis in Staphylococcus aureus

The expression of protein A (spa) is repressed by global regulatory loci sarA and agr. Although SarA may directly bind to the spa promoter to downregulate spa expression, the mechanism by which agr represses spa expression is not clearly understood. In searching for SarA homologs in the partially released genome, we found a SarA homolog, encoding a 250-amino-acid protein designated SarS, upstream of the spa gene. The expression of sarS was almost undetectable in parental strain RN6390 but was highly expressed in agr and sarA mutants, strains normally expressing high level of protein A. Interestingly, protein A expression was decreased in a sarS mutant as detected in an immunoblot but returned to near-parental levels in a complemented sarS mutant. Transcriptional fusion studies with a 158- and a 491-bp spa promoter fragment linked to the xylE reporter gene disclosed that the transcription of the spa promoter was also downregulated in the sarS mutant compared with the parental strain. Interestingly, the enhancement in spa expression in an agr mutant returned to a near-parental level in the agr sarS double mutant but not in the sarA sarS double mutant. Correlating with this divergent finding is the observation that enhanced sarS expression in an agr mutant was repressed by the sarA locus supplied in trans but not in a sarA mutant expressing RNAIII from a plasmid. Gel shift studies also revealed the specific binding of SarS to the 158-bp spa promoter. Taken together, these data indicated that the agr locus probably mediates spa repression by suppressing the transcription of sarS, an activator of spa expression. However, the pathway by which the sarA locus downregulates spa expression is sarS independent

A novel method for measuring the extragalactic background light: Fermi application to the lobes of Fornax A

We describe a new method for measuring the extragalactic background light (EBL) through the detection of $\gamma$-ray inverse Compton (IC) emission due to scattering of the EBL photons off relativistic electrons in the lobes of radio galaxies. Our method has no free physical parameters and is a powerful tool when the lobes are characterized by a high energy sharp break or cutoff in their electron energy distribution (EED). We show that such a feature will produce a high energy IC `imprint' of the EBL spectrum in which the radio lobes are embedded, and show how this imprint can be used to derive the EBL. We apply our method to the bright nearby radio galaxy Fornax A, for which we demonstrate, using WMAP and EGRET observations, that the EED of its lobes is characterized by a conveniently located cutoff, bringing the IC EBL emission into the {\sl Fermi} energy range. We show that {\sl Fermi} will set upper limits to the optical EBL and measure the more elusive infrared EBL.Comment: ApJL, accepte

Bicycle handlebar injuries - a systematic review of pediatric chest and abdominal injuries.

OBJECTIVE: The severity of handlebar injuries can be overlooked due to subtle signs and wide range of associated internal injuries. Our objective was to describe thoracoabdominal injuries due to bicycle handlebars and their outcomes in children. METHODS: Articles that reported thoracoabdominal injuries were identified from database conception to March 3, 2019 using PubMed, EMBASE, Cochrane Library, CINHAHL Complete, Web of Science and Scopus. A systematic review of studies of thoracoabdominal handlebar injuries in children ≤21 years on human-powered bicycles in English was performed. Information on demographics, clinical features, injuries, interventions and outcomes was noted. RESULTS: A total of 138 articles were identified from 1952 to 2019. There were 1072 children (males, 85.1%) and 1255 thoracoabdominal injuries. Mean age was 9.7 ± 3.3 years old. Common clinical features included abdominal pain and guarding, vomiting, fever and a handlebar imprint. The liver was the most frequently injured organ. Surgery was performed in 338 children with a mean age of 10.0 ± 3.3 years. Twenty-seven children (2.5%) were discharged and returned due to worsening symptoms, of whom 23 (85.2%) required surgery. Thirty-one children (2.9%) transferred to a higher level of care due to injury severity. Two deaths were reported. CONCLUSION: Bicycle handlebars can cause significant thoracoabdominal injuries. Presence of abdominal pain, vomiting, fever or a circular imprint on the chest or abdomen should prompt further workup. Future studies on diagnostic modalities and best practices are needed to lower the chance of missed injuries

Expression and Roles of Teneurins in Zebrafish

The teneurins, also known as Ten-m/Odz, are highly conserved type II transmembrane glycoproteins widely expressed throughout the nervous system. Functioning as dimers, these large cell-surface adhesion proteins play a key role in regulating neurodevelopmental processes such as axon targeting, synaptogenesis and neuronal wiring. Synaptic specificity is driven by molecular interactions, which can occur either in a trans-homophilic manner between teneurins or through a trans-heterophilic interaction across the synaptic cleft between teneurins and other cell-adhesion molecules, such as latrophilins. The significance of teneurins interactions during development is reflected in the widespread expression pattern of the four existing paralogs across interconnected regions of the nervous system, which we demonstrate here via in situ hybridization and the generation of transgenic BAC reporter lines in zebrafish. Focusing on the visual system, we will also highlight the recent developments that have been made in furthering our understanding of teneurin interactions and their functionality, including the instructive role of teneurin-3 in specifying the functional wiring of distinct amacrine and retinal ganglion cells in the vertebrate visual system underlying a particular functionality. Based on the distinct expression pattern of all teneurins in different retinal cells, it is conceivable that the combination of different teneurins is crucial for the generation of discrete visual circuits. Finally, mutations in all four human teneurin genes have been linked to several types of neurodevelopmental disorders. The opportunity therefore arises that findings about the roles of zebrafish teneurins or their orthologs in other species shed light on the molecular mechanisms in the etiology of such human disorders

Speech Processing Research Program

Contains an introduction and reports on five research projects.National Science Foundation Grant MIP 87-14969National Science Foundation FellowshipU.S. Air Force - Electronic Systems Division Contract F1 9628-89-K-0041U.S. Navy - Office of Naval Research Contract N00014-89-J-148

Computational cytometer based on magnetically modulated coherent imaging and deep learning.

Detecting rare cells within blood has numerous applications in disease diagnostics. Existing rare cell detection techniques are typically hindered by their high cost and low throughput. Here, we present a computational cytometer based on magnetically modulated lensless speckle imaging, which introduces oscillatory motion to the magnetic-bead-conjugated rare cells of interest through a periodic magnetic force and uses lensless time-resolved holographic speckle imaging to rapidly detect the target cells in three dimensions (3D). In addition to using cell-specific antibodies to magnetically label target cells, detection specificity is further enhanced through a deep-learning-based classifier that is based on a densely connected pseudo-3D convolutional neural network (P3D CNN), which automatically detects rare cells of interest based on their spatio-temporal features under a controlled magnetic force. To demonstrate the performance of this technique, we built a high-throughput, compact and cost-effective prototype for detecting MCF7 cancer cells spiked in whole blood samples. Through serial dilution experiments, we quantified the limit of detection (LoD) as 10 cells per millilitre of whole blood, which could be further improved through multiplexing parallel imaging channels within the same instrument. This compact, cost-effective and high-throughput computational cytometer can potentially be used for rare cell detection and quantification in bodily fluids for a variety of biomedical applications

Speech Processing Research Program

Contains an introduction and reports on five research projects.National Science Foundation FellowshipNational Science Foundation Grant MIP 87-14969U.S. Navy - Office of Naval Research Contract N00014-89-J-1489U.S. Air Force - Electronic Systems Division Contract F19628-89-K-0041National Science Foundation Fellowshi

Defusing the legal and ethical minefield of epigenetic applications in the military, defense, and security context

Epigenetic research has brought several important technological achievements, including identifying epigenetic clocks and signatures, and developing epigenetic editing. The potential military applications of such technologies we discuss are stratifying soldiers’ health, exposure to trauma using epigenetic testing, information about biological clocks, confirming child soldiers’ minor status using epigenetic clocks, and inducing epigenetic modifications in soldiers. These uses could become a reality. This article presents a comprehensive literature review, and analysis by interdisciplinary experts of the scientific, legal, ethical, and societal issues surrounding epigenetics and the military. Notwithstanding the potential benefit from these applications, our findings indicate that the current lack of scientific validation for epigenetic technologies suggests a careful scientific review and the establishment of a robust governance framework before consideration for use in the military. In this article, we highlight general concerns about the application of epigenetic technologies in the military context, especially discrimination and data privacy issues if soldiers are used as research subjects. We also highlight the potential of epigenetic clocks to support child soldiers’ rights and ethical questions about using epigenetic engineering for soldiers’ enhancement and conclude with considerations for an ethical framework for epigenetic applications in the military, defense, and security contexts.</p