An endomorphism of the Khovanov invariant

We construct an endomorphism of the Khovanov invariant to prove H-thinness and pairing phenomena of the invariants for alternating links. As a consequence, it follows that the Khovanov invariant of an oriented nonsplit alternating link is determined by its Jones polynomial, signature, and the linking numbers of its components.Comment: To appear in Adv. Math.; Brief summary of Khovanov invariant (math.QA/9908171) and previous result of the author (math.GT/0201105) adde

The discourse of ruination : interrogating urban renewal In Hong Kong

As stated in the Urban Renewal Strategy (2011), “the problem of urban decay” has been identified as the major task of urban renewal in Hong Kong. Rows of densely packed, “dilapidated” tenement buildings constitute the imaginary of a declining urban landscape that, much like the squatter areas of the 1950s, are seen to pose threats to public health and to the “prestige” of Hong Kong. I propose the concept of the discourse of ruination as a way to interrogate and at the same time, de-naturalise the pervasive assumption of the problem of decay, which serves to rationalise and perpetuate the cycle of destruction and renewal. I argue that crucial to this process is how certain sites are identified and framed as “pockets of decay”, which simultaneously “brings ruin upon” these spaces by rendering them as useless. This research investigates (educational) exhibitions, operated by the key actors of urban renewal to observe how exhibitions, as discursive practice, construct and consolidate knowledges about urban decay, and how it configures and normalises the logic of urban renewal. In the second case study, I present a critical reflection of the ongoing preservation project of the Blue House Cluster in order to highlight how heritage preservation is incorporated into the larger framework of urban renewal, and the erasures entailed in ‘preservation’ in the process of transforming ‘ruins’ to ‘heritage’. By converging insights derived from ‘ruin studies’, and studies on urban space and its power relations, this thesis aims to illuminate how the ‘discourse of ruination’ operates in the logic of urban renewal in Hong Kong

PhD

dissertationThrombus formation at blood interfaces is a critical factor in the design of medical devices and artificial organs. The thrombo-genicity of polymers was correlated with protein adsorption data from plasma. Surfaces with preferred adsorption of glycoproteins, such as fibrinogen and gamma-globulin, over albumin were shown to be more thrombogenic. The mole ratio of adsorbed fibriogen or gamma-globulin to adsorbed albumin provided an index to the thrombogenicity of the polymer surface. The mechanisms of platelet interaction and consequent platelet adhesion onto polymer surfaces were indirectly verified by the established hypothesis that the glycoproteins with terminal sugar units such as galactose or N-acetylglucosamine of incomplete oligosaccharide chains may interact with platelets via an enzyme-substrate complex formation. The degree of complex formation or platelet interaction with glycoproteins, which subsequently affects platelet aggregation and release, was determined by varying the number of exposed glactose groups at the terminus of oligosaccharide chains. The number of exposed galactose termini was controlled by enzyme treatments of neuraminidase and galactose oxidase or periodate treatment. Galactose oxidase-treated glycoproteins showed decreased aggregation and releasing activity as well as a weaker interaction with platelets due to the decreased number of the inteact terminal galactose groups. Periodate treatment, which selectively oxidizes carbohydrate residues of the glycoproteins, also significantly reduced the platelet aggregation and the serotonin releasing activity of the glycoproteins. The neuraminidase treatment, by which the increased number of galactose groups was exposed at the terminal position of the oligosaccharide chains, caused a greater interaction of platelets with the proteins followed by an increased serotonin release from the platelets. However, the increased number of terminal galactose groups failed to induce the correspondingly increased aggregating activity. The neuraminidase treatment resulted in a conformational change arising from removal of sialic acid. This conformational change, confirmed by circular dichroism spectra of the protein, may be responsible for the nonincreasing aggregating activity of the glycoproteins in spite of the increased terminal galactose groups. Such a conformational change could be observed by UV irradiation of the glycoproteins which also reduced the aggregating activity of the proteins. Therefore, the involvement of glycoproteins in platelet aggregation may require conformational integrity of the protein for the maximal aggregation effect. The similar interaction of platelets with the glycoproteins was determined from platelet retention experiments using protein-immobilized beads packed in columns. The retention of platelets, when citrated whole blood was passed through the columns containing protein-immobilized Sepharose 2B, was increased with increasing numbers of terminal galactose residues. Immobilization of galactose to beads also significantly increased the platelet retention in the galactose-immobilized bead columns. The results of the platelet interactions with adsorbed proteins on polymer surfaces were directly observed by scanning electron micrography and light micrography. These micrography results showed a similar pattern to the results previously described. An increased number of adhered platelets was observed on the neuraminidase-treated glycoprotein coated polymer surface, while platelet adhesion was markedly decreased on the galactose oxidase-treated or the periodate-treated glycoprotein coated surface to a level equal to that of albumin coated surfaces. The use of sialyltransferase inhibitors, such as aspirin and UDP, depressed ADP-induced platelet aggregation. The results obtained are supportive of the involvement of this proposed enzyme mechanism for platelet-protein interactions

PhD

dissertationThrombus formation at blood interfaces is a critical factor in the design of medical devices and artificial organs. The thrombo-genicity of polymers was correlated with protein adsorption data from plasma. Surfaces with preferred adsorption of glycoproteins, such as fibrinogen and gamma-globulin, over albumin were shown to be more thrombogenic. The mole ratio of adsorbed fibriogen or gamma-globulin to adsorbed albumin provided an index to the thrombogenicity of the polymer surface. The mechanisms of platelet interaction and consequent platelet adhesion onto polymer surfaces were indirectly verified by the established hypothesis that the glycoproteins with terminal sugar units such as galactose or N-acetylglucosamine of incomplete oligosaccharide chains may interact with platelets via an enzyme-substrate complex formation. The degree of complex formation or platelet interaction with glycoproteins, which subsequently affects platelet aggregation and release, was determined by varying the number of exposed glactose groups at the terminus of oligosaccharide chains. The number of exposed galactose termini was controlled by enzyme treatments of neuraminidase and galactose oxidase or periodate treatment. Galactose oxidase-treated glycoproteins showed decreased aggregation and releasing activity as well as a weaker interaction with platelets due to the decreased number of the inteact terminal galactose groups. Periodate treatment, which selectively oxidizes carbohydrate residues of the glycoproteins, also significantly reduced the platelet aggregation and the serotonin releasing activity of the glycoproteins. The neuraminidase treatment, by which the increased number of galactose groups was exposed at the terminal position of the oligosaccharide chains, caused a greater interaction of platelets with the proteins followed by an increased serotonin release from the platelets. However, the increased number of terminal galactose groups failed to induce the correspondingly increased aggregating activity. The neuraminidase treatment resulted in a conformational change arising from removal of sialic acid. This conformational change, confirmed by circular dichroism spectra of the protein, may be responsible for the nonincreasing aggregating activity of the glycoproteins in spite of the increased terminal galactose groups. Such a conformational change could be observed by UV irradiation of the glycoproteins which also reduced the aggregating activity of the proteins. Therefore, the involvement of glycoproteins in platelet aggregation may require conformational integrity of the protein for the maximal aggregation effect. The similar interaction of platelets with the glycoproteins was determined from platelet retention experiments using protein-immobilized beads packed in columns. The retention of platelets, when citrated whole blood was passed through the columns containing protein-immobilized Sepharose 2B, was increased with increasing numbers of terminal galactose residues. Immobilization of galactose to beads also significantly increased the platelet retention in the galactose-immobilized bead columns. The results of the platelet interactions with adsorbed proteins on polymer surfaces were directly observed by scanning electron micrography and light micrography. These micrography results showed a similar pattern to the results previously described. An increased number of adhered platelets was observed on the neuraminidase-treated glycoprotein coated polymer surface, while platelet adhesion was markedly decreased on the galactose oxidase-treated or the periodate-treated glycoprotein coated surface to a level equal to that of albumin coated surfaces. The use of sialyltransferase inhibitors, such as aspirin and UDP, depressed ADP-induced platelet aggregation. The results obtained are supportive of the involvement of this proposed enzyme mechanism for platelet-protein interactions

Korean Passive Sentence Comprehension Deficits and its Relation to Working Memory Capacity in Persons with Aphasia

The current study investigated Korean passive sentence comprehension deficits in aphasia and its underlying processing mechanisms using three types of syntactic structures: 1) active sentences with a 2-argument structure, 2) active sentences with a 3-argument structure, and 3) passive counterparts of active sentences with a 2-argument structure. Persons with aphasia showed differentially greater difficulties in passive than 2-place active sentences compared to the normal elderly adults, but the group differences were not significant between the passive and 3-place active sentences. Working memory, not the short-term memory, was significantly correlated with overall aphasia severity and performance on sentence comprehension tasks

Glucose Biosensors: An Overview of Use in Clinical Practice

Blood glucose monitoring has been established as a valuable tool in the management of diabetes. Since maintaining normal blood glucose levels is recommended, a series of suitable glucose biosensors have been developed. During the last 50 years, glucose biosensor technology including point-of-care devices, continuous glucose monitoring systems and noninvasive glucose monitoring systems has been significantly improved. However, there continues to be several challenges related to the achievement of accurate and reliable glucose monitoring. Further technical improvements in glucose biosensors, standardization of the analytical goals for their performance, and continuously assessing and training lay users are required. This article reviews the brief history, basic principles, analytical performance, and the present status of glucose biosensors in the clinical practice