30 research outputs found
Integrated information system via wifi technology / Ng Yin Chern
No full textIn the future work space, the ability to make decision based on live and updated data is ultimately important. The key motivation of this project therefore to enable and enhance data mobility. Wireless LAN (WiFi) application is becoming more popular and there are a growing number of WiFi hotspots around the country. This makes it feasible and suitable for the project to utilize the Wifi technology as tis core concept. Also, portable devices such as the PocketPC’s are now powerful enough for a full blown application. The project namely the integrated information system via WiFi technology sought to solve are enhancing data mobility and also enhance data integration by utilizing both the groundbreaking and new WiFi and PDA technologies. The outcome of the is project is to create a fully synchronize-able information system environment using wireless technology, updating information and schedules to the users of this system even when they are on the move securely via strong security encryption which is DES/TDES. A very modular approach in the development of the project is being taken by being modular, the codes could cosily be reusable throughout the system. This would easily solve the important issues of data integration. This project would try to solve this by being able to utilize and connect to different types of database. This could be done as the development of the project is very modular. Therefore, the groundbreaking NET Framework is the main development tool that would be used in the development of this project. Also, MS SQL Server 2000, MS Access and lastly database would be used depending on the different platforms in the systems
Fractional quantum Hall states of dipolar gases in Chern bands
No full textWe study fermions and hard-core bosons with long-range dipolar interactions at fractional fillings in a topological checkerboard lattice with short-range hoppings up to next-next-nearest neighbors [T. Neupert, L. Santos, C. Chamon, and C. Mudry, Phys. Rev. Lett. 106, 236804 (2011)]. We consider the case that the dipoles are aligned in the perpendicular direction by an external field without the complication of anisotropic interaction. Using exact diagonalization, we find clear signatures of fractional quantum Hall (FQH) states at filling factors 1/3 and 1/5 for fermions (1/2 and 1/4 for bosons) in the lowest Chern band with a robust spectrum gap at moderate dipolar interaction strength. The robustness of these FQH states against a long-range interaction tail and band flatness is investigated. When the dipolar interaction decreases, the fermionic FQH states turn into normal states, and the bosonic 1/4 FQH state turns into a superfluid state. The bosonic 1/2 FQH state survives even in the absence of the dipolar interaction, but vanishes when the hard core becomes a soft core with a critical on-site repulsion. In the thin torus limit, the static density structure factors indicate that the FQH state turns into a commensurate charge density wave state.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000349247900001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Physics, Condensed MatterSCI(E)4ARTICLE7null9
On the group of zero-cycles of holomorphic symplectic varieties
No full textFor a moduli space of Bridgeland-stable objects on a K3 surface, we show that
the Chow class of a point is determined by the Chern class of the corresponding
object on the surface. This establishes a conjecture of Junliang Shen, Qizheng
Yin, and the second author
Construction and classification of novel BPS Wilson loops in quiver Chern–Simons-matter theories
No full textAbstractIn this paper we construct and classify novel Drukker–Trancanelli (DT) type BPS Wilson loops along infinite straight lines and circles in N=2,3 quiver superconformal Chern–Simons-matter theories, Aharony–Bergman–Jafferis–Maldacena (ABJM) theory, and N=4 orbifold ABJM theory. Generally we have four classes of Wilson loops, and all of them preserve the same supersymmetries as the BPS Gaiotto–Yin (GY) type Wilson loops. There are several free complex parameters in the DT type BPS Wilson loops, and for two classes of Wilson loops in ABJM theory and N=4 orbifold ABJM theory there are supersymmetry enhancements at special values of the parameters. We check that the differences of the DT type and GY type Wilson loops are Q-exact with Q being some supercharges preserved by both the DT type and GY type Wilson loops. The results would be useful to calculate vacuum expectation values of the DT type Wilson loops in matrix models if they are still BPS quantum mechanically
The flotation of pyrite using xanthate collecters
No full textBibliography: leaves 117-123.The flotation properties of pyrite were found to be significantly influenced by variations in the pH. In acidic solutions the pyrite floatability is very high, and recoveries of 95% could be achieved using only a frother. A sharp decrease in floatability was observed in alkaline solutions, possibly due to the formation of hydrophilic ferric hydroxide. The addition of a xanthate collector improved the flotation properties of pyrite at all pHs. In acidic solutions the main effect observed was on the rate of pyrite recovery and on the grade of the concentrates. In alkaline solutions the addition of a xanthate collector improved the final recovery, the rate of flotation and the grades. Variations in the pH had no effect on the recovery of pyrite to which xanthate was added. There was, however, a continual decrease in the final grade of the concentrates with an increase in pH, due to the increase in the recovery of the gangue mineral
Characteristics of water quality of rivers related to land-use in Penang Island Malaysia
No full textMolecular characterisation of erythropoietic protoporphyria in South Africa
No full textIncludes bibliographical references
In vitro antibacterial activity of crude medicinal plant extracts against ampicillin+penicillin-resistant Staphylococcus aureus
No full textStaphylococcus aureus is the leading cause for foodborne diseases. Extensive use of antibiotics has led to emergence of antibiotic-resistant S. aureus. Hence, interest on natural plant-based alternative which limits the use of synthetic chemicals is growing. The present work evaluated the antibacterial capacity of garlic, aloe vera, galangal, pineapple peel, neem, papaya leaf, lemongrass, peppermint, nutmeg and clove separately extracted with hexane, ethanol and water to a final concentration of 10% w/v against ampicillin+penicillin-resistant isolates of S. aureus in vitro. Streptomycin was used as a drug control against the resistant isolates; BRS023, BRS068 and DRS072. According to the interpretive standards for inhibition zone diameter provided by the Clinical and Laboratory Standards Institute, isolates BRS068 and DRS072 were considered resistant (≤ 12 mm), and isolate BRS023 was considered intermediate (13-14 mm). Against these isolates, all crude plant extracts exhibited varying degrees of inhibition. However, a coherent trend was observed in the inhibition between resistant and intermediate isolates regardless of plants and solvents used. It was also found that extraction solvent types impacted the resulting antibacterial activity. In terms of positive inhibition, the solvents were ranked in the order of hexane (77%) > water (73%) > ethanol (57%). 10% hexane extract of galangal gave the overall highest inhibition zones (17.8 ± 1.4 mm) closely followed by 10% ethanol extract of nutmeg (16.3 ± 1.1 mm). Further phytochemical analyses of the antibacterial compounds from galangal and nutmeg, and their minimum inhibitory concentration (MIC) are needed. Potential applications of plant-based antibacterial compounds as natural, costeffective and less-toxic food preservatives against drug-resistant foodborne pathogens should be explored
Characterising the expression and interactions of the Endoplasmic Reticulum Oxidoreductase Erol β
No full textProteins destined for the secretory pathway and endoplasmic reticulum (ER) resident proteins are targeted to the ER through an N-terminal signal sequence. Proteins then follow a post-translational maturation process to fold into functional proteins. For most of these proteins the formation of disulfide bonds (S-S) at the correct position is essential for structure and function. In eukaryotes, protein oxidation in the ER is catalysed by Endoplasmic reticulum oxidoreductases (EROs) which donate disulfide bonds to (and accept electrons from) Protein Disulfide Isomerase (PDI). In yeast, Erol p is essential for viability and protein secretion. Two ER resident homologues have been identified in the human genome, Erolα and Erol β, which complement the yeast erol-1 temperature sensitive mutation. The main focus of this project was Erol β. Under steady state conditions in transfected cells, Ero 1 β was captured in higher molecular weight complexes in the presence and in the absence of an alkylating agent. Ero-PDI covalent interactions are alkylation dependent, but alkylation independent Ero Iß complexes were found in transfected cells and endogenous tissue. In Erolα the CXXCXXC C-terminal motif is important for protein folding, structural integrity and complex formation with the PDI. In Ero Iß, the AXXCXXC (C390A) mutation disrupts covalent PDI interactions but does not interfere with homodimer formation. The CXXCXXA (C396A) mutation caused disruption of Ero Iß homodimer formation. Modelling the dimer onto the Erol p crystal structure suggested that this 396 cysteine is indirectly disrupting dimmer formation by most likely displacing the cofactor FAD. Two FAD binding domain mutants, initially discovered in yeast, were constructed in Ero Iß and were found to cause instability of Ero Iß through misoxidation during temperature and reducing stress conditions. Ero Iß expression patterns were studied using immunohistochemistry on human stomach and pancreas tissues. The data indicated that Ero Iß is constitutively strongly expressed in enzyme producing chief cells and hormone producing pancreatic islet cells. An interesting result from immunohistochemistry stainings of healthy, Barrett's and oesophageal tumour tissue showed that the ER chaperone protein ERp57 is up-regulated only ill dysplastic and oesophageal tumour tissue. These initial findings suggest ERp57 has potential as a marker in oesophageal tumour diagnosis
Expression, purification and characterisation of protoporphyrinogen oxidases from diverse species
No full textBibliography: leaves 163-203.This work involved the characterisation of protoporphyrinogen oxidase (PPO), the penultimate enzyme in haem biosynthesis, from Bacillus subtilis, Myxococcus xanthus, and human. A defect in human PPO causes variegate porphyria, an autosomal dominant disorder characterised by skin photosensitivity and propensity towards acute neurovisceral crises. At the beginning of this project little information was available on the kinetic and biophysical properties of isolated PPOs due largely to difficulties associated with their purification from natural sources
